Document RpLqON8jDdQNDkrBxvk5kNZ7E
THE MOUNT SINAI MEDICAL CENTER
ONE GUSTAVE L. LEVY PLACE NEW YORK. N Y. 10029
o* I** or* W**MlWf* C0 tfwfOU
Mount Sinai School of Medicine `The Mount Sinai Hospital
April 11, 1979
Mr. Robert S. Magdelain, President Nilflsk of America, Inc. 201 King Manor Drive King of Prussia, Pennsylvania 19406
Environmental Seitncei Laboratory Cumminf, Basic 5cinc Buildtni 10 Eon 102 Street New York. New York 10029
Dear Mr. Magdelain:
This will report the results of air sampling tests conducted, In October 1978, to determine chrysotlle asbestos concentrations dur ing brake repair work.
Our major objective was to determine the efficiency of the Nilflsk
Asbestos System utilizing HEPA filters, particularly with regard to aubmlcroscople asbestos fibers. Studies conducted in our
Laboratory and elsewhere have demonstrated that free asbestos fibers present In brake drum dusts are predominantly shorter than 5um in length. In particular, It was found that about 752 of the fibers In such dusts were less than 0.3um In length, as determined by
transmission electron microscopy. Thus, the optical microscopic technique used by OSHA for determining asbestos levels In workplaces (In which only fibers 5um or longer are counted) would overlook a
large number of asbestos fibers In air samples. That la, the total asbestos exposure in terms of fiber number, mass and surface area
would be significantly greater than the levels determined using the OSHA fiber-counting method.
Therefore, it was of considerable interest to us to have an oppor
tunity to test the efficiency of the Nilflsk Asbesto-Clene System. To do this personal air sampling was carried out on the exhaust of
a HEPA-filtered vacuum dust collector and, simultaneously, on a garage mechanic cleaning a brake drum with the Nilflsk brake en
capsulation cylinder. Three such tests were made. Background air samples, also using personal air. pumps, were taken.
For each of the teats, ^ sample of settled dust was taken from the brake drum. The dusts wire analyzed by x-ray diffraction in the atepscan mode to quantitatively determine asbestos contents, using a technique previously published. Asbestos was found in all three
samples, ranging from 2.52 to 4,52 by weight.
The membrane filters were analyzed by both transmission electron microscopy (X25,000) and by the standard OSHA fiber-counting
technique, employing phase contrast optical microscopy. The results are as follows:
SCF-ALLF-07590
Mr. Robert S. Magdelain, President Page 2 April 10, 1979
Sample
Description
Nanograms/cu tneter
Fibers/milliliter
(electron microscopy) (optical microscopy)
TEST 01
N-l Background (70 feet from operator)
N-2 Operator (breathing zone - 6 ft. from dust collector)
N-3 Dust collector (HEPA-filtered vacuum)
400 0 0
0 0 0
N-4 N-5 N-6
N-4 N-7 N-8
TEST 02
Background (70 feet from operator)
Dust collector (HEPA-filtered vacuum)
Operator (breathing zone - 6 ft. from dust collector)
Background (same as in Test #2)
ntest
Operator (breathing zone - 6 ft.
from dust collector)
Dust collector (HEPA-flltered vacuum)
615 0
59,000
615 0 0
0.12 0 0.5
0.12 0 0
Mr. Robert S. Magdelaln, President
Page 3 April 10, 1979
Remarks and Conclusions:
V
The teBta demonstrate that asbestos levels are virtually eliminated
by the use of a system employing brake encapsulation device connected
to a HEPA-filtered vacuum du6t collector. Without the use of such
equipment, fiber concentrations during compressed air jet-blowing
of brake drros ranged from 6.6 to 29.8 fibers/milliliter. However,
when the Asbesto-Clene System was used, fiber concentrations on both
the mechanic and dust collector exhaust were not detected, as verified
by transmission electron microscopy. An Important exception to this ,
is observed in Test #2, the sample taken on the operator. Prior
'
to this test, this mechanic had worked on brake Jobs without using
the Asbesto-Clene System and without changing his work clothes.
This exposure had resulted In contamination of his clothes, re
flected In the high residual asbestos concentration of 59,000
nanograms/cubic meter and 0.5 flbers/milllllter. In contrast, the
operator in Test 01 and Test 03 wore clean coveralls. This points
up the need to adhere to the OSHA regulations concerning special
clothing, change rooms, etc. to minimize contamination.
The background asbestos measurements, of 400 and 615 nanograms/ cubic meter, are consistent with other background measurements taken
during brake repair work. They are the result of residual contami nation of the garage by asbestos.
ThlB study has been unique and fortunate in two respects; first
because of the great Interest and importance of determining chrysotlle asbestos levels In such circumstances. The data indicate that the Asbe6to-Clene System represents an outstanding advancement in industrial hygiene procedures to control asbestos exposure. It has also been a pleasure to work with you in preparing and conducting these tests. If there Bre any questions regarding the results or conclusions in this report, please do not hesitate to contact me.
ANR:jm
Environmental Sciences Laboratory
THE MOUNT SINAI MEDICAL CENTER
ONE GUSTAVE L LEVY PUCE NEW YORK. N Y 10029
4>TOMtMCWinIvOmMisirr
Mount Sinai School of Medicine 'The Mount Sinai Hospital
April 11, 1979
He. Robert S. Hagdelaln, President Nilflsk of America, Znc. 201 King Manor Drive King of Prussia, Pennsylvania 19406
Environmental Sciences Laborolory Cummuigi Basic Science! Building 10 Baal 108 Street New Yor*. New York 10029
1212> 050-0173
Dear Mr. Magdelaln:
This will report the results of air sampling tests conducted, in October 1978, to determine chrysotlle asbestos concentrations dur ing brake repair work.
Our major objective was to determine the efficiency of the Nilflsk Asbestos System utilizing HEPA filters, particularly with regard to submicro8copic asbestos fibers. Studies conducted in our Laboratory and elsewhere have demonstrated that free asbestos fibers present In brake drum dusts are predominantly shorter than 5pm in length. In particular, It was found that about 75% of the fibers In such dusts were less than 0.3pm In length, as determined by transmission electron microscopy. Thus, the optical microscopic technique used by 0SHA for determining asbestos levels In workplaces
(In which only fibers 5ym or longer are counted) would overlook a large number of asbestos fibers in air samples. That la, the total
asbestos exposure in terms of fiber number, mass and surface area would be significantly greater than the levels determined using the OSHA fiber-counting method.
Therefore, It was of considerable interest to us to have an oppor tunity to test the efficiency of the Nilflsk Asbesto-Clene System. To do this personal air sampling was carried out on the exhaust of a HEPA-ftitered vacuum dust collector and, simultaneously, on a garage mechanic cleaning a brake drum with the Nilflsk brake en capsulation cylinder. Three such tests were made. Background air samples, also using personal air pumps, were taken.
Por each of the teats, a sample of settled dust was taken from the brake drum. The dusts were aftalvzed by x-ray diffraction In the step8can mode to quantitatively determine asbestos contents, using a technique previously published. Asbestos was found In all three samples, ranging from 2.5% to 4.5% by weight.
The membrane filters were analyzed by both transmission electron
microscopy (X25.000) and by the standard OSHA fiber-counting technique, employing phase contrast optical microscopy. The results are as follows:
CAT-1020195
"I
Mr. Robert S. Magdelain, President
Page 2 April 10, 1979
Sample
Description
Hanograms/cu meter
Pibers/milllliter
(electron microscopy) (optical microscopy)
TEST #1
N-l Background (70 feet from operator)
N-2 Operator (breathing zone - 6 ft. from dust collector)
N-3 Dust collector (HEPA-filtered vacuum)
400 0 0
0 0 0
TEST 02
N-4 Background (70 feet from operator)
N-5 Dust collector (HEPA-filtered vacuum)
N-6 Operator (breathing zone - 6 ft. from dust collector)
615 0
59,000
0.12 0 0.5
TEST 03
N-4 Background (same as in Test 02)
N-7 Operator (breathing zone - 6 ft. from dust collector)
N-8 Dust collector (HEPA-filtered vacuum)
615 0
0.
0.12 0 0
CAT-1020196
Mr. Robert 3. Magdelain, President Page 3 April 10, 1979
ttomarfrn aod Conclusions;
The tests demonstrate that asbestos levels are virtually eliminated by the use of a system employing brake encapsulation device connected to a HEPA-filtered vacuum dust collector. Without the use of such equipment, fiber concentrations during compressed air Jet-blowing of brake drums ranged from 6.6 to 29.9 fJbers/milliliter. However, when the Asbesto-Clene System was used, fiber concentrations on both the mechanic and dust collector exhaust were not detected, as verified by transmission electron microscopy. An Important exception to this Is observed In Test #2, the sample taken on the operator. Prior to this test, this mechanic had worked on brake jobs without using the Asbesto-Clene System and without changing his work clothes. This exposure had resulted In contamination of his clothes, re flected in the high residual asbestos concentration of 59,000 nanograms/cublc meter and 0.5 fibers/milliliter. In contrast, the operator in Test 41 and Test 43 wore dean coveralls. This points up the need to adhere to the 0SHA regulations concerning special clothing, change rooms, etc. to minimize contamination.
The background asbestos measurements, of 400 and 615 nanograms/ cubic meter, are consistent with other background measurements taken during brake repair work. They are the result of residual contami nation of the garage by asbestos.
This study has been unique and fortunate In two respects; first because of the great interest and Importance of determining chrysotile asbestos levels In such circumstances. The data indicate that the Asbesto-Clene System represents an outstanding advancement in Industrial hygiene procedures to control asbestos exposure. It has also been a pleasure to work with you In preparing and conducting these tests. If there are any questions regarding the results or conclusions in this report, please do not hesitate to contact me.
ANR:jm
Arthur N. Rohl, Ph.D. Environmental Sciences Laboratory
CAT-1020197