Document RJrmxQDadLZqMzdjZkjRgJ1QV

FILE NAME: Neighborhood Exposures (NE) DATE: 1951 Mar DOC#: NE029 DOCUMENT DESCRIPTION: Trade Journal Article - Industrial Hygiene Considerations In Plant Location and Design AeoJ SYMPOSIUM OM INDUSTRIAL HEALTH AND SAFETY ' ' Industrial Hygiene Considerations In Plant Location and Design (I o EXHIBIT WILLIAM R. BRADLEY, American Cyanamid Co., New York, N, Y. Sick employees and aroused neighbors are a poor comple ment to a successfully designed and located industrial plant T bce -chemical engineer is aware of his responsibilities in the design of a manu facturing plant and its equipment, along with the selection of plant location, for errors in judgment may be costly. He must make no departure from engineering principles that are soundly conceived and executed. Consequently, he consults with his associates in chemical research and in pilot plant operation to benefit from their experience. Plant capacity is dis cussed with the sales department and problems in personnel and operation are reviewed with production people. Other interested groups also gather about his conference table so that his final blueprint is a result o f careful planning, down to the handling and flow of materials in the most economical manner. The industrial hygienist has now be come a member of this planning team. H e provides the chemical engineer with an understanding of the working environ ment that may result within the plant when the chemical process is begun. From a study o f the process he also provides an evaluation of how good a neighbor the plant will be in the community 'where it is to be located. More precisely, fthe industrial hygienist sees that operation of the new plant will not resu lt in employee ill health, through exposure of workmen to obetnical mists and vapors or to harmful gases or dusts. He tries to make certain that the new plant w ill not cause unfortunate commu nity relations because of air or stream pol lution. The industrial hygienist discusses the toxicology of the various chemicals, the raw materials, intermediates, products, and by-products, and interprets the ex tent and nature of any health hazard in their handling and use. It is then fre quently possible to plan for the control of both plant and community environ ment where it may be needed, and make this control a definite port of the chemical engineer's blueprint The important con sideration is that this control be applied in advance of plant construction and oper ation. Chemical Plant location Included In the many factors that deter mine the ultimate location of a chemical plant arc those pertaining to maintenance of employee and community good health. One factor is that of climate. Sudden changes in temperature, of course, will freeze pipes and burst valves unless planned for in advance. Sudden tempera ture changes also may lead to a higher incidence of respiratory illness among plant operators. Exposure of man is just as important as exposure of equipment. In colder climates, the chemical engineer can plan -his process so that workmen do not frequently need to leave and reenter a warm workroom in order to tarry out their duties. Such duties may be to oper ate valves or pumps or take measure ments at tanks or collect samples, to bring in raw m aterials. or remove products. Workmen often will not trouble to put on a cap and a heavy coat each time they must leave a warm building. A wanner climate offers less of this type of exposure, but thinking Ln terms of workmen should extend to protection against high wind, driving rain and snow, excessive heat, and becring cold. The high temperatures, perhaps as high as 120 F., and excessive radiant energy that occur at furnace-tending or lcdn- firing can be lessened by the use of reflecting baffles at operating points. Air-conditioned control rooms and ventilated steam line tunnels improve working conditions and lead to smooth production. The location of a plant in a warm cli mate also may offer certain disadvantages. The increased volatility of solvents, for instance, may constitute a potential health hazard of some magnitude. While toxic concentrations might be safely circum vented by local exhaust ventilation, the daily handling of solvents in a warm cli mate poses a problem of an elusive cbance exposure to vapor level concentrations that might not exist except for the fact that the average temperature is higher. Occasional spills, leaks, flushing of kettles, open filter presses, open drains, sumps, and so on may be sources of solvent vapor. These vapor sources may cause atmos pheric concentrations `of that low order of magnitude which consistently plague industrial hygienists for satisfactory an swers as to thoir physiological significance. Complementing the conditions cited above is the personal element involved in snoh exposure. Warmer climates mean less clothing and therefore more body sur face exposure to industrial materials. This means enhanoed opportunity for skin eoutact with imtant solids, liquids, and gases. Coupled with this are the factors of ex cessive workroom temperatures and the greater discomfort in wearing protective respiratory equipment and clothing. Once the working conditions with re spect to -climate have been resolved, there are other factors which might play a pan in the successful operation of a plant These include p re v a ilin g wind movement, terrain and adjacency to woods, mountains, farmland, streams, residential areas, and other industry. In considering plant loca tion, we move then from the- problems within tbe plant to those outside the plant The matter of prevailing wind move- W uxiA ju HoanrsoN B ratm-ex, who is chief in dustrial hygienist at the American' Cyanamid Co. in New York City, received his education in Iowa, first at Cornell College, then at Buena Vista College, and then at the State University. H e also did more graduate work at Wayne University in D etroit Before assuming his present position he was industrial hygienist at the Fidelity and Cas ualty Co. in New York and had served in the Detroit Department of Health as an industrial hygienist 1198 CHEMICAL AND ENGINEERING 2. S iTij- ,Ai day, it would form at another spot, de pending upon wind direction. It was not until a number of chemical reactions had been checked and process vent stacks examined that the two offending stacks were located. Hydrochloric acid was es caping one, and ammonia the other. Al though 100 feet apart, occasionally the two gases would escape at the same time when wind direction was fust right to carry the discharged gas from one stack directly across that from the other tack. A similar situation may occur when waste acid is discharged to a stream containing traces of ammonia. :nent \s of prime consideration m air pollution. Prevailing wind, with respect to the plant, should not b e in the direc tion of nearby residential areas or other industry if possible. Neither should the plant be located in the direction of un controlled or excessive "airfluent" from otiher industries, if, by inquiry or through chemical tests, it is revealed fchaf the wind carries airborne material of an undesirable nature. A proposed plant location should he carefully surveyed and evaluated for exist ing air pollution, preferably with the. aid of studies involving physical and chemical tests. The industrial hygienist, know? that any future investigation and control wall eventually fall upon his shoulders. At Docora, Pa., it was observed that a mountainous area can be conducive toward formation, of a weather condition known as inversion. W hen this condition pre vails, any discharged gases and fine dusts may stay near the plant Site without nor mal dilution or dispersion. Moreover, any plant located in a valley is limited as lo stack height and may discharge gases on a level with residential areas located on the hillside. Discharged air contaminants have been kncwn to follow the course of valleys downwind for several miles, dam aging plant life. The matter of terrain may he important :f sloping teiTain drains toward residential areas. While this consideration delves into the sphere of stream pollution experts, the industrial hygienist is well aware of these problems and watches lost his ac tivity contribute to stream pollution. For example, at one location, two set tling basins were established to hold liquid wastes. One contained add wastes and ;hc other a sulfur compound. If these wastes were combined, H:S gas would be formed in heuvy concentration at about the center oi the plant site. These two settl.ng basins were therefore dheharged bv 'eparate Humes tnd at different times to the sum** trtv.m a short distatuc auuy However, when this sty-a.M became stag nant, lh<5 two effluent su*stances united and a blanket of HaS ios<: up and drifted through a residential area Tin's usually occurred at night, and the annoying odor of gas awakened the inhabit ants. Control of such situations can be planned in advance. The potentially in jurious effects of airborne dximical sub stances to those handicapped by respira tory illnesses make such planning manda tory. What may be only a nuisance to healthy people may bo serious to patients m a hospital. It is, of course, assumed that adequate water supplies are available. If, however, the supply is from a stream or river, the advice of stream pollution experts may affect water treatment costs. If the waste discharge of the plant is into the same stream, then limnological surveys should be conducted, both before and after plant location, as a basis for avoiding litigation. `V.iiflvonG' from a plant situated near wood land might be damaging to trees. It is also conceivable that over a long period of tim e there might be sufficient deposition of solid flammable material to constitute a fire hazard, riant location with inspect to farmland and residential areas Is important because of potential odor nuisance or ohemical damage to buii lings, crops and foliage, or livestock eating contaminated foliage. When location of a plant site is being chosen, neighboring plant processes should be considered, for possible mixing of two or more airborne materials might produce undesirable odors or visible fume. A re view of some simple chemical reaction should serve to indicate what possible combinations would produce such fume H> boWdoric acid and ammonia consti tute ,m example. At a certain plant it is reported that these two gases would com together, forming an ammonium chloride fog that would form a dense blanket and carry down wind about the plant site and over into adjoining property. Or. anoihrr Chemical Process Design While industrial hygienists find many points of interest in the problems of chemi cal plant location, they can, perhaps, make their greatest contribution by applying themselves to preventive treasures that* will maintain industrial workers' health. In this activity they seek to prevent the exposure of people to the raw materials, intermediates, final products, or by-prodnets of the chemical industry* that may be toxic. Preventive measures can apply effectively in chemical and related indus tries, because it is here that a great variety of chemical substances are bandied by workmen. A number of the newer substances com ing from blxi research laboratories of the chemical industry, particularly the organic chemicals, arc found to exhibit some de gree of toxicity to human beings. The in dustrial hygienist seeks to examine these chemicals through toxicological investiga tion to learn more precisely the poten tiality of each chemical for causing illness. This field of industrial toxicology differs from the pharmacology of clinical toxi cology and chemotherapy and from crimi nal toxicology, in that animal exposure studies arc undertaken to simulate closely* the opportunity for worker exposure in in dustry. The information derived from in dustrial toxicological studies gives the in dustrial hygienist data on several types of exposure so that he may organize, evalu ate, and interpret this information for in dustrial management, chemical engineer ing groups, and plant operating personnel in terms of a safe, working environment. For the chemical engineer, this interpre tation must be in practical and understand able terms. It must answer questions such as: "May contact with the skin be per mitted, and, if not, what protection must be taken to avoid it? Is the inhalation of dust or vapors of this substance harmful, and what effect will it have on workmen? Can certain amounts of these chemicals be permitted in the form of dusts, mists, or vapors in the atmosphere of chemical plants and can they be tolerated by work men9" The answers to these and similar questions must tell the chemical engineer exact 1v how to use and handle toxic sub stance safely. When the industrial hygienist and the c hem ical e n g in e er sit dow n to g e th e r an d review plans for ,1 new chcr.ual process, then is a real opportunity for the pre- V C i. U M E 2 9, N O . 1 3 . . . M A R G H 2 6 , 1 9 5 1 1199 to iloign and install equipment outlied tn v a rio u s c h e m ic a l re a c tio n s Ita m iltn g Sev eral materials and resulting in a final product. This process equipment mast be housed in a suitably designed plant. What, then, is the interest of the industrial hy gienist in the design of production equip ment?" Hygienist Explains Hazards The industrial hygienist must discuss the nature of the raw materials and how raw material A must be handled with cure to avoid the inhaling of dusts, and how chemical B must likewise be handled cautiously, perhaps in a closed system so that vapors or gases given off will not form a contaminant in the workroom at mosphere. 'i bese factors must be care fully pointed out and the reasons given as to the nature and extent of hazard, so that a practical and economical solution can be attained. Between them, the planners may decide to install a ventilated hood enclosure at the manhole of a re action kettle. The engineer can see that his design would otherwise be inoperable because it might be directly responsible for *bo illness of workmen, unless the exhaust ventilation is install] Ixifore the process is Ixigv.n. In the handling of compound B, it may be decided to pump the material to a storage tank, then to a weigh scale, and then to the reaction vessel rather than to require men to pour the material into pails, cany it up ladders and dump it by hand, where they may be exposed to irri tant vapors or to skin contact from a splash or spill. Next, it may he necessary to mn the reaction prey]not through a filter press. From tb-.- nature of the reaction, the in dustrial hygienist can inform the design engiiv r ri:nt men who o j y t h e press to rcnn vc the filter cake will be exposed to solids or gases tiha-t may jc harmful. Between them, they notice tlwit no ventila tion enclosure has been provided for this filter press and so this provision may now be added to the blueprints. Lot ii-- follow the process a step farther. We may find open centrifuges, open whizzers, open settling tubs !nfonnation can 1 provided as to what, the working envirr :nent will be bke nen: this type of equipment, so that control measures, if needed, again can be applied to the blue print before process installation. Reeding Blueprints Tlv iodipjriial hygienist scs a line on a bhiepnnl {pointing upwai : and ending in an a-row. 'Ibis line is l^ v lle d 'Vent/' Loot blither, he comes a ross a line pointing downward ending n an arrow which is labeled "to the ewer.'* The question immediately arise ? as to what reaction products are discharged into the atmosphere or what waste products are discharge] to the sewer. T h 'v; is, at this point, a chance to proj: . ` the chemical pro<v"V design into miyts. or tupor* discharged into the jufrom tile reaction will result in an an pollution problem, then the design of some means of control, such as condensing or scrubbing, will need to be added to the blueprint. The treatment of waste prod ucts by neutralization or reaction to form an inert substance may be necessary in some cases and a sketch of this treatment, too. may be added to the blueprint as a phase of preliminary prevention It must be borne m mind that the in dustrial hygienist is only one member of U Liui vi muiistr) 5 .nnpvc}e - ........ picture An example of one diinc ik; uU> Sene -is an illustration. A rom was needed m .1 pU,,,, Jiuj om. wa> eburnea and located according to blueprint OH the Erst floor ot a building It se e m e d to be convenient to locate a chute from t ic second floor down mto the meiter, so that the rosin drums might he opened and the rosin dumped into a cru sh e r and run down mto the metter, It turned out, however, that dumping and crushing rosin was a dusty operation a planning team and does not begin to know all the answers. Other members of and a considerable nuisance to the "oper ator." Of course, when the meiter was the team include those from research heated, the vapors came up through the groups, product development, safety, pro duction, and sales groups. chute and crusher and into the budding, contributing to an already disagreeable Machines Must Fit the Man situation. There was absolutely nothing wrong with the design of the meiter, the Considerable thought is being given to chute, and the crusher. The foundation day to the design of industrial machines. was solid and the superstructures were This trend involves a study of human well supported, but the opeiatmg nuisance anatomy and the related subjects of fatigue might have been prevented. and health, so that machines may be de signed to fit the man who is to operate Convenient Housekeeping them. T-he same is true id the chemical Another item of design that is helpful and related industries. Process equipment to plant operating personnel is providing can be designed to fit the operating staff for convenient housekeeping. The slop who, after ail, have quite a responsibility ing of floors for flushing, the provision of in the success of any production. Suffi drains in the right places, a piped vacuum cient space between the equipment units cleaning system, and the location of equip has been mentioned. Available headroom and the introduction of stairways rather ment with proper clearances add much tu the case of housekeeping. than vertical ladders has been a contri I have only touched on bhe ways the bution of safety groups. The location of industrial hygienist may help the chemi sampling points is important, for it is cal engineer. The examples given are difficult to take a sample of a liquid if only indicative of the innumerable prob the valve is located two feet above the lems that may arise. Basically, the eoa- man's head. In the ease of certain liquids, tribertions that industrial hygienists may it would be unfortunate if any were make to the chemical and related indus spilled on the skin or splashed into tire tries in the matter of plant location and c>e. Then too, it should never be necessary design arc twofold: providing correction for existing unsatisfactory environmental to lie down on bhe floor underneath a re situations, and preventing such ocourrance action vessel in order to obtain a sample. Attention to such a detail as the technique in the future. While the industrial hygienist must be of taking a sample when hazardous chemi familiar with the problems of plant loca cals are involved becomes an item of con tion and design, his greatest responsibility siderable importance to the man who is is to incorporate bis special knowledge of engaged in sampling. Here again, pre health hazards with the considerations oi ventive engineering through forethought may prevent a bad burn, a skin rash, or efficient and economic production. There was a time when American industry- the loss of an eye. Provision for vacuum showed too little concern for the physical sampling, through a closed system, fre quently can be a matter of original de well-being of working men. However, for at least bhe last 20 years, management has sign. Neither is it necessary to open a become increasingly aware o f- its obliga large kettle manhole and dip out a sample tion to protect health and provide good using a flask on the end of a long stick. This method of sampling would not be wise if toxic vapors escaped the kettle manhole during sampling. The design and location of piping may result in discomfort unless the demands on the operator in the plant are kept in mind. Pipe location may result in tripping injury or head injury or may provide an obstruction which must be crawled under or climbed over several times a day in the working conditions for its employees Millions of dollars have been and are currently being spent in this human in vestment. Management also realizes that this consideration for its employees' health and for good working conditions, along with being an unobtrusive member of a local community as fax as air and stream pollution arc concerned, has paid off is 4 the additional benefits of better employee relations and general good will. course of an operator's duties. The loca tion o{ valves at convenient levels is also important. These arc but a few of the items that extend thinking beyond the THU first of a aeries of papers lo be p u b lisb ra ni successive issues of C&N'. T h e Sym posium LndustnaJ H ealth and Safety was presented the 117th national ACS m eeting m Detioiq April 18, 1950. .i 1200 C H E M I C A L A N D E N G I N E E R I N G N E W_*