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HASKELL LABORATORY MEDICAL RESEARCH PROJECT MR-1311 Pu3tine33 of Thermal Insulating Materials _ Introduction The study which is reported herein is part of a study initi ated by the Thermal Insulation Group of the Engineering Services Division. Purpose The purpose of the study was to attempt to devise a means of measuring the comparative du3tine3s of several competitive insula ting materials in relation to the risk of injury to health during their installation, use, removal, and disposal. The health risk in working with thermal insulating materials consists of the danger of contracting lung disease from excessive inhalation of fine dust, including, in particular, asbestos fibers. The magnitude of the danger is dependent upon (a) the amount of dust inhaled, (b) its particle size, and (c) the composition of the crystalline particles or fibers. Glossy, non-crystalline particles and fibers have not been implicated in producing lung disease. In this study we attempted to compare the amounts of dust generated from each of the test materials when subjected to mechanical energy in a repeatable, reproducible manner, to examine the relative amounts of coarse and fine particles, (roughly the irrespirable and the respirable) and to examine the crystallinity of the fine dust by x-ray diffraction. Methods The tests were carried out at the Engineering Test Center by Engineering Department personnel jointly with Haskell Labora tory personnel. They were done in a small, closed room at the Center in which there was a minimum of air movement. The thermal insulating materials that were chosen for entry into the comparative series were furnished by the Engineering Service Division. They were in the form of slabs-, 2 inches thick. Mechanical energy was applied to the slab by making a series of 18-inch cuts with a circular table saw operating at a fixed speed. The cuts were timed and the times were held constant for all of the materials. The sequence that was followed in making the cuts DUP 0973596 Dustiness of Thermal Insulating Materials (Cont`d) Page 2 and in collecting samples of airborne dust is presented in Appendix A. Sampling Equipment. Three series of samples of airborne dust were collected sirautaneously during the sawing and another three series were collected after the dus^ had had time to settle out of the air. The first series consisted of a sample collected by drawing air through a raillipore membrane filter (0.8 micron pore size) by means of a Unico Telmatic Air Sampler; a second series was collected by draw ing air through a similar filter by means of a small battery oper ated personal sampler of the type that has been in use in the con struction division for the past couple of years. The third series of samples was^ collected by means of the Unico 550 Turbinjet High Volume Air Sampler. It pulled the air first through a Model 240 Cyclone Separator. The fine fraction of dust passed through the cyclone and was deposited on Whatman No. 41 filter paper. In Appendix A, the high volume sampler is referred to as Hi-Vol and the millipore filter sampler is referred to as M. F. Fiber Counts. Thejnillipore filters from both the Telmatic samplers and the construction division samplers were used for counting fibers according to the method currently in use by the U. S. Public Health Service. This is a count with a 430 x magnification, using phase contrast illumination and counting all fibers greater than 5 microns in length. Weight Determinations. The cyclone separators were each weighed before and after dust collection and the difference was recorded as the weight of coarse dust. Each of the Whatman filter papers was weighed before and after collection and the difference was recorded as fine dust. X-Ray Diffraction. The filter papers on which had been deposited the fine dust were submitted to the Chemical Physics Department, Carnegie-- Mellon University, for identification of the minerals by means of x-ray diffraction. Statement of Results Fiber Counts. The results of fiber counts are presented in Table 1. In this table the designation C after the Roman numeral identification of each material refers to the sample collected by the use of the DUP 0973597 .mm. sbi ajjaeg- Dustiness of Thermal Insulating Materials (Cont'd) Page 3 construction division sampling equipment. The fiber counts that were obtainedjErom the raillipore filter used with the Telmatic sampler during sawing are presented in Figure 1. Figure 2 gives the results obtained from the millipore filter samples collected with the Telmatic sampler after settling. Figures 3 and 4 pre sent graphically the counts obtained from the millipore filter samples collected by use of the construction division sampling equipment during sawing and after settling respectively. Weight Determinations. In Table 2 are presented the results of the weighings of the cyclone separators and the filter papers with the calculated ratio of the coarse to the fine fractions. The ratios are plotted graphically in Figure 5 and Figure 6 representing the ratios dur ing sawing and after settling respectively. It will be noted that air volumes were not equal for all of the samples collected. It was satisfactory to calculate ratios of coarse to fine fractions with the weights that were actually obtained, but in order to make a meaningful comparison of the quantity of the fine dust generated by the sawing per unit volume of air, it became necessary to adjust the weights of the fine fractions to _an equal air volume for all samples. The results are given in Tables 3 and 4 and they are plotted graphically in Figures 7 and 8. Results of X-Rav Diffraction Analysis. The fine fractions of dust that were deposited on Whatman 41 filter paper after passage thru the cyclone separator were sub mitted for analysis by means of the Debye-Scherrer technique. The results are presented in Appendix B. It will be noted that with each material the composition as seen by x-ray diffraction remains the same for the fraction col lected during-sawing and that collected after settling. This rules out any selective settling of components of the mixture on a scale sufficient to influence the health effects of inhaled particles before and after settling. The finding with respect to Unibestos is clear-cut. It con sists of aroosite asbestos. In the group represented by Calsilite SS, Super-Caltemp, and Thermasil? and in the group consisting of Kaylo 20, the report states a possibility of the presence of either amosite or crocidolite. This question should be settled by reference to the suppliers because crocidolite would be less desirable from the health standpoint. There are reports of disease having occurred from relatively brief exposures in contrast to the slowly developing effects from long exposure in the case of the other asbestos forms. DUP 0973598 Dustiness of Thermal Insulating Materials (Cont'd) Page 4 If crocidolita is absent, the groups containing Calsilite SS Super-^altemp, Thermasil, and also Kaylo 10 STS and JM Silicated * Thermobestos are about equal with respect to composition: they are all mainly a non-asbestos mineral (tobermorite) and about 10 per cent of an asbestos. Minerals like tobermorite are classed among the "inert" qr nuisance particulates with respect to health effects, e.g., Portland Cement. Kaylo 20 was found to contain a higher asbestos content, and also an unidentified crystalline material. Comparison of Materials. Table 5 presents a conditional ranking of the subject materials based strictly upon the numerical results of fiber counts, weights of fine fractions and the ratios of coarse to fine fractions for each material. This classification, even when combined with the composition data, gives no clear-cut indication of superiority. It may be reasoned that Kaylo 10 STS and JM Silicated Therrao- bestos, both of which have low asbestos content, performed remark ably well with respect to numbers of countable fibers and favorable weights of fines and ratios of coarse to fine. The I&B Material and the Unibastos gave comparatively high fiber counts but were lowest in weight of fines and extremely favorable in ratio of coarse to fine fractions. It should be remembered that the fiber counts were made on whole airborne samples collected on mem brane filters without prior size-separation. The I&B Material and Dnibestos are apparently high in content of fibers that are count able by optics and by definition, but, when subjected to aerodynamic size separation, the dust cloud from both materials yielded extreme ly low weight of fines. Unibestos is less desirable on the basis of asbestos content. Calsilite SS, Super-Caltemp, and Thermasil behaved in a similar range of performance with respect to fiber counts and weights of fine fractions, A strong point in their favor is the low asbestos content (unless it should be crocidolite). Kaylo 20 is a favorable material with respect to fiber counts and weights of fines. More information should be sought on its asbestos content before passing judgment. J. F. Morgan/bjd Haskell Laboratory December 14, 1970 DUP 0973599 * m WFWKiiliaii mv*tm fflwal- ? ' TABLE 1 NO. Z I-C II II-C III III-C IV IV-C V v-c VIII VIII-C IX IX-C X x-c XI XI-C XII XII-C XIII RESULTS OF FIBER COUNTS Material 10 Fibers > 5 p. per Filter Unibestos 17.1 Unibestos 11.8 Unibestos 4.9 Unibestos 6.1 Thermasil 2.4 Thermasil 2.5 Thermasil 2.5 Thermasil 1.0 Kaylo 10 STS 1.1 Kaylo 10 STS Kaylo 10 STS Kaylo 10 STS 1.6 1.0 0.71 Kaylo 20 Kaylo 20 9.5 5.3 Kaylo 20 Kaylo 20 JH Silicated _ Thermobestos 6.9 3.6 1.3 ^ JM Silicated Thermobestos 0.41 JM Silicated Thermobestos 1.2 JM Silicated Thermobestos 0.46 Calsilite SS 17.5 Air Volume (ml) 14,400 10,400 -- 13,000 21,600 10,400 24,000 14,000 22,400 10,400 28,000 13,000 22,400 10,400 28,000 13,000 22,400 Fibers >5u Der ml 1180 1130 -- 470 111 240 104 72 49 154 36 55 424 510 246 277 58 10,400 40 28,000 43 13,000 35 22,400 780 DUP 0973600 TABLE 1 (COOT'D) No. XIII-C XIV XIV-C XVII XVII-C XVIII XVIII-C XIX XIX-C XX XX-c XXI XXI-C XXII XXII-G XXIII XXIII-C XXIV XXIV-C XXV xxv-c -- RESULTS OP FIBER COUNTS (CONT*D) Material 10 Fibers > 5 p. per Filter Air Volume ' fml) Calsilite SS 12.3 10,400 __ Calsilite SS* 7.9 28,000 Calsilite SS* 3.7 13,000 -- Super-Calterap Super-Caltemp 23.1 23.3 22,400 10,400 __ Super-Calterap 30.5 28,000 Super-Ca1temp Unibestos 7.5 ** 13,000 22,400 Unibestos 61 10,400 Unibestos unibestos 77.7 10.7 28,000 14,500 Therma3il 34.7 22,400 Thermasil Thennasil 12.3 10.2 10,400 28,000 Thermasil 4.0 13,000 Calsilite SS Calsilit*e SS 42.0 4.4 22,400 12,000 Calsilite SS Calsilite SS 11.4 3.7 28,000 14,500 I&B Material 1185-31,32,33 44.1 22,400 I&B Material 1185-31,32,33 24.4 10,400 Pibers >ne5r Pm,l 1180 282 284 1030 2330 1088 577 ** 5870 2780 740 1550 1180 366 307 1870 367 408 255 1960 2440 * There was a 4-minute delay in start. ** Reported too dense to count. 0tJP 0973601 -Life* -'MEgTiHi iSSIJ i TABLE 1 (COOT'D) No. XXVI XXVI-C ; results op fiber counts (cont'd) Material 106 Fibers > 5 ju per Filter Air volume (ml) I&B Material 1185-31,32,33 10.9 28,000 I&B Material 1 1185-31,32,33 6.8 13,000 Fibers >5u per ml 390 523 oHr I DUP 0973602 TABLE 2 -SIZE SEPARATED SAMPLES (Unico Cyclone - Whatman 41 Paper) Unibestos Therraasil Kaylo 10 STS Kaylo 20 Purine Sawing _____________________ After Settling Wt.Coarse Wt.Fines Ratio Wt.Coarse Wt.Fines Ratio gm gm Coarse/Fine gm gm Coarse/Fine ^Xo.osgo 0.0484 1.8388 XX0.0426 0.0186 2.2903 XXI .0432 .0773 .5589 XXII.0196 .0309 .6343 V .0548 0.0993 0.5519 V1II0.0438 0.0274 1.5985 IX.0211 .0388 .5438 x.0056 .0003 ^ 18.66{` JM Silicated Therraobestos Calsilite SS XI .0922 XIII.0444 XXIII.0490 Super-Calterap XVII.0449 I&B Material XXV.0872 .0701 .1235 .0930 .1103 .0142 1.315 .3595 .5269 .4021 6.1408 XII .0468 ^.0135 ""*0151 xxvx.0!61 .0367 1.275 .0282 0.4787 .0476 0.3172 .0459 .2919 .0024 6.7083 ^Apparently anomalous. DUP 0973603 TABLE 3 DUST WEIGHTS. SIZE SEPARATED SAMPLES (Unico Cyclone - Whatman 41 Paper) Adjustment of weights of fine fractions for equal air volumes. A. During Sawing Average air volume for all samples: 70.9 ftJ Material Semple No. Kaylo 10 STS* V Kaylo 20 IX JM Silicated Thermobestos XI Calsilite SSL XIII Super-Caltemp XVII Unibestos XIX Thermasil XXI Calsilite SS XXIII I&B Material XXV Air Vol. (ft3) 71.36 78.72 69.28 61.60 67.28 79.20 67.28 64.16 79.20 Wt. Pines (am) 0.0993 .0388 . .0701 .1235 .1103 .0484 .0773 .0930 .0142 Equivalent wt. Fines 0.0986 0.0350 .0716 .1420 .1160 .0433 .0814 .1025 .0127 09**60 t-wasmi t~ i i--i.iwt.i-a..3ii^.jeiii lisamMB&aiMiaissu TABLE 4 . DUST WEIGHTS. SIZE SEPARATED SAMPLES = (Unico Cyclone - Whatman 41 Paper) Adjustment of weights of fine fractions for equal air volumes. B. After Settling Average air volume for all samples: 98 ft^ Material Sample NO. Kaylo 10 STS ^ VIII Kaylo 20 *X Air,Vol. (ft3) 98.5 ' 99 JM Silicated Thermobestop XII Calsilite SS XXV Super-Caltemp XVIII 96.5 99 99 Unibestos Therraasil XX XXII 99 95.4 Calsilite SS XXIV. I&B Material XXVI 1185-31,32,33 96.5 99 Wt. Pines (am) 0.0274 0.0003* Equivalent Wt.Pines(am) 0.02725 .0367 .0282 .0459 .0186 .0309 .0476 .0024 .0372 .0279 .0454 .0184 .0137 .0483 .0024 * Apparently anomalous. Not to be plotted. UP 0973605 TABLE 5 . CONDITIONAL RANKING OF MATERIALS Fiber Cfounts Telroatic Sampler During After Sawing Settling Fiber <founts Constnaction Sam]aler During Sawing After Settling Weights Fine Fract ions During After Sawing Settling Ratios oi- Weights Coarse t:o Fine During After Sawing Settling Kaylo Kaylo 10 STS 10 STS JM Sil. Thermo. JM Sil. I&B . I&B I&B I&B Thermo. Material Material Material Material JM Sil. Thermo. JM Sil. Thermo. Kaylo 10 STS Kaylo 10 STS Kaylo 20 Unibestos Unibestos Unibestos BEST __________________________________________________ Kaylo 20 Kaylo 20 Calsilite Calsilite UniSS SS testos JM Sil. Thermo. Calsilite Calsilite Kaylo SS SS 20. Kaylo 20 JM Sil. Thermo. Kaylo 10 STS Therma- Kaylo sil 10 STS Super- ThermaCaltemp sil Tharma- Therraasil sil Thermasil Thermasil Kalo 10 STS JM Sil. Thermo. Thermasil I&B Material SuperCalterap I&B Kaylo Material 10 STS JM Sil. Thermo. Kaylo 20 Thermasil I&B SuperMaterial Caltemp I&B SuperMaterial Caltemp SuperCaltemp Super- Caltemp Calsilite Calsilite SS SS Unibestos Uni tes tos Uni tes tos Unibestos Calcilite Caleilit Super r SS SS Calterap Super" Caltemp DUP 0973601S WORST