Information Notice 1993-40, Fire Endurance Test Results for Thermal Ceramics FP-60 Fire Barrier Material: Difference between revisions

Fire Endurance Test Results for Thermal Ceramics FP-60 Fire Barrier Material
	ML031080040
Person / Time
Site:	Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, Mcguire, Nine Mile Point, Palisades, Palo Verde, Perry, Indian Point, Fermi, Kewaunee, Catawba, Harris, Wolf Creek, Saint Lucie, Point Beach, Oyster Creek, Watts Bar, Hope Creek, Grand Gulf, Cooper, Sequoyah, Byron, Pilgrim, Arkansas Nuclear, Three Mile Island, Braidwood, Susquehanna, Summer, Prairie Island, Columbia, Seabrook, Brunswick, Surry, Limerick, North Anna, Turkey Point, River Bend, Vermont Yankee, Crystal River, Haddam Neck, Ginna, Diablo Canyon, Callaway, Vogtle, Waterford, Duane Arnold, Farley, Robinson, Clinton, South Texas, San Onofre, Cook, Comanche Peak, Yankee Rowe, Maine Yankee, Quad Cities, Humboldt Bay, La Crosse, Big Rock Point, Rancho Seco, Zion, Midland, Bellefonte, Fort Calhoun, FitzPatrick, McGuire, LaSalle, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant
Issue date:	05/26/1993
From:	Grimes B; Office of Nuclear Reactor Regulation
To:	;
References
	IN-93-040, NUDOCS 9305260385
	Download: ML031080040 (14)
	v • d • e

Latest revision as of 04:19, 24 November 2019

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 May 26, 1993 NRC INFORMATION NOTICE 93-40: FIRE ENDURANCE TEST RESULTS FOR THERMAL

CERAMICS FP-60 FIRE BARRIER MATERIAL

Addressees

All holders of operating licenses or construction permits for nuclear power

reactors.

Purpose

The U.S. Nuclear Regulatory Commission (NRC) is issuing this information

notice to alert addressees to results of fire endurance and ampacity derating

test reports submitted by Thermal Ceramics on the FireMaster FP-60 fire

barrier system and the results of NRC staff reviews. It is expected that

recipients will review the information for applicability to their facilities

and consider actions as appropriate, to avoid similar problems. However, suggestions contained in this information notice are not NRC requirements;

therefore, no specific action or written response is required.

Descriotion of Circumstances

In Generic Letter (GL) 92-08, wThermo-Lag 330-1 Fire Barriers," the staff

stated it would evaluate other known fire barrier materials and systems that

are used by licensees to fulfill NRC fire protection requirements. The staff

is now evaluating fire barriers manufactured by other vendors to verify the

ability of the barriers to adequately perform their 1-hour or 3-hour fire

resistive functions and to meet stated ampacity derating values. Thermal

Ceramics, Inc., formerly the Insulating Products Division of Babcock and

Wilcox, Inc., of Augusta, Georgia, manufactures the FP-60 fire barrier system

and submitted reports on two fire endurance tests and one ampacity derating

test to the NRC in a letter of February 23, 1993.

Discussion

In its review of the Thermal Ceramics reports, the staff identified the

following information.

In its product literature, Thermal Ceramics states that the FP-60 product is

manufactured for use on cable trays, conduits, junction boxes, and other cable

raceways. The primary component, the FireMaster FP-60 blanket, is a ceramic

fiber blanket with thicknesses varying from 2.5 cm [1 inch] to 7.6 cm

[3 inches]. Optional aluminum or stainless steel foil, Kao-Tex (woven cloth),

or other cloth facings are provided for physical protection of the blanket.

The vendor claims that the material, when installed according to the

instructions, is qualified for up to a 13/4-hour fire rating using the American

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IN 93-40

May 26, 1993 Society for Testing and Materials (ASTM) Standard E-119, "Standard Test

Methods for Fire Tests of Building Construction and Materials."

FIRE ENDURANCE TESTS

According to one report submitted by Thermal Ceramics, a.1-hour fire endurance

test of the FP-60 fire barrier in various configurations was performed at

Underwriters Laboratories, Inc. (UL File R11044-1, Project 84NK8356, March 22, 1985). The test followed UL Subject 1724, "Outline of

Investigation, Fire Tests for Electrical Circuit Protective Systems,"

May 1984. According to the report, the furnace temperatures followed the

ASTM E-119 standard time-temperature curve for fire exposure, and the barriers

were subjected to a solid hose stream test. The report also states that

circuit integrity was monitored.

Documented test configurations included 91.4 cm [36 inch] wide open-ladder and

solid-back steel cable trays, an air drop assembly, 12.7 cm [5 inch] diameter

steel conduits, and a 30.5x15.2 cm (12x6 inch] steel Junction box. All

configurations contained cables. Two hundred fifty thermocouples were

reportedly used to measure temperatures of cables, cable trays, Junction

boxes, conduits and electrical circuit protective systdms on the unexposed

1 side of the assembly.

x According to the report, within 30 seconds of the start of the test, the

j filament tape around the blanket wrap ignited. At 5 minutes, flames

reportedly issued from seams and butt joints. The report also states that at

20 minutes, some of the wrap slipped out of position resulting in an opening

^ in the barrier, and at 60 minutes, there was a 8.9 cm [3X inch] opening

in the

barrier. Some thermocouple measurements reportedly ranged from 204 'C

[400 OF] to 260 eC [500 OF] at the end of the fire test.

After the test, some cables were documented to be fused together, and cable

jackets were melted and blistered. The hose stream eroded the bottom surface

of the cable tray barrier so that the tray was exposed.

The UL report concluded that the tested fire barrier had a 1-hour fire rating

because circuit integrity was maintained during the fire exposure and hose

stream test. However, it appears that the UL approval is limited to minimum

91.4 cm [36 inch] wide cable trays and 12.7 cm [5 inch] or larger-diameter

conduits with minimum No. 16 AWG jacketed multi-conductor cables or minimum

No. 300 MCM jacketed copper single conductor power cables with polyvinyl

chloride jackets.

The second fire endurance test report submitted by Thermal Ceramics documented

a Southwest Research Institute small-scale test, "One Hour Fire Qualification

Test of a Protective Envelope for Class 1E Electrical Conduit Circuits," (SwRI

Project 01-8305-053, February 1986). According to this report, the test

employed the ASTM E-119 standard time-temperature curve for fire exposure and

a subsequent solid hose stream test. The report also states that circuit

integrity was monitored. SwRI documented the use of a small-scale furnace

(maximum test specimen of 425.8 square cm (66 square inches]) to test a

2.5 cm [1 inch] diameter conduit with a pull box, a 5.1 cm [2 inch] diameter

conduit with a junction box, and an air drop. According to the report,. these

IN 93-40

May 26, 1993 test assemblies each contained a single-conductor power cable and two control

cables, all with PVC jackets.

Recorded cable temperatures (measured at the cable jackets) at the end of the

fire exposure ranged from 146.5 'C (296 *F] to 164 C (327 OF]. According hoseto

the report, circuit integrity was maintained during the fire exposure and

stream tests.

The barrier and cable conditions after the fire exposure were not reported.

The test report suggests that the hose stream test caused some barrier damage, although the test report did not clearly report the extent of damage. SwRI

did not report a conclusion as to the acceptability of the fire barrier

system.

In a letter of April 27, 1993 to Thermal Ceramics, Inc., the staff expressed

concerns regarding the ability of the FP-60 system to meet existing NRC fire

barrier acceptance criteria.

AMPACITY DERATING TEST

The ampacity derating test report submitted by Thermal Ceramics was SwRI

Project 01-8818-210, "Ampacity Derating of Fire-Protected Cables in Conduit

and Cable Trays Using Babcock & Wilcox, Incorporated's Passive Fire Protection

System," issued by SwRI on July 8, 1986. According to the report, a 1-hour

fire barrier was used in the test. Three-conductor XLPE-insulated 6 AWG

cables with Hypalon protective wraps were reportedly installed in a

61 cm (24 inch] wide by 10.2 cm [4 inch] deep cable tray, and 3-conductor

XLPE-insulated 3 AWG cables with Hypalon protective wraps were installed in a

10.2 cm [4 inch] diameter conduit. Both assemblies were reported to be

3.7 m [12 feet] long and completely filled. The report stated that

thermocouples were installed in slits' in the cable insulation.

According to the report, a steady-state temperature of 90 eC (194 *F) at the

hottest single thermocouple was monitored. Equilibrium temperature was

reportedly established when a steady-state condition (+/-1 eC per hour (+/-1.8 OF

per hour]) was achieved for 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> without any perturbation to the system.

The ampacity derating for the cable tray and conduit was estimated to be 62.4 and 41.4 percent, respectively, based on the test results.

Some licensees use the FP-60 fire barrier system to achieve physical

independence of electrical systems in accordance with Regulatory Guide 1.75, Physical Independence of Electrical Systems." Ampacity derating in fire

barrier systems installed to achieve physical independence of electric systems

is a consideration in the design of such systems as well as in those installed

to protect safe shutdown capability from a fire.

Cables enclosed in electrical raceways protected with fire barrier materials

are derated to ensure that systems have sufficient capacity and capability to

perform their intended safety functions. These cables are derated because of

the insulating effect of the fire barrier material. Other factors that affect

ampacity derating include cable fill, cable loading, cable type, raceway

construction, and ambient temperature.

IN 93-40

May 26, 1993 Cable derating calculations that are based on inaccurate or nonconservative

derating factors could result in installation of undersized cables or raceway

overfilling. This could cause operating temperatures to exceed design limits

within the raceways thereby reducing the expected design life of the cables.

In the letter to Thermal Ceramics, Inc., of April 27, 1993, the staff

requested additional information on ampacity derating.

The National Electrical Code, Insulated Cable Engineers Association (ICEA)

publications, and other industry standards provide general ampacity derating

factors for open-air installations but do not include derating factors for

fire barrier systems. The Insulated Conductors Committee of the IEEE Power

Engineering Society, Task Force 12-45, has been developing IEEE Standard

Procedure P848, "Procedure for the Determination of the Ampacity Derating of

Fire Protected Cables," for use as an industry standard. The industry

consensus standard development process may formulate an appropriate technical

approach to the determination of ampacity derating factors for cables enclosed

by fire barrier systems.

The staff is continuing to review this product for its ability to perform its

fire resistive function and will evaluate whether further generic

communications are needed to address the issues discussed above.

This information notice requires no specific action or written response. If

you have any questions about the information in this notice, please contact

the technical contact listed below or the appropriate Office of Nuclear

Reactor Regulation (NRR) project manager.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contact: Isabel M. Miller, NRR

(301) 504-2852 Attachment:

List of Recently Issued Information Notices

2 IN 93-40

May 26, 1993 Cable derating calculations that are based on inaccurate or nonconservative

derating factors could result in installation of undersized cables or raceway

overfilling. This could cause operating temperatures to exceed design limits

within the raceways thereby reducing the expected design life of the cables.

In the letter to Thermal Ceramics, Inc., of April 27, 1993, the staff

requested additional information on ampacity derating.

The National Electrical Code, Insulated Cable Engineers Association (ICEA)

publications, and other industry standards provide general ampacity derating

factors for open-air installations but do not include derating factors for

fire barrier systems. The Insulated Conductors Committee of the IEEE Power

Engineering Society, Task Force 12-45, has been developing IEEE Standard

Procedure P848, "Procedure for the Determination of the Ampacity Derating of

Fire Protected Cables,' for use as an industry standard. The industry

consensus standard development process may formulate an appropriate technical

approach to the determination of ampacity derating factors for cables enclosed

by fire barrier systems.

The staff is continuing to review this product for its ability to perform its

fire resistive function and will evaluate whether further generic

communications are needed to address the issues discussed above.

This information notice requires no specific action or written response. If

you have any questions about the information in this notice, please contact

the technical contact listed below or the appropriate Office of Nuclear

Reactor Regulation (NRR) project manager. Orginal ignd y

Brian K.Grimes

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contact: Isabel M. Miller, NRR

(301) 504-2852 Attachment:

List of Recently Issued Information Notices

See previous concurrence

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IMiller SWest DGable

05/06/93 , 05/06/93 05/10/93

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CMcCracken JGoldberg CBerlinger

5/20/93 5/20/93 05/25/93

DD:DSSA *D:DSSA *OGCB:DORS

MVirgilio AThadani GMarcus Grimes

05/25/93 05/25/93 05/25/93 S g&493 DOCUMENT NAME: 93-40.IN

IN 93-XX

May xx, 1993 Cable derating calculations that are based on inaccurate or nonconservative

derating factors could result in installation of undersized cables or raceway

overfilling. This could cause operating temperatures to exceed design limits

within the raceways thereby reducing the expected design life of the cables.

In the letter to thermal ceramics of April 27, 1993, the staff requested

additional information on ampacity derating.