Document XE2gqjNGY0y7erax66RexRYg

PLAINTIFF'S EXHIBIT DUP-1389 / E. I. du Pont de Nemours & Company Wilmington. Delaware i9S9 \ ENGINEERING DEPARTMENT CC: J.A. Sigman-Textile Fibers-Wilm J.A. Collins-M.L. Monack J.R. Allen January 5> 1971 R. B. HAYDEN TEXTILE FIBERS DEPARTMENT NEMOURS BUILDING, WILMINGTON INDUSTRIAL DEPARTMENTS MATERIALS ENGINEERING THERMAL INSULATION RELATIVE DUSTINESS STUDY Attached is a copy of a study report by Haskell Lab. on the dustiness of thermal insulation materials. This study was initiated by the Materials Engineering Group of ESD and was done in conjunction with Haskell Lab. and the Engineering Test Center as a part of the Company Thermal Insulation Program. The purpose of the study was to determine the relative potential dustiness, as received from the manufacturer, of the asbestos bearing thermal insulations presently in our engineering standards. With the information contained in this report and the following information in this letter, it should be possible to select insulations, when handled with reasonable care, that will fall within the presently established Threshold Limit Values (TLV) for asbestos dust. Conversely it points out the brands of insulation that present the greatest potential hazard. I recommend that the fiber count be used to determine the least hazardous material rather than the materials -with higher coarse/ fine ratios (irrespirable/respirable) since the fiber counts are made on what are essentially respirable samples. Note that the count of fibers greater than 5 microns in length represents only an 18 minute sampling period. The Threshold Limit Values (TLV) established by the American Conference of Governmental Industrial Hygienists represent time-weighted concentrations for a 7 or 8-hour work day and 40-hour work SETTER THINGS FOR SETTER LIVING . . . THItOUOH CHEMISTRV DUP IMJ 026 DU 055019 2 January 5i 1971 R. B. Hayden week. An insulator working under normal insulation shop conditions would be exposed to much less average concen trations. The ACGIH states "Time-weighted averages permit excursions above the limit provided they are compensated by equivalent excursions below the limit during the work day". The statement in the report that the composition of the samples taken during sawing were the same as the samples taken after a settling period is significant in that we should not favor materials that visibly appear to have rapid settle out of dust after working them. An inquiry to all of the manufacturers of the materials we tested determined that the types of asbestos in the insulations was either amosite or chrysotile; none con tained any crocidolite, which is considered to be the least desirable. The percent of asbestos content of each of the insulations, as advised by the manufacturers compared very closely to the amounts determined in our study. Specific recommendations have not been made because the insulations showing the least fiber count can be handled so carelessly that they can become the most hazardous, and conversely the ones showing the higher fiber counts can be handled so carefully that they become the least hazardous. Since insulation shops and operations vary widely throughout the Company the insulation selection should be made to meet the specific site conditions. If I can be of further service to you, please contact me. ENGINEERING SERVICE DIVISION G. E. Lang, Consultant Materials Engineering GEL/cgs Attach. DUP III 1027 DU 055020 ;V! V\ New Dust-Mist Respirator Put On the Market A new disposable dust-mist respi rator was introduced by the Safety Products Division of the American Optical Corporation on October 26. The commercial availability of the first effective disposable respirator culminates two years of effort on the part of the IIHRP to obtain a res pirator suitable for insulation work ers. (See Insulation Hygiene Prog ress Reports, vol. I, nos. 2 and 3, and vol. 2, no. 3.) Thu p^ttc "tent" fitted over Cepe Asbestos Ctopiny turbine controls dust during rip>^ out end sWtytng operetions. The smell portable vtcoiun exhauster seen, on the left provide*. negative praieure urnde the "tent." Anti-Dust CrewsXrained -With Special Va) Specially trained insuIatioiKdemo- lition and rip-out crews using nhwlv ^developed techniques and equipme including special vans fitted with'' change rooms--are now operating in Grear'Britain. The Choe Asbestos Corporation of London ha^nstituted the program in order to minimize the exposure of workers to insuNdon dust. Details of the program were re viewed with IIHRP personnel by Mr. Alex Cross and Dr. water Smither of Cape Asbestos. This part of the continuing program of coopera tion between insulation inanqry ^.scientists and engineers in unities and the IIHRP. Both Dr!' SmHher and Mr. Cross visited Mount SinaiNhiring the summer to study dust contaol measures developed here. Change Roctlqs and Showers Each special v\contains a "clean room" for taking ol^Jand later put ting on) street clothesNud a "dirty room" for putting on (lhter taking off) work clothes. Shower facilities are available for use after wore The men working with the unit are rained in the latest techniques to mhumize dust production. Moreover theyVue all necessary personal pro- tectioniquipment and clothing. This includes plastic or nylon coveralls and air-supplied or face respirators, when appropria During the rental of old insula tion material, the w^*k area is com pletely enclosed and ou)v trades are excluded. Material to beSsmoved is extensively wetted and localized ex haust systems are used whenever pos sible to minimize dust spread. Imimtim Dust Exposure program now introduces on land mateures similar to those used for insulation removal aboard ship. (See story ofepage 4 on insulation work in Britisn'Kaval shipyards) Dr. Smither, wVq is Medical Di rector of the Cape A^estos Corpora tion, emphasized that the workers in the special crews will norVxperience greater dust exposure than those ap plying new insulation. "The procedures and the protl ye squipwnt available to those i qce their dust exposure to a minimumtChe said. A tww disposable dust-mist respirator. It weighs only 1% ox. 90% of Dust Excluded The disposable respirator an nounced by American Optical has been awarded a United States Bu reau of Mines approval under Sched ule 2IB. Under this approval sched ule, certain respirator efficiency stan dards must be met. These include lack of penetration of dust through the filter material, low resistance to breathing with stan dardized loading, and little leakage about the face seal. It is this last standard that, in general, limits the efficiency of ap proved respirators. Under Schedule 21B, the face seal must exclude 00 per cent of the dust from a standard ized aerosol. Six Points in Favor The most important features of the American Optical respirator are: 1. a new fibrous filter medium that is highly efficient. 2. a large effective filtering area to provide very low resistance to breathing. 3. a weight only ounces. 4. a foam-face-sealing gasket that is efficient and, in. addition, improves wearer comfort, 3. a malleable metal frame that permits the wearer to adjust to the contours of his face, and 6. two adjustable harness straps to allow a good fit of the res pirator on the face. Worker Acceptance Other disposable dust respiratory, manufactured by the Minnesota Min ing and Manufacturing Co. and by the Welch Manufacturing Co. have been field tested by the IIHRP for worker acceptance. Also under development are mod els by other manufacturers, including Willson Products Division of ESB Inc. dup mi028 0Gi31 DU 055021