Document mBj75waOdBDBZq4LjgemK3a50

a URL 04144 International tarter V Writer John Dizard's point on the inefficiency of international barter is well taken ("The Explosion of International Barter,'' February 7). I tell my students that since the shoemaker wants bread more often than the baker wants shoes, in barter there is more often a want of coincidence than a coincidence of wants. The most infamous interna tional barter incident was a swap that Hitler made, giving Yugoslavia aspinn for its copper. The Yugo slavs were left with carloads of aspirin, not one of which could solve the headache of how to get rid of them. Charles Collazzo Professor ofManagement. Northeastern University Boston We haven't begun to see the dimensions to which this form of international commerce will reach. It is not difficult to understand why. Given the high cost of financing international purchases, the Third World is starting to bypass lenders alto gether by ignoring their money and offering goods is return, h is not inconceivable to imagine the day when the banks themselves, if they ever hope to recoup any of their huge international debt, will start accepting goods in payment. The Third World has been squeezed dry, and it is now starting to squeeze back. Let's hope the developed nations are creative enough to accept the challenge and adapt to the ways in which world trade is changing. Robert Linder Panagri Trading Corp. Panama Plastic Pipe I am writing to express my disappointment and that of the other officers and employees of Allied Tube & Conduit Corp. in "The Duhious War on Plastic Pipe" (February 7). It failed even to at tempt a balanced analysis of the serious issue of the toxicity of plastic materials. Fortune need only have looked at its own files to learn that "the interiors of even fire-resistant structures are often veritable plastic bombs wait ing to be ignited. When they are. clouds of toxic smoke--some of it invisible--are released, much denser and deadlier than smoke from natural sub stances" ("How to Manage Killer Smoke," Janu ary 26, 1981). While you make much of die receipt by the Foundation for Fire Safety of grants from our company--something in which we take pride and have never concealed--you fail to inform your readers of the following comparable facts about the sources on whom you rely: Dr. Irwin Benjamin, who is characterized in the article solely as "an eminent fire researcher and now a private consultant after many years at the Bureau of Standards," is a consultant for a major plastics manufacturer and has been proposed as a recipient of a research grant from the Society of the Plastics Industry. Professor Irving Einhom, described only as an adjunct professor at the University of Utah, has been affiliated with Springbom Laboratories, which has done substantia] testing for a principal manufacturer of PVC, and has testified as a wit ness for Carlon at public hearings on toxicity. The American Council on Science and Health, which you describe as a "consumer education group." is supported with contributions from at least three major plastics manufacturers and nu merous other petrochemical companies that have a commercial stake in the issue. You highlight the activities of Allied at the 1980 meeting of the National Fire Protection Associa tion (NFPA) in opposing the efforts of plastics "Despite the industry's attempts to intimidate Allied, we will continue our program." manufacturers to include thin-walled PVC tubing in the National Electrical Code. But you omit any reference to the efforts of the plastics industry at that same meeting to actively lobby support for its position. Nor do you report the fact that the plas tics industry appeal from the vote of the NFPA membership was rejected by the NFPA board of directors. As for the views of firefighters, those on-theline professionals who must deal with this prob lem daily, your article confines itself to the begrudging concession that, "conveniently for Al lied, some professional firefighters have strong opinions against plastics and will state them pub licly.'' Your notable failure to elaborate clearly re flects the "inconvenience" these views create for your argument. The article's obvious prejudice carries over to your attempted portrayal of our company as a dis ingenuous purveyor of the same toxic material that we are seeking to combat. In doing so. you chose to ignore information repeatedly given to your reporter by me and other Allied officials. Among other omissions, you neglected to mention the warning notice we placed in the catalogue, which reads, "The PVC-coated items in this sec tion are offered by Allied for these out-of-lheordi- nary corrosive applications. pvc-loated matkriai must be used wtTH CAUTiov When smoldering or burning, PVC emits highly toxic hydrogen chlo ride gas (HCI). Even short-term exposure may be hazardous." This article is particularly unfortunate not so much because it unfairly attacks Allied's motives, which it does, but because a magazine of For tune's stature has fallen into the trap of contribut ing to the plastics industry's massive attempt to divert attention away from the real issue. Despite the industry's attempts to intimidate Allied, we will continue our program of consider ation of toxicity of building materials as a factor in code approval, and we will continue to help those who by experience and scientific background have knowledge of the fire-gas toxicity of plastics to speak out on this issue. John M. Lison Vice President and General Counsel Allied Tube & Conduit Corp. Harvey. Illinois The quotation attributed to me was taken out of context and is misleading. My point is simply this: the potential toxic hazard of a material depends on the specific fire situation in which it is involved and on additional factors. In many circumstances, the contribution of PVC conduit would be minimal. In some, it could be significant. Research on com bustion toxicity at the Center for Fire Research is addressing the relative contribution of individual materials to the overall toxic hazards of fires. Jack E. Sneu Director. Center for Fire Research National Bureau of Standards U.S. Department of Commerce Washington "The Dubious War on Plastic Pipe "focused on Allied's campaign toportray PVCconduit as a ma jor cause offire deaths despite a lack of conclusive evidence that it is. The 1961 Fortise article. which dealt with ways of controlling smoke from all sources once a fire has begun, did not suggest that banning plastics in construction could reduce fire casualties. Dr. Benjamin and Professor Einhom are recognized authorities in this area. Since leav ing the government a year ago. Dr. Benjamin has done consulting work for Du Pont, but not on the PVC-conduit controversy. Professor Einhom has done work for both the plastics industry and its op ponents on matters offire safety; the financing he has received from the plastics industry in the last fiveyears has been minor. About 22% of the budget of the American Council on Science and Health is provided by plastics and petrochemical companies; the remainder comes from foundations and com panies with no stake in the plastic pipe debate. At the 1980 NFPA meeting, Carlon, the leading maker of plastic conduit, bought no new voting memberships. Allied and others in the metals in dustry bought scores of new memberships, vot- MARCH 7, 1983 FORTUNE 17 M U R L 04145 ing these against the plasties industry position. The quotation from Mr. Snell was checked with him for accuracy in the course of his interview with Fortune. The quotation and its immediate context were subsequently checked with a spokesman for the Center for Fire Research authorised to speak for Mr. Snell. The spokesman said that the quotation in context accurately reflected Mr. Snell's views. Fortune stands by its story. Representatives of the Foundation for Fire Safety have at various public forums challenged members of the plastics industry to enter a room of burning PVC while they enter a room of burn ing Douglas fir. The implication is that a wood fire is safe. Of course, this is completely false, as virtu ally any burning material, natural or synthetic, would emit carbon monoxide, a potent killer. You correctly quoted a government study as conclud ing that polyvinyl chloride and Douglas fir have similar combustion toxicity characteristics. Bud Hall Conoco Chemicals Co. Houston Foxy Uttlo Uso My. my. That foxy little Lisa ("Apple's Bid to Stay in the Big Tune," February 7). "She" sure sounds like a saucy wench. "Seductive." says writer Peter Nulty. "Disarming." Up to a "lady's tricks." It's a crying shame such a cube had to be given a Neanderthal brow. I'd be interested in knowing why Apple chose a woman's name for its new computer. Apple surely should have expected such cliche-ridden forays into the realm of insipid journalism. But I`d be even more interested in knowing bow Nulty would have described this same computer had it been named Ralph. Next time. Fortune, get a Lisa and use its mouse to put such writing in the garbage can, where it belongs. Luana Hellmann Hiu. Canby, Oregon Beautiful Persons In Fur It is obscene that people still get rich killing ani mals or selling their dead bodies ("The Fur Trade," February 7). Those who wear furs are no better. I have never seen a truly "beautiful person" in a fur--except the original owner. Ed Simpson South Pasadena, California February 7)? This superficial comparison ignores a critical difference: wood is generally a simple heat source, and nuclear energy is converted to electricity. About two-thirds of all electricity is used by the cornmercial/industrial sector and is critical to the national economy. On the other hand, the most ef ficient use for wood is not burning, but in pulp and paper and construction. Wood is an eminently en ergy-sensible construction material: a steel rafter requires seven times as much energy to make as a wood one: aluminum siding five times as much as plywood. Mark P. Mill? Vienna. Virginia Firings and Stockholders Professor Michael Levin missed a large and im portant point in his review of my new book. Do It My Way Or You're Fired.1 (Books and Ideas, February 7). In every account 1 described of competent, con scientious employee objectors, the owners would have benefited if a manager had not answered the employee with a pink slip. A faulty new product would not have been launched, an illegal practice would have been nipped in the bud before becom ing an operational tragedy, a neurotic dingbat in managerial clothing would have been exposed be fore doing more harm. This is not a theoretical argument. Every com pany that has instituted a due process procedure for resolving boss-subordinate conflicts--from Bank of America to Pitney Bowes--will testify to its practical values. What is more, the direct costs of corporate due process are peanuts. 1 can think of at least two companies now tied up in the courts by employee objectors that could have paid sever al times over for the cost of due process by avoid ing the litigation. David W. Ewing Managing Editor. Harvard Business Review Boston Mind-Probo Logic Writer Walter Kiechel's scathing indictment of the psychological testing industry, "The Manage rial Mind Probe" (Office Hours, February 7). was premised on some very faulty logic. To insinuate that, because some tests are invalid, all tests are is as ridiculous as asserting that since some medi cines are ineffective, all medicines are ineffective. Herbert M. Greenberg President, Personality Dynamics Inc. Princeton. New Jersey Burning Weed vs. Fission Can Fortune really be so easily taken in by a myth promoted by the split-wood-not-atoms crowd: "Wood burning produced more heat than nuclear energy" (The Washington Connection, Buoyant Transportation Idoas "Calling All Cars" (Keeping Up, February 7) re minds me of an equally good idea--one I proposed to the Air Force when I was a flight instructor: NEWS FOCUS k \y-^ . f* Ct U !K AV.U ' i 7* L r lA. /w^C_ URL 04146 Fire Hazards of Plastics Spark Heated Debate Researchers are studying the effects of toxic gases produced in fires by the combustion of plastics and other synthetic materials Rebecca L. Rawls, C&EN Washington In a real sense, these deaths, more than the thousands of other fire deaths during the same period, have led Americans are afraid of fires. And with good reason. several state legislatures and a number of national bodies If trends continue, some 7500 people will die in fires in concerned with fire safety issues to begin a major re the U.S. this year, and four times that number wii-l be examination of what happens to people in fires and what injured. That's a fire death rate per capita that is almost can be done to prevent deaths and injuries. This exami twice the international average, and one that is surpassed nation already has stirred up controversies and is raising by only one other country--Canada. And as for fire in serious questions about available methods for assessing cidence, the U.5. rate per fire risks and damage. capita is the highest in the I Eventually, researchers world. expect that sophisticated The fires Americans computer-based models seem most afraid of are will improve matters con those in public buildings siderably and perhaps lay like hotels, night clubs, and to rest many disagree even jails, where a single ments. incident can lead to scores Meanwhile, the current of deaths. Although these examination focuses large public fires focus attention ly on the effects of toxic on fire hazards, by far the gases produced when largest number of fire buildings bum. According deaths in the U.S. occur in to the Center for Fire Re homes. search, the federal govern On average, about 25 ment's principal organiza people per day in the U.S. tion for conducting re die in fires. But when 119 search in laboratories on people died between No fires, and a part of the Na vember 1980 and May 1981 tional Bureau of Standards, in three highly publicized 80% of fire deaths are due hotel fires in the U.S. and, to the inhalation of smoke more recently, 27 died in or hot gases and are not the one incident in the Harri result of bums. Further son County Jail in Missis more, the character of sippi, public concern smoke seems to have quickly focuses on the changed in recent years. As problems of fire safety. the U.S. National Fire Pro And that is when legisla tection Association's recent tors and other public offi report on the toxicity cials are called upon to do A laminar hydrocarbon flame is probed by a laser at of combustion products something about fire the Center for Fire Research in a study to determine points out, fire fighters are risks. what chemical species are formed reporting that fires appear January 3. 1963 CAEN News Focus URL 04147 to develop faster now than in years past and that smoke apparently develops more rapidly and is more obscuring and more irritating to the respiratory tract than it used to be. "There appears to be an increase in fire fighter casualties from smoke inhalation/' the report states. "The smoke in today's fires . . may be producing increased risk of inhalation injury to fire fighters as well as to building occupants." In the Mississippi jail fire late last year, the fire itself was confined to one room containing only one person who was not seriously injured. Yet 27 people w'ere killed in the fire and 61 others injured, almost all from inha lation of gases and smoke. Toxic gases spread from the burning cell to others through the jail's ventilation system. Gases caused the jailer to lose consciousness before he could unlock some of the occupied cells, thereby trapping many of the inmates who died. A jail, of course, is not a typical building; it is intended to be difficult to leave. But this pattern of toxic gases traveling through ventilation systems and by other routes to areas far from the actual fire, there to trap and kill people, is a common one in building fires. When the MGM Grand Hotel burned in Las Vegas on Nov. 21, 1980, for example, 85 people died--three from burns, one from a skull fracture when a portion of the building collapsed, and the rest from inhalation of smoke and toxic gases. Sixty-one of the victims were in a different part of the hotel from the fire, most of them 20 stories or more away from the fire itself. Whether it is the increased use of plastics in buildings and furnishings that is changing the character of com bustion products and causing many of these fire deaths is at the heart of much of the current examination of the causes of fire deaths. There is little question that the amount of plastics used in buildings is rising rapidly. In the mid-1960s plastics represented only 2% of total building materials con sumed, according to Predicasts, a Cleveland-based market research firm. By 1981 plastics' share of the building material market was 10%, or 6.5 billion lb val 10 January 3. 1963 CAEN ued at $5.7 billion. And gains may be even more rapid through the rest of the 1980s because of increasing cost differences between plastics and metals, the materials plastics most often replace in buildings. One of the leading voices contending that this in creased use of plastics bears a large part of the blame for the lethal gases produced in modem building fires is that of the Foundation for Fire Safety, an Arlington. Va.based organization headed by Gordon F. Vickery, former head of the U,S. Fire Administration and a former Seattle fire chief. "When materials burn, they release certain toxic gases," states a recent publication of the foundation. "Almost any material, man-made or natural, will give off carbon monoxide. But synthetic materials, namely plastics, bum twice as fast, twice as hot, and can give off up to 500 times as much toxic gases as more conventional materials." These are fighting words, and one of the most per sistent groups to fight them, not surprisingly, is the Society of the Plastics Industry, that industry's main trade association. "The metal electrical conduit industry has embarked on a 'fear and smear' campaign against plastics products in order to improve its position in the marketplace," 5PI claims in a recent news release. This campaign Is "based on a total distortion of scientific fact," says SP1. "The metal conduit industry' would have the public believe that toxic gases in a fire didn't exist before plastics; that is patently ridiculous," says SPI spokesman E. S. Nuspliger. "As long as 50 years ago, fire journals were lamenting the high number of fatalities from smoke and toxic gases." "We feel that plastics, where properly used, do not present any increased hazard in the fire environment," sums up John R. Lawrence, the society's technical di rector. If SPI can be regarded as the spokesman for plastics makers in this dispute, many would consider the Foundation for Fire Safety to be the spokesman for steel pipe and metal conduit forces. Indeed, the organization. q' \ 4H r -ia' * T X | Full-scale tests of how rooms bam, like i this one conducted at the National Bureau 1 of Standards' Center for Fire Research in f Gaithersburg, Md., dramatically illustrate ' the hazards of fires in buildings. In this 2 time sequence, smoke and gases accumulate near the ceiling of a mock living room until the gases become hot enough to bum themselves. This phenomenon, called flashover, makes the fire spread furiously to all combustible objects in the room. This entire sequence took place in less than three minutes (see clock in foreground). In a real fire, the room's occupants would have only that amount of time to escape URL 04148 which considers itself a private, nonprofit research and educational foundation, receives almost all its funding from the steel pipe and conduit industries. "We have tried to get more balance in our funding sources by getting the plastics people to fund some of our research, but so far they haven't seemed interested," says Merritt M. Birky, former head of the Center for Fire Research's program for toxicology of combustion products and current director of research for the Foundation for Fire Safety. Despite the heavy funding from an industry' that competes with plastics in the building trades, Birky says the foundation has been able to maintain its indepen dence and chart its own course of action. "On the one hand, we think it is commendable for the steel people to support this kind of research," Birky says, "but we do realize that they have an economic interest in it." Indeed they do. Pipes and fittings have been the fastest growth area for plastics in U.S. building con struction, rising from an annual use of 230 million lb in the mid-1960s to 2.27 billion lb in 1981. Another 738 million lb of plastics go into electrical applications, in cluding use as an alternative for metal electrical con duits. One of the strongest arguments of those who think plastics are not increasing fire hazards is that fire deaths have been decreasing steadily in the U.5., probably since World War II, despite increased use of plastics in build ings. Methods of counting such deaths have changed over the period, so trends are difficult to pin down, ex plains Frederic B. Clarke, a private consultant on fire safety issues and former director of the Center for Fire Research at the National Bureau of Standards. However, using adjusted figures, total fire deaths in the U.S. have fallen in the past decade from about 9000 in 1971 to 7600 in 1981. On a per capita basis the drop is even more dramatic--a 25^ decrease from 44 deaths per million population in 1971 to 33 per million in 1981. "There has definitely been a big shift in the fuels present in buildings over this period," Clarke says, re ferring to the kinds of combustible materials present in a building, so that "if there were a direct correspondence between plastics use and toxic gases, you'd expect to see a big increase in fire deaths, but you don't." Not everyone agrees that the falling fire death rate necessarily means that plastics are not increasing fire hazards in buildings. "We really have no statistics on whether the risk in building fires is increasing," says Yves Alarie, professor of respiratory physiology and toxicology at the University of Pittsburgh's school of public health and a leading researcher in the area of fire toxicity. The buildings that are burned down now are the old ones, he says, and we will have to wait 10 to 20 years before any change in fire hazard associated with greater use of plastics will start to show up in fire death statistics, Clarke, however, disagrees. 'The causes of fires are far more related to the things that are brought into buildings--like lighted cigarettes--than to the buildings themselves," he says. 'The age of the building has nothing to do with it." Another claim that is often made by supporters of plastics use, and contested by those who oppose them, is that by far the most important toxic gas in fires is car bon monoxide, which is produced in large amounts by any burning organic material, including wood and other natural products. Among the evidence cited to support this claim are a pair of studies sponsored by the U.S. Fire Administration and SPI in which firefighters carried gas sampling equipment into real fires to find out what gases were present. The first study, conducted by Harvard's school of public health and published in 1979, examined the gases produced when older, multistory dwellings burned in the city of Boston. The second study, done by Southwest Research Institute in 1981, looked at the fire products of more modem, single-story, single-family houses in San Antonio. "The results of [both studies] are consistent with the universal view that carbon monoxide is the most prevalent and potentially toxic combustion product in fire environments," says the San Antonio study. *r*my 3. 1963 CAEN 11 News Focus URL 04149 "Firefighters may encounter atmospheres in which carbon monoxide is present in sufficient quantities to incapacitate and cause death within a few minutes. More frequently, they are likely to be exposed to carbon monoxide concentrations below these levels but suffi cient to produce toxic effects that may markedly impair their performance and, possibly, disable them. Even the lower concentrations of this gas, which were detected in the majority of the fire samples, will diminish the supply of oxygen to the brain, and, possibly, disorient the individual and compromise his performance and safety," the study concludes. Other toxic gases, also commonly found in fires, in clude acrolein, hydrogen cyanide, and hydrogen chlo ride. These gases can be produced by certain natural materials, but hvdrogen cyanide and hydrogen chloride, in particular, are produced much more abundantly by many synthetic polymers than by wood. Determining which gases actually are responsible for deaths in fires requires finding out what gases have been inhaled by fire victims. Several studies of this type have been done, including several by the Foundation for Fire Safety's Birky. "It's correct that almost all fire victims in the past few years have had elevated carboxyhemoglobin levels in their blood (an indication that they have inhaled carbon monoxide], but that does not explain all fire deaths,'' Birky says. He estimates that carbon mon oxide poisoning can account for no more than 50% of these fire deaths Blood hydrogen cyanide levels are often high. too. he says, and hydrogen chloride also may be a contributing factor in fire fatalities, although its role is harder to document because of its natural presence in the body. Birky cites a study he conducted of the victims of a fire at the West Chase Hilton Hotel in Houston on March 6, 1982. All 10 of the people who died during the fire had elevated but sublethal blood levels of carboxyhemoglobin, he finds. All 10 victims also had elevated blood cvanide levels and in two cases the levels were high enough to have been responsible, by themselves, for death. In addition, the 10 who died in the fire and two who died afterwards all had severe respiratory riact damage, which Birky says was consistent with exposure to hydrogen chloride. The hydrogen cyanide, he says, came from flexible polyurethane carpet padding, nylon carpet and blankets, and a flexible polyurethane cushion \ found on an upholstered chair. The hydrogen chloride, A he says, came from a polyvinyl chloride wall cov ering. "Based on the findings of this study, it is doubtful that carbon monoxide and the obstructive nature of soot alone were the causes of the deaths in the rooms that had little evidence of soot deposits," Birky says. "It must be concluded that hydrogen cyanide and hydrogen chlo ride contributed to most, if not all, of these deaths. Synthetics in the fire room produced these two deadly gases during combustion, contributing to the ultimate deaths of 12 persons." As is often the case, SPI's Lawrence views things dif ferently: "There were a lot of synthetic materials in the room where the fire occurred, but there were a lot of burnable nonplastics, too," he says. The medical exam- 12 January 3, 1983 CAEN Tst method carefully controls animal exposure to combustion gases In the University of Pittsburgh method for measuring toxicity of combustion gases, four mice can be exposed to gases flowing past them from a furnace where the sample material is burned. Other test methods involve placing the furnace underneath the exposure chamber to allow the gases to flow upward, and burn ing the sample material in a flame rather than a furnace. Each method duplicates some of the conditions found in real fires: the differences reflect which fire conditions are thought to be the most life threatening iner found carbon monoxide poisoning the cause of death in every case except for the people in one room, who had lethal blood levels of hydrogen cyanide, says Lawrence. However, it takes very careful handling of blood after death to get an accurate measurement of the hydrogen cyanide present when the person died, Law rence points out, because the body itself will produce a certain amount of hydrogen cyanide. To make the question still more complicated, it is worth considering whether, if the cyanide had not been present, the people would have lived, says Richard GGann, who heads the fire measurement and research division at the Center for Fire Research. 'There is no good basis for saying that just because people died from a specific cause in a fire that they would not have died anyway," he says. "We need to find out when a partic ular measureable factor is the cause of toxicity," and fight the real hazard. It may be, he suggests, that increased use of plastics in buildings is making bad fires worse--even a lot worse. It is not only the combustion products of plastics that cause worry, but that some of them bum much faster and hotter than wood and other natural materials. Most of the heats of combustion of synthetic polymers are much higher than those for natural materials, Birky says. The heats of combustion of polyurethane, polystyrene, and polyethylene, for example, are similar to that of No. 1 fuel oil, he points out. "That means that once those ma terials are ignited, the heat produced is going to be much higher [than from wood]. The fire will develop faster and there will be less time to escape." Many plastics, however, don't have very high heats of combustion compared to wood. But other factore, such as ignition temperature, are also important in deter- mining how a material will contribute to the growth and spread of a fire, Lawrence says Polyvinyl chloride has largely replaced cotton as an insulating material for electrical wires, in part because its higher ignition temperature makes it less likely to burn. "We think that's an example increased fire safety from using plastics," Lawrence says. "A lot depends on hot* materials are used," he con tinues. "When properly used, plastics do not constitute an unusual hazard." The connection between the fire safety issue and the inroads of plastics into markets that were once held by conventional materials came up in recent debates in the California legislature. That state, along with New York, has passed legislation calling for an investigation of existing methods to test the toxicity of combustion products with an eve toward changing the state's building codes to exclude particularly hazardous mate rials from use in buildings if such materials can be identified. The California legislation, passed in August 1982, \ evolved from an earlier battle in that legislature over ^ whether use of polvvinvl chloride pipe in buildings should be restricted because of possible risk to occupants of cancer caused by substances leaching from the pipe or from the adhesives used to connect pipe segments. A coalition of metal pipe manufacturers and a plumbers' union worked for several years, without success, to restrict the use of plastic pipes in buildings on this basis. "When the metal-pipe people realized that they w'ere not winning on the carcinogen issue, they brought up the flammability question, but they were only interested in the flammability of [plastic] pipes," says one Califor nia state official who has watched the debate in the state legislature. The legislature, under pressure from the plastics industry, expanded its study to consider the combustion toxicity of all materials that are used in high-density occupancy buildings. Focusing on the fire hazards of pipes may not be so parochial as it seems at first glance. "Plastic pipes burn; metal pipes don't," savs Pittsburgh's Alarie. Because of stringent codes, most public buildings are made largely of noncombustible materials like concrete, glass, and metal. Thus, the major fire hazard is not the structure itself, but its furnishings and what Alarie calls the ser vices of the building: its plumbing, electrical wiring, and air conditioning. "Whenever a combustible material is used to replace a noncombustible one, we need to ask an awful lot of questions," Alarie says. "We are raising the fuel load everywhere in our buildings, and the fire im plications of that can be tremendous." The California study, set to get under way this week, has two parts. The state's department of industrial rela tions will assess the test methods currently available to measure combustion toxicity and "adopt or adapt the most appropriate existing test method to rate the relative toxicity of all materials intended for use in or as part of high-density occupancy buildings." These tests are ex pected to measure not only the lethality of a material but also the time it takes to cause death. Meanwhile, the state fire marshal's office will assess tests of combustibility and adopt or adapt the most appropriate existing test methods to rate materials on their igmtability, flame spread, rate of heat release, and rate and extent of smoke generation. "It is the intent of the legislature that the tests adopted ... be used to ultimately develop a hazard rating index," the resolution says. Though most observers praise the intent of the Cali fornia legislation, manv critics question whether the proposed studv is likelv to turn up anything useful. For one thing, no money was allocated for the project. For 33 s V? January 3. 1983 C4EN 13 I t i l N ' U / l ....... News Focus another, the department of industrial relations has no experience with combustion studies, although it has done toxicological testing in occupational settings. An other difficulty is that the two studies are to be com pleted bv April 30, which is considered by some critics too soon to do a thorough studv. The legislature's demands may be "unrealistic to a degree," admits California fire marshal Philip Favro, whose own position mav change with the new admin istration. However, he thinks it possible in four months to determine what tests have been developed and whether any are ready to serve as the basis of a com bustibility hazard rating. And he supports the concept of trying to set up a performance index of materials based on both their combustibility and the toxicity of their combustion products. 'T feel that to look at toxicity in isolation is naive," he says, citing as an example polvtetrafluoroethylene, more commonly known by its tradename. Teflon. "In some tests, this material is highly toxic when it burns, but it won't burn under ordinary conditions . . . Our feeling is that the real problem with synthetic materials is their ability to burn rapidly. Perhaps in an infrastructure that includes flame-retardant systems, sprinklers, smoke detectors, and other devices, they can be used safely." But. he adds, "any of these judgments are premature until we get a real rating of hazard. "I'm not confident that we'll be able to solve anything by April," Favro says, "but this is a question that needs a good airing, and what we are doing gets it out of the closet." Another airing is taking place in New York, where the state legislature has called for an outside evaluation of available test methods to determine the toxicity of var ious materials under heat conditions. The New York studv will look at the gaseous products of materials at different temperatures including just below the ignition temperature (when pvrolvsis, rather than combustion, products are given off) and just above ignition. The study is to review existing test methods, recommend im provements that can be made in them, develop a scale for rating the combustion hazard of materials based on the tests, and recommend additions to the state's build ing code on the basis of what toxicity tests can show. The contract for the New York study has been awarded to Arthur D. Little Inc., a Cambridge, Mass., research firm. The principal investigator is Rosalind C. Anderson, a former associate of Aiarie's at the University of Pittsburgh. Data from a literature search and an in dication of the feasibility of developing a rating scale are expected in an interim report around Feb. 1. The entire report is scheduled to be completed by May 31, and the secretary of state is to report back to the legislature concerning possible changes in the building code by June 30. Clearly, legislators in New York and California are hopeful that existing tests can identify the materials that pose the most serious hazards in building fires. But a number of scientists doubt whether this is the case. For example, in a study for SP1 published last summer. Southwest Research Institute reviewed the state-ofthe-art of combustion toxicology testing. "Materials 14 January 3. 1963 CAEN should not be regulated on the basis of data from labo ratory smoke toxicity tests," the study concludes, in part because "fire technologists and toxicologists do not yet know how to incorporate data from smoke toxicity tests into a hazard assessment." But there are other problems, too, such as variations in test results from lab to lab and even within the same lab. These variations can produce significantly different orders in rank among materials, the study says. "Even gross differences in smoke toxicity should be interpreted writh caution, since other flam mability properties are involved in assessing hazard." Available laboratory toxicity tests Can serve useful purposes, the study suggests. They can, for example, be of value to producers developing new products by suggesting potential toxicity problems. "Some investi gators have identified a few materials producing smoke claimed to be 'unusually toxic' in comparison writh most other materials Such a finding does, indeed, place a burden on the manufacturer to further assess hazard," the Southwest Research Institute report says. Gann, of the Center for Fire Research, basically agrees with the study's conclusions. He thinks that it's prema ture for states to regulate materials use based on the combustion toxicity tests now available. There's an "outside chance that they may be able to screen out bad actors" with current test procedures, he says, but current tests may be putting materials through conditions that they never would encounter in a real fire. Animal test procedures also have been developing at the same time that fire science has, he explains, so that combustion toxicity tests are based on assumptions about the nature of fires that now are known to be not really correct. Several newer test methods have been devel oped, including one by researchers at the Center for Fire Research, based on what the developers expect the isiw ion Gann: are plastics making bad fires even worse? life-threatening fire situation to be. But their choices were made before science could determine what the real health threats in fires are. In some respects, Gann says, we still do not know what fire conditions need to be duplicated to produce a meaningful test. Though it may be possible to design tests now that can provide useful information about the risks of using certain materials in particular situations, Clarke suggests, it is not possible to take existing tests designed for other purposes and apply them broadly to assess fire hazards under many different conditions. This is what he thinks California is trying to do. The combustion toxicity test developed at the Center for Fire Research was intended as a screening test to be applied to plastics during their development. "We were concerned," says Clarke, "that some new materials might be unexpectedly toxic even against the background of carbon monoxide and other things that were already present in fires and toxic." The test method they came up with was published last June, and it is one of a half dozen or so that California and New York will be ex amining. Though researchers at the Center for Fire Research are proud of their test method, it is not ideal in several ways. For one thing, the method of exposure used in the test--samples of material are burned in a furnace and the combustion gases diffuse into the test chamber--is not that of a real fire, explains center director Jack E. Snell. The test evaluates materials one at a time, so that syner gistic effects, which do exist, are not taken into account. And the test can turn up hazards that would not be present in a real fire; whether the test also misses some real fire hazards has yet to be determined. Finally, the center's tests, and all of the others currently available, are animal tests. "We need good models of incapacitation and of human response to irritants present in fires," Snell says. "It's very' unlikely we'll get this information from tests on mice or rats." Alarie, who has developed another animal test for the toxicity of combustion products, thinks the tests are ready to be used carefully to regulate materials used in buildings. "There's no question that the existing tests can separate materials on the basis of their toxicity," he says. "We're not going to regulate materials on the basis of small differences in test results--that would be stu pid--but we can use the tests to look for materials that are tremendously more hazardous." But even the tremendously more hazardous materials don't always perform the same way when test conditions are changed slightly. For example, when the Center for Fire Research evaluated its method, it ran tests on 12 materials, some synthetic and some natural. Toxicity ratings for 11 of the materials generally grouped to gether, Gann explains, but one material, polytetrafluoroethylene, came out 1000 times more toxic than the others. Alarie also tested polytetTafluoroethylene in his test, and here, too, its combustion products were much more toxic than those of most other materials. However, when Clarke and Du Pont toxicologist Stephen J. Wil liams retested the polymer using flame rather than a furnace to heat the sample, its toxicity value dropped back into the range common for other tested materials. Alarie also retested the material in his system using a flame, but he got the same high value he found when the sample was heated in a furnace. Such discrepancies "cut to some very fundamental issues in toxicity testing," Gann says. If relatively slight changes in the way samples are tested make such large differences in test results, and particularly if they make those differences only in some tests and not in others, then "there's an awful lot that still needs to be figured out to know what's going on," he says. Several explanations have been suggested for the test discrepancies. Alarie thinks the flame used by Clarke January 3, 1983 CAEN IS URL 04152 News Focus and Williams was much hotter than the one he uses or than the furnace temperatures used in his test and the Center for Fire Research's. Higher temperature would mean more complete oxidation of the sample and would bypass formation of intermediate combustion products including short-chain fluorinated hydrocarbons, some of which might be highly toxic. But Clarke says the temperature of his flame was the same as that of the furnace in the Center for Fire Research test. He thinks that polytetrafluoroethylene is a fairly unusual polymer in that it contains no hydrogen atoms. When it is burned alone, as in a furnace, it produces highly toxic by-prod ucts; but when it burns along with other materials that can supply hydrogen to the combustion mixture, as in a flame, further reactions occur and the highly toxic products are not formed. "This is the first case we've seen where a relatively small change in test conditions makes a big difference in results," Clarke says. "The real concern is, what if there are materials in which the change goes the other way?" Although researchers may disagree about just how useful current combustion toxicity tests are, they do agree about what needs to be done to really understand the hazards of fires in buildings and to control them. "What I'd like to see is a system that would take account of all the properties of fires and interrelate them so that I could tell you whether a particular material would be more hazardous than another material," Clarke says. Such a system would involve sophisticated modeling of fire situations and not fixed codes of the sort now used in regulation Many researchers think it will take some time to win over regulators to such an approach to fire safety, even when the system exists. Research to build such models is already well under way. Some of the more optimistic--like the Center for Fire Research's Gann--predict useful models that take into account not just combustion toxicity but other im portant properties of fires will be developed in three to five years. The current test methods are, in a sense, a form of modeling, says James Quintiere, head of fire modeling at the center They are based on their developer's idea of which aspects of a fire are particularly important. What needs to be done now is to incorporate more key variables into models, on the one hand, and to find out which fire variables are really the life threatening ones, on the other. Research into the mathematical modeling of fires is helping to do both of these things, says Howard W. Emmons, professor of engineering at Harvard. Not only do present models begin to pull together different as pects of a fire so that the problem can be considered as a whole, but the models also point to key data that are missing and suggest how to conduct experiments to get the data. Emmons and Quintiere are two of about a half dozen researchers worldwide who are trying to develop large-scale, compartmental models of what happens in a whole building as it burns. Many others are using modeling to look at particular components of a building fire--flame spread along a vertical wall, for example. But 1 January 3. 1983 CAEN Quintiere: modeling the burning of a building it is these compartmental models that address the question of combustion toxicity most directly. Emmons, for example, has developed a computer model of a hypothetical building. In the model, he can start a fire in one of the building's rooms and follow how heat and combustion gases will flow from that room through the rest of the building. So far, the model con siders only movement caused by convection from the fire and not the effect of the building's ventilation sys tem on gas and heat movement. But the model begins to look at where potentially dangerous gases will be found when a building burns. Such a model cannot determine whether the nature of the burning materials makes a difference in the amount and toxicity of the gases produced, Quintiere points out, but the model does re-emphasize the need for better data on these points. However long it takes to achieve, the picture Emmons paints of what models one day will do is a very attractive one. Someday, Emmons says, an architect will take the plan for a new building to a city's computer, which mathematically will burn the building down perhaps a dozen times or more, each time under different cir cumstances--fires starting in different rooms, critical doors opened or closed, and so forth. The model will predict when smoke detectors and other fire alarms will detect the fire, which parts of the building will become hazardous to occupants, how long escape routes will remain safe to travel in, and other factors key to the fire safety of the building. To do this, the computer will need to know not just what the building is made of, but how it is furnished. "The computer is not going to solve a problem, if there is one," Emmons says, "but it will find it and turn it back to the architect or some other person to solve." URL 0415 OJ URL 04154 NEW PRINCIPLES OF FIRE HAZARD ASSESSMENT FOR FLUID-FILLED ELECTRICAL EQUIPMENT Tor Orbeck. Dow Corning Corporation Presented At The 9th International Conference on Fire Safety January 16, 1984 PI Ip 1/5/84 I. INTRODUCTION The fire hazards associated with dielectric fluids in electrical power systems depend on the fire safety properties of the fluid, use of the fluid in an electrical system and installation of the system in a building. Electrical insulating fluids are widely used in such equipment as transformers, capacitors, switchgear cables and bushings. The potential for a fire in these devices is related to service conditions and the electrical and fire safety protection of the equipment (1/2,3) . In order for a liquid-filled electrical device to become a fire hazard, it is necessary that a rupture of the tank or cooling tubes and ignition/combustion of the fluid occur. Previous fire hazard analysis for fluid-filled electrical equipment was focused primarily on the catastrophic failure mode caused by instantaneous high current internal arcing and the risk for ignition and combustion of flammable electrical insulating material. However, recent fire incidents (4/5*6) have shown that under adverse conditions even the so-called nonflammable products such as fire-retardant resins and halogencontaining fluids can burn and produce hazardous fire products. Therefore, a total fire hazard assessment for electrical equipment requires technical information on all the fire products of the insulating material used in the system, including evolution of heat, smoke and fire gases. There are three basic types of fire risks for electrical equipment: A. Ignition and combustion of insulating materials caused by an external arc or any external fire source (5,6). B. Internal electrical insulation breakdown resulting in rupture of the fluid-containing device. The ignition of the fluid may be caused by the arcing which initiated the rupture. C. Nonviolent rupture of the tank or cooling tubes could occur as a result of either internal pressure caused by a low cur rent electrical breakdown or external mechanical damage to the electrical device during transportation and installation. The probability of ignition under these circumstances is very low. P2 ip URL 04155 -2- The electrical power transformer is a typical high voltage# high energy device and the author has selected this type of equipment for an analysis of the fire hazards of fluid-filled electrical apparatus. The end-user of electrical transformers has many different transformer alternatives: A. Liquid-filled transformers with fluids of three different fire hazard classifications: 1. Nonflammable halogen-containing fluids which do not have a measurable flash and fire point. 2. Less-flammable fluids that have a defined high fire point and a listed Heat Release Rate (HRR) value. URL 04156 3. Conventional mineral oils with specified flash and fire points. B. Dry-type transformers* insulated with: 1. Cast resin systems. 2. Resin-impregnated systems. These different types of transformers should be installed and and protected in accordance with the 1984 National Electric Code. Article " " " " " " " 450-21, 450-22, 450-23, 450-24, 450-25, 450-26, 450-27, 450-28, Dry-Type Installed Indoors Dry-Type Installed Outdoors Less-Flammable Liquid Insulated Transformer Nonflammable Fluid-Insulated Transformer AsJcarel-Insulated Transformer Installed Indoors Oil-Insulated Transformer Installed Indoors Oil-Insulated Transformer Installed Outdoors Modification of Transformers P3 IP iS lK l W i The conventional liquid-cooled transformers have a series of performance and safety advantages that make them attractive and useful in electrical systems: Outstanding reliability and safety record (7,8). High overload capability. High operating efficiency and low operating costs. Sealed system operational in all environments. Compact design requiring less space and weight. Low sound level. Use less expensive surge protection. Historically, the selection of dielectric fluids for indoor transformers was an easy matter. There were two classes of fluids -- mineral oils and polychlorinated biphenyls (PCBs or askarels). Use of the former fluid required auxiliary fire protection, such as a vault. In both cases installation was deemed fire safe and indeed the record is admirable. For example, 1978 National Fire Reporting System (NFIRS) shows only seven fires (out of 230,000 in the data base) beginning with indoor transformers. There were no reported injuries or deaths and the maximum reported damage was $2,000. In the late 1970s, the manufacture and distribution of the PCB's were banned. This reflected their potential biological hazards in the environment. The impact of the ban on the electrical systems was serious. The simplicity of the previous fire code ended, for a variety of fluids were developed and used to replace the PCBs. There has been considerable discussion and test development to produce fire safety criteria that will preserve the fine record of performance and safety of the fluid-filled transformer. This report describes some of the new principles of fire hazard analysis and gives data presently available for some transformer fluids. II. P4 IP PROTECTION OF TRANSFORMER INSTALLATIONS Newly developed concepts of fire hazards of systems are replacing the narrower concept of flammability of materials. Most valid fire hazard tests are those that evaluate the system or a product under conditions closely simulating the potential fire-failure mode and fire-failure condition in the equipment installation. 78n -4- Transformer fluid fires are rare because much fire protection is already built into the system. The severity of a transformer fire is not only dependent on the fire safety properties of the fluid, but.is directly dependent of the external safeguards such as control of power into the device, separation of the transformer from other flammable materials, containment of the fluids and use of fire detection and suppression systems. The installation of indoor small power transformers is covered by the National Electric Code and these requirements are listed in the next section. Transformer Fire Safety Protection Requirements The Appendix A shows the text of Section B of Article 450 of the National Electric Code (NEC) for 1984. The protection requirements can be summarized as follows: A. All transformers must be electrically protected by over-current device to limit arc currents. B. All transformers must be guarded against physical damage and ventilated to reduce thermal damage. C. All transformers rated over 35,000 volts must be placed in a vault or at least have a three-hour fire-resistant wall. D. All oil-filled transformers must be installed in a vault regardless of the rating. E. Transformers filled with nonflammable fluids, that have no specific flash or fire point, require no vault. P. Transformers rated at 35,000 volts or less and insulated with less-flammable liquids can be installed without the vault in noncombustible occupancy areas in noncombustible buildings provided there is a liquid confinement area. G. Transformers with less-flammable fluid installed in combustible buildings or combustible occupancy areas" must be provided with automatic fire extinguishing systems or installed in a vault. P5 lp -5- The essence of the National Electric Code is that the fire can be limited to a transformer itself by its fire con tainment and external protection. __ The Factory Mutual Engineering Corp. (FM) has established a Loss Prevention Data Sheet 5-4/14-8 and 5-4S/14-8S that makes detailed recommendations for the electrical and mechanical protection of the transformer installation. FM has a listing of less-flammable fluids (Class 6933) that requires a minimum of 300 degrees fire point and a specific value of the HRR of the fluid. The HRRs are analyzed relative to the building's ability to withstand such a fire. A graph showing how the HRR value is related to requirements for a safe transformer installation is shown in Figure 1. Fire hazards are associated with all existing transformer systems which will develop fire products that constitute fire hazards. Unfortunately, very limited data and information exists on the fire products of the halogen-containing fluids (9*10,11) ancj the fire-retardant resin systems Data and information do exist for the oil and less flammable liquids, and discussion of fire safety properties is limited to fluids of known characteristics. 6SLKJ Id fl III. FIRE SAFETY PROPERTIES OF LESS-FLAMMABLE INSULATING LIQUIDS More than 90% of all transformers use mineral oil or less-flammable insulating liquids as the dielectric coolant. The two most used less-flammable fluids are silicone fluid and high molecular weight (HMW) hydrocarbon liquids. The reliability and safety record of transformer installations with the new less-flammable fluids has been exceptionally good (8), and technical information about the fire safety properties of these fluids is readily available. The silicone transformer fluid is polydimethylsiloxane having the following general formula. CH CH CH lI CH - Si - O - Si - O - Si - CH II CH CH x CH x = 0 to greater than 2000. P6 IP URL 04160 -6- The fluid is characterized by a narrower molecular weight distribution than mineral oil or askarels. It has very low.total volatile content, less than 0.5%, which permits operation at high temperatures with low vapor pressure. Silicone transformer fluids are stable at maximum operating temperatures whereas mineral oil and askarels may shoto some degradation. The HMW 'hydrocarbon liquids are mineral oils with properties similar to those of conventional transformer mineral oil. However, the HMW fluids are subjected to a special hydro genation and stripping process to reduce the volatile content of the fluid, thereby increasing the viscosityand the firepoint of the fluid. The properties of the silicone fluid and the HMW hydrocarbon fluids are compared to regular mineral oil in Table I. The fire safety properties of these three types of trans former fluid can be discussed in six points: A. Gases developed under sustained arcing conditions. B. Ignition and flame spread. C. Heat release rates. D. Smoke ,and fire gases developed under fire conditions. E. Oxygen depletion. F. Extinguishment behavior. A. Gases Developed Under Sustained Arcing Conditions Both silicone fluid and hydrocarbon fluids evolve flammable gases under high current arcing and, therefore, can produce a flash or a fire ball under catastrophic failure conditions (13,14,15). However, testing has shown that even a "nonflammable liquid" can develop a fire ball under high current arcing conditions (13,16). The major arcing gases from the hydrocarbon and silicone liquids are hydrogen and lesser amounts of acetylene, methane, ethylene, and other gaseous hydrocarbons (see Tables II and III from reference 15). Considerable effort has been done to study the formation of arc gases and the potential hazard of a violent catastrophic rupture of the transformer tank. These studies are complicated by the many variables leading to P7 IP URL 04161 -7- a variety of different failure modes, dependent on the design,* construction, and protection of the transformer system. while this aspect of the transformer fire hazard is recognized, it has been up to this point impossible to establish a meaningful, reproducible test that related to the actual fire hazard of the transformer installation rather than to the arc behavior of the fluid itself <2). A very interesting phenomenon observed during the arc studies has been the propensity of the silicone fluids to build a bridge of solid matter between the electrodes if one of the electrodes is not rotated continuously <15). if the electrodes are kept stationary after arcing commences, solid matter immediately begins to accumulate in the electrode gap. Within a few seconds, a solid bridge forms across the electrode gap. The arc is extinguished and the generation of gas ceases completely. The behavior of silicone fluids in arcs is unique. When arcing begins, the silicone fluid that is very near the arc (but not in it) does not vaporize or decompose as hydrocarbon or askarel liquids would; instead, it gels. In the arc plasma itself, decomposition of the silicone fluid forms a large amount of silicon dioxide, silicon carbide, carbon, and probably silicon. By contrast, arc decomposition of hydro carbons and askarels produce a much smaller amount of solid matter consisting almost entirely of carbon. The solids formed in a silicone fluid do not disperse immediately. Instead they coalesce with gelled silicone fluid to bridge the electrodes gap. The resistance of the bridge has been measured at between 10 and 10 ohms, although this will vary considerably with arc conditions. The possible implications of the bridging phenomenon can be seen in A. M. Lockie's explanation of how most catastrophic transformer faults begin; Whatever the cause, the great majority of transformer failures start as faults between turns, or layers of turns, in the windings. Since most of the winding impedance remains in the circuit, the initial fault current is relatively small. Arcing at the initial failure point, however, causes the failure to spread to adjacent turns and layers, reducing the residual impedance and increasing the fault current <26). If it can be shown that a silicone fluid will form a solid high impedance bridge in that initial small turn-to-turn fault, preventing the arc from spreading and generating more gas, it could have tremendous implications from the safety standpoint. P8 IP IJRL 04162 8- - Although we know that resins and halogen liquids give off substantial smoke_and gases under conditions of arcing, the author has not been able to find technical information permitting a meaningful comparison of hazards associated with arcing in fire retardant and less-flammable materials. B. Ignition and Surface Flame Spread Flash and fire points are measured in accordance with ASTM D92. Table IV shows the flash and fire points for mineral oil, HMW hydrocarbon and silicone fluid. There is a substantial difference in the flash and fire points of the three liquids and the higher values for the silicone fluid indicate its reluctance to ignite. Ignition is defined as a process of generation and maintenance of a flammable fuel vapor/air mixture at the surface. Flame spread is defined as a series of consecutive ignitions at the surface. Ignition and flame spread are sustained at the surface when there is a balance between the energy supplied to the surface and the energy required to generate and maintain the flammable fuel vapor/air mixture near the surface. The ignition and the flame spread of the hydrocarbon and the silicone liquids have been studied in more detail in FM's flammability apparatus report. The FM tests were done in a small scale combustibility apparatus developed by Dr. A. Tewarson (I7). Figure 1 (from the FM report) shows a plot of the energy required for ignition as a function of the external heat flux for the silicone and a HMW hydrocarbon fluid. The FM flammability apparatus is designed to obtain generalized parameters to describe the fire behavior of liquids and solids under wide variation of fire conditions. The external energy is supplied to the fuel surface by radiant heaters. The air flow to the sample can be controlled. The fire parameters from the sample are continuously monitored and recorded. Thus, as the heat flux is increased, the ignition and surface flame spread are expected to be faster in the large scale fire. Under natural or forced air flow condition, the value of the ignition energy for silicone fluid is higher than for high molecular hydrocarbon fluid. Thus, in accordance with Tewarson <17) ignition and surface flame spread in larger scale fires are expected to be faster for the hydrocarbon fluids than for the silicone fluid. P9 Ip -9- URL 04163 P10 IP Comparison of the resistance to ignition of mineral oil and silicone liquid under arcina conditions -has been established by H. Kuwahara (15), and these results- are summarized in Table V. The silicone fluid again shows great resistance to ignition under, arcing conditions. It is recognized that the halogen transformer liquids will only burn with a pilot flame or with a sustained arc condition (5). C. HeatRelease Rates (HRR) HRR is defined as a product of vaporization rate and the heat of combustion of the fluid. The higher rate of HRR in a large scale fire, the higher the degree of the fire hazard. Table VI (from PM report) lists the HRR values obtained in the small scale and large scale FM com bustibility apparatus for methanol, heptane, HMW hydro carbon and silicone fluids. Figure III shows curves of the HRR of fluids as a function of the energy flux. The comparison to the HRR's of an askarel is obtained by the use of a pilot flame. A good agreement can be noted between small-scale and large-scale data for the radiative heat release rates for heptane and HMW hydrocarbon. The radiative heat release rate for silicone fluid obtained from external heat flux value in the range of 60-71 kw/m^ is higher than the rate measured in the larger scale fires. This suggests that the actual vaporization rate for dimethylsiloxane fluid for external heat flux values in the range of 60-71 kw/m2 is higher than the actual rate in the larger scale fire. Using the HRR data for higher luminous flame region from the degree of fire hazard expected for heptane is about two times the fire hazard expected from hydrocarbon fluid, about four times the hazard expected from methanol, and about twenty times the hazard expected for dimethylsilox ane. The fire hazard expected for HMW hydrocarbon fluids is about ten times the hazard expected for dimethylsiloxane under large-scale pool fire conditions. The lower degree of a fire hazard of dimethylsiloxane is due to its ability to form a solid crust at the surface in combustion reduc ing the fuel vaporization rate considerably. Since the NEC requires confinement of the liquid by curbs around the transformer, the hazards of heat release from burning liquid must be related to the total heat from the surface of the curbed area and the potential damaging effects on the building structure. -10- Pll IP D. Smoke and Fire Gases Developed Under Fire Conditions Smoke includes both particulate matter and liquid aerosols. Fire gases include products of combustion and pyrolysis (smoldering conditions). Smoke and gases produced on burning contribute to hazard in three ways: 1. Smoke and fire gases may be highly toxic, irritating and/or hot enough to cause damage to the respiratory system. 2. They may cause eye irritation and/or obscuration of light which substantially reduces the probabability of escape from enclosures. 3. Smoke and fire gases may corrode and damage equipment. Statistics show that inhalation of smoke and fire gases causes far hore deaths and injuries in fires in enclosures than does actual flame contact <18*. Complete combustion of hydrocarbons produces carbon dioxide and water vapor. Complete combustion of silicones produces carbon dioxide, water vapor and amorphous (noncrystalline) silica Complete combustion does not occur in large pool fires as mixing of air and fuel is inefficient and the turbulent flames are often oxygen-deficient. Carbon monoxide, smoke (carbon and liquid aerosols), hydrogen, gaseous hydrocarbons, and particularly oxidized products as well as carbon dioxide and water are produced in such hydrocarbon fires. Production of these products of incomplete com bustion will increase for fires which are more oxygen-deficient (e.g. very large fires and fires in enclosures which restrict access of air). Data and information exists for the less flammable liquids such as HMW hydrocarbon and silicone fluids. Southwest Research Institute (SWRI) data (20) for fires in the small Ohio State University calorimeter and the room size calorimeter gives comparative rates of oxygen consumption and production of common fire gases. Smoke release rates, using a method similar to the National Bureau of Standards (NBS) smoke chamber test, were also measured (Table VII). P12 lp -11- Lower, rates of oxygen consumption and smoke and fire gas production for the silicone fluid is a consequence of its much lower rate or burning. Note that data for the silicone are peak rates of short duration whereas hydrocarbon data are steady-state rates. The column labeled CHX represents total gaseous hydro carbons and partial oxidation products. In assessing toxicity of combustion products, the possibility always exists that an unsuspected or trace component of the smoke or fire gases will prove highly toxic. Animal exposure studies are often performed for this reason. The obvious causes of animal injury or death (oxygen depletion, carbon monoxide concentration, and test chamber temperature) should be closely monitored and maintained within nonlethal limits. HMW and silicone liquid were evaluated for toxicity of pyrolysis gases (Table VIII) using a screening method developed by Hilado (21,22). Pyrolysis, or smoldering conditions, is often found to produce more highly toxic products. A 1 gram sample is placed in a quartz tube and heated from 200 to 800C at 40C/minute. The quartz tube is connected to a 4.2 liter transparent chamber containing four mice. The apparatus is sealed during the heating stage. An experiment is performed at least twice and results are averaged. Animals are observed during a 30 minute test period in a sealed chamber and for 14 days thereafter. The average time to various stages of incapacitation and death (for at least eight mice) is considered a measure of relative hazard. Chamber temperatures and oxygen levels were nonlethal. Maximum carbon monoxide concentrations reached were high enough to cause death in 3 to 6 min. Burning silicone liquid exhibits significantly longer times than does HMW oil to produce all stages of incapacity, and ultimately death, of test animals. The time to the first signs of smoke is longer for PDMS than for HMW. Furthermore, levels of carbon monoxide and gaseous hydro carbons (CHX) are significantly lower for silicone liquid. A complete comparison of the smoke and gas evolution of less flammable fluids with fire products from halogen comparison of the smoke and gas evolution of lessflammable fluids with fire products from halogen fluids and resins is not possible because of lack of data. One report (25) shows a table (see Table IX) of the optical density of epoxy, polyester and silicone resin. The epoxy resin does show a considerable evolution of smoke. Another gives some information about the toxic gases from combustion of epoxy resins, but these data do not provide enough information to establish a fire hazard assessment. URL 04165 -12- URL 04166 Standardized test methods which will involve far more---, accurate/ elaborate and time consuming methods, generating classifiable dose-response curves, are presently under development at NBS and elsewhere. These tests should be used to evaluate all the products used in transformer systems including resins and halogenated liquids. The-fire hazards of smoke and fire gases of liquid must be reviewed with respect to transformer installation and potential hazards to people and damage to buildings or contents of buildings. In addition to the toxicity hazards, it is known that transformer fires can cause substantial smoke contamination (**. E. Oxygen Depletion Oxygen concentration may be reduced to life-threatening values for large fires in enclosures with limited access to air (23,24). An oxygen concentration of 10% is considered the minimum required for survival. Values below 10% have been found in large fires. The much lower burning rate of silicone fluids as com pared to the hydrocarbons leads to a lower rate of oxygen depletion. However, no information is available on oxygen levels reached in large pool fires. F. Extinguishment Behavior There are two basic types of fire detection, one using the principles of ionization and and the other using photo electricity. Based on the information given in this paper on generation of fire products, it is obvious that these detections can be effectively used both for protection of HMW hydrocarbon and silicone liquid-filled electrical equipment. The silicone and hydrocarbon fires are readily extinguished using water sprays (19/24) carbon diox ide (I9)f or dry-powder extinguishers (19,24). Tests using a calibrated overhead sprinkler system show that water delivery rates of 0.3 gal/min-ft^ will extinguish such fully developed 4 ft. pool fires within 15 seconds (I9 1 . IV. P13 IP CONCLUSIONS A. Fire Hazards exist for all forms of electrical power equipment regardless of the insulating material used. Even nonflammable liquids and fire retardant resins have burned. -13- B. While considerable information and data exist for- the lessflammable liquids such as HMW hydrocarbons and silicone., the author has been unable to find data for the combustion and arc products from the resin and solids used in dry-type and molded transformers and for the halogen fluids used in transformers. A meaningful safety comparison of all transformer alternatives is not possible before data is available for all major insulating materials used in transformers. C. A total fire hazard analysis of an electrical device requires complete understanding of code requirements and the protection systems used for the equipment. The fire safety properties of an electrical insulating product are only meaningful when reviewed in relationship to the installation of the equipment and its external safe guards . D. The fire safety properties of electrical insulating products can be defined as: evolution of arc gases, ignition, flame spread, and evolution of fire products such as heat, smoke, and toxic gases. E. The application of modern principles for fire hazard assessment for liquid-filled electrical transformers using less-flammable fluids shows that a silicone-filled trans former installed in accordance with the National Electric Code provides a high degree of safety because of its resistance to ignition and its low evolution of fire products under burning conditions. P13.1 URL 04167 -14- LITERATURE REFERENCES IJRl 04168 1. Draft of Proposed IEEE Guide in IEEE Standard Project PAR 774 (assigned to the Liquid Committee of the EIS-32), "Assessing The Fire Hazards of Insulating Liquids Used in Indoor Electrical Transformers". 2. R. G. Gann, "Development of Flammability Criteria For Transformer Dielectric Fluids", NBSIR 80-1992, NBS, March 1980. 3. T. E. Alverson, et al., "A Report on Research on Fire Safety Test Methods and Performance Criteria For Transformers Con taining PCB Replacement Fluids", Contract No. NB 795BCA0024, for U.S. DOC, NBS, and DOE Division of Electric Energy Systems. 4. K. Herberich, "Brand Eines Geisshart Transformers (Fire In a Cast Resin Transformer)", Jan. 1979 Brandschutz/Deutsche Feverwehr Zeiting. 5. San Francisco Chronicle, May 16, 1983, "Big PG&E Explosion San Francisco Highrise Shut". 6. Michael G. McGraw, "The PCB Problem: Separating Facts From Fiction", ELECTRICAL WORLD, February 1983, p. 56. 7. E. Goodman, "Today's Transformer Insulation Systems"!, IEEE Transactions, July 1972. 8. T. Orbeck, "Replacement Fluids for PCB in Transformers: Service Experience and Safety Considerations", 18th Inti. Doble Conference in Boston, April 1981. 9. V. L. Carter, et al., "Effects of Inhalation of Freon 113 on Laboratory Animals", Aerospace Medical Res. Lab, WrightPatterson Air Force Base, Ohio. U.S. National Technical Information Service, AD Rep., 70 (No. 727523). 10. J. Norris, "Assessment of Carcinogenic Potential of Perchlorethyiene for Man", 1980 Annual of Toxicology Forum. 11. L. Smith, et al., "Heat of Combustion of Organic Chloro Compounds Determined by 'Quartz Wool' Method", Acta Chem. Scand, 1953, No. 1. 12. F. S. Brugner, A. J. Jonnatti, "An Air Pyrolysis Study of Cast Bisphenol A Epoxy Transformer Coils", Paper 83 WM 113-3, IEEE Power Eng. Society for IEEE, Jan-Feb. 1983. 13. D. A. Duckett, RTE Corp., "Environmentally Acceptable Insulating Fluids May Replace Askarel", presented at: The General Meeting of the Edison Electric Institute, Transmission and Distribution Committee, Minneapolis, MN, May 8, 1975. P23 IP -15- URL 04169 14. J. C. Crouse, J. P. Kinney, Jr., "Silicone Dielectric Fluid: A Replacement for Askarel", INDUSTRIAL POWER SYSTEMS, June 1977. 15. H. Kuwahara, et al., "Study of Explosion and Fire Hazards of Silicone Liquids Under Arc Conditions", IEEE Inti. Symposium on Electrical Insulation, Montreal, Canada, June 1975, Paper No. E-7. 16. GE Film on Transformer Explosion Tests, 1976. Test includes test model filled with trichlorobenzene. 17. A. Tewarson, et al., "Fire Behavior of Transformer Dielectric Insulating Fluids, Report No. FRA/ORD-80/08, January 1980. 18. A. F. Robertson, ed., "Fire Standards and Safety", ASTM Special Publication 614, 1976; See also proceedings of ASTM Committee E-5 on Fire Standards. 19. J. Lipowitz, "Flammability of Polydimethylsiloxane, I. A Model for Combustion", J. FIRE AND FLAMMABILITY, 7, 482 (1976). 20. M. Kanakia, Southwest Research Institute, "Characterization of Transformer Fluid Pool Fires by Heat Release Rate Calorimetry", SWRI Project No. 03-5344-001, March 1979, Presented at the 4th International Conference on Fire Safety, U. of San Francisco, January 1979. 21. C. J. Hilado, C. J. Casey, D. F. Christensen, J. Lipowitz, "Toxicity of Pyrolysis Gases from Silicone Polymers", J. COMBUSTION TOXICOLOGY, 5, 130 (May 1978). 22. C. J. Hilado, "Screening Materials for Relative Toxicity in Fire Situations", MODERN PLASTICS, 54, 64-6, 68 (July 1977). 23. C. J. Hilado, "Flammability Handbook for Plastics, 2nd ed., Technomic Publ. Co., Westport, Conn., 1974, Chapter 2. 24. R. A. Hemstreet, Factory Mutual Research Corp., "Flammability Tests of Askarel Replacement Transformer Fluids", FMRC Serial No. 1A7R3.RC, August, 1978. 25. B. VanWert, T. Orbeck, "Flammability Testing of Dry-Type Transformer Insulating Materials", IEC Proceedings of the 12th Electrical/Electronics Insulation Conference, November 11-14, 1975. 26. A. M. Lockie, "Safety and Reliability Considerations for Distribution Transformers", 1972 Electric Utility Engineering Conference, Subject 424. P24 IP -16APPENDIX A URL 04170 NATIONAL ELECTRIC CODE ARTICLE 450 TRANSFORMERS AND TRANSFORMER VAULTS Section B: Specific Provisions Applicable to Different Types of Transformers 450-21, Dry-Type Transformers Installed Indoors (a) Not Over 112i kVA. Transformers installed indoors and rated 112i kVA or less shall have a separation of at least 12 inches (305 mm) from combustible material unless separated therefrom by a fire-resistant heat-insulating barrier, or unless of a rating not over 600 volts and completely enclosed except for ventilating openings. -* (b) Over 1121 kVA. Individual transformers of more than 112i kVA rating shall be installed in a transformer room of fireresistant construction. Exception No. 1 to (b): Transformers constructed with Class 80C rise or higher insulation and separated from combustible material by a fire-resistant, heat-insulating barrier or by not less than 6 feet (1.83 m) horizontally and 12 feet (3.66 m) vertically. Exception No. 2 to (b): Transformers constructed with Class 80C rise or higher insulation and of completely enclosed and ventilated-type construction. (c) Over 35,000 Volts. Transformers rated over 35,000 volts shall be installed in a vault complying with Part C of this article. 450-22, Dry-Type Transformers Installed Outdoors Dry-type transformers installed outdoors shall have a weatherproof' enclosure. Transformers exceeding 112i kVA shall not be located within 12 inches (305 mm) of combustible materials of buildings. P19 12/27/83 IP -17- 450-23, Less-Flammable Liquid-Insulated Transformers. Transformers insulated with listed less-flammable liquids shall be permitted to be installed without a vault in Type I and Type II buildings in areas in which no combustible materials are stored, provided there is a liquid confinement area, the liquid has a fire point of not less than 300C, and the installation complies with all restrictions provided for in the listing of the liquid. Such indoor transformer installations not meeting the restrictions of the listing listing, or installed in other than Type I or Type II buildings, or in areas where combustible materials are stored, shall (1) be provided with an automatic fire extinguishing system and a liquid confinement area, or (2) be installed in a vault complying with Part C of this article. Transformers installed indoors and rated over 35,000 volts shall be installed in a vault. Transformers installed outdoors shall comply with the safeguards of Section 450-27. (FNP):As used in this Section "Noncombustible" refers to Type I and Type II building construction and noncombustible materials as defined in Types of Building Construction, NFPA 220-1979. (FNP):See definition of "Listed" in Article 100. 450-24, Nonflammable Fluid-Insulated Transformers. Transformers insulated with a dielectric fluid identified as nonflammable shall be permitted to be installed indoors or outdoors. Such transformers installed indoors and rated over 35,000 volts shall be installed in a vault. For the purpose of this section, a nonflammable dielectric fluid is one which does not have a flash point or fire point, and is not flammable in air. P20 lp 11 ia n -18- 450-25, Askarel-Insulatsd Transformers Installed Indoors* Askarel-insulated transformers installed indoors and rated over 25 kVA shall be furnished with a pressure-relief vent. Where installed in a poorly ventilated place, they shall be furnished with a means for absorbing any gases generated by arcing inside the case, or the pressure-relief vent shall be connected to a chimney or flue that will carry such gases outside the building. Askarel-insulated transformers rated over 35,000 volts shall be installed in a vault. 450-26, Oil-Insulated Transformers Installed Indoors. Oil-Insulated transformers installed indoors shall be installed in a vault constructed as specified in Part C of this article. Exception No. 1: Where the total capacity does not exceed X12Vi kVA, the vault specified in Part C of this article shall be permitted to be constructed of reinforced concrete not less than 4 inches (102 mm) thick. Exception No. 2: Where the nominal voltage does not exceed 600, a vault shall not be required if suitable arrangements are made to prevent a transformer oil fire from igniting other materials, and the total capacity in one location does not exceed 10 kVA in a section of the building classified as combustible, or 75 kVA where the surrounding structure is classified as fire-resistant construction. Exception No. 3: Electric furnace transformers having a total rating not exceeding 75 kVA shall be permitted to be installed without a vault in a building or room of fireresistant construction, provided suitable arrangements are made to prevent a transformer oil fire from spreading to other combustible material. Exception No. 4: Transformers shall be permitted to be in stalled in a detached building that does not comply with Fart C of this article if neither the building nor its contents presents a fire hazard to any other building or property, and if the building is used only in supplying electric service and the interior is accessible only to qualified persons. URL 0-417 rvj P21 IP URL 04173 -19- Exception No. 5: Oil-insulated transformers shall be per mitted to be used without a vault in portable and mobile sur face mining equipment (such as electric excavators) if each of the following conditions is met: a. Provision is made for draining leaking fluid to the ground. b. Safe egress is provided for personnel. c. A minimum i inch (6.35 mm) steel barrier is provided for personnel protection. 450-27, Oil-Insulated Transformers Installed Outdoors. Combustible material, combustible buildings, and parts of buildings, fire escapes, and door and window openings shall be safeguarded from fires originating in oil-insulated transformers installed on roofs, attached, to, or adjacent to a building or com bustible material. Space separations, fire-resistant barriers, automatic water spray systems, and enclosures that confine the oil of a rup tured transformer tank are recognized safeguards. One or more of these safeguards shall be applied according to the degree of hazard involved in cases where the transformer installation pre sents a fire hazard. Oil enclosures shall be permitted to consist of fireresistant dikes, curbed areas or basins, or trenches filled with coarse crushed stone. Oil enclosures shall be provided with trapped drains where the exposure and the quality of oil involved are such that removal of oil is important. Transformers installed on poles or structures or underground shall conform to the National Electrical Safety Code, ANSI C2-1981. 450-28, Modification of Transformers. When modifications are made to a transformer in an existing installation which changes the type of the transformer with respect to Part B of this article, such transformer shall be marked to show the type of insulating liquid installed and the modified transformer installation shall comply with the applicable requirements for that type of transformer. P22 12/27/33 lp -20- URL 041 74 0 200 400 600 800 1000 Heat Release Rate Per Unit Curbed Area, kW/m2 STEEL FRAME ROOF Figure 1 -21- Exlernol Heol FluxUw/m2) Ignition flame spread for pure dimethylsiloxane AND HMW HYDROCARBON FLUIDS AS A FUNCTION OF EXTERNAL HEAT FLUX UNDER FORCED AND NATURAL AIR FLOW CONDITIONS, Figure 2 Heal Release Rate (kcal/min) 4" Dio. Pool URL 04176 -22. FACTORY mutual research corporation 1A7R3.RC External Heal Flux (watts /cm2) FIGURE 3 CONVECTIVE HEAT RELEASE RATES OF TRANSFORMER FLUIDS. LABORATORY SCALE APPARATUS URL 0417? TABLE I TYPICAL PROPERTIES OF INSULATING LIQUIDS Properties Dielectric Strength, kv (ASTM D 877) Dielectric Constant, 35C (ASTM D 877) Dissipation Factor, 25C (ASTM D 924) Volume Resistivity, 25C (OHM/cm 1x10^5j Viscosity, 25C, cSt (ASTM D 88) Specific Gravity, 25C (ASTM D 1298) Pour Point, C (ASTM D 92) Water Content,ppm* Modified K. Fischer Transformer Oil Initial Values 40 2.2 0.02 8.5x1015 16 0.88 -40 <25 HMW Hydrocarbon Initial Values 40 2.4 0.00001 8xl012 350 0.87 -15 <25 Initial Values 40 Silicone Liquid After 3 Yr Of Service After 5,000 Hr In Test Model 45.0 2.7 - 2.7 0.00002 - 0.0005 lxlO15 50 50 3 . GxlO11 50 ^ u 1 0.96 - - -60 - - <50 47 53 Specified levels to obtain satisfactory dielectric properties. P14 IP 24 TABLE I I P26 < *73 'T in N* CN cn rH 0) iji 0 X 1 ** n- iH o CN 4 o co CO n* Cfll un H <n m o CN o o 14 7 rH Cb r CN JJ O M 6- M a H < z O O' s o ca CO CN O' o <U r* a; u H o n U CN o in N* y y cj cc < to in Jj uo CO O 0 . JJ CN c 0 r-l CO 10 1 > CN 10 pH to . 5-i o to in rM *? in CN JJ jj H OS os s u a z < O' y a) 3 E cE o CN 00 CD y CN u -4 Q t <0 to m in CO m JJ u in 1 rH CN o uo u N1 0 < to cn JJ Jj o m JJ ^ 0 CN a sc a *0* CN i0 cn O < 73 oo > Cl 4 4 1 1 ( <n CN gj CN X r-* rr Tp CO CO H r- pH Cu 10 Cb o CN 73 M3 cn CT >4 H < O' s <D J 3 s ca i0 CN CN r* cn y < H J-l co 1 1 m O' z y in jj in r- H in o u n CO < c CO o r* pH jj o r-* JJ CN e-< y O rH z H CC w H O CO a. < cn s 6 C 0) <D o -J 0. i0 o r-* cn n* y y u o JJ JH (0 C0 1 CN CO 1 pH <0 O' rr O u Ui CN CO CO CO JJ ^ r* jj JJ < O cn o CC Cb o CO w hH JJ cu C X0 32 y X Vj UJ <11 a 73 y 77 Jj y <0 u pH 33 to y <0 <u to X CJ *sj CJ *j i-i c a. y w <n 5H c ca S e- a) o 73 a JJ o a \ o cm c uO y H 0) Jj U > 3 5-i O' H 3 y CN n* 0 0 ea 4 y cn X 22 pt* n rH p-H (0 CN O T* CN CN CN n m > 0 3o &3 U 4*4 a CJ CJ U CJ CJ U w > -25- TABLE III EVOLVED GAS VOLUMES UNDER ARC CONDITIONS IM LIQUIDS Current Level Lower Medium Higher Silicone Liquid Measured Calculated (m.tf/kWs) 35-40 8^5-9 5 40-45 75-85 100 - Mineral Oil Measured Calculated (mi/kWs) 42-46 55-75 45-55 45-50 100 URL 04179 P27 IP -- 26 -- TABLE IV FLASH AND FIRE POINT OF FLUIDS Flash Point, C (ASTM D 92) Fire Point, #C (ASTM D92) Transformer Oil 150 165 HMW 284 312 Silicone 300 343 IJPL 04180 P16 IP URL 04181 TABLE V TEST RESULTS OF FLAMMABILITY No. Liquid 1 Mineral 2 ft 3 ft 4 Silicone 5n 6 Mineral 7 If 8 ft 9 Silicone 10 ii Current A 6.1 ii fl Arc Location From Liquid Surface mm 10 20 30 Current Duration Min. 4 7 12 tl 10 25 II 20 27 13 10 11 20 . 3 II 30 2.75 If 20 13 H 10 8.5 Final Liquid Temp. 140 150 120 260 212 140 140 230 243 Resultinq Conditions Fire Fire Arc in liquid did not reach to a surface. No fire. Fire Gap was bridged with solids. No fire. Arc was sustained in air. Fire Fire Fire Fire (1) Applied Voltage: 6.9 kV (2) Distance between electrodes: 2 mm P28 ip (3) Liquid Volume: 1,350 m (4) Initial Liquid Temperature: 30 URL 04182 -372 -50 -422 A verage fo r e x te rn a l h e a t flu x v a lu e s 60 to 71.3 kw/m^ under fo rc e d a ir flo w c o n d itio n . ---3 T-- c. a C7 & cn *n S > ftto c o < rr c t< r-* r n 3 Qi & in o '.G rr c Tl ft a rr\ 0 If, CU 0 rt o 3 n> n ft CT & 0 ca 3 cy W < n cr --* Q in fii U O rr bD 0 rr fD DJ rr -- 3" 0 it 3 n t> fi> rr X in M 3 n SJ (t e b3 -- W o vr (t -J b M< a. ft b 0) fit i--i rr 3 H c a Ot b ft .. r* w A ft i-- V C 01 o> < 3 T b Qi a 3 D O o two n 1-1 3 w N fi> n fij rr --o c -- -1 it O 3 *- a o> b(rb+ --i Of ft 30 rr b b< O ra Q(/)j <r Or --w -- r- --c 5 a n b > 55 r> 3 n bo r t- 3 n& ---- rr r -- V 3 C <K c b b it fit -- c n f4 - rr c < fit ft rr O . rr O c < r~ 3 < kW. (B < ro < it 3 r: b 0P C Tj in *ij ft h- Q a> 3O ft 3 LTl --03 A U> u 1 1 Q3 ^ r- l/i aa NJNH -j nj _n o c& ii* ro -- LA o Ln KJ O LJ a Q. iii rLA Q3 N) CO Skl LA =t xb n > o rr o o Lj o 3 r- r*. -C t & ft pr o ft rr b ft c '.i <* >0 n o XQ 3 b O' rf c ft trt rr 3T O S3 "v. 3 fo = o rr o r-P) n o ? C7 c rr 0 3 3" X* C\ I~ N> l~ ** O S) Ul o * in UJ 1 11 l A A Uj hj A ^ *j r ?! o A i .i AL W^ O' a o W 3> A N W w r* nb a a* ft 2ft rr v- r 3 na0 b T f-l 1- o O It 0i 1 'a r rj b ft 1 "O CO -- ni * -- -- ^-- --t Xl ^ -- rj 2 1 CO cr ft .t n. u> a. ee M 33 j* Q t ft KJ CO fO <? ^3 i n mm a cu -- $ft Vi ,,_XT: -- m- 0b hf ft l7- C>it3 =J ]H> liHti i-3 > w < -*: - / Fluid HMW 04133 TABLE VII RATES OF SMOKE AND COMBUSTION PRODUCTS OUTPUT Pan Size 3" Dia. 6" Dia. 12" Dia. 24" Dia. SRR1 246 196 - 2 Depletion Rate (liters/min) Generation Rates (liters/min) C02 CO CHX3 19.5 36.7 1700 4012 6.75 23.0 330 1700 0.021 0.30 23 230 0.07 0.30 2.9 16 PDMS2 3" Dia. 6" Dia. 12" Dia. 24" Dia. 36'* Dia. 48" Dia. 38.5 67.0 - - - _ 2.0 20.0 60.0 - 300 600 1.5 3.5 56 100 80 300 lSRR * Smoke Release Rate - v/AL (log^o) where v = Air Flow Rate in OSU Apparatus, A = Area of Pan - sq. ft. L = Light Path Length - 0.4375 ft. %T = % Light Transmission 85 cfm ^Release Rates are Peak Values. ^Total hydrocarbon Equivalent of Methane. - 3.3 3.3 7.0 8.0 1.5 0.1 0.5 2.1 T> 1 *7 URL 04184 TABLE VIII TOXICITY TEST DATA, USF METHOD B (200-800C Rising Temperature^ 40 C/Min., No Forced Air Flow) Time In Minutes Sample Incapacitation Staqqerinq Collapse Convulsions Death PDMS 20.51+0.27 21.39+0.63 23.12+1.23 24.43+1.84 27.03+0.35 HMW 10.31+0.25 12.44+2.04 18.57+1.08 19.6210.57 21.43+0.82 Sample PDMS HMW Times are mean + standard deviation, for at least 8 mice. Time to First Sign of Smoke (min.) Highest Chamber Temperature Recorded Maximum Gas Concentration Oxygen CO ch4 (%)* (ppm) (ppm) 5.28 27 C 15.9 7,750 1,600 4.39 26 C 17.5 11,050 4,150 minimum concentration P18 IP i OJ O I S 3tw iu n PCBs, PCDFs, and PCPRs Resulting xrom Transformer/Capacitor Fires: An Overview Paul E. desRosiers Environmental Protection Agency Office of Research and Development Washington, DC 20460 Abstr act The purpose of this paper is to give an overview of what the author considers to he current information concerning PCP trans^ormer/capacitor fires in the U.S. On December 15, 1983, the Environmental Protection Agency issued a national dioxin strategy for investigating, identifying, and cleaning up sites contaminated by dioxin. thin the framework of this strategy is a plan that caKis for research to be conducted on PCB transformer/capacitor fires. This research will entail an investigation into the characterization of sources of PCDTs and RCDPs, that is, the chemistry of PCB fires and theoretical products of therma1 stress based on composition of askarel used; emergency response protocols ror firemen, including protective clothing; and practical remedial measures for building cleanup. The author also feels that only through the sharing of information and full cooperation among electrical utilities, chemical manu^acturers, firemen, insurers, EPRI, EPA, and NIOSH can "preventive maintenance" be performed to minimize or preclude future impacts of PCP transformer/capacitor ^ires. PREFACE On January 10, 1979, a railroad tank car carrying 75,000 liters of crude o-chlorophenol ruptured near Sturgeon, Missouri. Forty-seven workers from the Norfolk & Western Railway Company were employed to clean up the spill and in the process were exposed to a variety of toxic chemicals, including chlorinated phenols, phenol, and the toxic artifact, 2,3,7,8-TCDD (1). In fact, the concentration of this dioxin isomer amounted to only 22 ug/kg (ppb) (2). As a result of alleged exposure and the manifestation of certain perceived health effects and physiological symptoms, e.g., rashes, dizziness, loss of memory, extreme fatigue, impotence, upper respiratory difficulties, and in one case, cancer of the testicles and the skin, the workers brought suit in an Illinois court against the railroad company and the manufacturers of the tank car and the faulty coupling, including Monsanto, the manufacturer of the orthochlorophenol. On August 26, 1982, the Edwardsville, Illinois jury awarded the highest monetary judgments ever made as a result of a Presented at the EPRI PCB Seminar, Atlanta, GA, December 6-8, 1983. single tankcar spill - $57.^5 million (1). Prior to the commencement of the April 5 trial, Monsanto, General American Transnortation, and Dresser Industries settled out of court for an estimated $8 million. This court decision represents the first tine a jury has concluded that dioxin caused permanent harm to humans and thus has highlighted the more than 30 waste disposal sites within the State of Missouri that contain polychlorinated dibenzo-p-dioxins (PCDDs)(3). Recently, in November and December of 1983, three separate suits (4)(5) were filed in St. Louis Circuit Court: in one case, by 57 persons who contend they suffered general systemic effects ^ron dioxin-tainted soils at six sites in eastern and central Missouri - *or $684 million; in a second case, by 25 dockworkers and a widow of a former dockworker of a trucking firm in St. Louis - for $620 million; and finally, by 183 people at Times Beach and Castlewood who assert that they suffered serious health deficiencies as a result of dioxin exposure - for $1.8 billion. Therefore, this situation has catalyzed an acute public and governmental awareness of the potential severity and explosiveness of the PCDD problem. PCB transformer fires, accidental spills, and inappropTiate disposal have compounded the problem particularly in regards to PCDFs (furans) and to some extent PCEPs (biphenylenes). INTRODUCTION The most toxic and extensively studied polychlorinated dibenzop-dioxin (PCDD) and -furan (PCDF) isomers are 2,3,7,8-tetrachloro-pdioxin (2,3,7,3-TCDD) and 2,3,7,8-tetrachlorodibenzofuran (2,3,7,8TCDF), respectively. There are pronounced difference:; in biological and toxicological effects between different PCDD and PCDF isomers. Those isomers with the highest acute toxicity are 2,3,7,8-TCPD, (See Figure 1). ctCl Cl Cl Cl ti?8-Tu-COF U.3.',-pn'*<OP Cl l3^.7,8-^nta-CuP Figure 1. The most toxic PCDD and PCDF isomers (6) Each of these isomers has its respective four lateral positions substituted for chlorine and each has LD^o values in the range of 1-100 ug/kg for the most sensitive animal species (generally the male guinea pig). There exist 75 PCDD isomers and 135 PCDF isomers. Acute toxicity among the isomers can vary up to 100,000 times (See Table 1). In comparison, the most acutely toxic PCS isomer is only about one-fourth as toxic as 2,3,7,8-TCDD (8). Table 1. Acute oral toxicity of polychlorinated dibenzo-pdioxins as dose expected to cause death of 50?, of the animals within 30 days (7). Acute Oral LDgn, ug/kg Body Weight PCDD Di 2,7 2,3 Guinea Piq >300,000 Rat >1,000,000 Mouse >2,000,000 Tri 2,3,7 30,000 >3,000 Tetra l,3,6,8nmjXgj 1,3,7,9 2,3,7,8 >100,000 0.6 22 (M) 2.1 45 (F) 2 230 Penta 1,2,3,7,8 1,2,4,7,8 3 1,100 340 >5,000 Hexa 1,2,3,4,7,8 1.2.3.6.7.8 1.2.3.7.8.9 Mixed Isomers Hepta 1,2,3,4,6,7,3 Octa 1,2,3,4,6,7,8,9 73 70-100 60-100 >600 100,000 825 1,250 >1,440 >1,000,000 >4,000,000 URL U4187 -3- Recent information arising from a 1983 National Cancer Institute carcinogenicity study of a mixture of 1,2,3,6,7,8- and 1,2,3,7,8,9-HCDD in female rats led to the preliminary conclusion that this mixture of hexachlorodioxins was carcinogenic. Recause public comment criticized the manner in which the experiments were conducted, the National Institute of Environmental Health Sciences/National Toxicological Program (NIEHS/NTP) was asked to reexamine the results of the study. It is therefore the opinion of NIEHS/NTP that the hexachlorodioxin mixture v/as indeed carcinogenic under the conditions of the test (9). Analyses of Commercial PCB Mixtures PCBs contain a complex mixture of PCDFs with up to 40 isomers being present. Rappe and Buser (6) have analyzed a number of commercial PCBs and their findings are shown in Table 2. The highest concentration of PCDFs, found in a Mitsubishi PCB fluid used for over two years, amounted to 10 ug/g (ppm), with 1.25 ug/g being the 2,3,7,8-TCDF isomer. When correner ci al mixtures or well defined isomers are heated in air in a sealed glass container or ampoule, yields of PCDFs have been observed in the 1-5% range and this technique has been successfully employed.to prepare PCDF standards (10). Using the synthetic standards currently available, the major PCDF isomers present in commercial PDFs have been identified (See Figure 2). ii'ra-r.uj-cor 2JK.7.I-Fmta-CDF Ct lW7.4-Hcpta-CDF Cl Cl Cl Cl Cl Cl Cl Ufl.l-Titia-COF Cl U*.7l-r*M-C0F Cl Cl l.2.i.6A-H**-COF Figure 2. PCDF isomers identified in commercial PCBs (6) -4- URL 04189 Table 2. Concentrations of PCDFs in commercial pCBs, un/g (6). Sample 3-er 4-C1 5-01 6-01 7 - C1 Aroclor 1248 (1969) Aroclor 1254 (1969) Aroclor 1254 (1970) Aroclor 1254 Aroclor 1254 (lot KK 602) Aroclor 1260 (1969) Aroclor (Lot AK 3) Aroclor 1260 Aroclor 1016 (1972) Clophen A 60 Clophen T 64 Phenoclor DP-6 Prodelec 3010 Mitsubishi (used) - - 0.10 - - - 0.06 - - 0.10 - 0.41 2.13 0.5 0.1 0.2 0.25 0.05 0.1 0.2 0.30 <0.001 1.4 0.30 0.7 1.00a 4.00b 1.2 0.2 0.4 O./O 0.10 0.4 0.3 1.0 <0.001 5.0 1.73 10.0 0.35 3.30 0.3 1.4 0.9 0.81 0.02 0.5 0.3 1.10 <0.001 2.2 2.45 2.9 0.07 0.53 _ _ _ _ 1.35 _ _ 0.82 _ - Total PCDF p.O 1.7 1.5 1.9 0.2 1.0 0.8 3.8 .. 8.4 5.4 13.6 2.0 10.0 a Major isomer 2,3,7,8-TCDF b Contains 1.25 ug/g 2,3,7,8-TCDF Discussion of Various PCB Fires Ringhamton, New York On February 5, 1981 at approximately 5:30 a.m., an electrical panel in the basement of a 22 story office building located in a governmental complex was involved in an incident described as an explosion. A nearhy electrical transformer containing about 1100 gallons of Aroclor 1254 {65%) and tri- and tetrachlorinated benzenes (35*0 was involved. Leakage occurred and about 180 to 200 gallons of fluid leaked from the transformer. Due to the ventilation system of the building, smoke contaminated with soot-containing chemicals, was spread in a non-uniform fashion to most work areas of the building as well as to interstices within air conditioning ducts, false ceiling areas, elevator shafts, and within desks and file cabinets. This appears to have been facilitated by air ducts or simply open shafts running from the basement area, up to the top of the building, with openings into the men's and women's bathrooms on each floor. These bathrooms had only metal gratings separating them from the open shaft area. In addition to this architectural arrangement, fire or smoke safety doors, which were designed to open in the presence of smoke as a health measure, did just that during the series of explosions that occurred at the time of the incident. Recause the outside air temperature was below freezing at the time, the opening of safety doors on the roof, which were located above the building's two stairways, caused a small vacuum that sucked air containing smoke, soot, and as was later found, toxic chemicals from the bathroom areas on each floor and deposited the residue in a non-uniform fashion into most areas of the office building later tested. -5- URL 04190 Chemical analyses were performed at: Galson Laboratory in Syracuse, New York and at General Electric Laboratory in Schenectady, New York and revealed PCBs in soot and air, which was strongly suggestive of PCDFs present in substantial amounts; The National Fish and Wildlife Laboratory in Columbia, Missouri, which established the presence of many of the dioxin isomers; and by the New York State Health Department's Division of Laboratories and Research, which established the presence of 2,3,7,8TCDD. A later examination of material from the underground garage that was contaminated and washed (twice with steam and detergent) was found still to have trace amounts (nanograms per square meter) of PCDFs and PCDDs in some areas by Wright State University. Total PCDF isomers in the soot were initially found to be as high as 2160 uq/g, PCDDs 10-20 ug/g, and PCBs 100,000-200,000 ug/g (See Table 3). It is noteworthy that the most toxic isomers are the major components within each group, viz., 2,3,7,8-TCDD, 2,3,7,8-TCDF, 1,2,3,7,8-PCDD, 1,2,3,7,8-PCDF, and 2,3,4,7,8-PCDF (See Figure 1). Since the tri- and tetrachlorinated benzenes comprise 35% of the dielectric fluid, it is not unreasonable to assume that this diluent mixture represents the precursor to the PCDDs produced as a result of the fire. Nearby Binghamton City Hall, which was used as a staging area during the initial cleanup efforts in February 1981, was also contaminated. The County Building also next door to the Binghamton State O-ffice Building was contaminated to a lesser extent. There have been $12 million allocated so far by the State of New York for the cleanup. The building is self-insured so no insurance funds are available. It has been closed since February 5, 1981. Over S Lion in lawsuits have been threatened by some of the more than 500 persons who were, cr believe they were, exposed to toxic chemicals, and who are themselves concerned with physical or psychological/medical damages. Stockholm, Sweden In August 1981, a fire broke out in a 10 KV capacitor battery in an electrical power station in Stockholm, which was probably caused by a malfunctioning electrical system. Wipe tests were taken about one meter from the capacitor (13). Inspection of the chromatograms revealed several peaks, in addition to PCBs, with molecular weights corresponding to di-, tri-, tetra-, and pentachlorobiphenylenes (PCBPs). It is probable that these PCBPs were formed by a direct cyclization of PCBs present. The level of PCDFs was found to be 1375 ng/m^ (See Table 41, whereas a rough estimate for PCBPs gave levels of 25,000-30,000 ng/m'-. Polychlorinated pyrenes (PCPYs) were also detected, but not quantified. -6- URL 0419 Table 3. Levels of PCDFs (ug/g) from accidental burning of PCB-containing electrical equipment. Isomers _________ Capacitor Transformer Skovde, Sweden(lO) Binghamton(lO) 0.5m* 3m** Total PCDFs Total Tri-CDFs Total Tetra-CDFs 2,3,7,8-Tetra-CDF Other isomers 0.8 0.6 0.1 0.5 0.2 0.1 0.02 0.06 2160 28 12 16 Total Penta-CDFs 1,3,4,7,8-Penta-CDF 1,2,4,7,8- " 1.2,4,7,9- " 1,2,3,7,8- " 1,2,3,6,7- " 1,2,6,7,8- " 2,3,4,738- " 2,3,4,6,7- " Other isomers 0.1 0.04 670 65 25 22 310 60 25 48 12 no Total Hexa-CDFs 1,2,3,4,6,8-Hexa-CDF 1,3,4,6,7,8- " 1,2,4,6,7,8- " 1,2,3,4,738- " 1,2,3,6,7,8- " 1,2,3,6,8,9- " 2,3,4,6,7,8- 11 Other isomer 5 0.04 0.04 965 50 125 50 510 150 58 10 250 Total Hepta-CDFs 0.01 1,2,3,4,6,7,3-Hepta- CDF 1,2,3,4,6,7,9- " 1,2,3,4,6,3,9- " 1,2,3,4,7,8,9- " 0.01 460 230 120 55 55 Octa-CDF 0.005 0.005 40 soot sample taken 0.5m from capacitor on the floor soot sample taken 3m. above capacitor on the wall Detection 1imit: 10 ng/g t Detection 1imit: 100 ng/g Transformer Miami (ll),f n.d.-1.79 n.d.-0.18 n.d.-0.53 n .d. n.d.-l.O n.d.-0.13 n .d. n .d. Transformer Poston (12) 165 50 60 3 35 15 2 n. -7- Table 3. Levels of PCDDs (ug/g) from accidental burning of PCB-containing electrical equipment, (cont'd) Isomer s Capacitor Tr ansformer Skovds, Sweden(lO) Binghamton{10) 0.5m* 3m** Total PCDDs Total Tri-CDDs Total Tetra-CDDs 2,3,7,8-Tetra-CDFs Other isomers - _ - 20 1.2 0.6 0.6 Total Penta-CDDs 1,2,3,7,8-Penta-CDDs Other isomers - - 5.0 2.5 2.5 Total Hexa-CDDs 1,2,3,4,6,8-Hexa-CDD 1,2,4,6,8,9 " 1,2,3,4,7,8 " 1,2,3,6,8,9 " 1,2.3,7,8,9 " 1,2,3,4,6,7 - 1,2,3,4,6,7,9-Hepta-1CDD - 1,2,3,4,6,7,8- " - - - 4.7 1.2 1.2 0.7 0.6 0.4 0.5 4 3 Octa-CDD -- 2 Tr ansformer Miami (11) n.d. n .d. n.d. n.d. n.d. n .d. n.d. n.d. n.d. Transformer Boston (12)$ n.d. n.d. n.d. n.d. n.d. n.d. > jC n.d. n.d. n.d. * soot sample taken 0.5m from capacitor on the floor ** soot sample taken 3m above capacitor on the wall # Detection limit: 10 ng/g t Detection limit: 100 ng/g -8- 61hi iyn Table 4. Analyses of wipe samples from various C5 fires. Isomers Skovcfe(14) ng/m2 Total PCDFs n.d.-873 2,3,7,8-Tetra-CDF" n.d.-lOO 1,2,7,8-Tetr a-COF 2,3,6,8-Tetr a-CDF 1,4,6,h-Tetr a-CDF 2,4,6,7-Tetra-CDF 3,4,6,7-Tetr a-CDF 13,6,7-/1,3,6,9-Tetra--CDF Other Tetra-CDFs Total Tetra-CDFs <1-600 2,3,4,7,R-Penta-CDF 1,2,4,7,8-Penta-CDF 1,2,3,6,7-Penta-CDF 1,3,4,7,8-Penta-CDF 2,3,4,6,7-Penta-CDF I,2,4,6,8-Penta-CDF 1,2,4,7,8-Penta-CDF 1,2,3,6,7-Penta-COF 1,2,4,8,9-Penta-CDF 2,3,4,6,8-Penta-CDF 1,2,3,7,8-/l,2,3,4,8-Penta-CDF Other Penta-CDFs Total Penta-CDFs n.d.-lOO Total Hexa-CDFs n.d.-60 Total Hepta-CDFs n.d.-8 Octa-CDF n.d.-5 Total PCDDs Total Tetra-CDDs 2,3,7,8-Tetr a-CDDs n.d. n.d. n.d. Stockholm(ld) ng/m2 1375 150 150 125 75 37 7.5 300 750 1200 45 38 15 11 7.5 3.8 3.8 3.8 3.8 2 15 19 175 <0.5 Cincinnati(13 ng/m2 n.d. n.d. n.d. n.d. n.d. , n.d. -9- t'S w io n Skovde, Sweden In March 1982, a 400 volt capacity battery, serving a high frequency oven in a casting line of a foundry in Skovde, experienced an electrical malfunction leading to a fire (13)(14). The dielectric fluid employed comprised either mineral oil or PCBs. The fire started in a mineral oil capacitor and burned for about two hours before being extinguished. Temperatures exceeding 1100C were realized because copper electrical wiring melted. The smoke spread from the basement into the building above, an area of 60 x 30 meters. The capacitor battery contained 21 capacitors filled with 5 kgs of PCBs each. Post-fire inspection showed leakage from 12 of these capacitors. Both wipe tests and^samples were taken. Results are tabulated in Tables 3 and 4. These show that high levels of PCDFs (>100 ng/m^ and <800 ng/g) could only be found in an area near the fire. Concentrations of PCDFs dropped off dramatically with distance from the fire. The highly toxic 2,3,7,8-TCDF was one of the major tetra-COF isomers present. Other chlorinated compounds that may be present are the PCPYs, but verification could not be obtained due to lack of standards. Mo PCDDs were identified in samples taken from this fire (there were no chlorinated benzenes used as diluents). No PCBPs were observed. Miami, Florida On April 13, 1982, an underground electrical fire occurred in a transformer vault in Miami. City of Miami firemen were called in to extinguish the blaze. They also voiced their concerns about the possible contamination of fire equipment and protective clothing used during the performance of their duties. As a result, the International Association of Fire Fighters in Washington, DC, contacted the KOSH Region IV representative and the latter agency conducted a thorough investigation. Table 5 contains the results of the analyses of surface samples taken during the investigation. As expected, samples removed from inside the vault indicate the heaviest contamination levels (up to 27,400 ug/100 cm^ PCSs). Results of prior NIOSH investigations indicate that normal background levels of PCBs on uncontaminated surfaces should be less than 0.5 ug/100 crn^. As indicated by the sampling results, turnout coats, boots, helmets, and other personal protective equipment were not found to be contaminated from the fire. This is probably due to the decision to allow the fire to self-extinguish, thus minimizing exposures to the smoke and soot. The only contaminated piece of equipment found at the station was the smoke ejector fan, which contained greater than 31 ug/100 cm^ PCBs because the area wiped for this particular sample was estimated to be less than the standard 100 cm^. The fan blade guard was found to be heavily coated with soot and dirt from the smoke exhausted from the vault fire. Results of PCDD and PCDF analyses are shown in Table 3. Mo PCDDs were detected, but tri-, tetra-, penta-, and hexa-CDFs v/ere found, ranging from non-detectable (n.d.) to 1790 ng/g. No 2,3,7,8-TCDF was detected in any of the samples. However, the samples did exhibit high levels of PCBs through Cl and polychlor inated diphenylethers (PCDPEs) through Cl8. -10- Table 5. PCB residue from Miami transformer vault fire (11). Sample Location Inside transformer vault Wall behind transformer Top of primary cable above fire Primary cable support bracket Floor near isolating switch Ceiling near fire location Secondary bus near vault ceiling Wall next to exit ladder Rung of exit ladder Above transformer vault: Sidewalk grating Water at curb near vault Firemen's clothing/equipment: Miscellaneous clothing Smoke ejector fan Normal PCB Background*** Type Sample" pens* (ug/100 cm^) (soot) wi pe (soot) wi pe (soot) wi pe (dirt) wi pe (soot) wi pe (dirt) wi pe (dust) smear tab- -dry (dust) smear tab- -dry 434** 389 704 27*400 860 195 2 79 smear tab- -dry wipe 2 3 smear tab- -dry smear tab- -dry wi pe <0.1 >31 <*0.5 * As Aroclor 1260 (used as standard for quantifying samples). ** As mixture of Aroclor 1254 (231 ug) + Aroclor 1260 (203 ug). *** As determined by previous NIOSH Health Hazard Evaluation. r Wipe samples were collected on sterile cotton pads soaked in n-hexane. -11- URL 04196 Cincinnati, Ohio On December 3, 1980, a capacitor containing PCBs for a 1/2 HP electric motor overheated in a basement storage room of a private elementary school. This capacitor contained 22 ml of dielectric fluid comprised of 21.9 ml of a biodegradable fluid and C.l ml of PCBs. Approximately one-half of the fifth-grade students using three classrooms in the basement area complained of itchiness of the skin. Power to the electric motor was shut off and the exterior door was opened to allow ventilation of the smoke from the room. Since air is locally recirculated, central distribution via a mechanical system throughout the school did not occur. PCBs were not detected in any air sample at a limit of detection of 0.05 ug/sample, which is equivalent to an airborne concentration of approximately 1 ug/m^. Table 6 summarizes the results of 63 wipe samples collected by NIOSH. Fifty-one of the 63 samples were taken from surfaces within the school including books, desks, walls, floors, ceilings, and other surfaces. Two were taken from surfaces within a mobile classroom and ten were obtained from surfaces at three locations in eastern, central, and western Cincinnati to establish background levels of PCRs for this area. The 20 samples obtained from Room 27, which contained the overheated capacitor, ranged from non-detectable to 7200 ug/100 cm^ PCBs. The remaining rooms ranged from non-detectable to 0.45 ug/100 cm^. The two wipe samples with the highest PCR concentrations were also analyzed for PCDDs and PCDFs, with particular emphasis on the 2,3,7,8-tetra-isomers. Neither PCDDs nor PCDFs (See Table 4) were detected in either of the samples. The detection limits employed were 0.10 and 0.C9 ug/sample, respectively. Boston, Massachusetts In January 1982, there was an electrical fire involving PCBs in a Boston office building. One bulk soot sample was analyzed for PCDDs and PCDFs. Table 3 shows that high concentrations of the tri- through the hepta-CDFs were found in the soot sample, ranging from 2-60 ug/g (detection limit = 0.1 ug/g). No PCDDs were found. A considerate amount of the highly toxic 2,3,7,8-TCDF was detected--3 ug/g. Levels of PCSs were also found at 10 - 100 times that of the PCDFs. -12- Table 6. Summary of PCBs wipe sample results, Our Lady of Visitation School, Cincinnati, OH (capacitor fire) (15). Sample Location Room 27 (capacitor location) Room 25 Room 24 Room 26 Hallway Room 8 Room 22 Room 10 Room 11 Room 12 A.V. Room Pr incipal1s Office Mobile Classroom Background Levels (3 Cincinnati locations) Mean PCB 1evel, nn/lPO cm2 * n.d. - 7200** n.d. 0.14 n.d. - 0.06 n.d. n.d. - 0.07 n.d. _ 0.08 n.d. - 0.29 n.d. - 0.20 0.07 - 0.11 0.06 - 0.09 n.d. 0.05 - 0.45 0.C6 n.d. - 0.13 k Detection limit: 0.05 ug/sample (sample = quantity wiped per 100 cm2). ** Two wipe samples with highest concentrations of PCSs were found to contain no detectable PCPFs or PCDDs. 0 St. Paul, Minnesota On June 22, 1982, a transformer fire occurred in a public high school in St. Paul. NIOSH took both surface wipe and air samples on June 23 (the day after the fire) and on July 7 (after the area was decontaminated). Table 7 contains measurements of air contamination, pre- and post-cleanup, by PCBs, trichlorobenzenes, and tetrachlorobenzenes. The NIOSH recommended permissable limit of 0.001 mg/m-J (8-hr TWA) for PCBs was exceeded in all areas sampled except for two locations. The tri- and tetrachlorobenzenes found did not exceed any existing limits. Table 8 shows the effect of the decontamination methods employed. The transformer vault room PCBs (wipes) were reduced from a high of 4,000 ug/100 cm2 to 120 ug/100 cm2 or less. No PCDDs or PCDFs were found in the 1 iquid,.sample of Askarel provided (detection limit = 40 ng/g (40 ppb)). However, it is interesting to note that NIOSH did not analyze for PCDDs or PCDFs in the soot. The results may have shown significant concentrations of these isomers, given the areal concentrations of tri- and tetrachlorobenzenes detected. 13- Table 7. Areal concentration of PCBs and chlorinated benzenes, Hi 11-Mur ray High School, St. Paul, MN (transformer)(16). Sample Site Air bor ne Concentration. mq/m^ PCBs*# T3CBS T4C8S Transformer vault, 5 ft above floor Transformer vault, 1 ft above floor Outside of transformer vault doors Woodshop Head of stairs Cafeteria A 0.05 B 0.007c 0.09 - 0.02 0.004 n.d. n.d. n.d. n.d. n.d. n.d. A 22.6 B 0.331 A IS.2 B 0.651 17.6 _ 10.2 0.73 0.12 0.35 0.048 0.020 " 0.011 0.010 25.7 - 11.7 1.21 0.26 0.27 0.229 0.089 0.03-7 0.032 8-hr time-weighted average exposure criteria 0.001a 40b none A = June 23, 1982; B = July 7 , 1982 * = Detection limit : 0.001 mg/m^ # = as Aroclor 1260 a NIOSH recommended permissable exposure limit. OSHA permissable exposure limit is 0.001 mg/m-3 8-hour time weighted average. b ACGIH threshold limit value. Neither NIOSH nor OSHA has exposure criteria. c sample taken 3 ft above floor sf.twnan -14- Table 8. Analyzed PCBs^ in wipe samples, Hill-Murray High School, St. Paul, MN (transformer) ^(16). Sample Site Vault room Ventilation dust Corridor outside vault room Cafeteria Gymnasium Rooms 106, 109, 138 Outside Room 106 Woodshop PCBs^, ug/100 cm2 A n.d. - 4000 n.d. B 2 - 120 - n.d. 0.22 - 0.24 0.29 0.26 - 2.1 5.8 n.d. - n.d. - n.d. - 0.8 0.8 - # Detection Limit r 5 ug/sample A = June 23, 1982; B = July 7, 1982 t = no analyses conducted for PCDFs or PCDDs. URL 04199 -15- DISCUSSION The previous PCS transformer/capacitor incidents are but a representative sampling of cases where data are readily available. Other electrical equipment episodes include: Toronto, Ontario, Canada in 1977; and Morrtalje and Surahammar, Sweden and Imatra, Finland in 1982 (17). More recently, in the U.S., three such episodes have occurred: Date 5/15/83 9/28/83 12/21/83 Location San Francisco, CA Chicago, IL Syracuse, NY PCB Fluid 1242 only 653 Aroclor/353 Chlorobenzenes 873 1254 URL 04200 Because of the continuance of such incidents, the Environmental Oefense Fund and the Natural Resources Defense Council challenged the August 25, 1982 PCR Electrical Use Rule issued by ERA, As a result, a Start Action Request has been initiated by the EPA Office of'Pesticides and Toxic Chemicals, which includes the following court-ordered schedule for the issuance of an Advanced Notice of Proposed Rulemaking (ANPR) regarding PCB transformer fires (18): ANPR: March 1984 Proposed Pule: October 1984 Final Rule: July 1985 The objective of an ANPR is to present data that indicate a reason for concern and, more importantly, to solicit data for the Proposed Rule. The major elements of the ANPR include: o Description of risks associated with PCB transformer fires through analyses of Binghamton, San Francisco, Chicago, Syracuse, etc. events. o Description of number and distribution of PCR transformers, o Solicitation of data on number and location of such electrical equipment. o Presentation of information on other lesser-known fires, o Presentation of estimates of frequency of fires, o Solicitation of data on other fires and frequency of other fires, o Discussion of PCDF/PCDD formation (and PCBP, PCCY (crysenes), PCDPE, PCPY, etc. where data are available on these compounds), o Solicitation of data on mechanisms of formation, o Presentation of possible regulatory options, o Substitutes o Retr off 11ing o Fire hazard inspections o Costs/benefits of various mechanisms to reduce spread of PCBs, PCDFs, PCDDs, etc. from fires - use of early warning protection devices -16- Currently, the EPA Office of Research and Development (ORE), in support of the Agency's Dioxin Strategy (18), released publicly on December 15, 1088, is planning_to conduct research on PCR fires, which will cover three areas: (a) the chemistry of PCE fires and a theoretical discussion of products of thermal stress based on composition of askarel used; (b) emergency response protocols for firemen, including protective clothing (this research will be conducted in cooperation with NIOSH); and (c) practical remedial measures for building cleanup. As a result of my participation in the preparation of the Dioxin Strategy document and in several Agency dioxin workgroups, including the Dioxin Disposal Advisory Group and the PCB Transformer Fires Workgroup and based upon my expertise concerning the subject matter (20), I believe that I enjoy a perspective that few EPA technical staff have. Because of this, I can relate to you the following facts: Given that chemical production facilities in the U.S. no longer produce 2,4,5-trichlorophenol (the most significant historical source of 2,3,7,8-TCDD), I can state that soot produced as a result of PCB transformer/capacitor fires contains the highest concentrations of PCDFs and PCDDs (the latter only if chlorobenzene diluents are present in the askarel mixture) found in the U.S. today; on a weight basis, however, municipal combustion devices account for the largest quantity of PCDFs and PCDDs produced currently. The soot from the Binghamton fire was evaluated by the New York State Department of Health in tests using chick embryos in 1981 (21). Results were positive. In other words, the PCDDs and PCDFs in the soot were not inactivated (as in the case of fly ash from an incinerator or by activated carbon) as demonstrated by the chick embryo fetotoxicity and teratogenicity tests performed. The soot can therefore be considered toxic and nay contribute to "environmentally induced or promoted cancers, reproductive abnormalities, immunologic deficiency, and possibly premature death from infection, neurologic and gastrointestinal system pathology and possibly, hy elevating serum triglyceride and cholesterol levels, excess or avoidable cardiovascular and cerebrovascular pathology" (22, p. 678). I thus stand firmly behind the convictions that firemen responding to such incidents must have the most up-to-date information at their disposal and that remedial methods employed must be practical, sound, and effective. As a result, EPA-ORD is in the process of securing PCB samples from Binghamton, NY, Chicago, IL, San Francisco, CA, and Syracuse, NY. The EPA analytical laboratory in Cincinnati, OH will conduct a chlorobenzene isomer screen on the samples together with honologue analyses for PCBs, the purpose being an attempt to correlate PCOOs and PCDFs content of soot and wipe samples (in the vaults) with chlorobenzene and PCB content in the transformer fluid. The information gathered will be shared among the electrical utilities, insurers, firemen associations, EPRI and NIOSH. In closing, I wish to share some recent and quite pertinent information. The NIEHS/NTP has concluded two animal studies involving bioaccumulation of 2,3,7,8-TCDO from contaminated soils and has submitted these papers (23) to Science for publication. These papers conclude that 2,3,7,8-TCDD in soil from two sites in Missouri, namely. Times Peach and Minker-Stout, is absorbed in a highly efficient manner (>502) and that 2,3,7,8-TCDO -17- -contaminated soil presents a hazard to humans if ingested. Thus, further laboratory evidence has been amassed regarding potential risk to humans for 2,3,7,3-TCDD. I believe that this audience is sufficiently astute to comprehend the long-term implications of these investigations. References 1. Chemical Week. September 1, 1982, p. 14. 2. Harless, Robert. Deposition in Lowe v. Norfolk X Western Railway Company, Circuit Court, Third Judicial Court of Illinois, Madison County, No. 79-L-810. 3. Kleopfer, R.D., Bunn, W.W., Yue, K.T., and Harris, D.J. (1982). "Occurrence of TCDD in Environmental Samples from Southwest Missouri." Paper presented at the 184th ACS National Meeting, Kansas City, MO, September 14, 1982. 4. Anonymous (1983). "57 Missourians File $684 million Dioxin Suit." Post Tribune. Jefferson City, MO, November 29, 1983. 5. Anonymous (1983). "Missouri Dioxin Suit Seeks $1.8 billion." New York Times, New York, NY, December 17, 1983. 6. Rappe, Christoffer and Buser, Hans Rudolf (1981). "Occupational Exposure to Polychlorinated Dioxins and Dibenzofurans" in Chemical Hazards in the Workplace--Measurement and Control, ACS Symposium 'Series No. 149. 7. Leng, M. L. (1979). "Comparative Toxicology of Various Chlorinated Dioxins as Related to Chemical Structure" in CIPAC Proceedings Symposium Series I, Heffers Printers Ltd., Cambridge, Engl and. 8. Safe, 3.,et^l_. (1982). "PCBs: Structure-Activity Relationships." Paper presented at the Symposium: "Recent Advances in Exposure, Health, and Environmental Effects Studies of PCBs," Bethesda, MD, May 12-13, 1982. 9. Letter of October 31, 1983 from Paul K. Hildebrandt, D.V.M., Tracor Jitco, Rockville, MD, to E.E. McConnell, NIEHS/NTP, Research Triangle Park, NC, subject: Review of NCI Carcinogenicity Study of Hexachlorodibenzo-p-dioxin in Rats. 10. Rappe, Christoffer and Marklund, Stellan (1982). "Thermal Degradation of Pesticides and Xenobiotics: Formation of Polychlorinated Dioxins and Dibenzofurans." Department of Organic Chemistry, University of Umea, (Jmea, Sweden. 11. Letter of October 27, 1982 from Stanley A. Salisbury, NIOSH Region IV to Richard Duffy, International Association of Fire Fighters, subject: PCB Transformer Vault Fite, Miami, FL. -18- 12. Memorandum of October 1, 1982 from G. Choudhary and J. C. Posner, NIOSH, Cincinnati, OH to Kevin McManus, NIOSH Region I, subject: PCB Soot Analysis from Fire at U.S. DOL-OSHA. 13. Rappe, C., Marklund, S., Bergqvist, P.-A., and Hansson, M. (1982). "Polychlorinated Dioxins, Dibenzofurans and Other Polychlorinated Polynuclear Aromatics Forming During Incineration and PCB Fires." Department of Organic Chemistry, University of Umea, S-90187, Umea, Sweden. 14. Rappe, C., Marklund, S., Bergqvist, P.-A., and Hansson, M. (1982). "Polychlorinated Dioxins (PCDDs), Dibenzofurans (PCDFs) and other Polynuclear Aromatics (PCPNAs) Formed During PCB Fires." Chemica Scripta, Vol. 20, pp. 56-61. 15. Health Hazard Evaluation Report: Our Lady of Visitation Elementary School, Cincinnati, OH. NTOSH Report No. HETA 81-227-915, July 1981. 16. Letter of July 26, 1982 from John R. Kominsky, NIOSH, Cincinnati, OH to Darrell E. Anderson, State of Minnesota Department of Health, Minneapolis, MN, subject: PCB Fire at Hill-Murray Hiah School, St. Paul, MN. 17. Vuceta, J., Marsh, J.R., Kennedy, S., Hildemann, L. and Wiley, S. (1983), "State-of-the-art Review: PCDDs and PCDFs in Utility PCB Fluid." Prepared by SCS Engineers, Inc. for the Electric Power Research Institute, Palo Alto, CA. EPRI CS-3308, Research Project 1263-11, November 1983. 18. Memorandum of October 11, 1983 from Martin P. Halper, ERA Exposure Evaluation Division to Irwin P. Baumel, EPA Health and Environmental Review Division, subject: PCB Transformer Fires in Buildings. 19. Environmental Protection Agency (1983). "Dioxin Strategy." Office of Water Regulation and Standards and Office of Solid Waste and Emergency Response in conjunction with the Dioxin Strategy Task Force, Washington, D.C., November 28, 1983. 20. desRosiers, Paul E. (1983). "Remedial Measures for Wastes Containing Polychlorinated Dibenzo-p-dioxins (PCDDs) and Dibenzofurans (PCDFs): Destruction, Containment or Process Modification." Ann, occup. Hyg., Vol. 27, No. 1, pp. 57-72. 21. Seely, Hart (1983). "The Building That Won't Come Clean." The Syracuse Herald, July 31, 1983. 22. Schecter, Arnold (1983). "Contamination of an Office Building in Binghamton, New York by PCBs, Dioxins, Furans, and Biphenylenes after an Electrical Panel and Electrical Transformer Incident." Chemosphere, Vol. 12, No. 4/5, pp. 669-680. 23. Letter of November 9, 1983 from Edward N. Brandt, Jr., M.D., Assistant Secretary for Health, to Lee Thomas, EPA, AA for Solid Waste and Emergency Response, subject: NIEHS/NTP Studies on Bioavailability in Guinea Pigs and Rats of Dioxin in Soil (with two abstracts submitted to Science for publication.) -19- URL 04203 URL 0420*4 eZ-&  . ' v-v V. - ,{^i> / V.?:'/, . ' :iv : -T V* - 'r -,:v. "* - >- r4-A\ 4*-'-* SMOKE TOXICOLOGY A SPECIAL REPORT c. Where N the early morning of There's IMarch 6, 1982, fire broke out in room 404 of the Westchase Hilton Hotel in Smoke, Houston. The presumed culprit: a carelessly placed cigarette. Lo cal fire officials described it as a "simple room fire," and the dep There's Ire uty fire chief reported that extin guishing the blaze was a "fairly straightforward" operation. The room's occupants escaped un j\.s synthetics harmed. But ten other guests on the same floor died in their rooms from smoke inhalation. increasingly replace natural Smoke--not flames--has for materials in buildings, angiy many years been recognized as the primary killer in fires. Of the debate swirls around whether roughly 7,500 fire fatalities in the this heightens the danger United States each year, smoke fells more than 80 percent. Tra ditionally, nearly all smoke-in offires and whether any thing can--or should-- halation deaths have been summarily attributed to carbon be done. monoxide, a toxic gas produced during the combustion of essen tially everything that burns. However, researchers from the BY LINDA GARMON Foundation for Fire Safety pieced together a different pic ture of the Wesrchase fire. According to Merritt Birky, director of research at the foun dation during the investigation, blood samples taken from the victims did show elevated levels of carbon monoxide, but they were not high enough to be the direct or sole cause of death. On the ocher hand, all the victims had elevated levels of hydrogen cyanide in their blood, and two had levels high enough to be le thal. The victims also had sus tained severe respiratory damage, suggesting exposure to hydrogen-chloride gas. These poisonous gases were generated by the combustion of synthetic materials in the room, says Birky. The foundation's tests indicated that the hydrogen cyanide came from polyurethane carper padding, nylon carpet and blankets, and a polyurethane cushion on an upholstered chair. mMs mm a33 *&*$** Li; % .w '"Wkms gj&: ,"KS. iV: PHOTO-. TOM ROSENTHAL,' KOUR BY FIVE s moke-- notflames--is the primaiy killer in fires, and toxic gases generated when synthetic materials bum may be making smoke even more deadly. iO Z t'O 'W The hydrogen chloride came from a poly* vinyl-chloride wall covering. Birky says the srudy concluded rhat deadly gases from the burning synthetics "contributed to most, if nor all," of the deaths. Representatives of synthetics manufac turers have assailed Birky's conclusions. For example. John Lawrence of the Society of rhe Plastics Industry says, "There were a lot of synthetic materials in the room where the fire occurred, hut rhere were a lot of burnable nonplastics, too." He notes that the Houston medical examiner listed inhalation of carbon monoxide and soor as the cause of death of every victim except for the people in one room, who had lethal levels of hydrogen cyanide in their blood. Even then, Lawrence says that blood-cy anide measurements are often suspect be cause the body itself produces some hydrogen cyanide. "We feel rhat plastics, w here properly used, do not present any increased hazard," he concludes. Clash of Interests The dispute over the Westchase Htlton tragedy is parr of a larger, long-standing, and heated controversy in fire safety. There is no question chat use of synthetics in buildings is rapidly increasing. "We live in a synthetic world." says Birky, where plastics and other synthetic materials have become commonplace in furnishings. Per haps less visible is the growing role of syn thetics m construction. In the mid-1960s, plastics represented only 2 percent of total building materials. By 1981, they had cap tured 10 percent of that market, according to Predicasts, a Cleveland market-research firm. And trends suggest that use of plas tics may grow even more during the rest of the decade. Has this shift heightened the danger of fires? Should the use of plastics and other sv nthetics somehow he regulated based on the toxicity of the smoke generated when they burn? Are laboratory tests wellenough developed to compare the smoke toxiciries of various products, and to be come the basis for selecting--and perhaps restricting--the use of furnishing and con struction materials? Answers to these questions have proved elusive, partly because combustion toxi cology is a complex science, hut also be cause huge economic stakes are involved and the issues have been clouded by cor porate m.ineuverings and rhetoric. The most vociferous charges have been ex changed between the Society of the Plastics Industry (SPI), a trade association, and Al lied Tube & Conduit Corp., which pro duces steel conduits used to contain and protect electrical wiring. Such conduits, along with pipes used in plumbing and to carry gas, have been tine of the fastest growth areas for plastics in the U.S. con struction industry. Against this backdrop, an increasing number of toxicologists, legislators, and fire-safety officials has begun to sort through the tough regulatory and scientific issues. Indeed, the smoke-toxicirv de bate--which really gained steam during the widely publicized string of hotel fires starting with the Las Vegas MGM Grand Hotel disaster in 1980--has reached white-hot intensity. Spurring the latest round is a report urg ing New York State to require manufac turers of building and furnishing materials to use a standard laboratory rest to iden tify the poisonous gases generated when their products burn. The report, prepared by Arthur D. Little, a consulting firm based in Cambridge, Mass., recommends that such information on toxicity be filed in a central data bank. The New York Legislature, following rhe 1980 fire at Stouffer's Inn in Harrison, N.Y., which claimed 16 lives, had asked ADL to ex amine the feasibility of regulating smoke toxieiry. The fate of this proposal is still uncer tain. New York Secretary of State Gail S. Shaffer is expected to recommend thar the state establish a pilot program requiring manufacturers of mattresses, furnirure, and interior finishings such as wall cov ering to test their products and submit the results to a data bank. However, she is ex pected to exclude construction materials. Should New' York adopt even this lim ited program--which is considered likely--it would be a landmark in firesafety regulation. Of course, construction methods and materials are already subject to numerous other fire-safety-related reg ulations. A multitude of building-code provisions calls for fire alarm systems, fire doors, fire escapes, fire extinguishers, and exit corridors. And the Consumer Product Safety Commission has set mandatory flammability standards for mattresses and carpets and voluntary standards for up holstered furniture. But precious few codes, standards, or laws specifically ad dress smoke toxicity. One emerging code involves plastic con duit--a tube, composed mostly of poly vinyl chloride, or pvc, that is used to enclose electrical wiring. Because it is more flexible and easier to insrall, plastic con duit offers an attractive alternative to its metal counterpart in certain construction situations. But concern over the risk of smoke toxicity prompted the National Fire Protection Association to take action. The 1984 National Electric Code--a model code published even- three years by the association, which local jurisdictions can choose to adopt--recommends that pvc conduits be permitted only in struc tures no taller than three stories. Some cit ies have already taken other steps. For example, New York Ciry spent S2 million in 1982 to replace with metal some of the pvc conduits in the subway system. Other regulations related to smoke tox icity include general proscriptions in sev eral stares and local jurisdictions to the effect that building materials cannot re lease combustion products more toxic rhan those of wood. But these laws, writ ten years before scientists began devel oping standard laboratory tests of smoke toxicity, go largely unenforced. However, about a half-dozen states are now taking a hard look at just how toxicity testing might be used to regulate a broad spec trum of products. What New York decides to do with the ADL report could set the stage for these other states to act. Report Gets Mixed Reviews The ADL study evaluated the dozen or so published methods for testing the toxicity of combusrion products, including one thar Birky helped develop when he was at the National Bureau of Standards (NBS). The study, led by Rosalind C. Anderson, concluded thar the most useful test is one developed by Yves Alarie and Anderson when she was at the University of Pitts burgh. Anderson said she sees no conflict of interest in recommending a test that she helped design; she also helped design the .NBS toxicity test rhat was rejected. In the Pittsburgh test, mice in a special chamber are exposed to smoke from burn ing materials. This method determines what's called an LC,,,--the amount of ma terial that produces a "lethal concentra tion" of smoke noxious enough to kill iO percent of the animals exposed for 30 min utes. (Anderson says a shorter period wouldn't address most fire situations where people are waiting to he rescued. PHOTOS. NATION AL BUREAU OK STANDARDS TECHNOLOGY RtVILW '1 URL 04208 and a longer period would probably kill all the mice.) The lower the LC,,, value, the more toxic the material. According to the Pittsburgh test, the LC,,, of Douglas fir, for example, is 31 grams, while that of wire coated with polytetrafluoroethylene (Teflon) is 3 grams. The ADL report recommends that man ufacturers submit LC,,, data on their prod ucts to a state agency, where the information would be accessible to archi tects, engineers, and the public. Anderson says the ADL study ruled out, for the time being, other regulatory uses of the data, such as bans on specific materials and re quirements for product labeling. Reviews of the report have been mixed. Firefighters and fire-safety officials have generally approved, though some say they would have preferred ADL to voice stronger recommendations, such as the use of LC,0 data to ban specific products. Critics, on the other hand, have charged that a smoke-toxicity data bank would be worthless. "The problem here is that the kind of data collected will be of no value in saving lives,*' said G.R. Munger. pres ident of the Society of the Plastics Indus try, in his comments to the New York Legislature. Simple, small-scale toxicity tests are not representative of the complex hazards of real fires, he said. In fact, Munger and others claim that such tests could sometimes lead builders to select products that ignite more easily or whose flames spread faster as a trade off against their lower combustion toxic ity. For example, pvc has largely replaced cotton as an insulating material for elec trical wires, in part because its higher ig nition temperature makes ir less likely to burn. "We think that's an example of in creased fire safety from using plastics," says SPl's Lawrence. He also points out that m3ny fires are caused by electrical short circuits, which often result from im properly grounded metal conduits. And while burning pvc plumbing has been im plicated--controversially--in some of the 83 deaths in the MGM Grand fire, he points out that a short in a metal conduit started the fire. Thus, even if tests show gross differences in smoke toxicity, the re sults should be interpreted with caution since other flammability properties are in volved in assessing hazard. Barbara C. Levin of the NBS Center for Fire Research agrees that an LC,,, data bank is unnecessary. In her comments to the New York State Legislature, she stated that "a toxicity test alone does not con stitute toxic hazard assessment." She noted that NBS is now developing a com puterized method for assesing the hazards of combustion that takes into account a product's rate of heat release, ignitability, and ocher fire-related characteristics as well as smoke toxicity. The method is ex pected to be ready in about five years. ADL's Anderson counters that, while more research will undoubtedly improve assessment techniques, the fact that most fire victims are being killed by smoke means we shouldn't sit idly by until a haz ard index is developed. And there is an other pressing issue. "As melodramatic as it sounds, firefighters are out there watch ing their colleagues being hurt and even die," she says. She cites a study by the National Fire Protection Association that found that firefighters say that fires are getting harder to fight. Fires burn faster and hotter, and smoke develops more rap idly and is thicker and more irritating to the respiratory tract. "There appears to be an increase in firefighter casualties from smoke inhalation," the association con cluded. "The smoke in today's fires . .. may be producing increased risk of inhal ation injury to firefighters as well as to building occupants." SP1 officials maintain that there is only anecdotal evidence to support the conten tion that fires are now more threatening because of smoke from burning plastics. They point to two SPl-supported studies-- one reported in March 1979 by the Har vard School of Public Health and the other in May 1981 by the Southwest Research Institute--that show high levels of carbon monoxide to be the most hazardous air contaminant detected by gas-sampling APRIL 1*!H A. ;7ncs*a*Ol equipment worn by firefighters. However, Birky says the SPI-supported studies are not only limited; they also do not explain why postfire investigations have turned up subletha! doses of carbon monoxide in victims' blood. Such doses were found not only in the Wesrch ase fire, he says, but also in the MGM Grand dis aster, where half of the 83 people who died at the scene were found to have subiethal carbon-monoxide levels. He acknowl edges chat such an effect has been uncov ered in only a few instances, "not because it doesn't occur, but because the follow up toxicological studies on the victims have not been thorough enough to dem onstrate this factor." (Birky has left the Foundation for Fire Safety, located in Rosslyn, Va., to start a fire-toxicology con sulting service in Boonsboro, Md.) Charges and Countercharges Calling this the most important question in fire safety, the foundation last year em barked on a national study to pinpoint which toxic gases are causing deaths by smoke inhalation. "We have developed a post-mortem protocol," says Thomas Casey, former executive director and now a consultant to the foundation, "and we are working with paramedics, medical ex aminers, and fire services to ensure that more complete autopsies arc performed on fire victims. For example, we specify that blood samples be drawn within three hours of the fire and that they be properly stored and handled." Thirteen cities, in cluding Seattle, Miami, Denver, and Dal las, are already participating in the study. Thus far, the foundation has collected data on 60 fire victims, but plans to gather d3ta on 2i0 before drawing conclusions. SPI officials are already skeptical of the study. They point out that the foundation is largely funded by the Allied Tube Sc Conduit Corp. and other members of the metal industry. These firms, according to an SPI statement, have "embarked on a `fear and smear' campaign against plastic products in order to win back [their] po sition in the marketplace." John Lison, vice-president and general counsel for Al lied, counters such charges: "Instead of developing safe products, the giant plastics industry has used its extensive public-re lations apparatus to attempt to turn what is a very vital question of public safety . . . into a seemingly commercial battle be tween two industries." "There's no doubt that this is a com mercial fight," says Gordon Vickery, pres ident of the foundation and former head of the U.S. Fire Administration. "I do not offer one ounce of apology for the funding of the foundation by the Allied Tube Sc Conduit Corp, We invite, as we have in the past, the plastics industry to support us in like manner." The impact of commercial interests can also be seen in recent actions of the Na tional Institute of Building Sciences (NIBS), created by Congress in 1974 to unify and improve the heterogeneous net work of U.S. building codes. When the rash of hotel fires brought burning plastics under close scrutiny, NIBS officials felt pressured to address this issue. In June 1982, they formed a 12-member task force to consider whether the results of labo ratory rests of combusrion toxicity, such as the NBS and Pittsburgh methods, should be incorporated into building codes. For example, a code could forbid the use of products judged by one of rhose tests to be more toxic than wood, unless those products are accompanied by earlydetection fire-protection systems such as smoke detectors and sprinklers. Wayne El lis, manager of industry standards for the H.B. Fuller Co., which makes synthetic adhesives, sealants, and coatings used in building construction, was named chair man. The task force also included Sl'l's Munger, two DuPont officials, and rep resentatives from Dow Chemical, Rohm 8c Haas, and Armstrong World Industries. Only one member---James R. Bell of the National Fire Protection Association-- was nor affiliated with a corporation, trade association, or the government. Later that summer, the task force hosted I'HOTOS. 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The task force, which has conducted several hearings on the smoke-toxicity is sue, will issue a final report this year that "may very well have recommendations for legislation," Butts says. Like the ADL re port to New York State, this one will prob ably call for establishing a data-gathering agency for combusion toxicity. "We need to have some kind of data bank; we need to use some kind of testing mechanism," Butts says. "Now, 'specifiers' [architects, engineers, buildings owners, and so on) have no information on which to base their decisions. They are making decisions that may be allowing buildings to become more dangerous, and that may be leaving themselves vulnerable to lawsuits." Butts also says that insurance companies, fear ing "their clients will find themselves in a toxicity lawsuit," may soon become in volved in rhe smoke-toxicity debate. This, he envisions, would provide a powerful impetus to the movement to establish pro cedures for testing the combusriun toxicity of building and furnishing materials. That's the best-case scenario, ADL's Anderson says. For a worst-case scenario, she draws parallels to the asbestos story. Information on the health effects of as bestos "had been there for years," she says. "Unfortunately, some of the people who were in positions to make decisions and change policy had only fragments of that information. That's the type of situ ation some people are saying is developing as we bring new products into buildings. There is the fear that we are stacking the inJoor environment with materials that, if we could only see all the combustion* toxicity data available, would be deemed unacceptable in terms of fire safety," Says Anderson; "I'm not suggesting we ban products--we don't have enough data yet to take this regulatory route. And product labeling is good for only about 30 seconJs; once you have the wallpaper up. you've forgotten what's on the label. But if we had a central!) located combustiontoxicity data bank, we could start drawing useful conclusions." LISDA CAK.MO.V ij chemistry eJrlor of Sci ence News. She is uaw.i fellow in ihe Vunnei-jr Bush Fellowships in the Public V'lJcrstjinling of Technology juJ Science a/ Al./.T. TOMORROW'S LEADING SOFTWARE PROFESSIONALS ARE EARNING M.S.E.'S TODAY. At the Wang Institute ofGraduate Studies, students in the Master ofSoftware Engineering (M ,S.E.) program are preparing for positions ofincreasing technical and managerial responsibility. Studentsat the Wang Institute: study technical and managerial aspects ofsoftware development and maintenance; learn to plan, organize, and supervise software projects; work in teams in a cooperative environment; use a large and growing collection ofsoftware tools to analyze.specify.design, implement, test, integrate, and modify- software products; acquire the theoretical foundations needed to assess new developments and stay current follow ing graduation; interact closely with faculty members who have significant industrial and academic experience in software engineering; the current student teacher ratio is "to 1. Both fulltime and part-time programs ofstudy are available. More than 20 companies are currently sponsoring students at the Wang Institute. Graduate assistantships arc available for unspon sored full-time students. Educational programs at the Vi ang Institute are open to all qualified applicants. For more information, call or write: Janis Ackerman School ofInformation Technology Wang Institute ofGraduate Studies TyngRoad Tvngsboro.MA 018"9 Telephone (61") 6-i9-9"31 Please send me additional information about the school s Master ofSoftware Engineering degree program. th-484 Name: Business Address: ---------------------------------------------------------------------- ---------------- Home Phone;Bus Phone: Yrv software dev elopment exp.:---------------------Degrcef s >------------------------------------Field(s): -- TKHNOLOCY RtVlLW ?I URL 04211 1 TOXICITY OF COMBUSTION PRODUCTS: CURRENT KNOWLEDGE FREDERIC B. CLARKE, III In THE MARCH 19S3 ISSUE OF FIRE JOURNAL.*1 * the NFPA published a report on the* toxicity of the prod ucts of combustion. T!u* report is the result ofu \ear that the N FPA Standards Council's Committee on the Toxic ity of the Products of Combustion spent compiling and analyzing a vast amount of technical information. The Council's report sets forth a number ofsignificant princi ples and policies for both NFPA committees and for the fire community in general. Those who are unfamiliar with combustion-product toxicology max have been surprised to discover that a subject that excites so manv Questions provides so few clear answers. There are a number of reasons why this is so. The field is a new one. scarcely ten years old. Fur thermore. the most desired answers cannot be supplied by combustion toxicology alone, but must come from contributions from several different fields. It is likely, therefore, that combustion-product toxicity will occupy a prominent place in firesofety discussions, within the NFPA or elsewhere, for some time to come. Memlnrs of the NFPA will increasingly feel compelled to become acquainted with the subject, perhaps as par ticipants in the discussion and certainly as informed pro fessionals. Tins article is a brief introduction to combus tion-product toxicity-- the capabilities, limitations, and central issues. It supplements a comprehensive review of the subject prepared by Benjamin/Clarke Associates for the \ FPA Committee on the Toxicity of the Products of Combustion. (Copies of the review document are available from the NFPA.) 1929. In that fire, nitrocellulose film (then a newlydeveloped material) played a major role. For the first time, a major fire had produced considerable quantities of toxic combustion products, in addition to the* ubiqui tous oxides of carbon. Although the oxides of nitrogen produced by this material are not prominent in today's spectrum of common combustion products, the incident foreshadowed a concern that would become acute with the avalanche of synthetic materials in the 1950s and 1960s: how to assess the risks associated with combustion products from a multitude of new materials. The NFPA first began to inquire into the detailed ef fects of smoke in fires in the 1950s.* Since that time, a significant amount of literature has been published, primarily in the medical field, on the treatment of smoke inhalation victims. Cornish,9 Boettner.4 and Autian5 called specific attention to the threat that might arise from new, synthetic materials that became an increasing part of building fire loads in the 1960s. How ever, their concerns were prospective, arising from the recognition that synthetic materials differ chemically from traditional materials, rather than retrospective, i.e., arising from fire experience. We depend today on a variety of polymeric materials -- both man-made and naturally-occurring -- and the smoke produced when these materials bum can differ in its toxicity. While experience had taught us that there is no such thing as "healthy" smoke, it was suspected that different materials might produce combustion products for whose toxic properties we were unprepared. Some common families of polymers, both natural and syn- Early Concerns Over Toxic Combustion Products The first major recognition that the environment might pose threats from fire that were not anticipated by past experience came with the Cleveland Clinic fire in Dr. Clarke is President ot Benjamin.Clarke Associates. Inc.. Ken sington. Maryland. 1 "Report of the Committee on the Toxicity of Products of Combus tion to the Standards Council of the National Fire Protection Associa tion," Fine journal. Vol. 77, No. 2 (March lbb.1i. pp. 21-27. 84 FIRE JOURNAL -- SEPTEMBER 1983 * NFPA Committee on Fire Cas Research. "Fire Cos Research Report; Report of Research by Arthur D. Little, Inc.,'' SFP.\ Quar terly, Vo). Q4.5, 1952. pp. 290-306. * H. Cornish, and E. Ahar. "Toxicity of Pymlyxis Products of Vinyl Plastics." Archives of Envronmental Health. V oi. 10. No. 1. 1969. pp. 15-21. * Edward A. Boettner, and Benjamin Weiss. "Analytical System for IdentiRinj; the Volatile Pyrolysis Products of Plastics. ` American In dustrial Atrociafion Journal, Vo|. 26. No. 6. 1967. pp. 535--10. * j. Autian. "Toxicologic Aspect of Flammability and Combustion of PoU-meric Materials."Journal of Fire and Flammability. Vol. 1. 1970, pp.'239-66. URL 0421 rO thelic, are listed in Table 1. along with the combustion products that they may, on the basis of their chemical composition, possibly produce. The degree to which these products actually present new risks was unknown. Tlie first statistical examination of fire fatalities came from the United Kingdom. Bowes pointed out in. 1971 that, while there had been only a modest increase in overall fire casualties in Britain in the previous ten years, a relatively large increase had occurred in the number of smoke inhalation injuries. Bowes suggested that in creased amounts of synthetic polymers in buildings might account for this change. The British report dis counted the possibility that smoke from modern fires was any more toxic than smoke in earlier fires, since survival rates of smoke inhalation victims were unchanged. However, even this report contained some uncertain ties. In order for one category of injury to increase with out significantly changing the total number of injuries, it is necessary for burns, the other major category of fire injury, to have decreased in Britain during the same time period and there are no obv ious reasons for this to P. Bowes. "Smoke and Tavicitv Hazards of Plastics in Fire," Annals of Occupational Hygiene, Vol. 17, 1974, pp 143-157. occur. Other, more recent studies7 in the United King dom have shown that a large percentage of supposedly burned fire victims were actually victims of smoke inha lation, as well. Since postmortem examination of fire fatalities is a Fairly recent procedure. Bowes conclusion would be strengthened if it were known to what extent burn fatalities in early years were later counted as smoke inhalation fatalities. Systematic laboratory investigations of the toxicity of combustion products began in the early 1970s. Although there was already a large amount of chemical data, as well as preliminary biological experiments, it was recog nized that a much more systematic approach was re quired. Toxicity'*1Part in Today'* Fire Problem The sheer variety of combustible materials now in our everyday environment means that there is also a very broad spectrum ofcombustion products in typical smoke 1 VV. Harland. and VV. Woolley. "Fire Fatalitv Study, l/rmersiw of Cluacuw." Building Research Establishment. BBE Information Paper IP lb-79. London. August 1979. URL 04213 Polymer Same AcrylonitrileButadiene-Sri rene (ABS; Cellulose Keratin (protein* Polyacrylonitrile (PAN) Polyamide (nylon' Polymethylmethacrylate iPMM.V Polyphenylsulfone Poivethvlene (PE. HDPE! Polystyrene (PS. HIPS) Poktetrafluoroethvlene (PTFE) Polyurethane (PU) Polwinylchlonde (PVC) Table I. Some Common Polymers and Their Major Combustion Products Chemical Elements Present Commonly Found in Possible Combustion Products In Addition to CO.COi C. H. N C. H. O C. H. O. N. S C. H. N Appliances, phone components, pipe, engineering, plastic applications Wood, paper, cotton, jute Leather, wool HiO. HCN HjO. acrolein HjO. HCN Modacrvlic fiber HjO. HCN C. H. O. N C. H. O Engrg. plastics applications. carpeting Window panes, lighting fixtures HjO. NHj. HCN HaO. aldehydes C. H. O. S C. H C. H C. F Engrg. plastics applications Kitchen ware. upholstery, carpeting Appliances, cabinets. foam insulation, engrg. plastics (high impact! Coatings, wire insulation C, H. O. N C, H. Cl Rigid insulation. flexible seat cushions Upholsterv, wire coating, pipe, wall and floor covering HjO. SOa HjO. aldehydes HjO. aromatic hvdrocarbons HF. COFa. fluonnated organics HaO. HCN. isocyanates HjO. HCI. aromatic hydrocarbons FIRE JOURNAL --SEPTEMBER 1983 -85 tod.iv. It dues not follow, however, that the fire problem worsens as the use of synthetic materials increases. Since the number of fire deaths in the United States has de** dined significantly in recent years, one could argue, on the basis of those statistics, that modern materials result in increased safety. However, it is also conceivable that the decline in deaths would be even larger for a different mix of combustible materials, so such an argument is, at best, speculative. One due to the real situation may come from the fire experience of other countries. It is often noted that the US death rate is considerably higher than those of west ern European countries and Japan. Recently, building materials and furnishings that have been commonplace in this country for a number of years have appeared increasingly in Europe and Japan. If the US fire loss record is inescapably a result of the kind of materials that burn, one would expect to see dramatic increases in the fire death rates in these countries as their built environ ment and furnishings become increasingly similar to those in the United States. To our knowledge, this has not yet been observed. From a purely statistical point of view, there is little evidence to support the hypothesis thatj>resent-dav materials^ and the combustion products associated vviTfTthem "have exacerbatecTthe !Tre"prdB- Rowever. gross statistics do not provide the details needed on the causes of fire deaths. An investigation of the causality of fire deaths must include both the imme diate causes of fire fatality and the contributory causes, i.e., the reasons why the persons received alethal expo sure. Table 2 summarizes this information for fire deaths not involving bums. Note that the immediate causes of fire fatality shown in the table are poisonings by airborne chemical agents, or asphyxiation by oxygen depletion. Table 2. Causes of Fire Deaths PutsiWc Reasons for Lethal Exposure Vision oli'ieuratiou Irritants impeding visum and or escape capability Motor and/or judgment impairment Possible Immediate Causes of Fire Fatality Carbon monoxide poisoning Carbon dioxide intoxication and oxygen depletion Poisoning by other airborne fire product(s) The search for contributory causes is more difficult. For example, it is known that smoke can impair visibil ity, and thereby, it is suggested, impede a person's abil ity to escape. In such cases it is tempting to postulate other impairments to escape, such as irritants or incapaeitunts. Irritants might so preoccupy the victims that they no longer concentrate on escape; other incapaci- M. Kurter. "Fire Loss in the United States During 1980." FIR journal. Vo! 75, N. 5 (September 1981). p. 60. 86 FIRE JOURNAL --SEPTEMBER 1983 tants may disorient and confuse them. Although there are clinical methods for determining carbon monoxide poisoning, poisoning by other airborne fire products is n re difficult to detect; a potential agent must be iden tified before it can be analyzed, and a method of anaK sis must exist. The lethality of carbon monoxide, w hich seems to be present in virtually all accidental fires, has long been known. The presence ofcarboxyhemoglobin (COIlb) in levels equal to or greater than 50 percent of total hemo globin is generally assumed to be lethal.'10 1M1 any studies have also appeared11 on reduced biological, and presum ably motor, functionality of people exposed to sublethal amounts of carbon monoxide. Therefore, this sas may function as both the cause and the reason r fire fatalities. A check of carboxyhemoglohin level in the blood is generally the first step in determining the cause of death in fire. Postmortem detection of chemical irritants is uncom mon. If the irritant is pulmonary, the lungs can be exam ined, and pulmonary edema (the accumulation of Huids in the lungs) can be taken as evidence of pulmonary injury-. Howev er, detecting the actual agent of irritation is generally not possible. Pulmonary edema, for examFleT can be caused by aldehydes, such as acetaldehyde and acrolein from wood, hydrogen chloriJe. Tydrogen fluoride, and their precursors."Furthermore, death froin pulmonary edema can occur tip to several days after ex posure to the fire.12 In 1972. a major study of fire deaths in the state of Mary land was undertaken by The Johns Hopkins Uni versity- Applied Physics Laboratory-.13 Detailed postmor tem examinations were made of 511 fire fatalities occur ring ov er a five-year period. These comprised 64 percent of the statewide fire fatalities in Maryland during that -time. The study has some bias toward urban populations, but can generally be taken as the most comprehensive. and only systematic, study of fire fatalities conducted in the United States. The overall breakdown of Man-land fire fatalities by medical cause of death is shown in Table 3. The studyassumed that those victims whose bodies contained more than 50 percent carboxyhemoglohin died of carbon A. Cooper. ed.. "Carbon Monoxide; A Bibliography with Abstracts." US Dept, of Health. Education and Welfare, Public Health Service Bib. No. 68. 1968. p. 40. 10 This is the value generally accepted by forensic pathologists. However, the victim's physa-al condition, ate, and level of activity during fire exposure can have significant effects on the level found tn pistmortcm examination. 11 Cf. R. Stewart, et J., "Experimental Human Exposure to Car bon Monoxide." Archives of Environmental Health* Vnl. 21. 1970, pp. 154-164; and R. Stewart, et id., '`Experimental Human Exposure to High Concentrations ofCarbon Monoxide. Archives of Enteonmental Health. Vol. 26, 1973. pp. 1-7. 11 B. Zikria. et al., "Smoke and Carbon Monoxide Poisoning in Fire Victims." Journal of Trauma, Vo!. 12, No. 6. 1972. pp- 641-645- l* W. Beri and B. Halpin, "Human Fatalities from Unwanted Fires," NBS grant/contract report NBS-GCR-158, 1979, p. 57. h z w ia n Table 3. Clinical Causes of Death, State of Maryland, 1971-1977 Category Cfjnvc Percent of Dc 1 Burn-. 2 C.lll'oii nniiiOMilr alum- -CO 1 ll greater tli.in 30 |s r'iil' 3 C.tl I'un m.iiiosuLami other l.ntnrs* 4 Flt .it .mil carlioii munoxule nut wunificautlv involved Vi 4-S 16 IS 11 id iiilid in this category are victims x\ ith CO I III In-tueen 30 and 3d percent. [ilus cv.mide .uul nr pre-eviiUiin; heart discase. rnnnoxide poisoning. Searches for additional evidence of combustion-product toxicity focused on the fire fatalities that did not involve lethal levels of carbon monoxide or lethal heat exposure: categories 3 ami 4 in the table. Category 3 reflects the effect of contributory causes ^preexisting heart disease or simultaneous exposure to hy drogen cyanide1 on susceptibility to carlxjn monoxide. Unfortunate!}, the stud} did not record the relative im portance of these two very different contributors. Cate gory 4 includes those dying of all miscellaneous causes, including heart attacks, fulls, and the like. About half of the category, some JO percent of thejotalfire deaths, is, made up of those deaths that are essentially unexplained bv carbon monoxide, bunts, or other clear cause, and. includes those with s\ mptoins expected from pulmonary irritants. This portion of the fire deaths contains the major unknown effects of toxic combustion products. UitfortunateK. we have no way to determine whether this 10 percent is a recent phenomenon or whether there has always been a similar portion of fire deaths that has been essentially unexplained. Measurement Systems For Toxic Combustion Products The early discussions of combustion toxicology were characterized by debates on whether chemical analysis or animal testing was the bettor approach. As capabilities for chemical analysis improved, it became clear that a very large number of py rolys is produc ts could be gener ated even from materials whose original composition was well-characterized and relatively simple. Early work ers14 identified over 50 different compounds produced by the pyroly sis of a single suinple-of polyvinylchloride. Wood produced similar results.15 This complexity con 14 Edward A. Boeltner. and Benjamin Weiss. "Analytical System Sir Identity mg the Volatile* Pyrolysis Products uf Plastics, " American Industrial Hygiene Association Journal, Vo|. 26. No. 6, 1967, pp. XV5-M). 15 National Aeudcmv of Sciences. Proceetlint>i of the International Symposium on Physiology anti Toxicological Aspects uf Combust ion Products, Salt Lake City. Utah, March 1974. vinced early investigators that they could not confidently predict the toxicity of smoke by chemical analysis. Another draw back ofchemical analysis is that, without biological tests, there would be no way of detecting',! single toxic product unless its existence had been previ ously predicted. In 1977. an unpredicted toxic product was reported by- Pctajan and coworkers at the University of Utah 16 This toxin, identified as a bicyclic organic phospha; was produced by the reaction of a phosphorus-containing fire retardant with one of the components of the urethane formulation tested. The product was first detected by its acute effects on labora tory animals, including epilepsy-like seizures, as well as observable psychomotor effects on sev eral of the human investigators. Fortunately, the urethane formulations that produce the toxic agent are not reported to Ik* commercial prod ucts. Actually, it was later discovered that the sup posedly highly toxic agent was. in fact, no more potent than many other combustion products and was distin guished principally by the unusual nature of its eflects. Nonetheless, reports of this toxic agent created a great stir at the time, and served to resolve, at least for the moment, any lingering controversy between the chem ists and the animal testers. It was convincing evidence of the need for a screening device to identify' materials that produced unexpectedly toxic smoke. The development ofa screening-type of test to identify materials that produce highly toxic combustion products is commonly viewed as easier to accomplish than a test that determines how smoke from each burning material in a fire contributes to the overall toxicity hazard. How ever, whatever their specific goals, all such tests meth ods have several elements in common: a combustion and pyrolysis method, an exposure chamber, and toxico logical measurements. Combustion and Pyrolysis Method The method chosen to convert the solid sample into airborne materia! for exposure to test animals is crucial in determining the relation of any lalsoratory test method to full-scale situations. In general, one cannot simply build the expected room fire and expose laboratory animals, because the heat of the smoke will mask the toxic effects. If the smoke is cooled prior to the exposure, one risks condensing out components of the smoke before they reach the exposure chamber. Although there are almost as many methods of generating the smoke as there are test methods, the methods fill! into three main categories: tube furnaces, open cups, and radiant heat. Methods employing tube furnaces generally contain the sample in a glass tube that is inserted in a furnace or ' J. Pctjjati. et al., "Extreme Toxicity from Combustion Products of a Fire Retarded Polyurethane Foam." Stumer, Vol. 167, 1973. pp. 742-744. FIRE JOURNAL --SEPTEMBER 1983 H7 some other heating device whose temperature can be controlled. A stream of air or nitrogen is passed through the tube to earn.- the products to the exposure chamber and to support combustion if it occurs. The smoke gen erated in this way is frequently mixed with additional air after it leases the heated zone to provide cooling and dilution. The advantage of using this approach is good temperature control. In the open cup furnace, the sample is placed in a glass or steel cup and heated by heating the cup. This method allows smoke to be transported to the animal exposure chamber by convection. It permits the addition of a sam ple after preheating, so that the temperature that the sample encounters can be closely controlled. There are two principal disadvantages to this method. First, heat transfer to the sample is inefficient, especially for lowdensity materials. Second, and more important, access of air to the sample is hampered, especially when the sam ple fills the cup. and in such cases burning often occurs only with difficulty. In both furnaces and cups, heat is supplied to the sample largely by conduction from the hot walls of the apparatus. It has been suggested that the burning condi tions that result are not typical of most real fires, where radiation is the principal mode of heat transfer. Methods that use radiant heat avoid this difficulty. In addition, radiant heat appears to be the best method of exposing nonhomogeneous materials such as composites, since their combustion in either cups or tubes often re quires them to be cut into small pieces or pulverized. The utility of a given method of pyrolyzing or burning the sample depends largely on what the test method is intended to accomplish. One cannot, for example, take it for granted that combustion products in real fires will be similar in detail to those produced in tests, because real fires usually involve open flame, while none of the commonly used test methods employ Fames as a major heat source IrTat least one case, polytetrafluoroethylene. the use of a flame instead of an electrical heating method can reduce the toxicity of the smoke about one thousand fold.17 Although this is probably an extreme example, it suggests that one must decide whether it is important to maintain laboratory conditions similar to real fire condi tions. If actual fire conditions are intended, particular care must be used in interpreting test results. Exposure Chamber Exposure chambers, and the method used to move the combustion products to the chamber, vary considerably. In some cases, test animals are placed entirely in the chamber, a situation that approximates reality, in other tests, they are exposed "nose-only." The Litter method reduces heat stress on the animals, keeps them from ingesting combustion products orally or breathing through another animal's fur, and allows easier in strumentation of the animals. ,, Beyond their size and materials of construction, expo- i sure chambers differ principally by being either "static." where the entire charge of smoke is caught and held during the exposure, or''dynamic." where a continuous j flow of smoke from the combustion chamber is provided. Both types of chambers have their supporters and theii^ advantages. One attractive feature of the static chamber is that it permits read) calculation of the smoke concentration, since the volume is fixed, A schematic representation of a generic, static-type test apparatus is shown in Figure 1. The static arrangement simulates, to some degree, expo sure to a fire in or near the room of origin, in situations where the smoke accumulates, i.e., there is limited flow-through ventilation. One disadvantage is that the static chamber is impractical to use for studying pyrolysis products at a vary ing temperature over the course of the experiment, since the chamber contains the smoke gen erated over the entire temperature range. Another drawback of the static system is that considerable atten tion must be paid to ensuring uniform distribution of the smoke throughout the chamber. Finally, the chamber must be large enough so that oxygen will not be depleted during the course ofcombustion and carbon dioxide from the animal's respiration will not build up to interfering levels. CemBwation Dane* Oittuiian/ Canvactlon Van* Anmii Eieatu'i On I Samanngl X Anairm Animal I Animal Womtonng 0v>M Figure 1. Schematic representation of state-mode combustion prod uct toxicity test apparatus. The dynamic chamber design, schematically depicted in Figure 2, is more amenable to temperature variation and also permits dilution of the smoke. Thus, it is gener ally a good deal fester, and thereby less expensive, to screen an unknown material using a dynamic system. Toxicological Measurements n p i04216 lT S. Williams, and F. Clarke. "Combustion Product Toxicity: De pendence on the Mode of Product Generation.*' Fir* and Materials, Vol. 6. Nos. 3 and 4. 1982. pp. 161-162. 88 * FIRE JOURNAL--SEPTEMBER 1983 The variety of toxicological measurements made on the test animals is almost as large as the number of tests methods in existence. Most of the tests share the concept URL 04217 Pump Figure 2. Schematic representation of dynamic mode combustion product loMill', test app.ir.itMs. of lethality, although there is disagreement on whether time-to-death. lethal dosage, or both are the most ap propriate measures of potency. In addition, there are a number of techniques for determining incapacitation of the test animals, although the utility of existing incapaci tation techniques is still under discussion. Classical toxicity studies of lethality center around the concept of dose-response, in which a chosen biological function is monitored as a function of the dose of the toxic agent. Lethality is the "customary starting point" of most toxicological investigations. Relating the fraction of an animal population succumbing within a fixed time to a given amount of agent yields a dose-response curve for lethality. The number generally reported is the dose that kills 50 percent of the animals. In inhalation toxicology, dosage is normal!) expressed as the airborne concentration to which the animal sub jects were exposed, and tints "LC50" refers to the concentration at which 50 percent of the test animals succumbed. For dynamic systems, the actual smoke concentration at any time is nett generally known di rectly. so that data reported by the two systems gener ally cannot be directly compared. Lethality data are generally presented on a logarithmic scale, partly because different materials can have measured lethalities that span several powers of ten. In addition, the reproducibility of such meas urements is low, and potencies must differ by a factor of 3 to 5 before it is possible to attach any significance to the findings. Time-to-lethality is also an important concept, since the outcome of any life-threatening fire is determined by its relationship to the time needed to escape. For many materials, the product of dosage and time-to-death is a constant, e.g.. animals live twice as long when exposed to half the dose. At present, combustion-product lethal ity is determined by both time and dosage. The desirability of an incapacitation monitor has long been recognized, since escape capability is so important in firesafety. In recent years, a number of approaches have been developed. We shall examine just a few. The use of a tumble cage or variants, in which the animal is placed within a rotatable, wheel-like cage, is the basis of measurement in two test procedures. In one test, incapacitation is the point at which the animal can no longer maintain its equilibrium; in the other test, it is tile point at which the animal no longer shows an inclina tion to turn the wheel. Another approach involves monitoring the animal s av oidance of a tnild electric shock. Avoidance can Ik****Un conditioned ability to move to an mielcctrificd location in the apparatus^-1' or. if the animal is restrained, it can Ik* the ability to keep a fiK)t raised and out ofcontact with a charged electrical plate.20 The latter is the so-called "hind-leg flexion" response used in the development ol two test methods. Although all of these methods have been or are now ! incorporated in some test procedure, they have }>een found to vary in sensitivity depending on the type of smoke being evaluated. Incapacitation measurements have been criticized lx*cause the dosage for incapacita tion generally approaches the lethal level.21 Tin* Na- j tional Bureau of Standards {NBS} has observed that the i comparative toxicity of most materials is the same re gardless of whether incapacitation, immediate lethality, or immediate-plus-post-exposure lethality are used as | indices. These Eicts have prompted NBS to discontinue the separate measure of incapacitation in its test. Another approach to incapacitation is to use biological measurements such as respiratory rate, blood pressure. / and heart rate. These can be quite sensitive, and form f the basis for the procedures of Alarie22 ami Gamne.23l However, their relationship to actual incapacitation is] not well established. Common Test Methods In Table 4, we have tabulated the seven common test methods that are the best documented. The fact that there are so many is ample evidence that little consensus exists among combustion-product toxicologists as to the best method of measurement. Two of the seven methods. DIN and JMC, are used in material control, both abroad. Three others have been proposed as stand ard methods in ASTM E-5 -- R'F. NBS. and USF. The methods developed by Alarie and by FAA are also i- ** C. Pryor. J. Diilcy, R. Mckee, and S. Martin. "Betun iuml Tech niques in Fire Toxicolog)Paper presented at the first Culilonua Conference on Fire Toxicity, San Francisco, Culilnmu. 1979. l# R. Hartunt;, el J.. `The Performance of Ruts on a Rotorod Dorin c Exposure to Combustion Products of Riitid Polv urethane Foams and Wood. "Journal of Combustion Toxtcolouy, Vol. 4. 1977. pp 506522. * J. Petajan. "Survival Response Durine Fire Exposure'' in Physiological and Toiicolotiicai Aspects of Combustion Products. International Symposium of National .Academe of Sciences. National Research Council. Salt Lake City. Utah. 1976. *k Y. Alarie and R. Anderson. 'Toxicologic Classification ol Thermal Deconqmsition Products of Synthetic and Natural Polymers. Toxicoloey and Applied PharmuciAutiy. Vol. 57. 19M. pp. 161-6. ** Y. Alarie. Tmtatimt Properties of Airborne Materials to the Upper Respiratory Tract," Archuei of F.m irimmcntal Health. Vol. 1.1. 1966. pp. 433-449. J. Caume. P. Bartck, and II. Rostami. "Experimental Results on Time of Useful Function (TUF) After Exposure to Mixtures of Serious Contaminants," Aerospace Medicine, Vol. 42. So. 9. 1971. pp 967-90 FIRE JOURNAL -- SEPTEMBER 1983 89 J URL 0421B Tabic 4. Common Tct Methods for Toxic Combustion Products Method Fixes Federal \\ iatum sample size. Ailm. iFAA* temp. Cerntun National -.ample si/e. St.miLin! il>lN' exposure time University of Pitts. (Alarm' National Bureau of Standards (NBS1 Japan Ministry of Construct ion (JMC' University of S.m Francisco (USF NASA' BETR Laboratories ' R.- F1 rate of temp. risik, expos urc time temp, conditions exposure time radiant flux sample size temp, conditions radiant flux exposure time Varies -- (lo-.ige to diamlirr, ox eii temp. sample size sample size __ -- sample si/e Using Time to Death nits X nits mice X rats X l mice mice X rats X I Time to Ineupuri- tutitm X X X fnrn/ineitdting Dose Lethal Dote Lethal Sample iff. Lethal [ Pyrolysis ; Lethal Ti in/HTii- 1 Area lure Bnriu it Cut Anu/yti.t Blood Chcmistty or Pathology X 1 X! i i X X | 1 XI j 1 i | f X; Xj j 1 XI 1 X X x X |X ! j , iX : | 1X X ! eluded. The most striking feature of this table is the lack of commonality of experimental variables and constants, to sav nothing of the differences in experimental setup. FAA-CA.Mi Test This method, developed at FAA s Civil Aeromedical Institute by Smith. Crane, and co-workers, has been used to determine the acute toxicity of aircraft mate rials 24,25 It is a static system using a tube furnace. Rats are exposed to a fixed charge of material; times to in capacitation and death are reported. The FAA approach was designed to determine the comparutixe escape times available when different mate rials undergo a set of thermal conditions in an aircraft cabin. However, it presents the common problem of having a relatively contrived combustion scheme. consists of a tube furnace that exhausts into an exposure chamber containing four unrestrained mice. Air How can be provided and the system is operated with either a constant or linearly rising temperature. It can accommodate samples nfvarying size, but very little of the large amount of data reported by this lahoratorv involved dosage; the method has been used mainly to determine time-to-death or incapacitation, along with a periodic analysis of oxygen and carbon monoxide. The animals are not instrumented, and loss.of function is determined visually. The USF/NASA method is as simple and fast as the other methods are painstaking and complex. However, it also has drawbacks, the most serious of which is that visual observation alone is not a very effective way to determine or explain biological effects. XASA-t'SF Test Tins method was developed at the University of San Francisco by C. Hilado under contract to the National Aeronatuics and Space Administration (NASA).2**27 It ** C. Crane, ct al . Inhalation Toxicology. I Design of S>n<i//-Anim<j{ Tat `system. U Determination of the Relative Toxic Hazards of <5 Aircraft Cabin Materials. Federal Aeronautical Administration report no. FAA-AM-77 9. NTIS AD-A043 4#v9ST. 1977. p 59. ** C. Cram-. `Tin- Prediction nt Human Incapacitation by the Com bustion Products Carbon Monoxide and Hydrogen Cyanide Using a Small Animal Text Protocol." Ami. Meeting. Aerosjwce Medical As sociation. 1979. pp. 151-2. * C. Hilado. 'Evaluation of the NASA Animal Exposure Chamber as a Potential Chandler for Fire Toxicity Screening Tests.' Journal of Fire and Fluiiifiiabilitij. Cton/jicxficjn. Toxicology Supplement, Vol. 2, 1975. pp. 29S-314. 81 C. Hilado, A. Fnrst. and W. Marcussen. The Use of the NASA Animal Exposure Chamber in Fire Toxicity Tests," Proceeding of Western Pharmacological Society, Vol. 19, 1976, pp. 397-400. Japanese Ministry of Construction Test The only biological test method upon which an estab lished regulation is based is maintained by the Japanese Ministry of Construction and carried out by four differ ent laboratories in that country.28 The test applies strictly to wall linings, and is used in conjunction with fire tests for noncombustibility and surface flame. The toxicity test itself is dynamic, and uses female mice as the test subjects. The combustion apparatus is a small furnace in which a vertical sample is heated, first with a gas pilot flame, then with the pilot flame and a radiant heat source. Total heating time is 6 minutes; total exposure time is 15 minutes. (Continued on peer fW> * Anonymous, "Saiulurd Method of Testing t*r Fire Protection Properties of Wallcovering Materials." Wallcovering Association of Ja pan. 90 FIRE JOURNAL -- SEPTEMBER 1983 URLU4219 Toxicity of Combustion Products (amtinuvd from page** 90) The endpoint is Incapacition, as measured by the fail ure of the mouse to continue to turn the rotatable cage in which it is contained. The standard requires that accept able interior finish materials have an incapacitation time equal to or longer than that of the Philippine (Loan) plywood used as the test standard. Lethality is not detertnined- It i.s important to note that use of the test is restricted to products in a single application -- room interior finish; that the toxicity effects are measured in the hope of providing an empirical comparison of escape time; that the combustion method chosen is at least a logical mock-up of expected real exposure conditions; and that the test is used in conjunction with two other flammabil ity tests. Ccrtnan (DIS) Test This method, adopted by the German Commission on Standards as Deutsche Industries Normal 53 436.29 is the second of two "national " standard test methods. The DIN method is dvj^jUj^c. The design of the combustion tube and the dilution mechanisms used allow the deter mination of LC50 and the pyrolysis temperatures ac companying given levels of lethality. Rats are the test subjects; duration of the exposure period is 30 minutes. No incapacitation measurements are made. Mortality, phis postmortem pathological examination and blood analyses, and some chemical smoke monitoring are the primary diagnostics. National Bureau of Standards (SBS) Test The method that has received by far the most atten tion in the United States was developed by the Center for Fire Research, National Bureau of Standards.30-31 This is a static method using a cup furnace. It was de veloped at NBS in conjunction with an ad hoc committee of workers from industry, government, and academia. As such, the method developed has been closely scrutinized and exhaustively debated. It does not represent a con sensus -- there was none -- but it does represent a great deal of thought. The N BS method is the only US method that has been extensive!) checked for interlaboratory reproducibility. In this regard, it compares favorably with the DIN method. The principal biological measurement is lethal ity -- LC50. Despite a lengthy investigation, no practi Deutsche Industrial Normal ijarv 1974) DIN >3 436. 'EnMuiijiing Thennischer Zervetsungiprodiicktc von Wekstnffcn untcr Luftsufuhr uml ilm- TovikoloEiwho Pruning Part 1. ZersHzunq.si'ert under Bcstiminunq tier Vorsiu/hsU-mper-atur. Part 2. Verfahrcn zur thvrmischen Zcrwt/.unq." idrafti. * B. Levin, et al., Further Development of a Tent Method for the Assessment of the Acute Inhalation Toxicitv of Combustion Products." National Bureau of Standards, N'BSIR S2-2532. June 1482. ,l M. Birkv. et al., "Development of Iteoom mended Test Method for Toxicological Assessment uT Inhaled Combustion Products." Na tional Bureau of Standards, NTlS/PBHl-tUVdv*. 1961. cal incapacitation measure could be found that gave significant information beyond that provided by lethality data. The method also includes an optional provision for a 10-minute exposure at relatively high loading levels (30 mg/liter) of material. The most controversial aspect of the test method is its choice of combustion chamber --a cup furnace. Recently, the size of the cup was increased to approximately 1 liter, which improves its ability to handle substantial amounts of low-density material NBS has reported32 that materials were most toxic in the nonflaming mode just below the autoignition point and, similarly, toxicities in the flaming mode were high est just above the autoignition point. It is desirable* that any test used to screen materials avoid "false negatives, and choosing the most severe conditions would minimize this likelihood. Unfbrtunately. the premise that these conditions always exist near the autoignition point is em pirical. if not speculative (especially in view of doubts about the relev ance of the combustion device used1, and there is no guarantee that false negatives will always he avoided. At least seven laboratories in the United States have run the NBS method. Table 5 shows data collected for flaming exposures at a 30-ininute exposure period and a 30-minute and 14-day observation period. Given the un certainties of the measurements. UIkUk ckit^diMioL^iiP* pirt th- pfton-he:ir<;l statement that plastics. unlike natural products, are more toxic in the flaming mode. TI Hutu do ,->pp<:ir to confirm the assertion that mate rials are somewhat more toxic near their respective igniturn points than at a fixed temperature of 440'. With the exception of polytetraftuoroethylene (PTFE . however, the differences in toxicities between the two tempera tures are small. BETR Laboratories (RH > Test Recently, Packham33 at BETR Laboratories lias pro posed a test method that uses a radiant heat exposure in conjunction with the NBS chamber. The method uses radiant heaters located outside the chamber itself: this reduces the problem of by-product heat, which has gen erally been troublesome in radiant exposure. Samples are sized by surface area, rather than by weight. The procedure suggested by Packham is also novel. Both time to incapacitation and lethality are measured. Additional tests are made on appropriately sized samples if the lethality indicated by initial dose is high. To date, no data are available from Packham s procedure. It ap pears to have a number of desirable characteristics, par ticularly the merits of radiant heat, which have been discussed previously , and the ability to translate toxicity in units of surface area. a U- Levin, up at S. PiK'khiun. "Proposed Method of" Test lor Toxic Coiniitislion Products," submitted to ASTM Committee. E-j. I9M. 94 FIRE JOURNAL -- SEPTEMBER 1983 r Tahir 5. NormaJizcd Data From N'BS Test Method LC50 (Douglas FirVLCSO (Material 30 Minutes Ac 14 Days Material lied oak Flexible pohiirctlune foam Wool Polystyrene foam Douglas hr Puh plieuxlsulfime Polvvimkhlnride il'VCi Acrvlonitnle-stxlene-hutadcne ABS1 Rigid polyurethane foam Polyvinylchloride containing one fcrrocsanidc Modoc relic Pulytctrafluomcthylenc vPTFE' Flaming Erpmurr 65 = .2 A .86= .4 .91 = .1 (101 1.6= 1 1.9= 5 1.9= .4 2.8= 2 3.1 = .6 6.3 = 3 170= 170 Sonflaminc Ex)ui\urc .69= .2 .76= .2 .93= 4 A urn 14 = 9 3.4 = 4 0.8- .2 A 2.1 = .1 3.8 = 2 170= 100 440BC B R r*> - n B u.oi A l.l - .3 O.fi* A 1.9= .1 3.1 = 1 1.1 = .2 A: nnt reported lx-cauxe apparatus cannot arcTimmodate a Urge enough sum pie ti* reach LC50. normalized value < l. B "ignition |*iint lies within 50" of440"C. * .pie Llioraton -- no standard deviation calculated. URL 04220 Pittsburgh (Alarie) Test Professor Y. Alarie of the School of Public Health, University of Pittsburgh, and his colleagues have de veloped testing methods that take into account both senson' irritation and lethality.34J4 The apparatus consists of a temperature-programma ble furnace, a small (2.3-liter) exposure chamber, and a set of four mice as the test animals. The animals can be monitored for respiration rate. The method is a dynamic one. permitting the dilution of the product stream with air. A typical experiment using this method involves de composing the sample at a heating rate of 20C minute, and diluting the smoke stream with dry air. A typical time history is shown in Figure 3 for a sample of pcdviifetlumc* fpa.m at its L(^oCToa3ing.3 Different re sponses can occur at widely differing concentrations. Figure 4, for example, show s Alarie's plot of respiratory decrease and lethality for a sample of polyvinylchloride (PYC). From a research point of view, AlanVs approach is the most sophisticated one taken to date. Whether it is ap propriate fur assessment of aetual hazard has not l>een established. For example. Potts and Lederer37 have re ported that human subjects exposed to smoke from red oak experience no respiratory decrease or other ill effects at concentrations equiv alent to those that reduce respira tion in mice. Unfortunately, data for other materials are not available. Comparison of Test Data There are few published comparisons of any of the seven techniques, and the authors of the study for NFPA ** Y. Alarie. C Lin. and D. Geary, "Sensory Irritation Evoked by Plastic Decomposition Products," Arnrrican Industrial Hygiene Ajloriafion Journal. Vol. 35. No 10. 1974. pp. 6>]-61. ** Y. Alarie and S. Barrow. "Toxicity of Plastic Combustion Prod ucts. Toxicological Methodologies to Assess tlw* Relative Hazards of Thermal Decomposition Products from Polvmerio Materials.'' National Bore.iu of Standards. NBS Grant/Contract Report NT1S PB-267 '233/ 5ST, 1977. p. 313. ** Y. Alarie ansi R. Ands-rson. "Toxicologic Classification ofThermal Decomixixition Products of S>nthetic and Natural Polymers." Tox icology and Applied Pharmacology, Vol. 57, 19S1. pp. 161--S. ST XV. Potts and T. Lederer. "Ssime Limitations in the I'se of the Sensory Irritant Mctlu>d as an End-Point in Measurement of Smoke Toxicity, Journal of Combustion Toxicology, Vol. 5. 1978. pp. 1S2--95. Figure 3. Record of weight loss, carbon monoxide, and HCN release for polyurethane loam during increase in furnace temperature. Repro duced by permission. FIRE JOURNAL -- SEPTEMBER 19S3 *95 I Figure 4. Concentration-response curves obtained for sensory irrita tion, physiological stress, and acute mortality , for exposures to tliennal decomposition products of different sample sues of polyvinylchloride. The RDoQ, SHOO, and LC50 presented were obtained os given in the text. The sample-size range resulting in asphyxiation is also given. Reproduced by permission. therefore spent considerable effort surveying the litera ture to see where such comparisons can be made. The principal difficulty is in finding data on materials that were sufficiently well-characterized so that one could de termine whether they appeared in reports on more than one method. For comparison of the Alarie and NBS methods, there are six materials that we know are identi cal and two more that are probably so. This is no acci dent. since the Pittsburgh and NBS laboratories worked closely together and NBS supplied the samples to Pittsburgh as well as to these laboratories working on its own approach, The eight materials are two polyurethanes from the Product Research Committee (PRO38 sample bank, Douglas fir, urea-formaldehyde foam. wool, polytetrafluoroethylene, and two formula tions based on poly vinylchloride (PVC). The NBS protocol specifies a nonfiaming and flaming mode of exposure, and both 30-minute and 14-day ani mal observation. The Alarie protocol does not control flaming: observations are made for 30 minutes plus a 10-minute recovery period. One would expect closest agreement between the methods when Alarie's data are compared to NBS 30-minute data. Figure 5 shows this comparison. Results from the Alarie test are plotted against those of NBS for the same material. If the two methods give the same toxicity in comparison to Douglas fir, the points would fall on the plotted line of 43 degree slope; they do not. and there is poor correlation, whether flaming or nonflaming data from the NBS method are used. One possible explanation is that mice, used by Alarie, are more sensitive and show the same effects in 40 min- Figure 5. Comjftrison of lethality relative to Douglas fir for seven materials evaluated by methods of Alarie and NBS. utes that take two weeks to develop in rats. We have, therefore, also plotted the 14-day data from the NBS test against Alarie's results. As Figure 6 shows, this argument may hold true for one material, but For the others, results are essentially unchanged. Figure 6. ** The Products Research Committee- { PRO. 1976-lSihO. supported a significant amount of fire research and established j bank of wellcharacterized material samples so that work at various laboratories could be coin[ured on the basis of its having been Lurried out on the same materials. FIRE JOURNAL --SEPTEMBER 1983 ALAMt Ml* TH *sr*vi IMMIII IA*I iw HO** *r* *! Ih* *r* ** *IIM in* ><> XI -Co. f-a i'j It is possible that more data would fail to confirm the apparently greater toxicity of materials in the Pittsburgh method, i.e., if enough data were available, perhaps the points would scatter more or less symmetrically about the line shown in the two plots. If this is true, the inher-' ' ent imprecision of laboratory combustion-product tox icology will be approximately unvorder of magnitude. In other words, there will be no validity to comparisons of quantities that do not differ by at least a (actor of ten. Alternatively, it may be that more data will show that the difference in methods is real and systematic. If this is the case, they cannot both be "right." At present, it is not possible to determine if the differ ences between the two approaches are systematic or random. It is dear, however, that the differences are large, and more data are needed. In one series of experiments. Cornish39 has demon strated that the order of toxicity of a set of materials can be greatly influenced by the choice of combustion condi tions. In one procedure, rats were kept for four hours in a chamber containing smoke produced by sudden ther mal exposure of a material at 700C, In another proce dure. the same materials were gradually heated to the same final temperature over 1-40 minutes, and the smoke passed through the exposure chamber. The results, shown as sample weight to produce 50 percent mortality -- are presented in Table 6. The ranking can be almost completely reversed, depending on the combustion conditions. The essentials of Cornish's observations are borne out bv the comparison of the Alarie and NBS test methods. The Alarie dynamic method shows wool, polyvinyl chloride. and the urethanes to be substantially more * H. Cornish. K. Hahn, and M. Barth, "Exjx-nmont.il Toxicology of P> rulysis and Combustion Hazards." Entronmcnffl/ Health Perspec tives. Vol. 11, 1475. pp. 191- See also H. Kaplan. H. Crand. anil C. Hartzun. A Critical Review of the State-of-thc-Art on Combustion Toxicalory. Southwest Research Institute. Final Report No, 01-6862 (or the Soviets of the Plastics Industry, June 1982. Table 6. Data of Cornish, Showing Differences in Lethalities of the Same Materials by Different Test Methods. Srofif Chamber LC o. g Sample Most Toxic Dynamic Cham /IT Sample LCso. , 9 Red Ouk 1 Wool 0.4 10 Cotton 2 Polvpmpvlcne 0.9 21 ABS vFR) 3 PoUpropvlene 1.2 23 SAN 4 Urethane Foam (KK) 1.3 25 Polvpmp\lcne (FR) 5 Polv\ imlvhloride 1.4 as Pnl\ props lene 6 Urethane Foam 1.7 31 Pohshrene 33 ABS 7 SAN 8 ABS 2.0 2.2 37 Nvlon 66 9 ABS (FR) 2-3 37 Nvlon 66 (FR) 10 Nvlon 66 2.7 47 Urethane Foam (FR) U Cotton 2.7 50 Urethane Foam 50 Pnlvviuvlchloride 60 Wool 12 Nvlon 66 (FR) 13 Red Oak 14 Polystyrene 3.2 3.6 6.0 toxic than wpr>d (Douglas fir). The static NBS method shows the same materials to be comparabftMo or jome- what less toxic than wpotL It seems likely that the explanation for these differences is related to the (act that the static methods expose the animals to all the combustion products at once. By contrast, depending on the heating rate and the air flow', the dynamic methods can expose the animals to few products, or to a single product, at a time. This is particularly significant when the material is heated gradually during the course of the test. In thei case of polyvinylchloride, for example, the evolution of hydrogen chloride can "begin at temperatures well below the onset of carbon monoxide evolution. The dynamic- exposure chamber may therefore be cleared of hydrogen chloride before the animal encounters appreciable car bon monoxide. In the static chambers, the animal will ` encounter carbon monoxide and hydrogen chloride simultaneously, or at least close together. Since hydro gen chloride depresses respiration rate, its presence or that of a similar irritant will slow the uptake of carbon monoxide. (In Cornish's work, there may be an addi- \ tional problem: the static chamber, constructed of stain- | less steel, may have reacted with acid products like hv- J drogen chloride.) If the combination of slow uptake and j carbon monoxide level meets certain conditions of time : separation, the animal may survive a static exposure and j die in a dynamic one. Conversely, when two toxins are synergistic, i.e., when they magniiy the effects of one j another, one would expect materials burned in the static 1 chamber to show comparatively greater toxicity. I Interpreting Combustion-Toxicology Data: Time v$ Dosage The controversy over time measurements or dosage measurements as the better indicator of hazard is a long-standing one. Three of the toxicity test methods listed measure only time effects, two measure dosage, and two measure at least one aspect ofboth time effects and dosage. Supporters of time measurement argue that, since es cape time is the controlling variable in most fires, know ing how a material will affect this parameter is paramount. In the straight time tests, a relatively large sample is exposed to severe thermal conditions so that the time for decomposition is relatively short with re spect to the time of exposure. The Japanese test method is something of a variant. Its thermal conditions, w hile not particularly severe, were specifically chosen to ap proximate the performance of room wall linings when exposed to the radiant heat typical of a dev eloping fire. Alarie and Anderson40 have criticized the ' time to ef fect" approach because it groups all materials in a narrow range of times. In the FAA and VSF procedures, for 40 R. Anderson and Y. Alarie. "Screening Procedure to Recognize 'Supcrtoxic' Decomposition Products from Polymeric Materials Lnder Thermal Stress," Journal of Combustion Toxicology, \ ol. 5, 19.8. pp. 54--63 (Continued on page 10S) FIRE JOURNAL --SEPTEMBER 1983 97 X3 CD -Cx r- j nj r-o Toxicity of Combustion Products (Continuedfrom page 97i example, virtually all observed times-to-death cluster between 5 and 30 minutes. Alarie and Anderson claim that determining lethal dosage, by contrast, offers a range for possible values of al>out 1,000. Recall, how* ever, that Alarie's and NBS' measurements of lethality disagree by a (actor of ten. If the Ix'st one can expect from lethality measurements is accuracy to this level, then, on a logarithmic scale, the ratio of uncertainty to available range is log 10/ log 1000, or one-third. From this viewpoint, the superiority of using lethal dose to classify' materials is not quite so apparent. Packham has argued41 that the two quantities are so closely coupled that it is equally misleading to rely solely on either. He points out that it is possible for an agent to be rapidly incapacitating at levels below its lethal dose, just as it is possible to nave delayed lethal effects that would go undetected if time were the only discriminant. Packham's logic is most persuasive if the suitability of materials must be assessed for a variety of fire scenarios. For example, interior finish materials of high flame spread are likely to become involved fairly rapidly, pro ducing relatively large amounts of smoke in a short period, time measurements may be appropriate for this scenario. It may be no accident that the Japanese Minis try of Construction and the FAA have chosen to monitor time, since both tests are primarily conducted on com partment interior finish. By contrast, structural materials and some furnishings will produce smoke at a relatively constant rate over a longer period, since the surface-tovolume ratio is much lower. For these products, weight-based measurements may be better. In general, it may be most appropriate to concentrate on one or the other lethality parameter if the product or material use is known. Summary and Discussion A major concern in the field has been to identify' socalled "supertoxicants," whose presence in materials would go unrecognized in the absence of a specific test. The fire community was concerned that some smoke might contain highly-toxic materials that would either kill directly or would incapacitate at such low concentra tions, or at such an early stage in the fire, that escape would be impossible from an otherwise relatively tena ble situation. There is no consensus that any such materials have actually been found to date. The previously unknown cyclic phosphate discovered by the University of Utah group turned out to be unique, primarily in the type of effects that it showed and was, moreover, not produced commercially. Commercial materials that have attracted attention are urea-formaldehyde foam and PTFE. In 41 5- Packlum. op. tit. both cases, the materials have relatively high thermal stability and do not support their own combustion. Maintaining the high temperatures necessary' in practice for the decomposition of these materials requires that other fuels be burning. Thus, for PTFE, ureaformaldehyde, or any other thermally-stable material, the contribution to hazard in actual practice depends, first, on whether it produces a similar set of products under real fire conditions4* and second, on the degree to which the products contribute to the toxicity of the total smoke generated, since most of the smoke will come from other fuel(s). At present, the utility of a screening test would appear i to be more to prevent such hazards in new products than f to identify major existing threats. While NBS haa suggested that its test is useful as a screening tool (primarily for product development),43 others44 argue{ that any screening test for toxicity is v ulnerable on sev-J eral counts. First, they assert, there is no guarantee that/ the combustion or test conditions used are represenfa^ tive of real fires; second, controlling materials on the basis of toxicity could lead to a suboptimization based on this single property; and third, they believe that even aj well-thought-out approach could be misapplied, leading; to an overall increase in hazard. NBS45 has suggested* that a screening test should be used only to determine when a material should be subjected to detailed exam-j ination of all of its fire properties, but that the test itself was an insufficient basis for material control. The debate^ continues. The procedures for toxicological testing have varia tions in the method of pyrolysis, the method of exposure, and the animal model, It is not surprising, in view of the plethora of test methods, that there is also a range of test results. With respect to "validity," the only option av ail able is to compare different methods that purport to measure the same effect. Because identical materials have not been tested in each method, comparisons are limited, but the comparisons that can be made would indicate poor correlation or even contradictory' results. Comparison of relative toxicity data between Alarie and NBS test methods, for example, shows w-ide dis agreement in the toxicity of several materials relative to Douglas fir. The reason for the discrepancies may be several, among them the use of rats vs. mice and the effect of static vs. dynamic systems. However, at this time, there is no understanding of the differences and therefore no agreed-upon way to evaluate toxicity of (Continued on page 10S) 41 In {hr cast* of FTFE. there is evidence to suggest that real fire conditions produce much less toxic products: c.f. Footnote 17. 43 B. Levin, op. cit. 44 Cf. J- Punderxon, "A Closer Look at Cause and Effect in Fire Fatalities --Tlie Role of Toxic Fires, Fire and Materials, Vol. 5. No. 1. 19SI. 44 F Clarke. I. Benjamin, and M. Birky, "The Use of Laboratory Toxicity Measurements for Decision-Making," Fire and Materials, Vol. 5, No. 2. 1931. FIRE JOURNAL--SEPTEMBER 1983 101 Meeting of NFPA Board of Directors (continued from page 106) $1,221,909. He assured the Board gan. Mr. Roux also moved that the the ad hoc group, to review the rec that irr^pite of the results, financial Executive Committee of the Fire ommendations of the ad hoc group stability n2*s^ never been stronger. Marshals Association of North Amer and to report back to the Board on Growth, in fact,Nover the three-year ica report to the Board in May of the direction the Association should cycle just completed was in excess of 198-1 on the first year of operation take on this subject"' Dr. Bryan $525,000 (more than dquble that of and the adequacy of the arrange moved that thjM'^comrnendation be the previous cycle). DrN^ell also ments for the chapter. In particular, adopted byrtne Board. Mr. Johnson pointed out that early indicatibris for the Board should be informed of any seconded the motion and it passed 1983 are very favorable and growl problems that arise from the fact that unanimously. over the financial cycle just begin s number of the members of the" ning is anticipated to be better than Michigan Society of Fire Insj?etors 8. Mr. Martin, Chairman of the , that just completed. are not eligible for membership in Fire Equipmt-nt Manufacturers As the Fire Marshals^Association of sociation's Appeal Subcommittee, North America.-vDr. Bell seconded 5. Mr. Crant reported on several the motion.xihd xItvcarried unani- reported that the Subcommittee administrative changes within the considered fully each of the four is staff of the Association to strengthen mouslv sues raised by the appellant, and NFPA operations. / 6. Mr. Roux, Chairman joT^the Membership Committee; moved x i. Mr. Stevens reported tKirt^in response to the request of the Board,' the Standards Council voted to rec ommend to the Board that an ad hoc upon consideration of the issues and the arguments, it was the determina nt to affirm the action of the StandardsSquncil on NFPA 14. that the Board approve the proposal group be formed to include repre URL 04 of the Michigary^Society of Fire In sentatives of affected NFPA Techni 9. Mr. Sandei'Sx^onfirmed that spectors to form a chapter of the Fire cal Committees to conduct the study the December Boara'of,. Directors Marshais'Association of North Amerauthorize that the chapter be lown as Chapter No. 1 -- Michi on the contribution of furnishings and similar contents to the fire prob lem. The Council offered to establish Meeting will be held on December 2 and3,19S3at LuCosta Hoteland Spa. Carlsbad, California. . ro 1 ro Toxicity of Combustion Products (continued from page 101) pyrolysis gases. Until large-scale tests have been run with varying scenarios to validate the laboratory tests, the controversy will probably continue. Even where agreement is reached, whatever test ap proach is used will still have built-in limitations. As a consequence of inherent time-dependence, each fire may, at different times in its development, create differ ent conditions of combustion and occupant exposure. Moreover, a given material may be involved in not one. but a number of different fire scenarios. It should there fore be clear that there is no "correct" single set of real fire conditions identifiable with a material. By the same token, there is not a single "correct'* set ofsmaH-scale test conditions, nor a single "correct" ranking of mate rials based on toxicity tests. The situation is not the fault of existing test methods and will not be changed by more research; it is inherent in the complexity of fire and fire hazard. This does not mean that toxicity testing is fruit less -- far from it -- but it does mean that one is seldom free to take at free value the results of any given test. The other major problem is one where more research can help: how to integrate toxicity considerations with flammability parameters. As an illustration of the prob lem, consider the following hypothetical dilemma for a code official. The code now requires a flame spread of 73 (Class B) by NFPA 255 for many interior finish applica tions. Suppose a code official wishes to add a require 10 8* FIRE JOURNAL -- SEPTEMBER 1983 ment that smoke from wall linings be no more toxic than wood -- say, red oak -- when burned under similar conditions. (This is a commonly suggested code provi sion.) Now, untreated red oak has a flame spread of 100 and hence could not be used in this application. What is the toxicity of an acceptable interior finish so that the net effect is the same hazard level posed by red oak, which is not allow-ed in the first place? As an even more practical illustration, suppose a man ufacturer wishes to gain code approval of a new material with a flame spread of 40 but with a toxicity twice that of red oak. The amount of smoke produced is proportional to the amount of material burning, so there will be less smoke produced in a given time by the lower flame spread material. Since there wall be less smoke, is it permitted to be more toxic? One might intuitively an swer "yes" to this question, but then, how much more toxicity is acceptable? If, instead, one answers "no," it is possible that a safer material than those in use will have been barred. Although no one has clear answers to these questions, not long ago no one even knew enough to ask them. The evolution of new knowledge from laboratory findings to everyday practice is alway s a slow journey. As our un derstanding increases, our expectations from combustion product toxicology must undergo a corresponding evolu tion. This report may be helpful on both counts. C.