Information Notice No. 92-82: Results of Thermo-Lag 330-1 Combustibility Testing

                                UNITED STATES 
                         NUCLEAR REGULATORY COMMISSION
                            WASHINGTON, D.C. 20555

                               December 15, 1992



All holders of operating licenses or construction permits for nuclear power


The U.S. Nuclear Regulatory Commission (NRC) is issuing this information
notice (IN) to alert addressees to the results of Thermo-Lag 330-1
combustibility tests conducted for the NRC by the National Institute of
Standards and Technology (NIST).  It is expected that recipients will review
the information for applicability to their facilities and consider actions as
appropriate.  However, suggestions contained in this information notice are
not new NRC requirements; therefore, no specific action or written response is

Description of Circumstances

As part of a small-scale testing program of Thermo-Lag 330-1 fire barrier
material, NRC staff had NIST perform combustibility tests using the following
standards:  (1) American Society for Testing and Materials (ASTM) E-136,
"Standard Test Method For Behavior of Material in a Vertical Tube Furnace at
750 �C;" and (2) ASTM E-1354, "Standard Test Method for Heat and Visible Smoke
Release Rates for Materials and Products using an Oxygen Consumption
Calorimeter."  NIST documented the results of these tests in Attachment 1,
"Report on Test FR 3989, Analysis Of Barrier Material For Noncombustibility,"
of August 31, 1992.

Based on the ASTM E-136 testing standard, the NIST tests revealed that
Thermo-Lag 330-1 fire barrier material is combustible.  This testing standard
prescribes the material as combustible if three out of four samples exceed any
of the following criteria:  (1) the recorded temperature of the specimen's
surface and interior thermocouples rise 30 �C [54 �F] above the initial
furnace temperature; (2) there is flaming from the specimen after the first 
30 seconds of irradiance; or (3) the weight loss of the specimen during
testing exceeds 50 percent and either (a) the recorded temperature of the
surface and interior thermocouples at any time during the test rise above the
furnace air temperature at the beginning of the test or (b) there is flaming
of the specimen.  Each of the four Thermo-Lag specimens tested exhibited a
weight loss of greater than 50 percent and exhibited flaming beyond 30


                                                            IN 92-82
                                                            December 15, 1992
                                                            Page 2 of 3

NIST performed the ASTM E-1354 calorimeter test on four Thermo-Lag specimens,
subjecting them to an irradiance of 75 kW/m2 [6.6 BTU/ft2-s].  The total
amount of heat released from the Thermo-Lag exceeded that released from Gypsum
board and was about equal to the heat released from fire-retardant plywood.


Section 50.48(a) of Title 10 of the Code of Federal Regulations requires that
each operating nuclear power plant have a fire protection plan that satisfies
General Design Criterion (GDC) 3, "Fire protection," in Appendix A to 10 CFR
Part 50.  GDC 3 requires that "structures, systems, and components important
to safety shall be designed and located to minimize, in a manner consistent
with other safety requirements, the probability and effects of fires and
explosions.  Noncombustible and heat resistant materials shall be used
wherever practical throughout the unit, particularly in locations such as the
containment and control room."     

NRC-approved plant fire protection programs referenced by the plant operating
license and Section III.G, "Fire protection of safe shutdown capability," of
Appendix R to 10 CFR Part 50, require one train of systems necessary to
achieve and maintain hot shutdown conditions from either the control room or
emergency control stations to be free from fire damage.  

Section III.G.2 of Appendix R permits separation by a horizontal distance of
more than 6.1 meters [20 feet] with no intervening combustibles or fire
hazards as one of several methods to ensure that cables and equipment and
associated circuits of redundant safe shutdown trains located outside
containment are maintained free from fire damage.  If this method is used,
fire detection and automatic fire suppression must be installed in the area of
the redundant safe shutdown trains.  Some licensees use Thermo-Lag fire
barrier material to enclose intervening combustibles to achieve 6.1 meters 
[20 feet] of separation free of intervening combustibles between the redundant
safe shutdown trains. 

Section III.G.2.f of Appendix R allows licensees to separate cables and
equipment and associated circuits of redundant trains inside noninerted
containments by installing a noncombustible radiant energy shield as one of
several methods to achieve required fire protection for these circuits.  Some
licensees use Thermo-Lag to construct radiant energy heat shields inside

Related Generic Communications

Attachment 2 is a list or recently issued generic communications concerning
Thermo-Lag 330-1 fire barrier systems.

                                                            IN 92-82
                                                            December 15, 1992
                                                            Page 3 of 3

This information notice requires no specific action or written response.  If
you have any questions about the information in this notice, please contact
one of the technical contacts listed below or the appropriate Office of
Nuclear Reactor Regulation (NRR) project manager.

                                       ORIGINAL SIGNED BY

                                    Brian K. Grimes, Director 
                                    Division of Operating Reactor Support 
                                    Office of Nuclear Reactor Regulation   

Technical contacts:  Ralph Architzel, NRR
                     (301) 504-2804

                     Patrick Madden, NRR
                     (301) 504-2854

1.  Report of Test FR 3989, Analysis Of 
      Barrier Material For Noncombustibility
2.  List of Recently Issued Generic 
      Communications Concerning Thermo-Lag 330-1 
      Fire Barrier Systems
3.  List of Recently Issued NRC Information Notices

.                                                            Attachment 2
                                                            IN 92-82
                                                            December 15, 1992
                                                            Page 1 of 1

           List of Recently Issued Generic Communications Concerning
                     Thermo-Lag 330-1 Fire Barrier Systems

1.    Information Notice 91-47, "Failure of Thermo-Lag Fire Barrier Material
      to Pass Fire Endurance Test," August 6, 1991

2.    Information Notice 91-79, "Deficiencies in the Procedures for Installing
      Thermo-Lag Fire Barrier Materials," December 6, 1991

3.    Information Notice 92-46, "Thermo-Lag Fire Barrier Material Special
      Review Team Final Report Findings, Current Fire Endurance Tests, and
      Ampacity Calculation Errors," June 23, 1992 

4.    Bulletin 92-01, "Failure of Thermo-Lag 330 Fire Barrier System to
      Maintain Cabling in Wide Cable Trays and Small Conduits Free from Fire
      Damage," June 24, 1992

5.    Information Notice 92-55, "Current Fire Endurance Test Results for
      Thermo-Lag Fire Barrier Material," July 27, 1992

6.    Bulletin 92-01, Supplement 1, "Failure of Thermo-Lag 330 Fire Barrier
      System to Perform Its Specified Fire Endurance Function," 
      August 28, 1992

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