United States Nuclear Regulatory Commission - Protecting People and the Environment

ACCESSION #: 9508020190

DOW CORNING

July 21, 1995

RE:       Update  on SYLGARD [Registered Trademark] 170 Silicone
          Elastomer, SYLGARD [Registered Trademark] 170 Silicone Fast
          Cure Elastomer, and DOW CORNING [Registered Trademark] 96-081
          RTV Adhesive/Sealant

Dear Sir or Madam:

This letter is the final communication regarding Sylgard [Registered
Trademark] 170 Silicone Elastomer Part A, Sylgard [Registered Trademark]
170 Silicone Fast Cure Elastomer Part A and 96-081 RTV Adhesive Sealant
that deviated from our sales specifications.  In November of 1994, Dow
Corning notified customers that we had provided Sylgard [Registered
Trademark] 170 Silicone Elastomer Part A, Sylgard [Registered Trademark]
170 Silicone Fast Cure Elastomer Part A and 96-081 RTV Adhesive Sealant
that deviated from our sales specifications.  While the materials met all
sales specifications at the time of manufacture, retesting showed
deviations from sales specifications in specific areas.  Sylgard
[Registered Trademark] 170 Silicone Elastomer Part A and Sylgard
[Registered Trademark] 170 Silicone Fast Cure Elastomer Part A showed and
increase in the cure time of the materials.  96-081 RTV Adhesive Sealant
showed an increase in the flame extinguishing time of the material.

At the time of notification we advised that we would be taking steps to
correct the cause of the problem and implement appropriate corrective
actions to prevent a reoccurrence of the problem.  These steps have been
completed and appropriate corrective actions implemented.

A testing program was also developed in conjunction with Underwriters
Laboratories to determine whether there was any difference in performance
between material that met our specification and this suspect material
when used in Through Penetration Firestop Systems.  This testing has been
completed.  Attached are reports from Underwriters Laboratories and a
letter that summarizes the findings from the test program.

The United States Nuclear Regulatory Commission (NRC) also conducted an
inspection of Dow Corning facilities in Midland, MI and Elizabethtown,
KY.  A copy of the NRC Inspection Report is also attached for your review
(NRC Inspection No. 99901284/95-01).  Please note that the report also
addresses NRC Staff observations of activities that we performed to
investigate the Sylgard [Registered Trademark] 170 Silicone Elastomer
Part A, Sylgard [Registered Trademark] 170 Silicone Fast Cure Elastomer
Part A and 96-081 RTV Adhesive Sealant that deviated from our sales
specifications.

Please review these reports.  If after reviewing the reports you have any
questions or additional concerns regarding this matter, please contact
me.

                                   Robert M. Schroeder
                                   Fire Protection Engineer

RMS:jml
cc: NRC

DOW CORNING CORPORATION, MIDLAND, MICHIGAN 48686-0994
TELEPHONE: (517) 496-4000

This accession number is found at NUDOCS microfiche address 84925, 001-342.  In addition to
the letter above, the documentation includes proprietary inspection report 99901284/95-01 and a
lengthy report from Underwriters Laboratories, complete with graphs and temperature testing
results.

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