ASBESTOS CONTROL - AN INDUSTRIAL EXPERIENCE Joseph D. Wendlick
Weyerhaeuser Company Longview, Washington
PLAINTIFFS | EXHIBIT i UC-1586
ABSTRACT
Reductions in airborne asbestos fiber concentra tions by factors of 20-100 were accomplished by instituting an asbestos control program in a plant manufacturing an asbestos-containing calcium silicate. Ventilation techniques, changes in handling methods and improvements in work practices will be discussed as they relate to these reductions. Support programs including protective respiratory equipment, protective clothing, laundering, change rooms, separate lockers, area posting, employee education and orientation and medical sur veillance will also be discussed.
********
In the past 10-15 years, there has been an everincreasing demand for fire-rated products for wall construc tion, ceilings, flooring and floor coverings, interior finish (paneling) and doors. One of the more difficult of the fire ratings to achieve, at least for wood products, was that for fire doors, since traditionally all-wood stave (laminated 1" wood blocks) core or particle core doors showed only a 20-40 minute resistance to burn-through (as tested in accord
2.
ance with ASTM E-152. Metal doors enjoyed an exclusive set of fire ratings from 3 to 8 hours, their only draw back being the high radiant heats emitted from the unexposed face during a fire. There was an obvious need for fire doors with 3/4 hour (C-label), 1 and 1-1/2 hour CB'label) ratings to 1) prevent the spread of fire better than all-wood doors and 2) supply fire-rated doors for structures not required by fire codes to have 3 hours or greater rated metal doors. Because high radiant heats from metal doors have hindered escape from burning buildings in certain instances, a need also existed for a door construction with an intrinsically low thermal conductivity to permit emergency egress past the door in case of fire.
Born of this need was an all mineral core, wood faced and wood-railed door which possessed not only the esthetics of wood but the capability of withstanding the thermal stress and shock of the ASTM E-152 fire and hose stream test. Oxychloride and oxysulfate cements, gypsum board, asbestos-cement board, and magnesia-type block in sulation were all tried unsuccessfully before arriving at the mineral core suitable for this purpose: an asbestos reinforced calcium silicate.
Development of a successful door construction was measured carefully by the door's ability to be fabri cated, pass critical performance tests such as high-
3.
temperature-low temperature cycling without delaminating or warping appreciably and slam testing; but above all, pass the ASTM E-152 fire and hose stream test at Underwriters' Laboratories in Chicago for a 3/4, 1 or 1-1/2 hour rating. Initially and for several years following the successful development and testing of this construction, all of the mineral core block used in this operation was purchased from outside suppliers. However, soon after architects began to indicate a need for 4'x8' to 4'xlO' doors with both C-labels and B-labels and tests at Underwriters' Laboratories on fire doors fabricated with purchased mineral core failed with these larger dimensions, the decision was made to initiate intra-company research into developing an asbestos-reinforced calcium silicate which would meet these more stringent criteria. This intensive research culminated penultimately after 15 months with the successful fabrication and subsequent testing of 4'x8' and 4'xlO' doors at the Company's fire test facilities in Longview, Washington. Successful testing of similar doors at Underwriters' Laboratories approximately 6 months later represented attainment of the final step in development of this product for market.
Albeit success in product development was achieved considerably beyond expectations, a major new area of challenge emerged which demanded immediate attention. Approximately 100 employees at this location involved in either 1) the production
4.
of asbestos-reinforced calcium silicate and 2) the fabrica tion of mineral core fire doors from this calcium silicate material are occupationally exposed to airborne asbestos fibers throughout their 8-hour work shifts. The distinction between employees involved in the production of the calcium silicate and the fabrication of fire doors from this material was made because these two operations are physically separated by several hundred yards on the complex and were, at the time the asbestos control program was instituted, characterized by two markedly different (and efficient) ventilation systems. For the calcium silicate core production plant, employees (numbers in parentheses) are exposed to asbestos the following locations:
a. Weighing room and mixers. (1) b. "Wet" end handling operations. (5)
.c "Dry" end unloading stations. (2)
d. Trim saws (Trims along length of cores)
.e Timesaver sander.
f. Sorting and grading area.(2). g- Salvage saws. h. Lift truck driver.(1).
.i Factotum. (1)
j Quality control. (1) k. Foremen. (1)
.1 Lead man. (1)
m. Maintenance. (1)
5.
Since three crews per day are now engaged in the production
of asbestos-reinforced calcium silicate block, the total
number of employees involved in this part of the operation
should total 48. However, because only the day crew is as large
as indicated above,the actual number is closer to 44. The
process involves weighing and mixing ingredients (including
both chrysotile and amosite asbestos), indurating the slurry
to effect formation of the calcium silicate product, drying
the indurated blocks to achieve a light-weight substance of
density similar to pumice, edge trimming of the core blocks
out of the dryer, sanding top and bottom surfaces of the dry
cores, sorting and grading out the good cores from those which
are fractured, broken or crushed, and reclaiming portions of
reject core blocks through the use of the salvage saws.
Fabrication of fire doors from the calcium silicate
cores in the other half of the process exposes the following
work stations (numbers of employees affected in parentheses)
to airborne asbestos fibers:
a. Double-end tenoners. (4)
b. Electronics. (5)
c. Abrasive planer. (2) (Timesaver sander)
d. Sizing station and drying tunnel. CD
e. Inspection. (12)
f. Foremen. (3)
g- Routing out of lite openings. h. Mortising stations. (2)
(2)
i. Quality control. (1)
6.
Although, the night crew in the fabrication plant makes railed mineral core, generally no sanding of railed calcium
silicate block is performed on the abrasive planer. Detail ing, such as routing and mortising of mineral core doors, is only done on the day shift. Therefore, the approximate number of employees exposed in this plant totals 54. Other employees intermittently exposed are mainly maintenance personnel. A walk-through of the fabrication operation reveals the first operation to process calcium silicate cores from the production plant to be the double-end tenoners, where the tongue and groove configuration is cut along the length and width of the core blocks to match up with wood rails and stiles. From there the core blocks and wood rails and stiles are placed on roller conveyors and directed to set-up position on the "electronics." The core blocks are then railed, cured in an "electronic" press with RF and taken to the feeder position on the abrasive planer (Timesaver sander). Once sanded top and bottom, each railed calcium silicate, core is sized with a dilute phenolic adhesive and passed through a drying tunnel. A rigorous inspection of each railed mineral core block follows the drying tunnel in preparation for application of crossbands and face veneers. Detailing of the completed doors such as routing out lite openings and mortising out lock set openings represents .the last significant asbestos exposures within the plant.
7.
Fiber concentrations from the initial airborne .asbestos samplings of June 1972-February 1973 to determine the relative levels associated with each major work station and machine center in both the production and fabrication plants are given in the table below:
TABLE I
TYPICAL ASBESTOS FIBER CONCENTRATIONS IN Production"'^') AND TaTOCATICM' CP) PLANTS
Work Station
Fiber concentration, fibers/cc greater than 5/t in length
Weighing room* (P)
6.6 - 34.0
"Wet" end dryer loader (P)
1.5
Dryer unloader (P)
5.2 - 9.0
Trim saw operator (P)
3.2 - 6.6
Sorting and grading (P)
3.9 - 17.1
Salvage saws (P)
4.1 - 14.9
Factotum (P)
3.7
Quality Control (P)
2.2
Double-end tenoner feeder (F)
2.5 - (82.0)
Double-end tenoner offbearer (F) Electronic set-up (F)
2.6 - 25.5 6.2
Abrasive planer feeder (F)
6.3 - 19.4
Abrasive planer offbearer -(F)
4.6 - 29.2
Inspection (includes dry hand sanding)(F) 4.7 - 24.3
Routing* (F)
3.9 - 24.8
Mortising (F)
7.7
Clean-up* (compressed air blowing off of equipment) (F)
* Peak exposures only.
37.8
8.
Asbestos samples were collected in conformance with OSHA and NIOSH guidelines using a Mine Safety Appliances Model G Personnel Gravimetric Sampling pump in conjunction with open-face casettes containing Millipore type AA filters. Each sample was collected at 2.0 liters/minute, a flow rate established with a wet test meter. To avoid contributions from contaminated uniforms, a copper wire/baby food can casette holder was used to position the casette in the breathing zones of employees participating in this survey. Collection times varied from 1 minute to 22 minutes, depend ing upon how rapidly visible dust became in evidence on the filter face. From previous experience in sampling asbestoscontaining calcium silicate dusts, any more build-up than barely visible on the filter face made subsequent microscopic counting very difficult. Asbestos counts were made using Leitz microscope with phase contrast illumination at 400-450X magnification in the Company's Longview analytical laboratory.
Once the magnitude of the exposures had been ascer tained, the next step was to implement a multi-faceted control program, comprising: 1) the immediate initiation of a res pirator program 2) initiation of a protective uniform program, together with change rooms, separate lockers, shower facilities, lunch room separate from contaminated areas, and launderomg facilities, 3) improvement or modification of existing ventila tion systems including new pickup heads at the point of asbestos
9.
fiber generation, new ducting, new fans and a new baghouse, 4) instituting a complete medical program to include pre employment physicals, annual physicals thereafter, pulmonary function testing and chest X-rays, 5) an employee educational program to explain the hazard, the need for protective equip ment and the need for changes in some operating procedures and methods of handling and 6) engineering controls other than'ventilation methods. Mr. C. A. Mangold, et.al.'s report on "Asbestos Exposure and Control at Puget Sound Naval Ship yard" (March, 1970) provided the guidelines for the control program described in this report.
Respirator Program A respirator program was the first control applied
to these operations in view of the hazard from asbestos fiber inhalations. For both the production and the fabrication plants, the 3M-8710 disposal dust mask was used,mainly because of its light weight, wearing comfort and low breathing resistance. An overlap with the educational program was necessary to con vince employees of the need for wearing these masks and to demonstrate the proper way to wear them. Other discussions were held with employees to teach them to close the lids on boxes of protective masks to avoid contamination and not to hang these masks around their necks or on a nail at the end of their work shift such that airborne dust collects inside
10.
the mask, to be inhaled on re-application of the mask. For certain individuals whose noses became abraded from improper wearing of the 3M masks, a rubber-sealed MSA Dustfoe 66 respirator was temporarily substituted.
Protective Clothing Since many areas within both the production and fab
rication plants involved direct handling of the calcium sili cate core and were, at the time of the initial testing, in excess of the OSHA asbestos standard ceiling limits, protective clothing was issued to the employees. Separate lockers for street clothes and contaminated clothing were made available to all employees, as well as shower facilities at the end of the work shift. Contaminated uniforms are laundered every 3-4 days, or more frequently, if necessary, in washers and dryers sit uated within the plants. A lunchroom is available separate from the contaminated areas.
entilation Systems While the production plant had been built with a good
\Nntilation system included, the fabrication plant had a system w^ich was constantly overloaded and grossly inadequate for
dling mineral core dusts efficiently. The system that was bei\g used in the fabrication plant had originally been de signed to handle wood dusts from a few machine centers. As the n\>ed to ventilate additional equipment developed, more and
I
11.
more tie-ins to the old ventilation system were made until it became overloaded. A new system of ducting, fans and a larger baghouse with more capacity changed the airborne asbestos concentration in this area considerably. This system was also extended into the detailing department to capture the dusts generated during routing out of lite openings and mortising out lockset openings. Many of the pickup heads on machines were modified to present a high velocity, low volume situation to the point of asbestos fiber generation. A new vacuum system, was installed through out the production plant. Shortly after it became functional, all brooms and compressed air hoses were ceremoniously retired. A portable vacuum is available in the fabrication plant, since the presence of fugitive asbestos fibers is not nearly as ubi quitous. A short canvas skirt was installed on the asbestos weighing hopper in the production plant to increase the capture velocity of the negative air system.
Medical Program A complete medical program has now been in effect
for about 1-1/2 years. This program includes: a) pre employment testing of individuals who may be hired for either the production or fabrication plants to establish a reference X-ray, reference pulmonary function (FEV^and FVC) tests and medical information on pre-existing conditions (viz. - cardio-vascular, respiratory, gastro-intestinal,etc.)
12.
which may disqualify that individual from work with asbestosreinforced calcium silicate, and b) annual testing to provide a check on changes which might occur as a result of an employee's exposure to asbestos. A doctor from a local clinic has directed this portion of the program, and additionally, has provided the essential interpretations of the X-rays and pulmonary function testing.
Educational Program Demonstrably one of the most important aspects of an
asbestos control program, the educational programs presented to the employees resulted in some remarkedly reductions in air borne asbestos levels throughout the operations. Key points discussed at these sessions included: a) a review of the health hazards of asbestos inhalations, b) the OSHA standards, both now and after July 1, 1976, c) the need to wear protect ive dust masks and uniforms, d) the relationship of the med ical program, e) the ventilation system modifications and other engineering controls being put into effect by the Company and finally, f) how they can help as individual employees in this effort by more careful handling of the cores, better operating procedures, etc. In this latter category, such hazardous dust-producing practices as sweep ing, compressed air blowing, throwing of broken core blocks into trash carts or bins, rough handling when stacking or unstacking loads, unventilated skil sawing, hand sawing or
13.
drilling of mineral core blocks, failure to report system plug-ups or missing bolts in fan housings and dropping core blocks onto electronic set-up tables were either minimized or eliminated. All scrap clean-up with squeegees in the pro duction plant must now be done wet to reduce the airborne asbestos fiber contribution from this source.
Other Engineering Controls For certain areas such as the sorting and grading
area and salvage saw area in the production plant and the double-end tenoners, electronics and inspection in the fabri cation plant which defied most of the control methods attempted, a simple but novel approach was devised by plant personnel. Since glue sizing of the core blocks is necessary to effect an acceptable core to crossband bond in the finished product, several employees decided to try sizing each core which passes out of the Timesaver sander in the production plant and the abrasive planer in the fabrication plant. The net result was to bring several areas,' heretofore thought to be next to impossible to control by ''feasible" engineer ing means, into compliance with the 1976 OSHA asbestos standard.
Table II describes airborne asbestos concentrations at key work stations throughout the operation both from MayJune, 1973 and, for reference, those values reported in
14.
Table I earlier. It is difficult to single out any one control which was the most salient in effecting the reductions reported below since all controls have had a contributory effect on re ducing the airborne asbestos dust levels.
TABLE II
TYPICAL BEFORE AND AFTER ASBESTOS FIBER CONCENTRATIONS IN PRODUCTION (P) AND FABRICATION (Fj PLANTS-
Work Station. Weighing room* (P) "Wet" end dryer loader (P) Dryer unloader (P) Trim saw operator (P) Sorting and grading (P) Salvage saws (P)
fiber concentration, fibers/cc June, 1972-Feb.,1973 May-June,1973
6.6 - 34.0
3.0 - 7.3
1.5 1.2
5.2 - 9.0
3.6 - 5.9
3.2 - 6.6
0.50- 2.0
3.9 - 17.1
3.2 - 9.6
4.1 - 14.9
0.50 - 0.90
Factotum (P) Quality control (P) Double-end tenoner feeder (F) Double-end tenoner offbearer (F) Electronic set-up (F)
3.7 2.2 2.5 -(82.0)* 2.6 - 25.5 6.2
1.5 1.3 1.7 - 3.3 0.11--1/1 0.17- 0.60
Electronic offbearer (F) Abrasive planer feeder (F) Abrasive planer offbearer (F) Inspection Routing* (F) Mortising (F) Clean-up*
8.4 6.3 - 19.4 4.6 - 29.2 4.7 - 24.3 3.9 - 24.8
7.7 37.8
0.08- 0.17
5.4 - 7.6
0.30 - 1.1
0.21 -- 1.9 (on peak at 4.6)
6.5
-
1.50
* Peak exposures only.
IS.
Approximate Costs for Controls
Control of asbestos in the production and fabrica^
tion plants has been expensive, as shown by the cost break
down appearing below:
Equipment or Operation
Production plant; including exhaust and collection system (rated CFM = 50,000)
Approximate Cost $125,000
Glue Spreader - Production Plant
10,000
Fabrication plant; new ductwork, baghouse (rated CFM = 30,000)
90,000
Glue Spreader - Fabrication plant
10,000
New back sander - Fabrication plant
20,000
Total Estimated Capital Costs (to date) $255,000
Total estimated Maintenance Cost/year
(Includes $8,000 annually for baghouse maintenance)
$ 60,000
*****
As evidenced by the data in Table II, the controls although costly - have brought both plants nearby into com pliance with the OSHA 1976 asbestos standard of 2 fibers/cc greater than 5 microns in length for an 8-hour time-weighted average. With the additional controls due for implementation by February 1974, total compliance with the 1976 standard is very probable.
16.
References:
. 1. Criteria for a recommended standard - "Occupational Exposure to Asbestos" - U.S. Dept, of Health., Education and Welfare. National Institute for Occupational Safety and Health Criteria Document.
2. Federal Register Volume 37, No. 110 CJune 7, 1972), Part 1900 Occupational Safety and Health Standards, "Standard for Exposure to Asbestos Dust."
3. General Electric "Environmental Health Management Manual" Section 9 on Dust and Dust Diseases, Subsection 9.1 Asbestos, pp. 7-9.
4. "Industrial Ventilation," a manual by the Committee on Industrial Ventilation - American Conference for Govern mental Industrial Hygienists.
5. Mangold, C.A., Beckett, R.R. and Bessmer, D.J. "Asbestos Exposure and Control at Puget Sound Naval Shipyard," Puget Sound Naval Shipyard at Bremerton, Washington (Marsh, 1970).
REPORT OF CALL
CC for
Leon Persson-H&c
W. C. Thurber
J. E. Walsh NF Files
UNION CARBIDE CORPORATION
KC Files
P.O. Box 579 Niagara Palls, N.T. 14302
B> E_ Byrne
Date 1-14-74
Full Name WEYERHAEUSER CO.
3400 13th. Ave. S. W.
Address Seattle, Wash 98134
also ,, Longview, Wash 98632 Mfrs. of
Interviewed
Dr. R. E. Krelblch, Mgr. M. Frank Glllem, Polymer Research
Joseph D. Wendlick, Corp. Ind. Hyg.
OBJECTIVE
''
Attempt to overcome this companys reluctance to
continue evaluation of RG 244.
DISCUSSION
Dr. Krelblch had done promising R&D evaluations with RG-244 in a phenolic adhesive that had great market potential in laminating plywood veneers, and laying up trusses for the construction industry. Weyerhaeuser plants in Longview, Wa., Cottage Grove, Ore., and Albert Lea, Minn., were known to be potential users.
The OSHA regulations alarmed the various plant managers which inturn caused Dr. Krelblch to discontinue his work and the entire project ground to a halt. After
visiting with Dr.Krelblch & Frank Gillern who both gave glowing reports on the use of RG-244 in the above applications plus other unnamed product areas, we left them with the promise we would track down the problem in the Longview plant and try to resolve it.
Joe Wendlick was most cordial and confused as to why no one had bothered to ask his opinion on this matter. He went on to say that there was not an asbestos ban at Weyerhaeuser, and that he advised whoever in the organization ask, that asbestos can be used and used safely but you must be sure to follow the OSHA regulations. The Longview plant currently uses a combination Chrysotlle & Amosite in an asbestos-reinforced calcium
silicate block fire door. At first the plant had a
serious asbestos problem as many production areas exceeded the celling limit, but with controls and the necessary equipment Installed these were bought into
line. A copy of his paper Asbestos Control-An Industrial Experience Is enclosed.
CC for
REPORT OF CALL
UNION CARBIDE CORPORATION
P.O. Box 579 Niagara Palls, N.Y. H302
By____
PAGE 2
Date
Full Name WEYERHAEUSER CO.
Address
Mfrs. of
Interviewed
The results of the meeting were that Wendlick called Kreibich, the same day, advised him of the present status, and Kreibich ordered a 10# bag to continue evaluations. Kreibich actually seemed grateful we took the time to correct this problem as he earlier in the day informed us that 244 was the only product
that would give the desired results in his applications.
'I o'
ASBESTOS CONTROL - AN INDUSTRIAL EXPERIENCE Joseph D. Wendlick
Weyerhaeuser Company Longview, Washington
ABSTRACT
Reductions in airborne asbestos fiber concentra tions by factors of 20-100 were accomplished by instituting an asbestos control program in a plant manufacturing an asbestos-containing calcium silicate. Ventilation techniques, changes in handling methods and improvements in work practices will be discussed as they relate to these reductions. Support programs including protective respiratory equipment, protective clothing, laundering, change rooms, separate lockers, area posting, employee education and orientation and medical sur veillance will also be discussed.
********
In the past 10-15 years, there has been an everincreasing demand for fire-rated products for wall construc tion, ceilings, flooring and floor coverings, interior finish (paneling) and doors. One of the more difficult of the fire ratings to achieve, at least for wood products, was that for fire doors, since traditionally all-wood stave (laminated 1" wood blocks) core or particle core doors showed only a 20-40 minute resistance to burn-through (as tested in accord
2.
ance with ASTM E-152. Metal doors enjoyed an exclusive set of fire ratings from 3 to 8 hours, their only draw back being the high radiant heats emitted from the unexposed face during a fire. There was an obvious need for fire doors with 3/4 hour (C-label), 1 and 1-1/2 hour (B-label) ratings to 1) prevent the spread of fire better than all-wood doors and 2) supply fire-rated doors for structures not required by fire codes to have 3 hours or greater rated metal doors. Because high radiant heats from metal doors have hindered escape from burning buildings in certain instances, a need also existed for a door construction with an intrinsically low thermal conductivity to permit emergency egress past the door in case of fire.
Born of this need was an all mineral core, wood faced and wood-railed door which possessed not only the esthetics of wood but the capability of withstanding the thermal stress and shock of the ASTM E-152 fire and hose stream test. Oxychloride and oxysulfate cements, gypsum board, asbestos-cement board, and magnesia-type block in sulation were all tried unsuccessfully before arriving at the mineral core suitable for this purpose: an asbestos reinforced calcium silicate.
Development of a successful door construction was measured carefully by the door's ability to be fabri cated, pass critical performance tests such as high-
3.
temperature-low temperature cycling without delaminating or warping appreciably and slam testing; but above all, pass the ASTM E-152 fire and hose stream test at Underwriters* Laboratories in Chicago for a 3/4, 1 or 1-1/2 hour rating. Initially and for several years following the successful development and testing of this construction, all of the mineral core block used in this operation was purchased from outside suppliers. However, soon after architects began to indicate a need for 4*x8' to 4'xlO' doors with both C-labels and B-labels and tests at Underwriters* Laboratories on fire doors fabricated with purchased mineral core failed with these larger dimensions, the decision was made to initiate intra-company research into developing an asbestos-reinforced calcium silicate which would meet these more stringent criteria. This intensive research culminated penultimately after 15 months with the successful fabrication and subsequent testing of 4*x8* and 4'xlO' doors at the Company's fire test facilities in Longview, Washington. Successful testing of similar doors at Underwriters' Laboratories approximately 6 months later represented attainment of the final step in development of this product for market.
Albeit success in product development was achieved considerably beyond expectations, a major new area of challenge emerged which demanded immediate attention. Approximately 100 employees at this location involved in either 1) the production
4.
of asbestos-reinforced calcium silicate and 2) the fabrica tion of mineral core fire doors from this calcium silicate material are occupationally exposed to airborne asbestos fibers throughout their 8-hour work shifts. The distinction between employees involved in the production of the calcium silicate and the fabrication of fire doors from this material was made because these two operations are physically separated by several hundred yards on the complex and were, at the time the asbestos control program was instituted, characterized by two markedly different (and efficient) ventilation systems. For the calcium silicate core production plant, employees (numbers in parentheses) are exposed to asbestos fibers at the following locations:
a. Weighing room and mixers. (1) b. "Wet" end handling operations. (5) c. "Dry" end unloading stations. (2) d. Triin saws (Trims along length of cores). e. Timesaver sander. f. Sorting and grading area.(2). g. Salvage saws. h. Lift truck driver.(1). i. Factotum. (1) j. Quality control. (1) k. Foremen. (1) l. Lead man. (1) m. Maintenance. (1)
5.
Since three crews per day are now engaged in the production
of asbestos-reinforced calcium silicate block, the total
number of employees involved in this part of the operation
should total 48. However, because only the day crew is as large
as indicated above,the actual number is closer to 44. The
process involves weighing and mixing ingredients (including
both chrysotile and amosite asbestos), indurating the slurry
to effect formation of the calcium silicate product, drying
the indurated blocks to achieve a light-weight substance of
density similar to pumice, edge trimming of the core blocks
out of the dryer, sanding top and bottom surfaces of the dry
cores, sorting and grading out the good cores from those which
are fractured, broken or crushed, and reclaiming portions of
Teject core blocks through the use of the salvage saws.
Fabrication of fire doors from the calcium silicate
cores in the other half of the process exposes the following
work stations (numbers of employees affected in parentheses)
to airborne asbestos fibers:
a. Double-end tenoners. (4)
b. Electronics. (5)
c. Abrasive planer. (2) (Timesaver sander)
d. Sizing station and drying tunnel. (1)
e. Inspection. (12)
f. Foremen. (3)
g- Routing out of lite openings. h. Mortising stations. (2) i. Quality control. (1)
(2)
6.
Although, the night crew in the fabrication plant makes railed mineral core, generally no sanding of railed calcium silicate block is performed on the abrasive planer. Detail ing, such as routing and mortising of mineral core doors, is only done on the day shift. Therefore, the approximate number of employees exposed in this plant totals 54. Other employees intermittently exposed are mainly maintenance personnel. A walk-through of the fabrication operation reveals the first operation to process calcium silicate cores from the production plant to be the double-end tenoners, where the tongue and groove configuration is cut along the length and width of the core blocks to match up with wood rails and stiles. From there the core blocks and wood rails and stiles are placed on roller conveyors and directed to set-up position on the "electronics." The core blocks are then railed, cured in an "electronic" press with RF and taken to the feeder position on the abrasive planer (Timesaver sander). Once sanded top and bottom, each railed calcium silicate, core is sized with a dilute phenolic adhesive and passed through a drying tunnel. A rigorous inspection of each railed mineral core block follows the drying tunnel in preparation for application of crossbands and face veneers. Detailing of the completed doors such as routing out lite openings and mortising out lock set openings represents -the last significant asbestos exposures within the plant.
7.
Fiber concentrations from the initial airborne .asbestos samplings of June 1972-February 1973 to determine the relative levels associated with each major work station and machine center in both the production and fabrication plants are given in the table below:
TABLE I
TYPICAL ASBESTOS FIBER CONCENTRATIONS IN Production cp) aND fabrication (F) PLANTS
Work Station
Fiber concentration, fibers/cc greater than 5A in length
Weighing room* (P)
6.6 - 34.0
"Wet" end dryer loader (P)
1.5
Dryer unloader (P)
5.2 - 9.0
Trim saw operator (P)
3.2 - 6.6
Sorting and grading (P)
3.9 - 17.1
Salvage saws (P)
4.1 - 14.9
Factotum (P)
3.7
Quality Control (P)
2.2
Double-end tenoner feeder (F)
2.5 -(82.0)
Double-end tenoner offbearer (F)
2.6 - 25.5
Electronic set-up (F)
6.2
Abrasive planer feeder (F)
6.3 - 19.4
Abrasive planer offbearer =(F)
4.6 - 29.2
Inspection (includes dry hand sanding)(F) 4.7 - 24.3
Routing* (F)
3.9 - 24.8
Mortising (F)
7.7
Clean-up* (compressed air blowing off of equipment) (F)
* Peak exposures only.
37.8
8.
Asbestos samples were collected in conformance with OSHA and NIOSH guidelines using a Mine Safety Appliances Model G Personnel Gravimetric Sampling pump in conjunction with open-face casettes containing Millipore type AA filters. Each sample was collected at 2.0 liters/minute, a flow rate established with a wet test meter. To avoid contributions from contaminated uniforms, a copper wire/baby food can casette holder was used to position the casette in the breathing zones of employees participating in this survey. Collection times varied from 1 minute to 22 minutes, depend ing upon how rapidly visible dust became in evidence on the filter face. From previous experience in sampling asbestoscontaining calcium silicate dusts, any more build-up than barely visible on the filter face made subsequent microscopic counting very difficult. Asbestos counts were made using Leitz microscope with phase contrast illumination at 400-450X magnification in the Company's Longview analytical laboratory.
Once the magnitude of the exposures had been ascer tained, the next step was to implement a multi-faceted control program, comprising: 1) the immediate initiation of a res pirator program 2) initiation of a protective uniform program, together with change rooms, separate lockers, shower facilities, lunch room separate from contaminated areas, and launderomg facilities, 3) improvement or modification of existing ventila tion systems including new pickup heads at the point of asbestos
9.
fiber generation, new ducting, new fans and a new baghouse, 4) instituting a complete medical program to include pre employment physicals, annual physicals thereafter, pulmonary function testing and chest X-rays, 5) an employee educational program to explain the hazard, the need for protective equip ment and the need for changes in some operating procedures and methods of handling and 6) engineering controls other than'ventilation methods. Mr. C. A. Mangold, et.al.'s report on "Asbestos Exposure and Control at Puget Sound Naval Ship yard" (March, 1970) provided the guidelines for the control program described in this report.
Respirator Program A respirator program was the first control applied
to these operations in view of the hazard from asbestos fiber inhalations. For both the production and the fabrication plants, the 3M-8710 disposal dust mask was used,mainly because of its light weight, wearing comfort and low breathing resistance. An overlap with the educational program was necessary to con vince employees of the need for wearing these masks and to demonstrate the proper way to wear them. Other discussions were held with employees to teach them to close the lids on boxes of protective masks to avoid contamination and not to hang these masks around their necks or on a nail at the end of their work shift such that airborne dust collects inside
10.
the mask, to be inhaled on re-application of the mask. Fot certain individuals whose noses became abraded from improper wearing of the 3M masks, a rubber-sealed MSA Dustfoe 66 respirator was temporarily substituted.
Protective Clothing Since many areas within both the production and fab
rication plants involved direct handling of the calcium sili cate core and were, at the time of the initial testing, in excess of the OSHA asbestos standard ceiling limits, protective clothing was issued to the employees. Separate lockers for street clothes and contaminated clothing were made available to all employees, as well as shower facilities at the end of the | work shift. Contaminated uniforms are laundered every 3-4 days, or more frequently, if necessary, in washers and dryers sit uated within the plants. A lunchroom is available separate from the contaminated areas.
entilation Systems While the production plant had been built with a good
\Yntilation system included, the fabrication plant had a system w^ich was constantly overloaded and grossly inadequate for
dling mineral core dusts efficiently. The system that was i used in the fabrication plant had originally been desig 1 to handle wood dusts from a few machine centers. As the ^ed to ventilate additional equipment developed, more and
11.
more tie-ins to the old ventilation system were made until it became overloaded. A new system of ducting, fans and a larger baghouse with more capacity changed the airborne asbestos concentration in this area considerably. This system was also extended into the detailing department to capture the dusts generated during routing out of lite openings and mortising out lockset openings. Many of the pickup heads on machines were modified to present a high velocity, low volume situation to the point of asbestos fiber generation. A new vacuum system was installed through out the production plant. Shortly after it became functional, all brooms and compressed air hoses were ceremoniously retired. A portable vacuum is available in the fabrication plant, since the presence of fugitive asbestos fibers is not nearly as ubi quitous. A short canvas skirt was installed on the asbestos Weighing hopper in the production plant to increase the capture velocity of the negative air system.
Medical Program A complete medical program has now been in effect
for about 1-1/2 years. This program includes: a) pre employment testing of individuals who may be hired for either the production or fabrication plants to establish a reference X-ray, reference pulmonary function (FEV^and FVC) tests and medical information on pre-existing conditions (viz. - cardio-vascular, respiratory, gastro-intestinal,etc.)
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which may disqualify that individual from work with asbestosreinforced calcium silicate, and b) annual testing to provide acheck on changes which might occur as a result of an employee's exposure to asbestos. A doctor from a local clinic has directed this portion of the program, and additionally, has provided the essential interpretations of the X-rays and pulmonary function testing.
Educational Program Demonstrably one of the most important aspects of an
asbestos control program, the educational programs presented to the employees resulted in some remarkedly reductions in air borne asbestos levels throughout the operations. Key points discussed at these sessions included: a) a review of the health hazards of asbestos inhalations, b) the OSHA standards, both now and after July 1, 1976, c) the need to wear protect ive dust masks and uniforms, d) the relationship of the med ical program, e) the ventilation system modifications and other engineering controls being put into effect by the Company and finally, f) how they can help as individual employees in this effort by more careful handling of the cores, better operating procedures, etc. In this latter category, such hazardous dust-producing practices as sweep ing, compressed air blowing, throwing of broken core blocks into trash carts or bins, rough handling when stacking or unstacking loads, unventilated skil sawing, hand sawing or
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drilling of mineral core blocks, failure to report system plug-ups or missing bolts in fan housingsand dropping core blocks onto electronic set-up tables were either minimized or eliminated. All scrap clean-up with squeegees in the pro duction plant must now be done wet to reduce the airborne asbestos fiber contribution from this source.
Other Engineering Controls For certain areas such as the sorting and grading
area and salvage saw area in the production plant and the double-end tenoners, electronics and inspection in the fabri cation plant which defied most of the control methods attempted, a simple but novel approach was devised by plant personnel. Since glue sizing of the core blocks is necessary to effect an acceptable core to crossband bond in the finished product, several employees decided to try sizing each core which passes out of the Timesaver sander in the production plant and the abrasive planer in the fabrication plant. The net result was to bring several areas, heretofore thought to be next to impossible to control by "feasible" engineer ing means, into compliance with the 1976 OSHA asbestos standard.
Table II describes airborne asbestos concentrations at key work stations throughout the operation both from MayJune, 1973 and, for reference, those values reported in
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Table I earlier. It is difficult to single out any one control which was the most salient in effecting the reductions reported below since all controls have had a contributory effect on re ducing the airborne asbestos dust levels.
TABLE II
TYPICAL- BEFORE AND AFTER ASBESTOS FIBER CONCENTRATIONS IN PRODUCTION (P) AND FABRICATION (F) PLANTS-
Work Station.
Fiber concentration, fibers/cc June. 1972-Feb.,1973 May-June,1973
Weighing room* (P)
6.6 - 34.0
3.0 - 7.3
"Wet" end dryer loader (P)
' 1.5
1.2
Dryer unloader (P)
5.2 - 9.0
3.6 - 5.9
Trim saw operator (P)
3.2 - 6.6
0.50- 2.0
Sorting and grading (P)
3.9 - 17.1
3.2 - 9.6
Salvage saws (P)
4.1 - 14.9
0.50 - 0.90
Factotum CP)
3.7 1.5
Quality control (P)
2.2 1.3
Double-end tenoner feeder (F)
2.5 -(82.0)*
1.7 - 3.3
Double-end tenoner offbearer (F)
2.6 - 25.5
0.11--1.1
Electronic set-up (F)
6.2 0.17- 0.60
Electronic offbearer (F)
8.4 0.08- 0.17
Abrasive planer feeder (F)
6.3 - 19.4
5.4 - 7.6
Abrasive planer offbearer (F)
4.6 - 29.2
0.30 - 1.1
Inspection Routing* (F)
4.7 - 24.3 3.9 - 24.8
0.21-1.9 (one peak at 4.6)
6.5
Mortising (F)
7.7
-
Clean-up*
37.8
1.50
* Peak exposures only.
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Approximate Costs for Controls
Control of asbestos in the production and fabrica
tion plants has been expensive, as shown by the cost break
down appearing below:
Equipment or Operation
Approximate Cost
Production plant; including exhaust and collection system Crated CFM * 50,000)
$125,000
Glue Spreader - Production Plant
10,000
Fabrication plant; new ductwork, baghouse (rated CFM = 30,000)
90.000
Glue Spreader - Fabrication plant
10.000
New back sander - Fabrication plant* *****
20,000
Total Estimated Capital Costs (to date) $255,000
Total estimated Maintenance Cost/ye it
(Includes $8,000 annually for baghouse maintenance)
$ 60,000
*****
As evidenced by the data in Table II, the controls although costly - have brought both plants nearby into com pliance with the OSHA 1976 asbestos standard of 2 fibers/cc greater than 5 microns in length for an 8-hout time-weighted average. With the additional controls due for implementation by February 1974, total compliance with the 1976 standard is very probable.
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References:
. 1. Criteria for a recommended standard - "Occupational Exposure to Asbestos" - U.S. Dept, of Health., Education and Welfare. National Institute for Occupational Safety and Health Criteria Document.
2. Federal Register Volume 37, No. 110 (June 7, 1972), Part 1900 Occupational Safety and Health Standards, "Standard for Exposure to Asbestos Dust."
3. General Electric "Environmental Health Management Manual" Section 9 on Dust and Dust Diseases, Subsection 9.1 Asbestos, pp. 7-9.
4. "Industrial Ventilation," a manual by the Committee on Industrial Ventilation - American Conference for Govern mental Industrial Hygienists.
5. Mangold, C.A., Beckett, R.R. and Bessmer, D.J. "Asbestos Exposure and Control at Puget Sound Naval Shipyard," Puget Sound Naval Shipyard at Bremerton, Washington (Marsh, 1970).