Document OzpLoqpXDNB7bkL8GEyLdzxaM

~kZ '"V'P.f'V^-T &) rstJ ). f. 0. /$ // INSULATION *&*-*' T HYGI MON-237 PROGRESS REPORTS FROM THE IIUSULATIOni INDUSTRY HYGIENE RESEARCH PROGRAM Irving J. Selikoff, M.D., Program Director ; Vol/3, No* 4 ' ' Winter 1971 pTfig Here Are' Some, of . . Many, Ways to . Reduce Dust;:..; pened in other environmental [Situations. . . .. b. Does the new material meet engi- . ... neering specifications-and .will-it perform adequately under Condi- 7,.,;'' tions of use? . ise of an unventi- lout the back lightof the dust would Cutting pipe with band *saw equipped with high-velocity, low-volume exhaust system. Compare absence of any air borne dust with that shown in uncon trolled cutting (picture left.) ad Procedures tode- s All Insulation 1970 issue' of Insulation Hygiene Progress Re* ced a joint effort by the Insulation Industry Tch Program, the U.S. Navy, the Department of ulation manufacturers and contractors to control tos dust exposures. ... _ that effort, Duncan A. Holaday and William B. IHRP prepared a procedures guide for shipyard ilication and removal.. Because of its relevance m work, portions of it are given in this issue of pene Progress Reports. ' ; report was presented by the authors at* the Inter* .osium on Safety and Health in Shipbuilding and g, at Helsinki, Finland, on August 30, 1971. Materials-containing reduced amounts of asbestos have been used in the fol lowing applications:. ; -- ' a. Blanket and pad filling <7/; Substitution of the proper types of other pad fillers not only re duces asbestos dust during fabri- ..: cation and installation but also [ tends to lessen the problems dur- [ ing subsequent "rip-out". Addi- tionally, asbestos cloth which has been treated with a dust suppres- . sant is available and its use should . also be encouraged. There are re ports that much less dust will be produced./:/ - '. b. Pipe covering and block ' " Serious consideration should be given to those products contain ing lower amounts of asbestos fiber. Several. British firms have . introduced asbestos-free calcium silicate block and pipe covering.' To date, however, this material has not been adequately evaluated in the United States to determine how it will perform in use... Reduction of Dust by Changes A. Holaday x B. Reitze 1 in air insulation maintain a clean : concentrations of _ist counts") in the ; used to identify lation and to point control methods, for control of exmust be placed on of operating rules. Control of Asbestos-Containing Dusts in Work Methods by Use of Substitute Materials a. Mixing Asbestos Mortar Substitution of materials' contain ing reduced proportions of asbestos or no asbestos at all, is becoming more common in ship construction. Before a material is substituted for asbestos, however, two questions must be carefully considered: a. Has the substitute material been tested? If not, it may turn out to be of the same or greater hazard This operation has usually been done at the job site. While the time spent in mixing is quite. short, considerable dust is pro duced. A tested method of control is to mix the mortar dockside under controlled conditions and : " package the mixed mortar in sev eral containers for transportation to the job site. than the material of known haz ard. This sort of thing has hap- Mortar is also available packaged (Continued on second page) t Puget >yard :xhaust-ventilated gang f pipe assemblies in t assemblies are quite nd are troublesome to n place. A satisfactory doing these jobs, parduring ship repair, mployed by the Puget ml Shipyard, is to ressembly in conveniently >ns and transport them d. Here the old insulamoved, any jiecessary "the pipes performed, issembled section re- top ' . ; is dust dispersion, reit is much more con- re-lag the section in-the when it is in place Any insulation which 1 during transport and epaired after the sec1 place. . ing at job sites 1-cutting at job sites is e. However, dispersion Y these operations can red. A portable downis used by the Puget al Shipyard. This table ; legs so that it can be vn companionways and veniently to the work, lustrial vacuum cleaner :e of exhaust. Scrap is to_a plastic bag, and a :d on third page) rv n co H co H fyj at Puget Sound Naval andiing bend sections, ut in fabrication shop, r and placed in plastic is then labelled with cription. 6113 23830 Reduction of Dusts by Use of Local ,. saws for cutting asbestos cement :: Exhaust Ventilation board are well controlled with these systems. . Dampening fibrous glass blanket filler before cutting. Note lateral draft hood _in which fabrication is done*___ ______ (Continued from second page) dropcloth is placed on the deck under the equipment. f. Fabrication of Pads and Blan kets Pads for valves and machinery should be fabricated in the shop whenever possible. Amosite has been largely replaced by fibrous glass filling with covers of an asbestos cloth which has been treated with dust suppressants. As an effective means for suppressing dust dispersion and collection, the fibrous glass blanket is unrolled, dampened and rerolled. This pro cedure insures that all the blanket will be dampened. The blanket and asbestos cloth shapes are cut in the lateral draft booth. a. Ventilation of Large Power Tools---Band Sates > Control of Humber of Workmen ' . Extensive use of band saws both Exposed . .. in dockside fabrication, shops and, 'on board larger ships such as aircraft carriers make emissions from band saws a major source . of asbestos dust. Control devices for..'such saws have been known for years and are relatively simple. Conventional low-velocity, high-volume . systems, using a negative pressure baghouse for air cleaning, are practical in a fixed installation fabrication shop. a. Scheduling of Insulation Work . Standard industrial hygiene"prac- "i' " tices call for insolating operations which contaminate the atmosphere `"'.-with toxic materials. Areas where insulation work is being done '. under conditions in which dust might be created should be' iso- lated by non-flammable curtains or . other means. Whenever possible, work should be scheduled . 'to Because some' degree of porta' bility is desirable in a temporary shipboard fabrication area, a high-velocity, low-volume dust collection unit is" desirable for ' - minimize the numbers of other tradesmen in the area. Ship con-, struction operations are.jmore! / ; readily scheduled than are ship '- repair or ship-breaking ' jobs. However, every effort should be made to keep the number, of men "exposed at a minimum. In- par-- ticular, rip-out of old insulation ! should always be isolated and, if necessary, performed on an off- shift. Trained workmen supplied . with proper protective equipment ... should always be used for rip-out iwork and it should be scheduled y .for rapid completion. Personal Protective Equipment In addition to dust suppression and dust control procedures, personal pro-, tective equipment is often necessary to reduce exposure and limit, the spread of contamination. The equip ment described below is used in con trol programs; ..... *. *. g. Housekeeping and Clean-up Portable down-draft table developed by a.Protective Clothing Essential parts of a dust control program are housekeeping and __ clean-up procedures. Meticulous attention musPhe given to re stricting the spread of dust and larger wastes. Use of a dropcloth Puget Sound Naval Shipyard for use Protective clothing is required to shipboard. Lightweight- Industrial vac ."'.' .keep, contamination confined .to uum cleaner is used as the air mover. Note plastic bag for scrap and drop- Tcloth-on deck. > > jjVx--; . ... the work areas. One method is to tissue disposable' coveralls_~which ' can be removed when leaving the such use; it may also be suitable .f (Continued on fourth page),- . under a work area vividly illus for, fixed installations. The air trates how much.waste would be . :mover is an industrial vacuum distributed over the general area .-cleaner which pulls ' about 50 . or to lower decks if one were not . cubic feet of air per minute past; used. the saw blade at velocity of more Areas should be cleaned up at the lunch break and the end of each shift, using an industrial than 10,000 feet per minute. This system is a very efficient dust col*, lector. Units such as this can also vacuum cleaner to collect dust be designed to control dusts pro and small scrap. duced by table saws and gang In all possible instances, work ' saws.' men should clean up their own b. Ventilation of Hand Power areas. Where work rules prohibit this, the clean-up crew should be under the direction and super Tools High-velocity, low-volume collec tion systems control dust emis vision of the insulation foreman sions from most small power tools to insure that proper attention is given to this important subject. adequately. Saber saws for cut Use of dropcloth to contain wastes and ting pipe covering and rotary facilitate dean-up. 6113 23831 . pirator-fitting, training of work men and maintenance, detailed in 2188-3-1971 should be followed. a) Reusable particulate-filter- } ing respirators , A variety of reusable particulate- filtering respirators are available. To insure proper fitting, 'several Saber saw equipped with high-velocity, low-volume exhaust system. different makes should' be avail able from which the workman can A small industrial vacuum cleaner being used by a Local 62 asbestos worker for clean-up. (Continued from third page) work area or some time prior to entering the locker room and placed in plastic bags for disposal. powered. ' a) Air-line respirators in which air is supplied to a hood, helmet or facepiece give the greatest de gree of protection. Air is fed to the facepiece from a compressed air-line. The air source must be select one. No one model respira tor facepiece will fit all faces. Routine maintenance is absolutely necessary to replace clogged filters and leaking inhalation or exhala- tion valves. Unmaintained res pirators produce a false sense of security. . Resin Impregnated Paper located, in an uncontaminated Maintenance Troublesome area and if the source is not .` A satisfactory type of protective ^specifically designed for breathing b) Disposable particulate-filter clothing consists of resin impreg purposes, a temperature sensing ing respirators r '. nated paper coveralls. These are alarm must be installed on the Operation of an adequate respira inexpensive and readily disposa compressor or a* carbon mon tor maintenance program can be ble. They prevent spreading con oxide monitoring device must be -troublesome and, if only a few tamination to laundries and elimi- installed in the air-line. men are involved, impractical. . nate pilferage. They are worn for Disposable respirators are avail one shift, then removed and Disposable Hood. ; a able which are designed "to be placed in plastic bags for disposal with other asbestos-containing ' ' worn for no longer than one shift Anti-freeze compounds should not and then discarded. . -be used in the compressor system; 6. ... wastes. Respiratory Protective Equip ment Occasionally some operations gen erate so much dust that it is virtually impossible to maintain satisfactory atmospheric concen trations of asbestos fibers and respiratory protection must be provided to the workers. A variety of respiratory protective equip ment is available from which devices suitable for various situa tions can be selected. American National Standard Z88.3-1971, Safety Guide for Respiratory Protection Against-Asbestos-Containing Dusts (obtainable from Amer . water vapor must be removed by dessicant5 and oil mists removed by a filter. . .' ''' . A plastic, disposable hood has been developed by the Puget Sound Naval Shipyard for situ ations where a "very high degree of protection is required. This hood and other similar ones are available commercially. The air- . line should be fastened to the hood with a quick-disconnect fitting.... Self-powered Respirators b) Air-line respirators connected to a compressed air supply limit ------ movement, and this limitation-can be troublesome. Self-powered res . Education and Training No dust control program can be effec tive unless workmen and supervisors understand the hazards associated with the jobs, the sources of the hazards and the reasons for following recommended procedures carefully. Understanding is only obtained by education of personnel and training in correct operating procedures. For an education and training program to be successful, both management and labor must be concerned and partici pate. As with all safety programs, it is essential that first-line supervisors be interested in and cooperate in the work. ican National Standards Institute, pirators do not impose such limi The harmful effects of neglect of pro 1430 Broadway, New York, N.Y. . 10018) should be referred to for detailed information. tations, but they do add to the equipment the workman must carry and they also require care ful maintenance. cedures for controlling asbestos dust are not apparent for many years. Therefore, it is more difficult to con vince workmen and supervisors of Invisible Dust - 2. Particulate-filtering Respira the necessity of following rules for It is emphasized that unsatisfac tory amounts of respirable dust can be present in tire air even though conditions are not visibly dusty. 1. Air-supplied Respirators Extremely dusty jobs, such as ripout of old insulation where dust tors There are several types of par ticulate-filtering respirators. Those with a half-mask facepiece are considered most suitable for use by insulators. Only thoseY ap proved for protection against as bestos dust by the U.. S. Bureau of Mines should be used.' These working ' with insulating materials than if more obvious physical haz ards were involved. Education in hazards associated with. use of insulating materials and in struction in correct work practices should be included in apprentice training programs. concentrations are very high, re quire use of air-supplied respi rators which will deliver clean, dust-free air to a facepiece or devices are recommended for use in situations where the atmos pheric concentration of asbestos PHOTO CREDITS: Pg. 1, I.I.H.R.P.; pg. 2, Ryder. Industries and Puget Sound Naval Shipyards (P.S.N.S.); hood. Two general types are fibers is at relatively low levels. p. 3, P.S.N.S.; pg. 4, I.I.H.R.P. and --'affable: air-line and ' self- All the recommendations for res- P.S.N.S. 6113 23832