Document 5kXwOOJggdBXava93BokDBB5e

T TO: Dr. 0. E. Kurt FROM: E. . Brignac DATE: November 15, 1946 SUBJECT : TS 46-4SV, Respirator Filter Tests at Schuylkill Products Company Tests on two M SA "corafo-metal" respirator filter units to datennine their efficiency in removing lead fumes from the atmosphere gave about 95$ removal of lead from air to give an average exit air analysis of 0.004 mg./cu.ft. or less over a period equivalent to four days breathing time. This is within the allowable limits of lead concentration for inorganic lead. The test method consisted of drawing air through the filter which was sealed into a funnel. The funnel was connected to two iodine scrubbers in series followed by a meter to measure the air flow. A standard air sampler was connected in parallel to determine the lead content of the ambient atmosphere. P o o r ' agreement was obtained between the ambient air analysis and the total lead collected in the filter units and train, probably because of varying effect of air currents on the quantity of dust collected by th two types of collection openings, The ambient air was collected through a small glass tube and the filter air ws collected through a comparatively large area opening. Consequently, only results of analyses obtained on the filter train are used in the determination of filter efficiency. The first unit was tested at a height of approximately eight feet above ground level in an area of dense fumes near the Schuylkill Products'Company lead smelter. The second unit was tested at a height of approximately 5-1/2 feet above ground level at the same location. Results of the two test3 are summarized in the attached table. . . During the first test, lasting approximately 120 hours, l,46l cu.ft. of air was drawn through the filter and 5 5 4 mg. f lead was retained on the filter, or an average of 0.0359 mg./cu.ft. was collected. The total lead collected.in the iodine scruboers and on the filter averaged 0.0373 mg./cU.ft. to give a lead removal efficiency of 94$ for the filter. The lead concentration in the air leaving the filter remained at less than 0.002 mg./cu.lt. throughout the test period equivalent to over four days breatning time. The initial concentration of dust in air leaving m e n i c e r was larger than the concentration at the end of the test indicating an increase in filter efficiency as a dust layer builds up on che filter. ' K un vn fui </ 68 N9577 Dr. 0. E. Kurt -2 November 15* 19^6 During the second test, lasting approximately 190 hours, 2,252 cm..ft. of air was drawn through the filter and 206.7 mg. , of lead vas retained on the filter, cr an average of 0.0917 mg./ eu.ft. was collected. The total lead collected in the iodine scrubbers and on the filter averaged 0 .0 9 58 mg./cu.ft. to give a lead removal efficiency of $60 for the filter. The lead concentration in the air leaving the filter remained at less than 0.002 mg,/cu.ft.'during the initial period equivalent to 4 days breathing time, with the exception.of one 0.4-day period in which abnormally high analyses were obtained on both the ambient air and filtered air streams. These results- cannot be explained from the information available. The increased efficiency with time cf use noted in the first test filter was not obtained vi th the second. Rather a decrease in efficiency,, was observed, wi th an increase in lead concentration to 0.007 mg/ cu.it. at the e;ad of the' test. This is probably due to differences in filter units Pressure drop measurements taken during the second test sh&wed an insignificant increase in pressure drop through the fil r unit {less than 0 .0 5 inches of water) during the test -period These tests indicate the filter units provide adequate protection against, lead d u a t : however, additional tests should be made to determine the variation that might exist between filter units. - Notebook References !C60. EVB/mew E . ,, Brignac K 0007869 % RESPIRATOR FILTER TEST RESULTS Sam ple D ate T52 S 1 8/28 2 8/29 3 8/30 4 9/4 5 9/5 T o t a l <Dr Avg. Lead Content of Air at Sample Point Sam ple Mg. Pb Mg. Pb Volum e in per c u . f t . Scrubber c u . ft . Lead Content of Air __After Filter S a m p l e M g . P b "M g T T b Volum e i n per c u . f t . Scrubber c u . f t . d u m u lative Days o f B re akin g T e s t Wo . 1 10 2 15 4 6 6 .0 1 2 . 8- 14 .2 * 0 .15 4 1,5 0 0 2 .50 0 0 .79 2 3 4 9 -0 5.8 0 2 0 .0 0 15 .0 0 9 7 .0 379 .0 0 21 224 10 7 3 75 4 l8 .13 1 0 .0 34 3 1,4 6 1 0 .38 8 .13 4 .4 4 6 .0 32 .0 64 1.0 6 4 0 .0 0 17 .0 0 13 .0 0 12 .0 0 0 0 8 .0 0 0 19 0 .6 .9 2 .0 3 .2 4 .2 0 .0 0 0 9 4 .2 *> 9/25 2 9/26 3 10/1 4 10/2 5 10/3 6 10/7 7 10/8 8 10/9 Total or Avg. 156 37.1 ,. 141 98.7 91.2 111.6 118.5 754.1 Test Ho . 2 1.840 6.410 0 .78 0 .034 .620 2.466 1.070 0 .0 118 38 1 .1727** 136 .0055 ,0004 .0068 315 275 262 285 ,0221 311 ,0090 28 7 13.220 0,0326 2,,252 0.280 2.686 0 .60 0 .312 .367 1.244 1.710 2.040 9.239 0.0007 1.1 .0197** 1.5 .0 0 19 2.4 .0 0 11 3.2 ,0014 3=9 .0043 4.7 ,0054 5.6 .0071 6.4 0.0052 6 .4 '^Vacuum cut off "before end of run, The resulting small sample size makes results unreliable. ....................... **Abnormal results which cannot be explained from the data obtained. ***Air meter not working. OuOt\ & C lo N9577.01