ML19209A363
| ML19209A363 | |
| Person / Time | |
|---|---|
| Site: | Trojan File:Portland General Electric icon.png |
| Issue date: | 02/25/1974 |
| From: | Donna Anderson, Ingebrigtson D DOW CORNING CORP. |
| To: | |
| Shared Package | |
| ML19209A316 | List: |
| References | |
| TAC-07551, TAC-11299, TAC-7551, NUDOCS 7910030653 | |
| Download: ML19209A363 (12) | |
Text
ATTACIDfENT 2 AFFIDAVIT OF E. W. EDWARDS CI 2A & C PAGE 1 of 10 BURN TESTS ON SILASTICS RUBBER-COATED GLASS DROP CLOTHS by D. N. Ingebrigtson Analytical Services Department and D. R. Anderson Industrial Hygiene Department Dow Corning Corporation Midland, Michigan 45640 February 2f, 1974 1086 104 ygro oso ss~3
ATTACHMENT 2 AFFIDAVIT OF E. M. EDWARDS CI 2A & C PAGE 2 of 10 1
Burn Tests on SILASTICe Rubber-Coated Glass Drop Cloths Abstract Two samples of silicone elastomer-coated glass cloth were burned under controlled conditions using an oxygen-acetylene cutting flame in a closed chamber 100 ft3 in volume.
Evolved gases and solid particles were collected and analyzed.
1086 105
ATTACHMENT 2 AFFIDAVIT OF E. W. EDWARDS CI 2A & C PAGE 3 of 10 2
Table of Contents Page I.
Introduction 3
II.
Experimental Equipment and Procedure 3
III.
Results and Discussion 4
IV.
Degree of Hazard from Evolved Vapors and 5
Gases V.
Degree of Hazard from Evolved Dust 5
VI.
Documentation 5
Tables I through III Figs. 1 through 6 1086 106
ATTACHMENT 2 AFFIDAVIT OF E. W. EDWARDS CI 2A & C PAGE 4 of 10 3
I.
Introduction The objective of this investigation was to determine the degree of hazards which might exist when SILASTICe brand silicone elastomer-coated glass cloth is used as a drop cloth for welding operations in an enclosed area.
During welding operations, the oxygen-acetylene torch may be dropped, or the flame may be accidentally direct 2d on the drop cloth.
Cutting operations with the oxygen-acetylene flame generates slag and hot droplets of molten metal which fall onto the drop cloths.
The situations described above can cause thermal decomposition of the Silastics rubber coating on glass fabric.
These situations were simulated in a 100 ft3 test chamber using an oxygen-acetylene welding torch.
Provisions were made to sample the volatile gases evolved as well as any dust particles generated.
II.
Experimental Apparatus and Procedure A test chamber approximately 6 ' x 3 ' x 5-1/2 ', with a volurue of 100 ft3 was constructed of 18-gauge sheet metal (Fig. 1).
Sample ports were provided for collection of dust and gas samples.
Th-tip of the oxygen-acetylene torch was inserted into the chamber through an air-tight seal in such a way that the flame could be controlled from the outside.
A window in the chamber, located just above the torch, permitted observa-tion of the sample during burning tests.
A small fan inside the test chamber was used to ensure complete mixing of the gases.
The drop cloth, 18" x 18", was placed vertically in the test cabinet, perpendicular to the flame and 5-3/4" from a No. 2 tip on the oxygen-scetylene torch.
The sample was exposed to the cutting flame for 30 seconds.
The gases were then mixed for 5 minutes and samples were collected in evacuated 125-ml glass sampling bulbs (seen at the top of the chamber in Fig. 1).
Approximately 10 liters of gas was drawn through the bulbs before samples were taken.
The sampling bulbs were removed and a gas cell of 20.25-meter path length was filled for infrared spectroscopic analysis.
Dust particles were collected using a 25-mm diameter Metracil membrane filter with 0.45-micron pore size, mounted near the center of the chamber on a suction line (see Fig. 2).
The drop cloths were also subjected to molten metal and welding sparks using the oxygen-acetylene torch to melt 3/16" drill rod suspended about 5-1/2" above the drop cloth (Fig. 2).
Each cloth was subjected to at least 2.5 gm of molten metal.
Samples of the ambient gases and dust particles were collected as previously described.
1086 107
ATTACHMENT 2 AFFIDAVIT OF E. W. EDWARDS CI 2A & C PAGE 5 of 10 4
The filters were weighed before and after exposure to de' ermine the amount of particulate material in the air.
Microscopic examination of the collected material was made to determine type of material.
Analysis of gas samples was done using infrared spectroscopy and gas chromatography.
The drop cloths were also analyzed by emission and atomic absorption spectroscopy for heavy metals.
Total chloride was determined by sodium peroxide fusion of drop cloth followed by a potentiometric titration with silver nitrate as described in CTM 0186.
III.
Results and Discussion Results of the analyses of d'op cloths for metals and chloride are listed in Table I.
Burn test results are given in Table II.
Gas samples were examined by both infrared spectroscopy and gas chromatography.
Infrared analyses were performed using Perkin Elmer Model 467 spectrometer with a 20.25-meter gas cell.
GLC analyses were performed using a combination of FID and TC detectors with Porapak R 6' x 1/8", Tenax 3' x 1/8",
and Porapak S 10' x 3/16" columns.
The later column was used with N2 carrier gas for the determination of hydrogen.
Mass spectrometry was used to identif. trace materials observed by GC.
Results of the analysis of suspended particulate solids are summarized in Table III.
Sone general observations may be of interest.
CF-2137 appeared to withstand the burning test better than 2351.
When the cutting flame was applied to glass cloth, the area exposed to the flame (about '"-3" diameter) was at red heat within a few seconds.
The silicone rubber did appear to burn in this area; however, flaming ceased when torch was removed (Fig. 3).
The 2351-coated material burned more vigorously in the area exposed to the flame.
The flames and heat generated from the torch were sufficient to cause the area directly above the burn spot to ignite.
This area continued to burn for several seconds after the torch was removed.
Fig. 4 shows the larger burned area of the 2351.
Drop cloth CF-2137, when exposed to welding sparks, did develop one small hole where a piece of molten metal had fallen (Fig. 5).
The metal did not burn through but was fused to the glass cloth and left a small hole when the metal ball (1.2 gm) was removed.
The 2351 sample was scorched and burned where exposed to the molten metal but left no holes. when metal was removed.
Fig. 6 shows the effect of welding sparks on the 2351-coated cloth.
1086 108
ATTACIDfENT 2 AFFIDAVIT OF E. W. EDWARDS CI 2A & C PAGE 6 of 10 5
IV.
Degree of Hazard _from Evolved Vapors and Gases As shown in Table II, the concentration of H 0, CO2, H2, and 2
hydrocarbons given off during the tests was found to be approximately the same as the blank except for 2351 burn where the concentration of CO was found to be 50-100 ppm.
The OSHA limit is 50 ppm for CO, and it refers to the time-weighted average (TWA) concentration for an 8-hour work day and a 40-hour work week.
The concentration of 50-100 ppm for CO found during the 2351. burn should not represent a health hazard due to short exposure time that would be encountered for an accidental burn of the drop cloth.
Based on toxicology data and our experience, the exposure to concentrations of 3-5 ppm of (Me2Sio)x cyclics found for the burning tests should not present any health hazards.
The only other gas detected was a trace of SO2 for 2351 exposed to welding sparks,and again it should not present a health hazard due to the short exposure time.
V.
Degree of Hazard from Evolved Dust The major component (9 3%-99 % ) of the dust evolved when the drop cloths are burned is amorphous SiO2 The OSHA limit for amorphous SiO2 is given by:
80 mg/m3
, 80 mg/m3
= 0. 8 3 mg/m3
% SiO2 96 As shown in Table III, the CF 2137 burn produced an amorphous SiO2 concentration of 3 mg/mg in the test chamber and the 2351burngave173mg/m].
These high concentrations would present a health hazard if a worker were exposed for a long period of time but for an intermittent short term exposure, the health hazard should be minimal.
For example, a 10-minute exposure to 173'mg/m3 would give a 40-hour TWA exposure of 3
0.72 mg/m ; therefore, a worker exposed to 173 mg/m3 for 10 minutes during a 40-hour work week would not exceed the OSHA limit.
As shown in Table III, the concentration of amorphous SiO2 generated from the welding sparks is low and should not present any health hazards.
VI.
Documentation The original experimental work described in this report can be found in Dow Corning workbook A 1934, pp. 7-13.
1086 109
ATTACHMENT 2 AFFIDAVIT OF E. W. EDZUWS CI 2A & C PAGE 7 of 10 TABLE I Analysis of Drop Cloths CF-2137 (Red Stock)
Metals Mg 0.003%
Sb N.D.
<0.003%
Ti,Al,Fe
>0.06%
Pb,Sn,V,Co,Ni N.D.
<0.001%
Ca 0.007%
Ge,Mo,Bi,Be N.D.
<0.0005%
Zr 0.017%
Cu,Ag,Mn N.D.
<0.0005%
Cr Tr <0.001%
Hg N.D.
<0.0002%
P N.D.
<0.05%
Ba,As,Na,Zn N.D.
<0.01%
Chloride, Total:
104 + 10 ppm.
2351 (White)
Metals Ba 0.07%
1r 0.0074 Mg 0.2%
A1,Ca
>>2%
Pb 0.0025%
Mn,Cu Tr <0.001%
v4 0.003%
P N.D.
<0.1%
Fe 0.15%
As,Zn N.D.
<0.025%
Ti 0.06%
Sb N.D.
<0.005%
V 0.005%
Sn,Co,Ni N.D.
<0.0025%
Na 0.04%
Ge,Mo,Bi,Be,Ag N.D.
<0.001%
Hg N.D.
<0.0002%
Chloride, Total:
230 + 15 ppm Tr = Trace N.D.
= Not detected 1086 i10
TADI.E II Gas Analysis from Burn Tests on SILASTICs Brand Silicone Rubber-Coated Drop Cloths flyd ro-(Mc2SiO) 1I 0 CO
!!2 carbons x = 3,4,N 2
Sample CO2 ppm pp i ppm ppm Other Remarks CF-2137
- Trace,
- Unidenti{ied Burn Major
<501
<1502
<202
<31 material 2351 Irrace2,3
- Unidentified Burn Major 50 to 1001
<l502
<25 51 l
material All conditions Blank Major 501
<l502
<202
<3
- Unidentified ma crial
- .o cample.
CF-2137 Welding
- Unidentified 2.5 gm metal 1
1 Sparks Major
<50
<1502
<202 3
materiall drop cloth 2351 Trace SO2 3.9 gm metal Welding by mass spec.
on drop cloth Sparks Major
<501
<l502 1
<202 3
- Unident. mtrl.1 CC)
~
C0 s0%h CN Q uM y 1.
By infrared analysis
>gO wg
[][
2.
By GLC analysis
- OH d 5
%w 3.
tiot enough to identify, but may be propane from retention time.
n,
- This material was shown to be a product of the oxygen-acetylene flame itself and is not due to the drop cloth, g
c
TAPfE III Particulate Matter Analysis from Burn Tests on SILASTICe Brand Silicone Pchber Drop Cloths Volume Sampling of Air
% -ticNiste 1
- Time, Flow Sampled
..eight Conc Sample Minutes 1/ min (1)
(gm)
Mg/M Remarks 3
= r =:-
CF-2137 Cutting flame.
Sample 2
Burn
'.3 7.4 111
.00458 33 perpendicular to oxy-acetylene fit e, 42 Tip, 30 sec burn.
2351 3
Burn 15 3.7 55.5
.010n6 173 Same condi,tions Blank 30 7.4 222
.00183 84 All conditions the same except no sample.
CF 2137 Regular welding flame.
Welding 2.54 gm of molten metal 4
Sparks 15 6.6 99.5
.3068 Nil on cloth.
2351 CD Regular welding flame.
Welding 3.9 gm of molten metal ff[
Sparks 15 8.1 122.1
.00118 1.5 on cloth.
4
{Ohh
- $U#
-a e
1 3
{]
A blank of 8 mg/M subtracted from sample burns.
EnUg Microscopical examination shows the dust.. be an amorphous powder.
There is no evidence of appreciable amounts of crystallinity.
!iF ashing gave about a 93% loss which would indicate -
emorphous silica.
The residue has a brown to red color indicating iron oxide pigment.
3 M
The dust collected from this burn is again primarily amorphous powder by microscopic y
examination.
There are only occasional particles present which show crystallinity.
g IIF ashing volatilized approximately 99% of the dest.
The dark color in the sample m
appears to be due to a trace of residual carbon.
4Particulate material is amorphous carbon.
ATTACHMENT 2
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AFFIDAVIT OF E. W. EDWARDS CI 2A & C
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E00Rr0RIGINAL 1086 113
PROFESSIONAL QUALIFICATIONS OF EDWIN W.
EDWARDS PRESENT Field Construction Manager, Bechtel Power Corporation EDUCATION B.S.,
Electrical Engineering, University of Oklahoma, Norman M.B.A.
General Management - Golden Gate University of San Francisco PROFESSIONAL Registered Professional Electrical Engineer, DATA California, Florida, New York
SUMMARY
2 years:
Field Construction Manager 1 year:
Cost / Schedule Supervisor 2 years:
Assistant Field Construction Manager 3 years:
Project Superintendent 2 years:
Field Superintendent 2 years:
Project Superintendent 1 year:
Senior Field Engineer 6 years:
Field Engineer, Electrical EXPE RIENC E Mr. Edwards is a Field Construction Manager assigned to the Trojan and Skagit projects.
Before being assigned to his present position, Mr. Edwards was Cost / Schedule Supervisor for the Pebble Springs Nuclear Plant.
Previously, he was Assistant Field Construction Manager at the Trojan Nuclear Power Plant.
This assignment was during preparation for initial operation of the plant.
As Project Superintendent he was fully in charge of the construction effort at the Gerald Andrus Steam Electric Station in Greenville, Miss.
Prior to this assignment Mr. Edwards was Field Superintendent at Unit 2 of the Baxter Wilson Steam Electric Station, Vicksburg, Miss, and Montville Unit 6, Montville, Conn.
BN-20 1086 114
Edwin W. Edwards EXPERIENCE (Concluded)
Mr. Edwards was Project Superintendent managing various contractors in construction of gas tur-bine facilities at the Missouri Avenue Station, Atlantic City, N.J.
As field engineer, electrical and senior field eng ineer, Mr. Edwards worked on Cocoa Unit 1 and Turkey Point Units 1 and 2 at Cocoa and Florida City, Florida respectively.
With a previous employer, Reynolds Electric and Engineering,
Mr. Edwards worked as a Field Engineer, electrical on the Titan ! Missile bases, Rapid City, S.D.
and at the Nevada Test Site, Mercury, Nevada.
BN-20 1086 i15