Document BR98xGrpZx6j8pxkRvoEBp86j
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Supimixtr 13, 1967
Hr. Ln.lc .1, "railay
Director, ~"pic'orialopy ar.d Field Studies*
:;a^io.'.al 0enter Tor Urban and Industrial Koaltb
Vujaac ile.alr.h Service 10lh 'tiroi\v':i\y
visiai*_*.ti, f.-hio IZ202 rear ih*. Crr.Uey*
mTC* T^i-S i)-j cu
MflT COiVii'f^'iiS ri "J1
' *"*"* d.e.r.J.e. Lr.virc*n*-":tital Sv.rvey frr Aab-astas-at
Cornir.- Tyler> ttEiaa and I'crt Allounny plants
, _. ?1`at
I an still auaiitin;-: copies ef the rep arts on tho sublact vaia* assist:-.; ics in this matter Mill bo appreciated.
for you.' iafori.rrsicn, I hove enclosed a copy of. a reeej-t o" a. :!/p.cn3 u.::,jineoir^. -er fcy ^ ? Destefatio, our 0I~S3 Division's Tr..;uyt-*-*-t---1*
Sincerely,
lnr ' cc: >-. j. w. I!e;:illan
. L. 0. Griffith
13 3. Grant, M.9.
I BB 0001449
O 0INDUSTRIAL HYGIENE SURVEY
PITTSBURGH-C0RNIN3, TYLER, TEXAS
At the request of Lee E. Grant, M.D., a dust survey was made of the Tyler plant on November 29, and 30, 1966. The purpose of this survey was to re-evaluate the plant in terns of any significant changes in levels of airborne
dust since the last survey of August, 1963, by the Industrial Hygiene Foundation.
In evaluating a dusc exposure, the threshold lim..t values as promulgated by th.*
American Conference of Governmental Industrial Hygienists are used as guidelinvs.
They represent levels of dustiness which should rot be exceeded on a time- * ^.
v/eighted average basis for an eight hour day for a man's useful working life. --
The threshold limit value for asbestos dust is 5 million particles per cubic
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foot of air' (mppcf).
Before discussing the results it would be well to explain some of the changes that have taken place in recent years with regard to dust counting techniques. Most of the threshold limit values for dust (particularly silica dust) were developed in the 1930's in the granite sheds of Vermont. In those studies,
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the counting technique called for light-field illumination at 100X magnification
Since that time, hov/ever, better optics, giving better resolution at higher
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magnification have become more common. Therefore, the desire to use the more CO
sophisticated optical systems of today must be balanced against the excellent
correlation v/ith medical'findings that the Vermont granite studies produced.
This is perhaps, an over-simplification of the situation, but the point being
made is that one of the better optical systems was used for evaluation of the lUJ
samples from the current study. It is believed that this is the reason for
the dust counts reported herein being approximately ten times greater than
previous studies of the same plant. In addition to total dust counts, however,
this study also presents fibrous dust counts. It can be seen that these fib
rous dust counts are of the same order of magnitude as previous studies. The
reason being that a fiber, which is defined as a particle with a length at
least three times greater than its width, is large enough to be seen at the
old 100X magnification as well as the more sophisticated systems.
*
Th results of the study are shown in Table 1. A comparison of the fibrous dust counts v/ith the threshold limit value of 5 nppcf indicates that sever, of the sixteen values exceed this limit. It is felt* that the values reported herein are representative of conditions in the plant at the time of the visit, and the following recommendations are being made from the test results as well a personal observations:
, * *.
1. Better ventilation, or a better materials handling system, or
a combination of both, is needed on the feeders.
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2. Constant Inspection and immediate correction of any air leaks in the equipment is needed as is indicated by a dust count of 20 mppcf in the general area of No.' 2 mill.
3. Better ventilation is needed in the sawing area. An evalua
tion of the present system by means of suitable air velocity
measuring equipment would be a logic? 1 first step.
*
4. The use of sand on the floor as a lubricant for the movement of cardboard boxesshould be discontinued. The addition of
a silica hazard to an asbestos problem is unwarranted.
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JTD/jcw* 9/11/67
The air cleaners should not be located inside the building. Positive pressure bag collectors'of -this sort may be inexpen sive, but undetected leaks can put a significant amount of dust back into the air. Furthermore, re-circulation of exhausted air is poor practice, in aodition to being illegal in some states, because it assumes a collection efficiency approaching 100# which is rarely true, especially in older installs-tions. The proper type of di st collector would eliminate the excessive dust concentrations from shaking the dust bags.
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Destefano Safety 8, Industrial Hygiene Engineer
NOT'D >
DID: /'PG FILES'
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oo TABLE 1
Process Area
Total Dust mppcf
1. *BZ Scrap Crusher Operator
34.7
2. BZ Feeder Operators
38.8
3. No. 2 Mill - General Area
77.5
4. Production Floor - between.Nos. 1 and 2
12.5
10. BZ Feeder Operator
45.0
11. No. 3 Mill - General Area
-
15. B2 Scrap Crusher Feeder
2.5 / 56.3
16, Production Floor - between Nos. 2 and 3
10.0
Sawing Area
5. BZ Butt End Catcher - big end cut & rip saw
43.2
6. BZ Tie Machine Operator - packing (inspjction also>)) 10.0
7. BZ Block Band Saw
53.0
8. Saw Room Inspection Station & Tying
26.2
9. BZ Butt" End Catcher - big saws
7.5
13. B* Z Saw, # Operators - both block saws operating 14. BZ Saw Fender - big saws
Miscellaneous
' 30.0 15.0
12. BZ Operator shaking dust bags
17.5
Wi
Fiber Dust rcpogf
3.3 6.3 20.0
"1.3 0
. 2.5
*
;i5.o 2.5
' 10.5 - 2.5
0 7.5 2.5
32.5
BZ - Breathing Zone
JTD/jcw 9/13/67
| BB 0001452 1
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