ML19329A905

Fire Equivalency Test for Silicone Foam.

ML19329A905
Person / Time
Site:	Davis Besse
Issue date:	05/25/1977
From:	TOLEDO EDISON CO.
To:
Shared Package
ML19329A902	List: ML19329A901 ML19329A905
References
NUDOCS 8001150802
Download: ML19329A905 (5)

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-TOLEDO EDISON COMPANY DAVIS-BESSE NUCLEAR POWER STATION UNIT 1 t

l Ji FIRE EQUIVALENCY TEST l

l EUR l SILICONE FOAM (SF-20 vs Dow Corning 3-6548)

May 25, 1977 H

800'1150 [C 2

. .' q y Introduction The purpose of this report is to describe the circumstances leading up to the need for a substitute naterial for BISCO SF-20 silicone foam, the se-1ection and testing of Dow Ccrning Corporation 3-6548 silicone foam, and our evaluation of the suitability of DC 3-6548 for use at Davis Besse Nuclear Power Station Unit 1.

Discontinuation of BISCO SF-20 The BISCO SF-20 silicone foam is a four-part mixture of Dow Corning material.

The formulation of this four-part mixture is a proprietary process with BISCO.

Subsequer.t to the BISCO development of their formulation, Dow Corning pro-caeded to develop a two-part mixture which was proprietary to Dow Corning and which is available to any applicator and is marketed under the name of Dow Corning 3-6548 Silicone RIV Foac. The BISCO SF-20 material had been fully qualified by testing for application at Davis-Besse and was approved by NEL-PIA for fire barriers on the project.

On April- 6,1977 bisco informed us that some components of the SF-20 formula-tion were no longer being manufactured by Dow Corning and would not be available to comp.ete the BISCO work. Immediate action was required as the project was preparing to load fuel that month.

As a result of this disclosure, BISCO was requested to be at the Davis-Besse site on April 7 to review this situation. We contacted Dow Corning and were informed that there was no possibility that additional production of the com-ponents for the BISCO SF-20 material would be undertaken.

Efforts were made to review i 's in the country that might have a stock of- this material, including General Electric and TVA, but no material could be found.

On April 8 discussions at the Davis-Besse site between Bechtel, BISCO and TECo led to the decision to attempt to qualify the DC 3-6548 material for use on the Davis-Besse project. NEL-PIA indicated titat they would approve this ma-terial based upon an equivalency fire exposure test performed in accordance with the requirements of ASTM E 119-73 " Standard for Fire Tests of the Building Construction and Materials".

Testing A three-hour fire exposure test was performed at the Fire Research Laboratory of the Portland Cement Association in Skokie, Illinois on April 12, 1977. A 12-inch thick concrete slab was prepared containing four one-foot square blockouts. Two of the one cubic foot blockouts were filled with SF-20 ma-terial, and the other two of the one cubic foot blockouts were filled with Dow Corning 3-6548 silicone foam. Each blockout was filled to the full depth L of.12 inches, which is the minimum depth .used as a fire barrier at Davis Besse Unit'l.

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The fire endurance test was conducted in accordance with ASTM E 119-73.

The test slab was placed horizontally on the furnace such that the heat would impinge. upwards against the material. The foam materials were exposed to heat in accordance with Section 2, Time-Temperature Curve, of ASTM E 119-73.

The temperatures within each seal were measured during the fire exposure.

The actual temperature data taken during this test is attached in Tables I, II, III and IV. During the test the temperatures at the unexposed surface did not exceed the ASid Heat Transmission End Point Criteria. The temper-ature 3 inches beneath the unexposed surface (as close as less than 2 inches from the charring surface) did not exceed 160'F. The temperatures at the surf aces of each seal, and the temperatures at similar depths within each seal correspond with slight exceptions.

Following the three-hour fire exposure it was noted that no smoke or flame had oenetrated or bypassed the unexposed seal surface. When the test slab was removed from the furnace it was placed charred-face downward on a re-fractory blanket and allowed to cool. During this cooling period the ma-terial was allowed to smolder, thus continuing to degrade the sealing material. Af ter approximately 30 minutes the slab was raised, and the charred material was scraped away so that depth measurements could be made. The SF-20 material was charred to a maximum depth of 6 inches in both blockouts.

The Dow Corning 3-6548 material was charred to a maximum depth of 7 3/8 inches in one blockout and 71/2 inches in the other blockout.

Evaluation The fire equivalency test satisfied the requirements of ASTM E 119-73 and NEL-PIA and is consistent with testing pcrformed to qualify the SF-20 ma-terial for use at Davis-Besse Unit 1.

The arrangement of the test apparatus provided conservatism in that by being placed above the flame, much of the charred material fell from the blo< kout during the test. This caused the remaining material to be exposed to rore direct furnace heat, thus increasing the rate of cut arial degeneration Additional conservatism was provided when the material was allowed to amolder for 30 minutes following the fire exposure test. This caused the mate rials to char to a greater depth than had occurred daring the test.

The differences in the depth of charring betwaen the two materials is not con-sidered to be significant as compared with the total depth of the penotration seal. More importantly, in no case did the seal permit the transmission of flame or smoke, the unexposed surface of the seal remained near ambiest temperature, and even seal material within 2 inches of the charring eurface remained cool with respect to the furnace temperature.

Conclesions The results of the fire equivalency test provide complete confidence that the Dow Corning 3-6548 silicone foam will perform as a suitable fire barrier.

The testing, which was observed by representatives of Toledo Edison Company, Bechtel Company, BISCO and NEL-PIA, met the conditions of acceptance of ASTM E 119-73. By virtue of this test and receipt of NEL-PIA approval of the material, all established criteria had been satisfied to qualify Dow Corning 3-6548 silicone - foam as a three-hour fire barrier.

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3 HOUR FIRE EXPOSURE EQUIVALENCY TEST of-

. BISCO SF-20 POUR COMPONENT SILIC0dc FOAM -

and DOW CORNING CORP. 3-6548 SILICONE FOAM TABLE I Surface Temperature OF 1

Minutes A B C D 0 90 90 90 90 30 85 80 85 85 60 80 80 80 80 90 85 85 80 85 120 85 85 85 85 150 85 85 85 85 180 90 90 85 90 TABLE II Temperature immediately below skin OF Minutes A B C D 0 80 80 90 90 30 80 80 85 85 60 80 85 80 ed 90 80 85 85 90 120 80 85 90 90 UO 85 80 90 90 180- 85 85 95 100 Note: Seals A & B - BISQ SF-20 Seals C & D - Dow Corning 3-6548 3

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m 3 HOUR FIRE EXPOSURE EQUIVALENCi TEST of

. BISm SF-20 NUR COMPONENT SILICONE POAM and DOW (DRNING CORP. 3-6548 SILICDNE MAM TABLE III Temperatures 3" from surface OF Minutes A B C D 0 80 80 80 90 30 80 85 85 90 60 80 85 90 90 90 85 85 100 100 120 90 85 110 120 150 115 90 125 140 180 150 105 150 160 TABLE IV Temperatures 6" from surface OF Minutes A B C D 0 80 . 80 90 90 30 85 85 100 100 60 85 95 130 125 90 90 110 190 170 120 125 130 270 245 150 330 200 350 330 180 495 340 460 450 Note: Seals A & B - BISCO SF-20 Seals C & D - Dow Corni. g 3-6548 4

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