Document Rj0bMX9REB7Ja6No3NqdgE5Dk
INDUSTRIAL HYGIENE DUST SURVEY CERTAIN-TEED PRODUCTS CORPORATION
600 ST. CYR ROAD ST. LOUIS, MISSOURI 63137
PREPARED BY D, BHATIA
ENGINEERING SUPERVISOR APRIL 13, 1973
CTD017831
I. INTRODUCTION II. SUMMARY III. CONCLUSIONS IV. RECOMMENDATIONS
V. DISCUSSIONS VI. APPENDIX
Industrial Hygiene SurveyData Sheet Industrial hygiene AnalysisReport Field Analysis Report
1 1 2 2 3 $
6 8 10
CTD017832
I. INTRCDUCTICN
At the request of the Management of Certain-Teed Corporation, an Industrial Hygiene Dust Survey of the St. Louis Plant was conducted on March 13th and lUth, 1973. The primary purpose of this survey was to determine the asbestos concentration at those locations where employees were suspected of exposure and to evaluate the effectiveness of some engineering controls. This report documents the results based on the operating conditions found on the days of our survey.
We were assisted by Mr. W. Fisher, Safety Supervisor in the air sampling and the survey of the plant. We reviewed with Mr. S. Layshock, Plant Manager our sampling procedures, locations where samples were collected, and the results of previous test samples.
This survey was completed by Field Assistant Tuttle and the writer.
II. SUMMARY
Asbestos exposure was evaluated by sampling air in the breathing zone
of workers at pipe machine feed end in the manufacturing plant,at the
re-work saw area,and at the Plant No. 3.
The samples were taken to
reflect an average concentration and the maximum concentration during
work periods. The results indicate that average asbestos concentrations
range from 0.3U fibers per ml to 1.16 fibers/ml and that maximum or peak
concentrations range from 2.5 to 3.1(6 fibers/ml.for asbestos fibers of
greater than 5 microns in length. None of these concentrations exceed
the present allowable limits for asbestos' which is 5 fibers/ml for
8 hr. time weighted average (TWA), and 10 fibers/ml as a ceiling con
centration. No exposure due to asbestos is deemed to exist.
Quartz was also detected in the samples collected in the manufacturing
plant, and the concentration of this contaminant in the total dust sample
varies from 3 to 20$.
The calculations show that Mszzane clean-up man
is the only worker who is exposed to silica, the concentration of which is
1.53 mg/M^ on 8 hr, TWA basis. The permissible concentration on the same
basis is 1.37 mg/M^ total dust containing 20$ quartz.
The performance of several exhaust ventilation hoods for controlling the contaminants levels were evaluated by measuring hood velocities. The duct velocity of several hoods could not be measured as the plant mechanic was not available for drilling boles in these ducts. The velocity measure
ments indicate that improvements are desirable for hoods which are used in several sawing operations to further reduce the asbestos levels, although sample results show that the asbestos concentrations in the air are not excessive. Improvements are needed in dust removal system for silica transfer and weigh system to reduce the exposure to silica dust.
CTD017833
-2-
III CONCLUSIONS
1. All locations which were sampled in this survey, employee exposure to asbestos fiber ( 5 microns) does not exceed the current permis sible limits of 5 fibers/ml.
2. Only Mezzane clean-up man is exposed to silica dust because of deficiencies in silica dust removal system.
3. The design and effectiveness of some of the hoods is not adequate based on contaminant capture velocity requirements recommended by American Conference of Governmental Industrial Hygienists.
h. Leaks at the secondary scrap crusher are one of the causes of the asbestos dust detected in this area.
IV. RECOMMENDATIONS
Although, exposure to asbestos is not deemed to exist, the following recommendations are submitted to improve the performance of engineering controls provided, and to assure that asbestos concentration would con tinue to remain at the acceptable level.
1. Repair the leaks at the secondary scrap crusher to prevent the dispersion of asbestos fibers in the air. Asbestos dust was observed to be leaking at several points under the scrap crushing system and accumulated at the ground level after falling through air.
2. Increase the hood entrance velocity to 1000 fpm at elbow blank saw, re-work saw, and coupling saw to improve the performance of these hoods. Considerations should be given to possibly redesign these hoods so that the sawing operation can be conducted in an enclosure.
3. Newly installed Moody Fluffer hood should have a face velocity of 75 fpm for capturing any asbestos dust released from the bags.
k. Exhaust air velocity under the Fines Weigh Scale Hopper should be at least 100 fpm to capture silica dust. The present hood is partially plugged and not effective under the hopper where a large volume of silica dust is generated everytime the hopper is emptied.
5. Exhaust ventilation systems in the plant should be monitored periodi cally (one to two months) to insure their effectiveness in removal of air contaminants. The monitoring program should consist of the following measurements:
a) Static pressure at each saw hood
b) Face velocities of large hoods
C-1 1769 (B) PRINTED IN U.5.A
CTD017834
T
-3-
IV. RECOMMENDATICNS
5. (continued)
c) Pressure drops across each dust collector equipment
d) Duct velocities in branches and the mains. The velocities should be maintained at h$00 fpm in branches and 3500 fpm in the main lines to assure that dust particles won't settle out in the ducts.
V. DISCUSSIONS
All samples for asbestos exposure were collected within the breathing zone of the workers on membrane filters of 0.8 micron porosity in an open-face holder. The filter holder was attached under the chin of the worker as he went about performing his normal tasks. Samples were collected for the determination of 8 hr. TWA concentrations and of ceiling concentrations of asbestos fiber, with only a few exceptions. The sampling data is recorded on an Industrial hygiene Data Sheet and analytical results of these samples are shown on an Industrial Hygiene Analysis Report, both of which are attached.
As expected, the samples which were taken to determine the average con centrations i.e. those which were collected for a longer time period showed lower concentration of asbestos than those which were taken for a determination of ceiling concentrations. However, results show that none of these concentrations for asbestos exceed the permissible limits.
Since silica is handled in the manufacturing plant, crystalline quartz
was detected in the Samples No. 722A, 709A and 73UA. On the basis of
percent qudrtz analyzed in these samples, only Mezzane clean-up man
(Sample No. 73ljA) is exposed to quartz in the total dust sanple. His
calculated 8 hr. TWA concentration is 1.53 mg/M3 as compared to allowable
limit of 1.37 mg/M^ total dust.
The allowable total dust concentration
is calculated from the following formula for 20? quartz in the dust:
Total Dust = 30 mg/M3 %-51$ * 2
Silica transfer and weigh system is only source of quartz, and the ventilation measurements showed that local exhaust hood under the weigh scale hopper is ineffective. At present, this exposure is being controlled by use of respirator by the men working in this area. We recommend that the entire silica transportation system should be inspected for leaks,and dust removal ducts and hoods should be repaired to insure that sufficient
dust capture and transport velocities are available.
C-1 1 769 < B! PR in TED in u.S a
CTD017835
-14-
V. DISCUSSIOtS (continued)
Air velocity measurements were taken at the face of several hoods to determine their effectiveness in removing contaminants. All hoods for cutting saws have low capture velocities, and their effectiveness is further reduced by entrapment of dust in the pipe being sawed. This entrapped dust is released at the open ends of the pipe (particularly at re-work saws) which consequently disperses into the work environment. The feasibility of capturing dust from an open end of pipe or conducting the sawing operation in a partial enclosure should be investigated.
Observations at the scrap recovery area indicated that there are several leaks at the secondary crusher end which are releasing asbestos fiber into the air. Repairing these leaks would continue to maintain a low concentration of asbestos in the air.
We noticed that all locations where samples were taken, use of approved respirators was enforced to protect the worker.
C-1 1769 (B) PRINTED
CTD017836
VI APPENDIX
C-1 1769 <B) PRINTED in li.S.a
CTD017837
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CTD017841
Engineering
-8
^ALYS'S
142-73(3)
| CUSTOMER 1 Certain Teed Prod.
JAMPLC SINT 0V
Bhatia
OATE RECEIVED
3/16/73
DATE REPORTED
4/4/73
MATCRML <LIIC3
Asbestos, '/. Quartz, Total particulate
SAMPLE NUMBER
LOCATION
Af ORtSS
St. Louis
i ANALYST
1
722A
#1 Pipe machine - fiber feed
CHEMICAL, ENVIRONMENTAL & PRODUCT EVALUATION UNIT
TEST RESULTS
THRESHOLD LIMIT VALUE (TLV)
0.28 mg
356 L
.
0.79 mg/M tota^L
particulate
1.08 fibers/ml 5 fibers/ml >5u
fin length asbes:
8% quartz
732A 709A
If2 Pipe machine - Fiber feed 02 Pipe machine - Fiber feed
3.37 fibers/ml 5 fibers/ml
asbestos
in length asbes;
0.32 mg
420 L 0.76 mg/M^ total
particulate i
0.75 fibers/ml 5 fibers/ml >1
asbestos
cLn length asbt
3% quartz
'
734A
Mezzane Clean-up man
0.35 mg
206 L
1.7 mg/M total
particulate
0.65 fibers/ml fibers/ml >5;
asbestos
jin length asbest
20% quartz
690A
Rework saw
695A
Rework saw
735A
Coupling saw
ANALYTICAL Mi TrtOD
Gravimetry Microscopy Spectrophotometry
3.46 fibers/ml |5 fibers/ml >5t
asbestos
tin length asbes:
0.86 fibers/ral |s fibers/ml >5y
asbestos
jin length asbes:
2.6 fibers/ml 15 fibers/ml >5y
asbestos
in leneth nsbes:
CTD017842
C-IS449 NEW 1-72 TrinTCD tN u.S .
TRAVELERS INSURANCE COMPANIES
HARTFORD, CONNECTICUT
Engir. Turing
AM /L* 5' S NO. 142-73(3)
SAMPLE sent by
MATERIAL analyzed
j CUSTOMER
| DATE RECEIVED
SAMPLE NUMBER
DATE REPORTED
LOCATION
AO /RESS
analyst
715A 691A 728A 693A 729A
Coupling saw Elbow blank saw Elbow blank saw Fittings truck driver Tennant mobile sweeper
CHEMICAL. ENVIRONMENTAL PROOUCT EVALUATION UNIT
TEST RESULTS
THRESHOLD LIMIT VALUE (TLV)
1.16 fibers/ml 5 fibers/ml >5y
asbestos
in length asbesto
2.5 fibers/ml 5 fibers/ml >5u
asbestos
Ln length asbestc
1.01 fibers/ml 5 fibers/ml >5u
asbestos
in length asbestc
0.34 fibers/ml 5 fibers/ml >5u
asbestos
in length asbestc
1.06 fibers/ml 5 fibers/ml >5-u
asbestos
in length asbesto
AKAl> TICAL ''iTCD
C-IMI9 NfW 1-72 RRINTLO
CTD017843
TRAVELERS INSURANCE COMPANIES
HARTFORD. CONNECTICUT
Engineering
FfELD ANALYSIS REPORT
CUSTOMER
Certain Teed Products Corporation
SERVICING ENGINEER
So Tuttle and D. Bhatia
SAMPLE NUMBER
-10-
LOCATION
LOCATION
SOO St. Cyr Road, St. Louis, Mo. 63137
SERVICING OFFICE
OATE OF SURVEY
St. Louis. Ho.
3/l3-lli/73
TEST RESULTS
#1 Fiber Feed Hood #2 Fiber Feed Hood Moody Fluffer Hood Primary Scrap Crusher Re-Work Saw Hood Fines Weigh Scale:
6" away from hood Under Weigh Hopper
Coupling Saw Hood Coupling Saw Stop Hood Elbow Blank Saw Hood Elbow Blank Flange Hood
Velocity fpm
Measured
Recommended
230 150
175 150 35 75 90 100
650 1000-1500
100 0
1300 U30 UUo 390
100
1000-1500 1000-1500 1000-1500 1000-1500
INSTRUMENT USED
Alnor Velometer - 6000 P, TIC #8
MATERIAL SAMPLED
Exhaust Hood Velocities
C-15448 NEW 1-72 PRINTED IN U.S.A.
CTD017844
TRAVELERS INSURANCE COMPANIES
HARTFORD, CONNECTICUT