NUREG/CR-2607

SAND82-0431

RP

FIRE PROTECTION RESEARCH PROGRAM FOR THE

U. S. NUCLEAR REGULATORY COMMISSION

1975-1981

Donald A. Dube

Systems Safety Technology Division

Date Published: April 1983

Sandia National Laboratories

Albuquerque, New Mexico 87185

operated by

Sandia Corporation

for the

U. S. Department of Energy

Prepared for

Division of Engineering Technology

Office of Nuclear Regulatory Research

U. S. Nuclear Regulatory Commission

Washington, DC 20555

Under Memorandum of Understanding DOE 40-550-75

NRC FIN No. A1010

ABSTRACT

Since early 1975, Sandia National Laboratories has been

conducting fire protection research for the U. S. Nuclear

Regulatory Commission. Testing has been done on grouped

electrical cable fires including electrical initiation, fire

propagation, the effects of fire retardant coatings and

barriers, suppression, and characterization of the damageability of electrical cables. In addition, several studies of

a more generic nature such as fire detection, ventilation, and

fire-hazards analysis methodologies were performed.

This report condenses all of the test results, reports,

papers, and research findings of the past seven years.

Research conducted by contractors to Sandia National

Laboratories is also summarized.

iii

TABLE OF CONTENTS

Page

Abstract ......................................... iii

Table of Contents ............. v

List of Figures ........ vii

List of Tables ................ .. ....... ix

Acknowledgement . . . .......... .. x

Executive Summary ............... ............. 1

I. Introduction ................... 9

II. Testing Program .............................. 10

II1. Industry Survey ............ 10

11.2 Cable Tray Separation Tests ........... 11

11.2.1 Electrically Initiated

Fire Tests ........... ..... 11

II.2.2 Exposure Fire Test ............. . 12

11.3 Fire Retardant Coatings and

Fire Shield Tests ................... 17

II.3.1 Small-Scale Testing

of Coatings ...... .............. 19

11.3.2 Single-Tray Full-Scale Tests 19

11.3.3 Two-Tray Full-Scale Tests. .... 21

11.3.4 Diesel-Fueled Exposure Fires 23

II.3.5 Fire Shield (Barrier) Tests.... 23

II.4 Corner Effects Testing .......... 31

V
Table of Contents (cont'd)

Page

11.5 Fire Suppression Tests ................ 33

II.5.1 Fire Barrier and Suppression

Test (UL) .... .... ......... 33

11.5.2 Halon Suppression Tests ....... 38

11.5.3 Water Sprinkler Tests (NFPA 13) . -... I...... ......... 46

II.5.4 Directed Water Spray Tests

(NFPA 15) . ........... ...... 48

II.6 Penetration Seal Tests ............ 51

11.6.1 Small-Scale Tests (UL) ..... 51

11.6.2 Large-Scale Tests

(UC-Berkeley) ............... 59

11.7 Browns Ferry Replication Test ......... 64

11.8 Radiant Heat Tests .................... 68

III. Analysis ...................... 75

III.1 Characterization of Cable

Tray Fires ............. . ........ 75

111.2 Studies of Generic Fire Protection

Issues ............. ........ 78

111.2.1 Ventilation Systems .......... 78

111.2.2 Fire Detection Systems 81

111.2.3 Fire Barriers ........... 84

111.2.4 Fire-Hazards Analysis ...... 86

IV. Summary ............................. 89

V. References ................. . . ......... 90

VI. Conference Reports ................ 95

vi
LIST OF FIGURES

Figure Page

1. Outside View of Fire Test Facility 4

2. Inside View of Fire Test Facility ...... 5

3. Affiliations of Fire Protection

Research Consultants ................... 8

4. Random Placement of Cables in Tray 13

5. Seventeen Tray Arrangement ............... 14

6. Post-Test Results of July 6,

1977 Test '................ e.-.......16

7. Coating "C" Prior to Test 33 ........... 24

8. Results of Test 33 Using Coating "C" 25

9. Test 47 Diesel-Fueled Fire ............. 26

10. Ceramic Fiber Board Fire Shield ......... 29

11. Corner Effects Test Arrangement ...... 32

12. Cable Weight Loss as Function of

Corner Distance ........................ 34

13. Maximum Heat Flux From Cable Tray

Fire as Function of Corner Distance .... 35

14. UL Fire Barrier and Suppression Test .... 37

15. Immediate Suppression of Flames

by Halon 1301 ......................... 41

16. Temperature Drop in Flaming Region ...... 42

17. Indication of Deep-Seated Fire

and Reignition of Cables .... 43

18. Mass Loss in Presence of Halon ....... 44

19. Mass Loss Without Halon Suppression ..... 45

vii
List of Figures (cont'd)

Figure Page

20. Water Sprinkler Test Arrangement

(Vertical Configuration) ................ 49

.21. Directed Water Spray Test Arrangement

(Horizontal Configuration) .............. 52

22. Indication of Effectiveness of

Directed Water Spray .................... 53

23. Small-Scale Penetration Seal Tests

at UL ............................ ,....... 57

24. Large-Scale Penetration Seal Tests

at UC-Berkeley .......................... 60

25. Upper Portion of Browns Ferry

Replication Test Setup .................. 65

26. Full-Scale Radiant Heat Test ............ 70

27. Correlation Between Time to Electrical

Failure and External Heat Flux .......... 73

28. Correlation Between Time to Non-Piloted

Ignition and External Heat Flux ......... 74

29. Temperature Profile on Burn Mode

Matrix for Pre-IEEE-383 Cable Test ...... 77

30. Comparison of Models for Assessing

Fire Severity in Nuclear Power

Plants ............................. 88

viii
LIST OF TABLES

Table Page

I. Test Matrix of Coatings Tests ......... 18

II. Results of Small-Scale Coatings

Tests at 4 W/cm 2 ....................... 20

III. Results of Full-Scale Single-Tray

Coatings Tests .......................... 22

IV. Test Matrix of Barrier Tests ............ 27

V. Results of Full-Scale Two-Tray

Fire Shield Tests .................... 28

VI. Fire Retardant Coating Tests Ranking

of Resistance to Combustion

(Relative) . ....... ...................... 30

VII. Halon Suppression Tests Summary ......... 39

VIII. Water Sprinkler Suppression

Tests Summary ........................... 47

IX. Directed Water Spray Suppression

Tests Summary ........................... 50

X. Summary of Small-Scale Penetration

Seal Tests .............................. 54

XI. Conditions at Each of the Six

Penetrations During Experiment No. 1 ..... 61

XII. Conditions at Each of the Six

Penetrations During Experiment No. 2..... 61

XIII. Conditions at Each of the Six

Penetrations During Experiment No. 3 ..... 62

XIV. Operation Times of Detectors .............. 67

XV. Time to Short Circuits ................... 69

XVI. Summary of Radiant Heat Tests .............. 72

ix
ACKNOWLEDGEMENT

The assistance of Leo J. Klamerus in gathering together the

many reports and papers which form the basis of this study is

greatly appreciated.

x
EXECUTIVE SUMMARY

Objectives

Sandia National Laboratories has been conducting a fire

protection program for the U.S. Nuclear Regulatory Commission

since early 1975. The program was in fact underway before the

fire at the Browns Ferry nuclear power plant which occurred on

March 22, 1975.1 Since then the program has grown to cover

many areas of fire protection. This report summarizes the

major activities of this program from 1975 to 1981.

The objectives of the Fire Protection Research

Program at Sandia National Laboratories are to:

1. Provide data either to confirm the

suitability of current design standards

and regulatory guides for fire protection

and control in light water reactor power

plants, or to indicate areas where they

should be updated.

2. Obtain data to facilitate either

modification or generation of standards

and guides (changes are to be made where

appropriate to decrease the vulnerability

of the plant to fire, provide for better

control of fires, mitigate the effects

of fires on plant safety systems, and

remove unnecessary design restrictions).

3. Obtain fire effects data and assess

improved equipment, design concepts,

and fire prevention methods that can

be used to reduce the vulnerability

to fire.

4. Conduct special tests to assess the adequacy

of specific designs.

Areas of Research

When the project was conceived in July 1974, the only task was

to provide the experimental and analytical information to evaluate the adequacy of cable tray spacing designated in Regulatory Guide 1.75, Section 5.14, which covers separation of

protective systems in areas of the plant where power cables

are included and the only source of fuel is that provided by

the cable materials. 2 All evaluations were to involve the

-1-
testing of equipment and configurations representative of

those in new nuclear power plant designs.

Since then, research at Sandia National Laboratories and its

contractors has expanded to cover the following areas of fire

protection research:

Testing

1. Cable tray separation for both electrically

initiated fires and exposure fires.

2. Effectiveness of fire-retardant coatings

and fire shields.

3. Contribution of reradiation from walls and

ceilings to fire intensity (corner effects

tests).

4. Small-scale and large-scale testing of the

effects of furnace pressure on cable

penetration seal performance.

5. Halon 1301 suppression effectiveness.

6. Water sprinkler (NFPA 13)3 and directed

water spray nozzle effectiveness (NFPA 15).4

7. Full-scale replication of several cable

trains and the fire protection system for

an area in the Browns Ferry Reactor

Building.

8. Full-scale testing of the damageability of

electrical cables to radiant heat.

Analysis

1. Characterization of cable tray fires.

2. Examination of compartment ventilation

in nuclear power plants.

3. Investigation of the adequacy of fire

detection as well as the requirements for

detector siting in the context of nuclear

power plant safety.

4. Assessment of the adequacy of current

standards which govern the design and

testing of fire barriers.

-2-
5. Examination of the adequacy of existing

fire-hazards analysis methodologies.

With the exceptions of the penetration seal tests and the

Browns Ferry Replication test, most of the testing was

performed at Sandia National Laboratories' Fire Test

Facility. Figures 1 and 2 show the test facility after

modification in 1979.

Major Findings

As a result of the test program conducted at Sandia National

Laboratories and its contractors, a number of important findings have emerged which have a direct impact on the suitability of design standards and which provide important

information on fire prevention methods. In particular, the

following general statements summarize the important

conclusions drawn from this research.

1. With regard to cable tray separation,

Regulatory Guide 1.75 was found inadequate

for exposure fires.

2. All fire retardant coatings offer a

measure of additional protection, but

there is a wide range in their relative

effectiveness.

3. All fire shields tested inhibited fire

propagation from tray to tray.

4. In the corner effects test, an inverse

relationship was found between fire

intensity and wall/ceiling distance;

beyond a diagonal distance (from tray

edge to corner) of 6 ft (1.8 m) there

was little effect.

5. Halon 1301 suppresses deep-seated cable

fires if the soak time and concentration

are sufficient.

6. Area water sprinklers (meeting NFPA 13-

1980) are effective in suppressing cable

tray fires in the vertical configuration

as well as the horizontal configuration

(up to three levels of trays tested).

7. Directed water spray nozzles (meeting

NFPA 15-1980) are very effective in

suppressing cable tray fires.

-3-
Figure 1

Outside View of Fire Test Facility
U1

Figure 2

Inside View of Fire Test Facility
8. Positive furnace pressure and excess

pyrolyzates are important parameters

in cable penetration seal tests.

9. Large-scale tests performed on the

damageability of electrical cables to

radiant heat generally verified the

results of small-scale tests performed

at Factory Mutual Research Corporation.

10. Despite the fact that the Browns Ferry

Replication test was conducted under

stringent conditions, i'.e., without any

automatic or manual fire suppression

efforts attempted, functional capability

was not lost and the test verified the

survivability of one redundant safety

train.

In addition to the above findings which resulted from the test

program conducted by Sandia National Laboratories, a number of

conclusions have been drawn from studies of generic issues

such as fire detection and ventilation.

1. Current standards and regulatory guidelines

inadequately define criteria for design of

ventilation systems and their operation

under fire emergencies.

2. Current design and regulatory guidelines

alone are insufficient to ensure satisfactory fire detection system performance;

the use of in-place testing of detectors

under conditions expected to occur

normally in areas being protected is

recommended.

3. Because the standard fire (ASTM E-119) 5

cannot be considered as representative of

compartment fires, the fact that a given

barrier has received a standard rating

does not mean that it will last for the

rated duration in every fire situation

or that a comparative quality rating is

achieved.

4. No one fire-hazards analysis method can

satisfactorily circumvent the subjective

nature of current fire hazards analysis

practice.

-6-
Interaction With Fire Research Community

Ever since the Fire Protection Research Program was first

conceived in 1974 and effectively underway in early 1975,

Sandia National Laboratories has been interacting actively

with the rest of the fire research community in order to stay

abreast of important issues. Figure 3 illustrates the affiliations of Sandia's contractors and consultants. Professor R.

Brady Williamson of the University of California at Berkeley

has been involved with large-scale testing of cable penetrations. The small-scale penetration seal tests, Browns

Ferry Replication Test, and other cable tray fire tests have

been performed at Underwriters Laboratories under the direction of L. J. Przybyla and W. J. Christian. Professional Loss

Control Incorporated has on several occasions served as consultants on various aspects of testing and analysis. John

Boccio at Brookhaven National Laboratory has been instrumental

in the work performed on early detection of cable tray fires.

In addition, the Fire Protection Research Program at Sandia

National Laboratories has been presented at workshops and

conferences held by the American Nuclear Society, the Society

of Fire Protection Engineers, the Institute of Electrical and

Electronics Engineers, the National Academy of Sciences and

the Electric Power Research Institute (see listing of Conference Reports). Moreover, interactions have taken place with

other institutions doing research in fire safety such as the

National Bureau of Standards Center for Fire Research, the

Applied Physics Laboratory of John Hopkins University,

Lawrence Livermore National Laboratory, Southwest Research

Institute, Factory Mutual Research Corporation, Naval Sea

Systems Command, and the Naval Research Laboratory.

Internationally, research information on cable tray fires has

been exchanged with Professor K. Yahagi of Waseda University

of Japan as well as with representatives of Toshiba Corporation, Hitachi Corporation, the Fujikura Cable Works Ltd., and

the National Testing Institute of Sweden.

On September 7, 1978 the Nuclear Regulatory Commission Fire

Protection Review Group Meeting 6 was held in Albuquerque,

New Mexico and was attended by 170 representatives of electrical cable manufacturers, architect/engineering companies,

electric utilities, consulting companies, vendors of fire

protection equipment, national laboratories, and government.

Sandia National Laboratories' Fire Protection Research Program

was presented along with parallel efforts being conducted by

other consultants to the Nuclear Regulatory Commission.

-7-
C

-

4

41

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Uj UE4-)

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U

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0--,

0 z

0

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Ch,

CD

z

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(f0 toU

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0m 4-4

0

Figure 3

Affiliations of Fire

Protection Research

Consultants

9

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-8-
I. Introduction

Sandia National Laboratories has been conducting fire

protection research for the U. S. Nuclear Regulatory Commission since early 1975. The program on cable tray fires was

actually underway before the March 22, 1975 Browns Ferry

nuclear power plant fire. 7 Since then, a great deal of research has been done on grouped electrical cable fires including electrical initiation, fire propagation, the effects of

fire retardant coatings and barriers, suppression, and characterization of the damageability of electrical cables. In

addition, several studies of a more generic nature such as

fire detection, ventilation and fire-hazards analysis

methodologies were performed.

It is the purpose •of this report to condense under one cover

all of the test results and research findings of the past

seven years. Altogether, some 30 reports and 75 tests are

summarized. Only an introduction to the particular test

series and major test results are given in this report. The

reader should refer to the appropriate citations in order to

obtain more information on the background of the test, test

procedures, and detailed test results. The reference list is

exhaustive and, in one report or another, includes all of the

major test results through late 1981. No reference is cited

for the water suppression tests (both NFPA 13 and NFPA 15)

which as of this writing are not complete, although some general statements about the tests conducted to date are given.

A selected list of papers on the fire protection research program given at various conferences and workshops is also provided for additional reference. In general, the outline of

this report follows in chronological order the testing program

conducted at Sandia National Laboratories and its contractors.

The analytical studies are grouped separately.

-9-
II. Testing Program

II.1 Industry Survey

Early on in the program it was decided that a survey of

industry should be made to determine current design practices

concerning cable tray spacing and cable types. The cooperation by members of the nuclear power industry was outstanding. Personal visits and correspondence elicited

responses from 13 architect-engineering firms, 13 utility

companies, and 13 cable manufacturers. Three nuclear power

plants were visited, although design practices of existing

nuclear power plants were not evaluated. Information obtained

during this survey has proven valuable in determining cable

and cable tray configurations, cable loading, and types of

cable assignments in cable trays. The survey also solicited

information about previous incidents and experiences, including the cable tray fire at San Onofre 1 in 1968 and the

subsequent investigation to determine the cause. 8

Since initiating a fire in power cable electrically may be

difficult, it was decided early in the project to conduct the

test with 12 AWG, the smallest power cable normally used in

nuclear power plants, to minimize the amperage demands in the

test setup. A preliminary heat transfer analysis was also

performed at that time. Only a rough analysis was considered

necessary to determine the approximate current required to

raise the cable insulation to a combustion temperature and to

determine if the conductor temperature is at its melting point

(1083 0C) when the outside of the cable insulation is at its

combustion temperature. The analysis showed that currents in

the range of 100 to 120 amps would raise the cable insulation

to its combustion temperature. This agreed with subsequent

testing.

With the results of the survey and the preliminary analysis as

guidelines, a test facility was designed and constructed to

perform full-scale testing of electrically initiated fires.

Although it was originally intended to test all known types of

cable currently specified and accepted, the large number of

cable types, coupled with budget limitations, precluded such

broad testing. Screening indicated that tests of two cable

types most likely to propagate a fire would comprise a.

conservative approach.

The relative ranking of cable types was based on three

different evaluations and were chosen to complement, not

duplicate, other evaluations. The evaluations used were: a

small-scale electrically initiated cable insulation fire test,

Underwriters Laboratories (UL) FR-I flame test, 9 and a pyrolyzer and thermal chromatograph test (measure of insulation

outgassing as a function of temperature).

-10-
Although the small-scale electrically initiated cable

insulation fire test and the UL FR-l test indicated that none

of the cables under evaluation would be capable of propagating

a fire (in support of IEEE-383 qualification) ,10 two cable

types were designated for use in the full-scale tests by a

relative figure of merit. Work performed in Europe in 1975 on

radiation and fire resistance *of insulating materials was

brought to Sandia's attention and is in good agreement with

its ratings. 1 1 These designated cable types were (1) a

three-conductor No. 12 AWG, 30 mil (0.76 mm) cross-linked

polyethylene (PE), silicon glass tape, 65 mil (1.65 mm)

cross-linked PE jacket, 600 V, and (2) a single-conductor No.

12 AWG, 30 mil (0.76 mm) crosslinked PE, no jacket, 600 V.

These were used on all subsequent electrically initiated and

exposure fire tests whenever IEEE-383 qualified cable was to

be used.

11.2 Cable Tray Separation Tests

11.2.1 Electrically Initiated Fire Tests

Three phases of full-scale electrically initiated fire tests

in horizontal cable trays were performed.' Altogether, nine

full-scale tests were run. The first phase was intended to

evaluate the adequacy of cable tray spacing as designated in

Regulatory Guide 1.75, Section 5.14. Vertical separation of

independent safety divisions is designated as 5 ft (1.52 m)

and the horizontal separation as 3 ft (0.91 m). The second

phase was concerned with varying the separation distance

between cable trays. Phase three required a stacking of 14

cable trays as one division with cable trays representing the

second division separated by distances as specified in Regulatory Guide 1.75. The vertical and horizontal separations in

the first division were 10.5 and 8 in. (0.27 m and 0.20 mi),

respectively, while the separation between divisions was again

5 and 3 ft. All testing involved equipment and cables

representative of those in new nuclear power plant designs.

The first phase involved two tests using single conductor

no. 12 AWG cross-linked PE insulation in 24-ft (7.3-m)-long,

open ladder type aluminum trays. Five cable trays represented

the two safety divisions. Current was increased in the ignition tray until a short circuit was observed and flaming

started (about 95 to 99 amps). In these tests, all circuits

other than the ignition tray circuits remained functional and

the fire did not propagate from the ignition tray.

-11-
There were four tests run in the second phase, all using three

conductor No. 12 AWG cross-linked PE insulation. The first

three of these tests involved 24 foot (7.3 m) long, open

ladder aluminum trays whereas the fourth test used 12-ft

(3.7-m) long, galvanized steel trays. Moreover, the fourth

test used a figure 8 pattern (see Figure 4) for the placement

of the cables to allow maximum passage of air, and spacing was

reduced to 10.5 in. (0.27 m) vertically and 8 in. (0.20 m)

horizontally between safety divisions. In these tests, short

circuits and fires occurred between 112 and 174 amps in the

ignition tray. However, all the circuits in the other trays

remained functional and fire did not propagate.

The third phase involved three tests, each consisting of two

vertical stacks (total of 14 trays) for one safety division,

and three trays for the second division. The spacing conformed to Regulatory Guide 1.75. A mixture of one-conductor

and three-conductor No. 12 AWG cross-linked PE cables was

used. Short circuits and fires occurred between 94 and

105 amps. Once again, electrical damage was confined to the

ignition tray and the fire did not propagate. Figure 5

illustrates the test configuration for the phase three tests

as well as the July 6, 1977 exposure test described below.

In all nine tests, all circuits other than the ignition tray

circuits remained functional. This was determined by operation of these circuits for some period of time after the

test. In addition, samples of the cable insulation at the

bottom of the tray over the fire zone were measured for any mechanical change. They showed less than 10 percent increase

in elongation due to the fire. Quite often this small increase is attributed to a small change in cross-linking due to

heat. Results of these electrically initiated fire tests were

reported in seven "quick look" reports to the NRC1 2 - 1 8 and

two summary reports. 1 9 - 2 0

Major Findings

As a result of this testing program it was determined that

Regulatory Guide 1.75 was adequate for electrically initiated

fires in horizontal tray configurations using IEEE-383

qualified cables.

11.2.2 Exposure Fire Test

A full-scale fire exposure test was performed at Sandia

National Laboratories on July 6, 1977.21-22 The test was

conducted with a single safety division being represented by

14 filled cable trays. Again the 14 trays were spaced

10.5 in. (26.7 cm) vertically and 8 in. (20 cm) horizontally.

Three additional filled trays representing the second or

redundant safety division were placed vertically

-12-
H

Figure 4

Random Placement of Cables in Tray
Figure 5

Seventeen Tray Arrangement

-14-
-and, horizontally adjacent to the top-of that 7 x 2 matrix.fOf trays, as shown in Figure 5. The separation distances between

redundant divisions were- ,those minimum-distances allowed by

Regulatory Guide 1.75. Flame retardant cables (IEEE-383

qualified), were used.

A 5-minute exposure to standardized (IEEE-383 ribbon type)

propane- burners produced a fully developed fire within a

single cable tray. Optimized parameters for this type of fire

were obtained in a series of.12 single-tray tests performed

earlier.' A barrier was placed over the donor tray until after

the propane burners were turned off and was then removed to

allow- the single-tray fire, with only the cable as fuel, to

act as a propagation source. The fire not only propagated

through the closely stacked trays of one division but also

ignited the -cables in the-redundant safety division. The

after effects of the test27are shown in Figure 6. This illustration is -a bit deceiving in that the cable tray supports.

were made of aluminum rather than steel, and hence were more

susceptible tostructural damage resulting from high temperatures. The important point to make is that the fire

propagated from the ignition tray up through the first safety

division and to the second safety division.

Comparison of data from this test with the previous

electrically initiated fire tests shows that size (area of

fire) and time (length of time flames reached a given area in

upper trays) were the principal parameters which allowed propagation of-this fire. The typical electrically initiated fire

had an axisymmetric luminous zone about 6 in. (15.2 cm) in

diameter while the luminous zone in the exposure fire test was

approximately 2 ft (61 cm) long and 1.5 ft (45.7 cm) wide.

This increase in characteristic dimensions increased the-emissivity and view factor which in turn increased the radiation

heat transfer to the higher trays. The longest period of time

an electrically initiated fire remained on the thermocouple or

calorimeter area was 240 seconds while this same area was in

the flames for 400 seconds in this exposure fire test.

Comparison of thermocouple records for previous tests and the

test described here shows a 14000 F (7600 C) temperature above

the cables at 3/8 in. (0.95 cm) in the electrically-initiated

fires and at 2.5 in. (6.35 cm) in this fire. A temperature of

10000 F (5830 C) was seen at 3 in. (7.62 cm) above the cables

in the electrical fires but 8 in. (20.32 cm) above the cables

in this fire. These temperatures suggest that the fire resulting from the exposure fire was slightly more severe, but

this could have been merely because of a larger fire zone

which caused the thermocouples to read closer to true local

gas temperature.

-15-
Figure 6

Post-Test Results of July 6, 1977 Test

-16-
Heat flux was comparable in both types of tests, varying

within 20 percent at corresponding heights on all tests.

This fact, plus the lack of large changes in other measurable

characteristics, might suggest that the electrically initiated

fires were marginally below the capability of propagation

across the minimum (10.5 in. or 27.7 cm) vertical distance

between trays used to represent one of the redundant divi--

sions. By the same token, this exposure fire test was marginally above ignition as seen from the fact that the donor

fire tray stopped flaming within one minute after the tray

vertically above this one ignited.

Schedule 40, 3-in. (76.2 mm) pipe was used as conduit

containing additional cable and was included in this test.

Continuity and insulation resistance measurements of the

cables in the conduit were taken before and after the test.

Although continuity measurements were normal, insulation

resistance showed short circuits to the conduit on all

conduits above the third tray. The insulation appeared to

have turned to ash without flaming, leaving the conductors

touching each other and the pipe.

Major Findings

The results of this test show that fire propagation with flame

retardant (IEEE-383 qualified) cable in an open-space horizontal configuration between redundant safety divisions,

separated by the minimum distances specified by Regulatory Guide 1.75, is possible if a fully developed cable fire is

assumed.

11.3 Fire Retardant Coatings and Fire Shield Tests

The test of July 6, 1977, showed that additional measures were

required to protect essential safety systems against the effects of fire and confirmed the Nuclear Regulatory Commission's position in requiring that protection. Two of these

additional measures are fire retardant coatings applied on the

cable trays and fire shields between cable trays. Small-scale

and full-scale testing was performed on the fire retardant

coatings. Full-scale testing of the coatings consisted of

both propane and diesel-fueled exposure fires. Propane-fueled

exposure fires were used to test the ability of various fire

shields to prevent fire propagation between horizontal cable

trays. These tests are reported in Reference 23 to 25. A

summary of the coatings tests conducted is given in Table I.

-17-
Table I

Test Matrix of Coatings Tests

Single Tray Tests.

383 Qualified Cable Non-383

Single Three Three

Coating Conductor Conductor Conductor

Small Scale Test

Two Tray Tests 383 Qualified ,Cable

383 Qualified Single Three

Cable Non-383 Conductor Conductor

DieselFuel

Fire

Non-383

Two Tray

0

None

A

B

C

D

E

X

X

X

X

X,

X

X

X

X

X

X

X

X X

X

X

X

X

X

X

X

X

x

X

X

X

X X

x

X

X

X

X

X

X

X

X

X

X,

X

X

F

G. X X X X X X
11.3.1 Small,-Scale Testing of Coatings

For small-scale testing, coatings were applied to both types

of electrical cable used in the electrically initiated and

exposure fire tests at Sandia. The cables were cut into 6-in.

(15.2-cm) pieces and placed in wood forms lined with plastic,

a 6 x 6-in. sample size. The coatings were then troweled to

the manufacturer's specified wet thickness and allowed to cure

at least 30 days. Each sample was mounted in the holding fix- ture fronted by 1-in. (2.54-cm) wire mesh and backed by one

layer of aluminum foil and cement board.

The Ohio State University release rate apparatus tested two

types of cables and six types of fire-retardant coatings to

varying levels of radiant heat flux to determine the ignition

time and smoke and heat release rates. The apparatus used a

flow system in which a known, constant flow rate of air~enters

an environment chamber. Rate of heat release is monitored by

changes in temperature of air leaving the chamber and. rate of

smoke release by optical density of gas leaving the chamber.

The sample is put into the environmental chamber and a small

pilot flame is placed to impinge on the center of the lower

edge of the vertical sample. A radiant panel provides exposure in terms of heat flux to the sample. The test conditions provide air flow of 84 ft 3 /min (0.04 m3 /s) with

tests at room temperature and at radiant heat flux levels of

1, 2, 3 and 4 W/cm2 . Table II summarizes the important

measurements at a radiant heat flux level of 4.0 W/cm. 2

11.3.2 Single-Tray Full Scale Tests

For the full-scale tests performed at Sandia National

Laboratories, coatings were applied to the same cables

previously described. The cables were loaded into galvanized

steel, open-ladder trays 18 in. (45.7 cm) wide and 12 ft (3.7 m)

long. Although the trays were filled to approximately the

tops of the 4-in. side-rails of the cable trays, the loading

technique allowed maximum air passage through the cables. The

loading pattern is a figure 8 in the tray, with the crossing

point advancing progressively up and down the tray. For the

three'-conductor cables. this resulted in a 25 percent fill by

cross-sectional area and for the single-conductor, a 15 percent fill (90 three-conductor cables per tray and 450

single-conductor cables per tray). Non-IEEE-383 qualified

cable was loaded into additional cable trays to be included in

the testing. This cable was three conductor, 20/10 Poly PVC

polyethylene insulation, 45 mil (1.14 mm) PVC jacket. The

number of cables per tray and percent filled by cross section

were the same as the qualified three-conductor cables

previously described.

-19-
Table II

Results of Small-Scale Coatings Tests at 4 W/cm2

Coating

A

C

D

E

F

G

Time to.

Ignition:

Minutes_

8

8

14

24

5

12.5

Time to

Maximum

Heat Release

Minutes

16

17

28

34

12

22

Cumulative Heat

Release atl1O Minutes

MJ/m 2

14.6

28.6

4.1

16.2

23.5

Cumulative Heat

Release at 15 Minutes

MJ/m 2

39.1

43.7

8.1

22.5

60.4

I

I

21.5

45.7

37.5

No Coating 78.0

383 Cable

0.8 6
Coatings were sprayed onto the loaded cable trays by their

respective manufacturers. The nominal wet thickness applied

to the tops and bottoms of the loaded cable trays was the same

as that used in the small-scale tests and was applied according to the manufacturer's specifications. The test described

here was designed to reproduce the ignition tray conditions of

the full-scale stacked-tray test of July 6, 1977.22 An

important difference of course, is that only the ignition tray

itself was used in this first phase of the fire-retardant

coatings tests. The test procedure and setup were essentially

identical to the July fire test. An insulated barrier was

placed 9.5 in. (24.1 cm) over the ignition tray. The twin

burner assembly was so placed beneath the tray that rungs of

the cable tray were not directly over either burner. The

distance between the top of each burner and the bottom of the

cable was 4.75 in. (12.1 cm). Cable thermocouples were in

place before spraying of coatings began.

Propane and air were turned on for 5-minute periods for each

burn cycle. Previous tests had shown 5-minute periods as

optimum for creating the largest donor fire in a cable tray

loaded with IEEE-383 qualified cable, provided an open or

random cable fill pattern was maintained. If a fully developed cable tray fire yas not achieved after applying this

ignition source for 5 minutes, additional 5-minute ignition

cycles (up to a total of six) were repeated after 5-minute

delays. Fifteen tests were conducted as indicated in Table I.

Table III summarizes the test results.

11.3.3 Two-Tray Full Scale-Tests

A series of two-tray tests was conducted to test for fire

propagation between trays. In these tests, the physical

arrangement of the lowest two trays in the July 6, 1977, fire

test was used. The trays were placed horizontally, with one

tray 10.5 in. (26.7 cm) above the other. When IEEE-383

qualified cable was used, the bottom tray was loaded with

three-conductor and the top with single-conductor cable. An

insulated -barrier was placed 9.5 in. (24.1 cm) over each

tray. The barrier over the bottom tray was movable and could

be swiftly removed from between the cable trays when a fire

developed in the bottom tray. As in the single-tray tests,

thermocouples and calorimeters were placed in each tray.

The same 5-minute burn cycles used in the single-tray tests

were repeated in these two-tray tests up to a maximum of six

ignition cycles. Electrical resistance and current measurements of the cable were made as in the single-tray tests. Not

including the diesel-fueled fire tests and the barrier tests,

a total of thirteen two-tray tests were conducted. The

results in terms of the relative rankings of

-21-
Table' III

Results of Pull-Scale Single-Tray Coatings Tests

Maximum

Cable

Test Temperature

Number ' Coatin '(IF)

~A A 1280

2* 1600

3' B 840

4 A 1340

S B 1250

6 C 1240

70 0 200

0 D300

9 No Coating 1600

.383

10 Nýo Coating 1580

383

Maximum

Calorimeter

Temperature

(OF)-

525

1380

1150

740

480

1525

290

350

1490

1400

550

280

1600

900

460

Maximum

Barrier

Temperature

(°F)

Not Taken

1500

.1450

950

440

1580

380

420

1550

1480

750

325

1515

600

600

Time to

Electrical

Short (min)*

26

15

60

60

60

24

60

60

9

5

60

60

6

40

60

Time to 900"F

in Cables

(min)t

16

12

60

5

22

60

60

5

6

60

60

.1

30

,60

Time to

Ignition

(min) t

10

5

15

10

20

10

60

60

5

Length

of

Burn

(min)

15

40

7

6

7

15

0

0

13

Length

Affected

Area

(in.)

30

43

40

ýs

43

58

0

0

27

K)3

5 10 34

11

12*

13'

26

27*

E

No Coating

Pre 383

G

a

187

230

1510

1330

525

60

60

5

60

30

0

36

0

4

0

0

70

30

30

*Three-conductor cable

tA value of 60 minutes (length of the test) indicates no short circuit or ignition occurred.
the coatings were generally in good agreement with the

single-tray tests. References 25 and 26 give detailed

results. Figures 7 and 8 show the cable trays coated with

Coating C before and after Test 33 (nonqualified PE/PVC

three-conductor cable in a ladder configuration).

11.3.4, Diesel-Fueled Exposure Fires

Another series of tests used the two-tray configuration

previously described. However,ý the ignition source was a

diesel-fueled -fire which burned for about 13 minutes before

self-extinguishing. Another important difference is that no

barrier was placed between the trays so that both trays might

be exposed to the diesel fire. Five tests were conducted

altogether. The rankings of the relative performance of the

cable coatings was in good agreement with single-tray and

two-tray tests. Figure 9 shows the intensity of the fire

during Test 47 (Coating C, unqualified cable in an,open ladder

configuration),. Detailed results can be found in References

25 and 26.

11.3.5 Fire Shield (Barrier) Tests

In addition to the fire retardant coatings tests, eight

single-tray and five two-tray tests were conducted using various fire barriers or shields such as solid bottom trays,

1-in. solid barriers (ceramic fiber board), and ceramic wool.

The test program is summarized in Table IV. Results of the

two-tray tests are given in Table V. Note that in all instances fire propagation was prevented. In these tests, no

fire-retardant coatings were used. Additional. results are

provided in Reference 26. Figure 10 illustrates the use of

the ceramic fiber board as a fire shield.

Major Findings

These tests indicate that all coatings and barriers offer a

measure of additional protection against cable tray fires. No

propagation to the second tray was observed in any of the two

tray tests where IEEE-383 qualified cable was used. In the

three tests where propagation to the second tray was observed,

non-qualified cable was used.

There is a wide range in relative effectiveness of the

different fire retardant coatings tested here. Table VI

summarizes a ranking of coating effectiveness derived from the

small-scale and full-scale tests reported here and in Reference 25. These rankings are based on both combustion and

propagation properties.

-23-
Figure 7

Coating "C" Prior to Test 33
U'

Figure 8

Results of Test 33 Using Coating "C"
N7)

50'

Figure 9

Test 47. Diesel-Fueled Fire
TABLE IV

Test Matrix of Barrier Tests

Single Tray Tests

383 Qualified Cable Non-383 Two Tray Tests

Barrier

Type

Ceramic wool

blanket over

ladder tray

Solid bottom

tray no cover

Solid cover

no vents

ladder tray

Vented cover

solid bottom

1-in. fire

barrier

between trays

Single

Conductor

Three

Conductor

Three 383 Qualified

Conductor Cable

X

Non-383

X

X X X

x

x

x

X

x

X

X X

-27-
Table V

Results of Full-Scale Two-Tray Fire Shield Tests

IlJ

I

Shield and

Cable Type

Solid Bottom

Tray, Non-383

Cable

Top

Bottom

Solid Bottom

Tray, Vented

Top, Non-383

Cable

Top

Bottom

1-inch Solid

Barrier Between

Open Ladder Tray@,

Non-383 Cable

Top

Bottom

Solid Top, Open

Ladder Tray,

Non-383 Cable

Top

Bottom

Ceramic Wool,

Ladder Tray,

Non-383 Cable

Top

Bottom

Max

Cable

Temp

(F)

91

650

Max

Calorimeter

Temp

(IF)

127

480

265 170

1300 780

Max

Barrier

Tamp

128

430

190

430

Time to

Electrical

Short

(min)

60

8

45

5

14*

2

60

5

60

2

Time to

900* in

Cable

(mi n)

60

60

60

16

60

1

Time to

Ignition

(min)

60

20

60

10

60

Length

of Burn

(min)

0

4

0

55

Length

Affected

Area

(in)

0

43

Weight

Loss

(lbs)

0

1.5

No

66 12.5

Propagation

No

265

1350

250

1500

100

900

-- 560

-- 400

0 0

42 120

0

37.5

0

17.75

NO

87 NO

305

98

330

94

340

116

500

60 60

4 10 67.5

0

45

0

120

0

108

60

13

60

15

No

12.5

*Short occurred beyond end of B-ft barrier as fire progressed beyond that point in bottom tray.

ýA value of 60 minutes (length of the test) indicates no short circuit or ignition occurred.
Figure 10

Ceramic Fiber Board Fire Shield
TABLE VI

Fire Retardant Coating Tests

Ranking of Resistance to Combustion (Relative)

(Lowest Numerical Value Provides Most Resistance)

Coating

A

Small

Scale

4

B

C

D

E

F

G

Single-Tray

Tests

5

4

ý6

1

2

Full-Scale

Two-Tray Tests

Propane Fueled

4

3

6

Full-Scale

Two-Tray Tests

Diesel Fuel Fire

3

2

5 5

1 1

2 2

6

3

7

1

Uncoated

383 Cable

Uncoated

Pre-383

Cable

3

7

,8

5

7

8

4

-30-
11.4 Corner Effects Testing

Throughout the previous testing, cable tray arrays were

arranged to simulate the open plant area with no ceiling or

wall in proximity. To get some quantitative measure of the

effect of reradiation of heat to the cables, a modest series

of full-scale tests was conducted. 2 7 - 2 9 'The same cable

types, ladder trays, fire facility and fire testing procedures

were used in these tests as in the previous tests.

Originally, it was planned to have concrete walls and ceilings

provide a corner to simulate the usual conditions found in aý

nuclear power plant. A review of fire literature and a brief

investigation led to the conclusion that a corner made of ceramic fiber boards would be little different from a concrete

corner for the duration of the test fire. 3 0 - 3 2 This construction was used for ease of assembly and economy. Six 4 x

8 foot (1.2 x 2.4 m) ceramic fiber boards 1 in. (2.54 cm)

thick were arranged as shown in Figure 11 to form a corner

above and beside two horizontally oriented cable trays, with

the top tray 10.5 in. (26.7 cm) above the other.

The cables were loaded into galvanized steel, open-ladder

trays, 18 in. (45.7 cm) wide and 12 ft (3.7 m) long. Although

the trays were filled to approximately the tops of the 4-in.

side rails of the cable trays, the loading technique allowed

maximum air passage through the cables. The cables formed a

figure 8 with the crossing point advancing progressively up

and down the tray. This resulted in a 25 percent fill by

cross-sectional area for three conductor cables (90 cables per

tray).

Two types of cable were used in these tests. One type was

IEEE-383-qualified three conductor No. 12 AWG, 30 mil (0.76

mm) cross-linked PE, silicon glass tape, 65 mil (1.65 mm)

cross-linked PE jacket, 600 V. The other type was non-IEEE-383

qualified cable, three-conductor, 20/10 Poly-PVC, polyethylene

insulation,ý 45 mil (1.14 mm) PVC jacket.

Six tests were run in this series, three each' with the

IEEE-383 qualified and unqualified cable. The three distances

from the ceiling to the top tray were 10.5, 18, and 120 in.

(0.27, 0.46, and 3.05 m). The wall distances to the edge of

the tray were 5, 10.5, and 60 in. (0.13, 0.27 and 1.52 mi).

-31-
K77

Figure 11

Corner Effects Test Arrangement
Effective measures of the corner effects are weight loss (from

cable pyrolization) and maximum heat flux from the cable tray

fires. These values are plotted in Figures 12 and 13 for both

the IEEE-383 qualified and the unqualified cable. The diago- nal distance is measured from the top of the top tray to the

corner (intersection of wall and ceiling).

As expected, the effect of reradiation of heat from walls and

ceilings varies inversely with distance. Although the relationship between corner proximity and certain fire severity

parameters is demonstrated, these functions are derived for

two types of cable. It is expected that all cables would

demonstrate similar effects but differ in magnitude of fire

severity.

The minimum corner distance used in these tests is a

reasonable minimum in order to allow access to the trays in a

real power plant situation. The proximity of ceiling and wall

would probably introduce a secondary effect of oxygen depletion in the limiting case of small distances, but this was not

found to be a factor in these tests.

Major Findings

An inverse relationship was found between fire intensity and

wall/ceiling distance in these corner effects tests. Beyond a

diagonal distance (from tray edge to corner) of 6 ft (1.8 m)

there was little effect.

11.5 Fire Suppression Tests

11.5.1 Fire Barrier and Suppression Test (UL)

On September 15, 1978, a full-scale fire test was conducted at

Underwriters Laboratories Incorporated to demonstrate the

effectiveness of a ceramic fiber blanket and automatic fire

suppression system in protecting a vertical cable tray configuration. 3 3 The spacing of the cable trays was in compliance

with separation criteria guidelines at the time. An open pool

fire fueled by liquid hydrocarbon was used.

A corner-ceiling assembly approximately 20 x 20 x 15 ft high

(6.1 x 6.1 x 4.6 m) was used to simulate a corner-room situation. The walls and ceiling consisted of steel framing and

1/2 in. (1.3 cm) thick marinite boards. The five cable trays used in the tests were open ladder type and made from

-33-
0

i'

In

0

eq

0

xi

(K)

M'SONnOd

Figure 12

Cable Weight Loss as Function of Corner Distance

-34-
! ! ! I'** I I ' ' '

NY

IU X

Inw

0 a

V-4 -

C4 0

izi

0,

en X00

X M

+n

0

in

in

0

in

0

0

in wj

z

V

1-4

An

A C', 0

in

.1!. * . | . . I . I . . . I . .I. . I - - I~zJ §II

Nl CY

CO

HI 'iJH bs/fl19

0-

Figure 13

Maximum Heat Flux From Cable Tray Fire as

Function of Corner Distance

-35-
galvanized steel. Three-conductor, No. 12 AWG PE/PVC

electrical cables were used (not qualified to IEEE-383). A

steel pan about 25 ft 2 in area (2.3 m2 ) was used to

.contain the 2 gal (7.6 P) of heptane fuel. The barrier

installed about each cable tray consisted of an assembly of

1-in. (2.54-cm)-thick ceramic wool blanket pieces. Three

upright automatic sprinklers rated at 165 0 F (74 0 C) and 35 psig

(2.4 x 105 Pa) were installed 12 in. below the ceiling. One

ionization chamber type and one photoelectric type smoke

detectors were also installed at the ceiling.

All cables were energized at low voltage during the test, and

each circuit carried low current and was monitored continuously for shorts between conductors or between conductor and

tray. In addition to the three open-head sprinklers, three

dummy sprinkler heads without connection to the water supply

were suspended near each open head. The dummy heads were

monitored electrically, and only after activation of all three

dummy heads at one location would the water system be manually

operated. Temperatures at various locations within the cable

trays were recorded.

Figure 14 shows the heptane fire about 1 minute into the

test. Maximum flame height during the test was about 3 ft

(0.9 m), and flaming continued at various levels of intensity

for up to 40 minutes. The two smoke detectors were activated

in less than 15 seconds. Only two of the nine dummy heads

were activated at all, and these occurred about 53 seconds

into the test. Hence, the sprinkler system was never activated manually. Recordings indicated that short circuits

first occurred at 3 minutes and 13 seconds. Posttest inspection of the cables indicated thermal damage near the base

of four of the five cable trays.

Major Findings

Analysis of the cable temperatures during the test indicates

that had the ceramic fiber blanket been adequately sealed at

the base, physical and electrical damage to the cables in this

test probably would not have occurred. Moreover, if a

2-out-of-3.logic had been used for activation of the water

suppression system by the dummy heads, the suppression system

would probably have extinguished the fire before short

circuits were observed.

-36-
Figure 14

UL Fire Barrier and Suppression. Test
11.5.2 Halon Suppression Tests

A series of nine tests were conducted at Sandia National

Laboratories to determine the effectiveness of Halon .1301 in

suppressing flaming and deep-seated cable tray fires. 3 4

This halogen compound is produced by E.I., DuPont de Nemours

and Company, Incorporated and has the chemical formula

CBrF 3 . Halon 1301 has been extensively testedý as a fire

suppressant. 3 5 In addition to the retardant action on

fires, it is believed that Halon 1301 presents less of a

personnel hazard than carbon dioxide or nitrogen inerting

systems. According to human effects experiments conducted by

Haskell Laboratories 3 6 the health hazard threshold for Halon

1301 is 7, percent by volume., The room volumetric concentration of Halon did not exceed 6 percent for this series of

cable fire suppression tests.

The experimental facility used in all earlier tests had to be

modified in order to install the various suppression systems

to be tested. One new feature of the facility was a ventilation system, installed to allow simulation of normal air

ventilation and circulation in a room of a nuclear power

plant. The flow rate of the ventilation system, when used,

was set to approximately 2100 ft 3 per minute which provided

an air turnover rate in the room of about once every 4.6

minutes.

Tests were conducted in both the horizontal and vertical

configuration of cable trays, and both IEEE-383 qualified

(cross-linked polyethylene, 3 conductor) and unqualified

(PE/PVC, 3 conductor) cables were used as in previous tests.

Trays were separated by 10.5 in. (27.6 cm). "Dummy" trays

consisting of an insulating barrier were placed adjacent to

the two trays (vertical tests) or above the top tray (horizontal tests) to provide reradiation of heat. In these tests,

the ignition tray was designated the donor tray, while the

second tray was designated the acceptor tray. Five-minute

on-and-off burn cycles using a total of 140,000 BTU/HR (41-kW)

propane burners were used until a "well-developed" fire was

started. At this point, an insulating barrier separating the

two cable trays was removed and 1 minute later the .,Halon

discharged. The discharge rates complied with NFPA

12A-1980. 3 7 The room was also sealed at the time of

discharge as required.

Table VII summarizes the tests conducted as well as the

results. Tests 58 and 59 used no Halon but instead allowed

the fire to proceed until the ventilation system was

-38-
TABLE VII

Halon Suppression Tests Summary

Test

Number

56

57

58

W 59

Configuration

Horizontal

Horizontal

Horizontal

Horizontal

Horizontal

Horizontal

Vertical

Vertical

Vertical

Cable Type

IEEE-383

Qualified

Qualified

Qualified

Qualified

Qualified

Unqualified

Unqualified

Qualified

Qualified

Suppression

Method

45-minute soak

using Halon

10-minute Halon

soak

No Halon; 45

minutes without

ventilation

No Halon; 10

minutes without

ventilation

4-minute Halon

soak

16-minute Halon

soak

75-milnute Halon

4-minute Halon

soak

Halon discharged

but room continuously vented

Results

No reignition after

admission of fresh air

No reignition

Self-quenched after

30 minutes

Burning after -10

minutes

Reignited when

ventilated

No reignition

No reignition

No reignition

No re'ignition

60

61

62

63

64
turned on later. In only one instance using Halon, Test 60,

did the cable insulation reignite after readmission of fresh

air. The soak time represents the amount of time the room was

sealed, i.e., time between discharge of Halon and readmission

of fresh air using- the ventilation system.

Halon 1301 was very effective in suppressing flames. Figure

15 shows that 5 seconds after discharge the flames have been

extinguished and all that remains is smoke and condensed water

vapor. Figure 16 taken from Test 61 shows the dramatic temperature drop in the flaming region as Halon is discharged.

Halon 1301 was not as rapid in suppressing deep-seated cable

tray fires. Figure 17 indicates that even after the Halon has

been discharged the interior cable bundle temperature

continues to rise, probably resulting from continued

combustion of cable insulation. The second increase in temperature occurs after the readmission of air and reignition of

the cable insulation.

Finally, Figures 18 and 19 show the dynamic mass loss of cable

insulation in the donor trays for Tests 57 and 59. These two

tests were identical in every respect except that in Test 57 a

10-minute Halon soak was provided whereas no Halon was used in

Test 59. However, only 3.7 kg of insulation was lost when

Halon was used (most of it before Halon discharge) compared to

a loss of 6 kg when the fire was allowed to self-extinguish.

Clearly, Halon is an effective fire suppressant agent even for

deep-seated cable fires.

Major Findings

Six very obvious but important items stand out among all

conceivable findings from the;Halon suppression systems

tests. They number as follows:

1. No damage to, or reduction in, the acceptor: tray

cables' current-carrying capacity as a result of

Halon was observed in any of the tests.

2. In all of the tests in which it was used, the Halon

effectively extinguished fires-in both the acceptor

and donor trays. In only one test (60) was a flame

rekindled in either tray after the room was

ventilated.

-40-
Figure 15

Immediate Suppression of Flames by Halon 1301

.- 41-
0

00

0:1

0

CC .0

•O 1-1:,0' , I-, 

0 - - •'• u •]:i .: , ••.

-J

CECO0 cc,

ra=a

U) 0 C) HOC)O-C0"Q

UJ C ) , 4 4, o C

snLINDI SlI3NUf3l

Fi ure 16 ,. D io

I-.00000 0000"•=0

W 0 * 0 010• • 0f N, l

SflIS'I3I S33U9:U

Figure 16

Temperature Drop in Flaming Region

-42-
4 ..0

C. . ,.

zg g p IIp I | | 0

I- I- z z10

OW

0~ 0m

I-I-r $ o o 10o -O -E 04

ILI

ow

EFigur1017

0

0o 0 NOV 03UH~I 

Figur 17

indication of Deep-Seated Fire and

Reignition of Cables

-43-
ZOý

.0

00

I-z

w40

'-U.

CD 0

N U3O=OUVHOSIU NO'IVH

CO0

W W

LUU)-

w<

J 0 o.... 0

00

w, 0 0JIN I SU0 N afl9

WFigure.1

Mas Loss i PrI -

0* 0) 0~ O. 0. 0) 0. 0) 0* 0

Figure 18

Mass Loss in Presence of Halon

-44-
4

0-

CC

0

-Iz

00

ZO

_N_

C0

UC)

w4

O0

01o

I0

04

z_

In

0

It

0

0*U~0*It)* OW

0WW~~0

000000

I- ~ I~ Y~ y- V

0 C4 C

000m V V- V- coo~

SUINVU901)

Figure 19

Mass Loss Without Halon Suppression

-45-
3.' No flammable concentrations of unburned

hydrocarbons were pyrolyzed during the

Halon soak time in any of the tests.

4. A time limit on the Halon's ability to .permanently extinguish a cable tray fire may

have emerged. While a 10-minute interval of

Halon soak was enough to extinguish a fire in

a horizontally oriented tray filled with

qualified cable, a 4-minute interval was

inadequate for this task.

5. As mentioned above, the Halon permanently

extinguished a fire after only a 10-minute

soak time, whereas the same time limit on

simple oxygen deprivation was insufficient to

keep the flame from returning upon ventilation.

6. While a 4-minute soak time was not enough to - prevent a rekindling in a horizontally

oriented tray filled with qualified cable, it

was enough to prevent reignition in a

vertically oriented tray filled with the same

cable. From this, the conclusion is that

Halon more effectively quenches fires in

vertically oriented trays than in those

- horizontally oriented.

11.5.3 Water Sprinkler Tests (NFPA 13)

A series of tests was conducted to determine the effectiveness

of overhead sprinklers in suppressing cable tray fires. The

original intention was to duplicate the Halon test series in

order to get a direct comparison between Halon suppression and

water sprinkler suppression. Although no final report on the

water tests has been issued as yet, the results are briefly

summarized here. Table VIII lists the tests performed and the

results.

Two pendent-type, open-head sprinklers with standard orifices

of 1/2 in. (1.3 cm) diameter were used. The sprinklers were

12.5 ft high (3,.8 m), were offset from the cable trays and

were separated by 12 ft (3.7 m). The water system was designed

to produce a',pressure of 35 psig (2.4 x 105 Pa) at each open

head. A total flow rate of 71 gal per minute (4.5 Z per

second) was obtained. The system was activated manually. The

-46-
TABLE VIII

Water Sprinkler Suppression Tests Summary

Test

Number Configuration

65

66

67

68

Vertical

Vertical

Vertical

Horizontal

Horizontal

Horizontal

Horizontal

Cable Type

IEEE-383

Qualified

Qualified

Unqualified

Qualified

Qualified

Qualified

Unqualified

Suppression

Method

71.GPM For 4

minutes

71 GPM for 4

minutes with

ventilation on

Results

-I

71 GPM for

minutes

71 GPM for

minutes

71 GPM for

minutes

71 GPM for

minutes

5

15

i0

Fire extinguished.i '.

(water caused short in

acceptor tray)

Fire extinguished

(water caused short in

acceptor tray)

Fire extinguished

(short in acceptor

tray before water)

Fire extinguished

(water caused short

in acceptor tray)-

Fire extinguished

(no short)'

Fire extinguished, but

continued temperature

rise for 5-10 minutes

(watercaused short 'in

acceptor tray)

Fire extinguished

(water caused short

in acceptor tray)'

69

70B

71

5

71 GPM for 16

minutes
ýspacing and flow densities were in compliance with NFPA.

13.. Figure 20 shows the water sprinkler setup for the

vertical configuration. The test procedure was very similar

to that used in the Halon tests.

The water sprinklers were successful in extinguishing all

cable trays fires in the configurations tested. Suppression

was more effective in the vertical configuration, with 4 to

5 minutes of suppression an adequate amount of time for

vertical trays but marginally adequate for horizontal tray

fires. Short circuits occurred quite readily in the acceptor

tray when the water was discharged, but the cause of the

shorts is uncertain.

Major Findings

Area water sprinklers are effective in suppressing cable tray

fires in the vertical configuration; they are somewhat less

effective for trays in the horizontal configuration. No

general statements can be made concerning their effectiveness

for horizontal tray fires of more than the three levels of

trays tested.

11.5.4 Directed Water Spray Tests (NFPA 15)

Another series of water tests was conducted to determine the

effectiveness of directed water sprays in suppressing cable

tray fires. Tests were conducted in both the vertical and

horizontal configurations, and with both IEEE-383 qualified

and unqualified cables. A total of five, 12-ft (3.7-m)-long

cable trays filled to 25 percent were used in each test.

Unlike the Halon and water sprinkler suppression tests, the

intention in these tests was to obtain fully developed fires

in four of the five cable trays before manually activating the

water suppression system. Although no final report on these

tests has been issued as yet, the results are briefly summarized here. Table IX lists the tests performed to date and

the results.

Flat, fan-type spray nozzles were used. A uniform

distribution of spray was provided over an angle of 1000. The

orifice size was 7/64 in. (2.8 mm) and each of the ten nozzles

used in all the tests provided 2.7 GPM (0.17 £/s) at a

static pressure of 81 psig (5.6 x 105 Pa), or a flow density

of 0.3 GPM per ft 2 (12.2 k/min-m2 ) of cable tray

surface area. These values are in compliance with NFPA 15

standards for identified fire hazards.•

-48-
Figure 20

Water Sprinkler Test Arrangement

(Vertical Configuration)

-49-
TABLE IX

Directed Water Spray Suppression Tests Summary

Test

Number

Suppression

Configuration Method

72

73

74

Horizontal

Horizontal

Horizontal

Vertical

Vertical

Cable Type

IEEE-383

Qualified

Qualified

Unqualified

Qualified

Unqualified

Results

0.3 GPM/ft 2 , Fire extinguished

5 min, no venti- easily

lation

0.3 GPM/ft 2 , More severe fire than

5 min, forced 72 but, 'easily

ventilation extinguished

0.3 GPM/ft 2 , Fire extinguished.

5 min, forced easily

ventilation

0.3 GPM/ft 2 , Fire extinguished

5 min, forced easily

ventilation

0.3 GPM/ft 2 , Fire extinguished

5 min, forced easily

ventilation

OCC)

I

75

77
Figure 21- shows the setup for the horizontal configuration in

Test 73. In general, the directed spray was a very, effective

means of suppressing cable tray fires. Most flaming was suppressed in a matter of 15 seconds or less, and near-ambient

temperatures were obtained within the cable trays in a matter

of minutes. Hence, there was no chance of reignition after

5 minutes of water spray. Figure 22 illustrates this dramatic

temperature drop during Test 75.

Major Findings

Directed water sprays are a very effective means of

suppressing cable tray fires, including deep-seated fires, and

means of preventing reignition. Five minutes of waterý. sprlay

at a flow density of• 0.3 GPM/ft 2 (12.2 Z/min-m2 )j was

adequate for suppressing large cable tray fires.

11.6 Penetration Seal Tests

11.6.1 Small-Scale Tests (UL)

An experimental investigation was performed at Underwriters

Laboratories to determine the effects of pressure differential, fire exposure conditions and sample construction on the

performance of fire stops used to seal electric cable and

conduit penetrations through concrete fire ba rriers. 3 8

Experiments were conducted using a differential pressure of

-12 to +125 Pa, various sample constructions and two fire

exposure conditions.

This investigation consisted of conducting 50 small-scale fire

experiments using several types of fire stop samples. A summary of the experiments conducted ,is shown in Table X. These

experiments were organized 'into 21 groups to facilitate comparison of results. Within each.group, the parameter under

consideration was varied with Ithe s ample and test procedure

held constant.

Each sample was subjected to the prescribed fire exposure

until either flaming-occurred on the unexposed side or until

the appropriate information was obtained. During each experiment, temperatures of the unexposed surface and -visual observations of physical performance were recorded. For some

experiments, temperatures within the fire stop naterial were

recorded for supplemental information.

-51-
un

Figure 21

Directed Water Spray Test Arrangement

(Horizontal Configuration)
.j0

40.n

U) 00) Cd,

Z)

.• . 0

W .i. NO agxNuniL AV~dS. -.

WI- ,-

_Lo z-:

(N.

4CL

1.0

iz'

-:zI.. 0 0) 0 0 0 0 .GD. to - 0 V V) N

snws,) SUD03U

Figure 22

Indication of Effectiveness of Directed Water Spray

-53-
TABLE X

Summary of Small-Scale Penetration Seal Tests

Parameter Gr oup Exyeriments DIcr~t inn

Groun Description

Pressure

Differential

1 P22, P19, Pressure +2 to +125 Pa;

Pl, P3, P5 silicone foam; cables

2 P23, P20, Pressure +2 to +125 Pa;

P2, P4, P6 silicone foam; no cables

3 P9, P11 Pressure +2 and +125 Pa;

silicone elastomer; cables

4 Pl0, P12 Pressure +2 and +125 Pa;-

silicone elastomer; nocables

5 P13, P15 Pressure +2 and +125 Pa;

device;.cables

6 P14, P16 Pressure +2 and +125 Pa;

device; no cables

7 P7, P8 Pressure +2 and -12 Pa;

silicone foam; cables

8 P21 Pressure +125 Pa; silicone...

foam with formed crack

9 P17, P18 Pressure +3 and -12 Pa;

silicone elastometer with

two holes created by

cable pull

Fire 10 FCI, FC2 Silicone Foam--less

Exposure severe temperature curve P7* Silicone Foam--ASTM E119

temperature curve

11 FC3 Silicone Elastomer--less severe temperature curve

CLl* Silicone Elastomer--ASTM,.-

E119 temperature curve

Sample 12 CT1, CT3 300 MCM CU Cable

(Conductor CT2, CT4 300 MCM AL Cable

size & Type) 13 CSI 3C/12 AWG Cable--Silicone

.Elastomer

CS2 7C/12 AWG Cable--Silicone

Elastomer

CTl* 300 MCM Cable--Silicone

- Elastomer

*Experiment used for comparison'with others in. group, -

-54-
Table X (Cont'.d)

Parameter: Group Experiments Description"

14 CS3 3C/12 AWG Cable--Device

CS4 . 7C/12 AWG Cable--Device

CT4* 300 MCM Cable--Device

Sample. 15 T1 Cable Type A--Silicone

(Cable Type) ýElastomer

T2 Cable Type G--Silicone

Elastomer

T3 Cable>Type Hr-Silicone

Elastomer

CS2* Cable Type F--Silicone

Elastomer

16 T4 Cable Type A--Device

CS4* Cable Type F--Device

Sample 17 Psi 1 in. *Steel Pipe

(Pipe) PS2 3 in. Steel Pipe

Sample 18 CDI .1 in. Steel Conduit

(Conduit) CD2 1 in. AL Conduit

19 CD3 3 in. Steel Conduit

CD4 3 in. AL Conduit

Sample 20 CLI One Layer of Cables

(Cable CL2 Three Layers of Cables

Loading)*

Sample 21 Si 2-in. (51-mm) Opening

(Opening) S2 6-in. (152-mm) Opening

S3 9-in. (230-mm) Opening

S4 13-in. (330-mm) Opening

*Experiment .used .for comparisohnwith others in group

-55-
All fire stops were installed in 6-in. (150-mm) thick concrete

floor slabs. Openings in all but three slabs were

either circular 6 in. (150 mm) in diameter or 12 in. (310 mm)

square. The remaining slabs had circular openings of 2 in.

(51 mm), 9 in. (230 mm) and 13 in. (330 mm) in diameter.

The fire stop materials used were silicone foam, silicone

elastomer, and a fire stop device. These are representative

of materials currently used in nuclear power plants. The

silicone foam and silicone elastomer were two-component

materials which vulcanized at room temperature (RTV). These

materials were mixed, poured into the openings, and cured in

accordance with the manufacturer's installation instructions. Testing was in accordance with IEEE 634-1978.39

Figure 23 shows the small-scale floor furnace setup used in

these tests.

Results indicated that for those materials which remained

integral during the test and did not allow a path for gas

flow, the effect of changes in pressure differential was not.

significant.

In tests with a positive pressure differential between 0.01

and 0.50 in H2 0 (2 and 125 Pa) , no significant change was

observed in the transmission of heat through the material,

in the time at which flaming occurred, or in the formation

of cracks in the decomposing material. (The rate of heat

transmission through the silicone foam and silicone

elastomer materials can be seen by the rate at which a

specific temperature propagates through the material. The

propagation rate of the 725 0 F (2850C) temperature was

selected for comparison since it also represents the

approximate front of the char layer.)

The time at which flaming occurred on the unexposed side was

not affected by changes in positive pressure differential,

nor were the formations of cracks in the decomposing

material affected by these pressure changes.

Testing with a negative pressure differential did not

significantly affect the performance of the silicone foam

material installed without through openings. However,

testing with a positive pressure differential affected the

performance of the silicone elastomer material installed

with through openings of 0.50-in. (12-mm)-diameter holes.

-56-
UI

Figure 23

Small-Scale Penetration Seal Tests at UL
Three experiments were conducted with a fire less severe in

temperature than the standard temperature-time curve specified in ASTM E119. 5 As expected, temperatures on the

unexposed side of the samples for these experiments were

lower than for comparable samples subjected to a ASTM E119

fire exposure. Consequentially, the time to failure

increased for the samples exposed to the less severe fire.

Changes in sample construction investigated were conductor

type and size, cable type, conduit or pipe type and size,

cable loading, and opening size. Results indicate that

changes in fire stop construction can affect the performance.

Changes in conductor type (copper vs. aluminum) affected

unexposed surface temperatures of the fire stop material

near the conductor. The temperature rise near the copper

300 MCM cable was greater than at the aluminum 300 MCM

cable. Increasing the conductor size also resulted in

increased temperature on the unexposed surface of the fire

stop material near the conductor.

The size of pipe or conduit affected the temperature of the

surrounding fire stop material. Based upon the temperature

at the material-pipe interface, the temperature tended to be

greater near the 3-in. pipe than at the smaller 1-in. pipe.

The type of conduit, either steel or aluminum, also had an

effect on the surrounding fire stop material temperature.

The temperature at the material-pipe interface tended to be

generally greater near the aluminum conduit than near the

steel conduit.

It was also observed that increasing the number of cables

penetrating the' fire stop increased the temperature of the

fire stop material near the cables. The temperature near a

three-layer bundle of cable was greater than the temperature

near a one-layer bundle of cable.

The size of the opening appeared to affect the structural

integrity of the material. It was observed that for the

larger openings 6 in. (152 mm) , 9 in. (230 mm) and 12 in.

(300 mm) , the material tended to deflect downward at the

center of the opening during fire exposure. Therate of

deflection appeared to increase with increasing opening

size. This downward deflection tended to affect the

performance of the material by causing cracks along ýthe

periphery of ;the opening, which in turn decreased the

structural integrity of the material.

-58-
Major Findings

Results of these tests indicate that the effect of pressure

differential is not significant for those firestop materials

which have no cracks or other through openings that allow

passage of gases during fire exposure. However, if the

material allows passage for gases through cracks or other

holes, such as those left open after a cable pull, the pressure differential affects fire stop performance. Effects of

the size of the opening, size, location and type of the penetrating items installed through the opening, and severity of

fire exposure on the performance of fire stops were

demonstrated.

11.6.2 Large-Scale Tests (UC-Berkeley)

Three large-scale tests were conducted at Lawrence Berkeley

Laboratory, operated by the University of California, to

assess the effects of furnace pressure and excess pyrolyzates on the postflashover fire performance of barrier

assemblies that contain cable penetrations. 4 0

The large-scale vertical furnace used in these experiments

consists of a reinforced concrete frame lined with refractory material. The furnace opening is 3.66 m (12 ft-0 in.)

wide and 3.35 m (11 ft-0 in.) high. The furnace is fired by 44 burners using natural gas fuel. The burners can be

operated in either a premixed or diffusion mode. During

these experiments the burners were operated in a premixed

mode. The 44 burners are arranged so that the furnace

temperature can be maintained in accordance with the

standard temperature-time curve as specified by ASTM

Designation E-119.

Each of the three experiments employed identical walls (see

Figure 24). The walls consisted of a 76 mm (3 in.)-thick,

phenolic impregnated, paper honeycomb core covered on each

side with three layers of 13 mm (1/2 in.)-thick gypsum wall

board. The finished walls were 0.152 m (6 in.) thick, 2.44

m (8 ft-0 in.) high and 3.66 m (12 ft-0 in.) in length. A

total of six penetrations were introduced into each wall.

The penetrations measured 0.152 m x 0.152 m (6 in. x 6 in.)

and were symmetrically arranged. The conditions present at

each of the penetrations during the experiments are

summarized in Tables XI to XIII.

-59-
Figure 24

Large-Scale Penetration Seal Tests at U-C Berkeley
TABLE XI

Conditions at Each of the Six Penetrations

During Experiment No. 1

Penetration

Designation

1A

1B

2A

2B

3A

3B

Pressure

Differential

Positive

Negative

Positive

Negative

Positive

Negative

Excess

Pyrolyzates

Yes

Yes

No

No

No

No

Cable

Present

No

No

No

No

Yes

Yes

Penetration

Seal

No

No

No

No

No

No

TABLE XII

Conditions at Each of the Six Penetrations

During Experiment No. 2

Penetration

Designation

1A

lB

2A

2B

3A

3B

Pressure

Differential

Positive

Negative

Positive

Negative

Positive

Negative

Excess

Pyrolyzates

Yes

Yes

Yes

Yes

Yes

Yes

Cable

Present

Yes

Yes

Yes

Yes

Yes

Yes

Penetration

Seal

No

No

No

No

Yes

Yes

-61-
TABLE XIII

Conditions at Each of the Six Penetrations

During Experiment No. 3

Penetration

Desianation

Pressure

Differential

Excess

Pvrolvzates

Cable Penetration

Present Seal

1A

lB

2A

2B

3A

3B

Negative

Negative

Negative

Negative

Negative

Negative

Heating Oil

Paraffin

Paraffin

Paraffin

Paraffin

Paraffin

No

Yes

Yes

Yes

Yes

Yes

No

Silicon Foam

Ceramic Fiber

Ceramic Fiber

Silicon Foam

Urethane Foam

-62-
Excess pyrolyzates were introduced locally to selected

penetrations by the installation of a fuel pan beneath the

penetration. The fuel pans consisted of steel containers

measuring 0.152 m x 0'.152 m x 0.30 m (6 in. x 6 in. x

12 in.) in Experiment No. 1, and 0.152 m x 0.30 m x 0.30 m

in the other two tests. Each fuel pan contained a total of

1 kg (2.2 lbs) of polyethylene in Experiment No. 1, 6.8 kg

(15 lbs) of polyethylene in Experiment No. 2, and 6.8 kg (15

lbs) of paraffin in Experiment No. 3 (in this test one

container used No. 2 heating oUi).

The experimental assemblies were subjected to the ASTM E-119

temperature-time history for a period of 33 minutes in

Experiment No. 1, and one hour in Experiment No. 2. Experiment No. 3 lasted 46 minutes, but difficulty with furnace

control due to the large amounts of excess pyrolyzates during this experiment prevented maintaining the ASTM E-119

temperature-time history after the first 18 minutes.

The effects of furnace pressure, without excess pyrolyzates

on open penetrations were investigated at penetrations 2A

and 2B during the first experiment. During periods of pos- itive pressure, the temperature at the center of penetration

2A closely approximated the furnace temperature. However,

when the pressure was reduced to a negative value, at an

elapsed time of approximately 14 minutes, the temperature at

2A was reduced by about 450 0 C to a value of approximately

400"C. Similar behavior was noted at penetration 2B. The

effects of excess pyrolyzates at penetrations 1A and lB

during Experiment No. 1 were not pronounced because of the

small amounts used.

The effects of excess pyrolyzates were, however, very

pronounced during Experiment No. 2. An examination of the

temperatures recorded at penetrations 1A and lB during

Experiment No. 2 indicated the effects of excess pyrolyzates

in combination with both positive and negative furnace pressures. Peak temperatures of approximately 10000 C were attained for penetration 1A (positive pressure), whereas the

temperature at penetration lB did not exceed 100 0 C during

negative pressure conditions.

The effects of negative furnace pressure and excess

pyrolyzates were investigated at penetration 3B during

Experiment No. 3, for the case of a highly combustible

-63-
penetration seal material. During this experiment,

penetration 3B was sealed with a highly combustible urethane

foam boardstock. The furnace pressure at penetration 3B was

maintained at a negative pressure throughout this experiment, thus preventing leakage of combustion gases and excess

pyrolyzates through the penetration. The temperatures at

penetration 3B showed a steady increase in temperature

caused by progressive combustion of the urethane foam seal.

The performance of the urethane foam during this experiment

served to illustrate the inadvisability of evaluating the

fire resistive capabilities of proposed penetration seal

designs using a test furnace that is operated at negative

internal pressure differentials.

Major Findings

These experiments investigated the effects of two variables,

test furnace pressure differential and excess pyrolyzates,

on the performance of penetrations into fire resistive wall

assemblies. The results indicated that these variables can

have a pronounced effect on the measured fire resistance of

penetrations.

11.7 Browns Ferry Replication Test

A full-scale replication type experiment was conducted at

Underwriters Laboratories to assess the performance provided

by a specific fire protection configuration designed in

accordance with NRC fire protection guidelines and found

acceptable to the staff. 4 1 The experimental configuration

was constructed to replicate several cable trains and the

fire protection system for an area in the Browns Ferry

Reactor Building (elevation 593 ft, Area p to q and R6 to

R7, Unit 1). In this area there are many electrical circuits in cable trays and conduits, water pipes, and other

equipment used in operating the plant. Of specific concern

is the group of electrical circuits located along the north

wall near the centerline for this area. At this location is

a group of vertical cable trays and conduits (see Figure 25).

One of these cable trays and one conduit contains Division

II safety circuits, while another conduit contains Division

I safety circuits.

The fire protection for this area consists of detection

systems, a suppression system, flame retardant cable

coating, and steel cable tray covers. The detection system

-64-
Figure 25

Upper Portion of Browns Ferry Replication Test Setup
includes ionization type ceiling mounted smoke detectors and

line type cable tray mounted heat detectors. The suppression system is an automatic water spray system which is

activated upon signals from both smoke and heat detectors

from one fire protection zone within this area. Most cables

in trays are protected with a flame retardant coating. TVA

specifications allow installation of ten cables or less

within a tray without application of the coating. When

there are more than ten uncoated cables in a tray, the entire uncoated cable bundle is to be protected with the coating. Although TVA specifications require a minimum 1/8 in.

(3.2 mm) dry thickness of coating, cables in this area are

protected with an approximate 1/4 in. (6.4 mm) dry thickness

of coating.

The ten cables or less which are not required to be coated,

are coated with a 1/4 in. dry thickness of material for a

minimum of 5 ft (1.52 m) from a wall or floor opening as

part of the fire stop design. Tray covers, both front and

rear, are installed on vertical trays away from walls for

10 ft (3.05 m) above the floor. Additionally, tray covers

are installed on top of trays which are used for low level

signal cables. This fire protection configuration was designed in accordance with the NRC fire protection guidelines

and found acceptable to the staff.

Originally, the program was to consist of three experiments,

but the outcome of this first test (which was the most

conservative case) eliminated the need for the last two

tests. The fire source in this test was 5 gal (18.9 ) of

heptane which was spilled about a group of vertical trays.

The water spray system was purposely made inoperable to simulate a malfunction of the system. The fire was allowed to

burn without any suppression for 45 minutes which permitted

an assessment of the flame retardant coating. Also, by observing the severity of the fire at several time periods,

information was obtained regarding the protection provided

by different response times of a plant fire brigade.

The following is a summary of observations made after the

experiment. Pull Box 2576 and associated conduits were

unchanged with no observable deformation damage. The cover

of the box remained securely fastened. The condition of the

cables inside of the conduits remained unchanged, ie, no

observed physical damage. However, damage to coated cables

-66-
TABLE XIV

Operation Times of Detectors

Smoke-Detectors

No. Activation Time(s)

1

2

3

4

12

9

8.

9

Heat Detector

Zone Activation Time(s)

1E 56

Sprinkler Head

No, Operation Time(s)

1

2

3

45

*Fusible link had functioned but the time at which it

occurred was not obtained due to malfunction of

recording equipment.

-67-
was found in each of the vertical trays. The damage

consisted of consumed insulation material which exposed the

copper conductors. The cable insulation and jacket of the

ten uncoated cables were consumed to about a height of 19 ft

(5.79 m). The trays, coating, and cables of the upper horizontal tray group remained unchanged. Table XIV summarizes

the activation times of the smoke and heat detectors and the

operation time for the sprinkler head. Table XV shows the

times to short circuit in each of the vertical trays.

Major Findings

In this test of a particular configuration of the Browns

Ferry Reactor building, a liquid-fuel exposure fire resulted in the disruption of the circuit integrity in all

four vertical trays, one of which was a simulated Division

II safety circuit. However, the simulated Division I safety

circuit inside a conduit located near the tray group remained functional. This test verified the survivability of one

redundant safety train during a postulated fire.

11.8 Radiant Heat Tests

A series of tests was performed at the Radiant Heat

Facility, Sandia National Laboratories, to determine the

damageability of electrical cable insulation to heat. 4 2

The cables were exposed to thermal radiation at various

levels to determine the threshold level of heat flux

(kW/m 2 ) at which significant damage to IEEE-383 qualified

and unqualified cables occur. A device was constructed at

the Radiant Heat Facility to expose a cable tray, 8 ft

(2.44 m) long by 1 ft (0.31 m) wide to thermal radiation at

power levels of up to 60 kW/m 2 . The cable tray was mounted under a semi-circular cylindrical steel shroud which was

heated by three banks of quartz infrared lamps. The ends of

the shroud were open to permit ventilation over the top of

the cable tray, under the shroud, and to permit observation

of the exposed cable during the testing. Figure 26 shows

the setup for these tests.

Each cable tray was filled with five bundles, eight loops

each, (approximately 800 ft, (244 m) and three 8-ft (2.44-m)

lengths of cable for thermocouple placement. Two types of

cable were used in these tests. One type was IEEE-383

-68-
TABLE XV

Time to Short Circuits

Tray Time, Min:Sec

Ve 0:50

KS-ESII (Division II) 2:18

KT 14:42

TE 22:40

All shorts were individual conductor to tray (ground) type shorts.

The circuits in all three conduits remained functional

during the experiment.

-69-
I,

Figure 26

Full-Scale Radiant Heat Test
qualified three conductor No. 12 AWG, 30 mil (0.76 mm)

cross-linked PE, silicon glass tape, 65 mil (1.65 mm)

cross-linked PE jacket, 600 V. The other type was

non-IEEE-383 qualified cable, three conductor No. 12 AWG,

20/10 Poly-PVC, polyethylene insulation, 45 mil (1.14 mm)

PVC jacket. The cable was energized during testing with

320 vdc and 5 amps AC. Cable currents, both AC and DC, were

recorded during testing and current from cable to cable tray

was recorded to detect electrical failure (a short from

cable to cable tray). Cable temperatures were also

monitored.

A total of ten tests was conducted, five each on IEEE-383

qualified cable and unqualified cable. A brief summary of

the results of the tests is given in Table XVI. The damage

threshold levels of heat flux were calculated for IEEE-383

qualified cable, and unqualified cable. Electrical failure

and nonpiloted ignition were the failure criteria. Figures

27 and 28 show graphically the correlation between external

heat flux and time to electrical failure or nonpiloted

ignition.

Major Findings

As a result of these tests, the critical heat flux for

electrical failure was determined to be about 8 kW/m 2 for

non-IEEE-383 qualified cable and 18 kW/m 2 for IEEE-383

qualified cable. The critical heat flux for nonpiloted

ignition was likewise determined to be about 22 kW/m 2 for

unqualified cable and 28 kW/m 2 for IEEE-383 qualified

cable.

-71-
TABLE XVI

Summary of Radiant Heat Tests

Measured

Test Power ievel

Number kW/m

1

2

21

11

41

31

Time of

Exposure

min

30

40

6.6

26.5

Time to

Electrical

Failure

min

Time to

Fire

min

t 30*

Weight

Loss

lbs

1.0

0.1

3

4

5

6.6

9.5

6.5

26.5

3.0

7.4

0.0

0.2

7

6

7

8

9

11

30

30

30

30

22.5.

23 7.5 t 30¶ 5.1

6 -- 0.2

30

29

7

6

4

4

7

6

2.3

10 1.2

*Partial electrical failure had developed at 30 minutes and it is assumed

that total failure would occur if the exposure were continued.

Note that Test No. 2 was run 10 minutes longer than normal.

The first five tests were with IEEE-383 qualified cables, the last five with

unqualified.

¶Thermocouple readings indicated that the cables were very close to

ignition temperature (600 0 C) and it is assumed that fire would develop if

the exposure were continued.

-72-
0

i~1

1'

f -OW

00

0 0

ro1* S/T 'aOU.•

Figure 27

Correlation Between Time to Electrical

Failure and External Heat Flux

-73-
q

Fq=

0.4

o q

L0) o>

ra 00)

I I " eI6 

zT -/x'oT

00

Ignition and External Heat Flux

-74-
III. Analysis

III.1 Characterization of Cable Tray Fires

Characterization of cable tray fires 2 0 , 4 3 - 4 4 , 5 2 was based

upon a review of the data that was collected in the fullscale testing described earlier in this report. In particular, the cable tray separation tests (Section 11.2) and

the Halon suppression tests (Section 11.5.2) were most useful. With regard to the differences between electrically

initiated fires and exposure fires, observation of films

taken of the tests revealed the following:

1. In electrically initiated fires the intense

period of the fire persisted at a particular

location for between 40 and 240 seconds before

die-out began to occur. In propane-fueled

exposure fires the minimum period found to

consistently ignite a tray of IEEE-383

qualified cable was 300 seconds.

2. In electrically initiated fires the luminous

flame zone fluctuated rapidly between 4 and

10 in. (0.1-0.25 m) in height. In propanefueled fires the luminous flame zone fluctuated

between 10 and 12 in. (0.25-0.30 m) in height.

In the diesel-fueled fire the luminous flame

zone fluctuated between 30 and 50 in. (0.76-1.3

M).

3. Gas temperature in the luminous zone was

roughly 1900°F (1300 K) in all fires.

4. Velocity of rising gases was about 3 to 4 ft/s

(0.91-1.22 m/sec) in all fires.

5. The luminous zone of the electrically initiated

fires was optically thin with an apparent

emissivity of the order of 0.1 while the

exposure fires had an optically thicker and

correspondingly higher emissivity.

6. Heat transfer to immersed objects is convection

dominated in the electrically initiated fires

and radiation dominated in the exposure fires.

-75-
The mechanism of fire spread, as observed in the

July 6, 1977 exposure test, 2 2 was determined to be a leap

frog process. A fire in one tray, say no. 1, induces a fire

ball above the next tray, no. 2, against the underside of

the third one. The fire ball then grows downward until it

contacts tray no. 2, at which time that tray ignites and the

fire-ball burns out.

The thermodynamic phenomena observed and measured during

cable fire tests have been classified into burn modes. They

are, in fact, event modes from the statistical standpoint.

Once identified, the burn modes can be used to'describe and

evaluate electrical cable fires. Consequently, the development of the burn mode concept for cable fires is regarded as

an important development in fire physics.

The electrical cable thermodynamic phenomena are temperature

dependent, and the burn modes are defined within temperature

limits characteristic of each particular type of cable.

Except for extreme burn modes at either end of the temperature spectrum, temperature boundaries for the modes are

determined by abrupt changes in the rate of rise of cable

temperatures in the cable fire tests. The established burn

modes are continuous use temperatures, accelerated aging,

pyrolysis, smoldering, deep-seated fire, interior gas

combustion, fireball, surface fire, flashover, and deflagration. Figure 29 shows a representative cable temperature

history plotted on a burn mode matrix. Similar temperature

profiles have been developed for the other cable fire

tests. The temperature boundaries are shown by dashed lines

to indicate one standard deviation (± 1 a) in the test

data. The direction of the temperature profile curve is

indicated, and the data points represent 30-second time

intervals. A cross shown on the figure indicates the time

at which an electrical short (if any) occurs.

The burn modes for electrical cable fires are by nature

divided into oxygen-sufficient and oxygen-starved categories

upon the evolution of pyrolytic gases. The temperature

limits for the various modes are dependent on the composition of the combustible material used for the insulation in

the different types of electrical cables and are determined

by abrupt increases in temperature rise rates.

-76-
BURN:. 

C;ABL•. MOM F T FS'v

tAA4 T')X

Figure 

29 

o M

n Burn Mode Matri

... profile 

3 cable 

Test

Tem peratu re EE- 83 C for pt e - 1 3B

-7'7 -
Major Findings

Characterization of fires revealed a margin of safety in the

separation criteria of the regulatory guide for electrically

initiated fires in IEEE-383 qualified cable. However, exposure fire tests have shown it is possible for a fire to propagate across the vertical separation distance between

safety divisions if a fully developed cable fire is the

initiating event.

111.2 Studies of Generic Fire Protection Issues

An earlier Sandia National Laboratories fire protection

study4 5 surveyed the guidelines and standards pertaining

to nuclear power plant fire protection and the investigative

reports which followed in the aftermath of the Browns Ferry

Nuclear Power Plant fire of March 22, 1975'. The purpose of

that survey was to establish a firm basis for future activities in assessing the adequacy and development of improved

design criteria for nuclear power plant fire protection systems. Based on this and several other considerations, the

NRC Office of Standards Development funded a new program to

carry out a more detailed investigation. In particular, the

following tasks were identified for study:

Task 1. Ventilation Systems

Task 2. Fire Detection Systems

Task 3. Fire Barriers

Task 4. Fire-Hazards Analysis

This section briefly summarizes the major conclusions and

recommendations drawn from these studies.

111.2.1 Ventilation Systems

It was the objective of this task to examine the role of

compartment ventilation as it affects nuclear power plant

fire protection safety. 4 6 To do this, the following

general approach was used:

1. Review and compare existing standards for

ventilation systems to evaluate the adequacy of

the guidance provided.

-78-
2. Develop technical bases for ventilation--system

functions and performance in fire emergencies

and identify topics requiring further investigation or testing.

3. Recommend changes or additions to existing

guidance to clarify intent and define design

criteria.

The existing guidelines and standards, as they apply to the

effect of ventilation systems on fire protection in nuclear

power plants, were reviewed from the point of view of a

design organization attempting to bring a facility into

compliance. Specific criteria were listed and examined to

determine if they were adequate to evaluate and specify

system designs.

Current literature in the fire protection field was surveyed

to locate investigative research reports on ventilation

related aspects of fire phenomenology. Particular attention

was directed to reports dealing with the effects of variable

ventilation rates on the growth of compartment fires and

burning rates in fully developed compartment fires.

Information gathered from the review of the standards and

the literature search was used in formulating and evaluating

four candidate tech .iical bases for ventilation system

design. The four bases were smoke removal, smoke control,

fire control, and temperature control. Each candidate basis

was examined to determine whether or not it fully met the

intent of the guidelines and standards. The question of

feasibility was also addressed in each case, with regard to

equipment design, plant layout implications, and the

availability of data upon which to base design parameters.

It was concluded that, based on the current state of the art

in fire protection technology, the technical design basis

for the fire protection design of ventilation systems should

be that of heat removal from the involved fire area for the

purpose of controlling fire temperatures. The only problem

found with this design basis was that of control of radioactive releases from controlled areas of the plant. The

normal HVAC system, which is equipped to remove these

radioactive substances, is generally incapable of handling

the particulate concentrations and temperatures associated

-79-
with fire-generated effluent. If a system of prefilters

were added to the normal filter banks serving the controlled

areas, the particulate concentration of contaminated smoke

could be reduced to manageable levels. The addition of an

upstream water curtain and demister would reduce temperatures and corrosive properties before filtration. But the

design or backfitting of such systems would be a formidable

task.

Further recommendations include:

1. An evaluation needs to be made of the benefits

and detriments of a heat removal fire ventilation system relative to other available fire

protection measures (eg, automatic suppression,

automatic detection, or separation) . This

effort should be completed before serious

consideration is given to implementing a

temperature control ventilation scheme in

nuclear power plants.

2. If the use of a heat removal fire ventilation

system is evaluated as worthwhile, the technical design basis for the fire venting system

should be the required rate of heat removal

from involved fire areas.

3. Existing guidelines and standards are generally

lacking in sufficient detail to function as

criteria for the design of ventilation systems

as an integral part of the fire protection

system.

4. Current fire protection research activities are

directed primarily toward the solution of light

fire loadings, which are not typical of all

areas of a nuclear power plant setting. Experimental programs should be proposed to provide

basic fire performance data on combustibles

normally found in critical areas of power

plants.

5. In areas of the plant which involve high

probability for entrainment of radioactive

containments in the smoke and gases and in

-80-
backfitting of existing facilities,. emphasis

should be placed on the design and reliability

analysis of fire detection and suppression

systems with accompanying deemphasis on venting

requirements.

6. To allow sufficient flexibility of operation

during fire emergencies to adequately control

the spread of smoke and provide makeup air for

fire vented compartments, the fans, isolation

dampers, and their associated power supply and

control cables should be protected from fire

damage. Manual remote operation capability

should be provided so that regulation and

realignment of the systems can be accomplished

as the particular fire situation demands.

Major Findings

Current standards and regulatory guidelines inadequately

define criteria for design of ventilation systems and their

operation under fire emergencies.

111.2.2 Fire Detection Systems

The fire detection subsystem review was undertaken to

evaluate the following from the standpoint of overall plant

safety:47-48

1. The technical bases for detection system

design criteria.

2. The adequacy of detailed design guidance

currently available.

3. The effectiveness of qualification testing

procedures to simulate actual design applications.

For each of these three evaluations categories, numerous

recognized fire protection information sources were chosen

for review. The assignment of each information source to an

appropriate evaluation category was based upon the level of

detail and scope of information available in each source.

After establishing evaluation categories and information

sources, it was decided to focus on the selection and use of

detector sensing units, rather than to investigate either

-81-
the internal design details of the units or the operation of

each ancillary detection system component (ie, transmitters,

alarm units, satellite stations, or interconnection

wiring). This decision stemmed from a realization that:

1. Existing detection theory lacks the ability to

predict detector performance solely from known

internal sensing unit design features.

2. Ancillary detection system components primarily

function to transmit electrical signals from

detector sensing units to various panels and

alarm devices, generally through the use of

fundamental electrical design techniques which

have been accepted and used extensively

throughout other nuclear power plant systems.

The following five major types of commercially available

detectors were chosen for investigation:

1. Area heat detectors.

2. Continuous line heat detectors.

3. Ionization type products of combustion detectors.

4. Photoelectric smoke detectors.

5. Ultraviolet/infrared flame detectors.

Topics considered in this investigation were (1.) establishing

area detection requirements, (2) selecting specific

detector types, (3) locating and spacing detectors, and (4)

performing installation tests and maintenance. The major

conclusions drawn from these investigations can be

summarized as follows:

1. Establishment of Area Detection Requirements

-- Current insurance and regulatory agency

criteria are inconsistent and often conflict

by referring to various plant areas by

different names and by requiring different

levels of detection coverage for the same

plant areas.

-82-
2. Selecting Specific Detector Types--Although

it is possible to make gross judgments in

choosing a particular detector type, such as

an area heat detector in preference to a

smoke detector, it is difficult to make more

subtle selections among similar detector

types, such as ionization versus photoelectric detectors. Furthermore, since different

detector types are tested under different

conditions, it is doubtful whether any

predictable correlation of detector performance can be made for candidate detectors.

This is because there are conditions under

which detectors now are not fully tested.

3. Locating and Spacing Detectors--Locating and

spacing cannot be accomplished in an

analytical manner based on present testing

methods. Instead, engineering judgment and

vendor recommendations must bridge the gap

between test conditions and installed

conditions. Unfortunately, judgment and

recommendations can vary widely, depending on

the skill of the individual providing the

guidance.

4. Performing Installation Tests and Maintenance--There is no uniformly applied set of

installation tests and maintenance procedures

at this time. Only the recommendations of

detector manufacturers are available to a

designer. Since detector manufacturers often

have diversified interests, only a fraction

of which may involve nuclear power plant fire

protection, there has been little incentive

for a manufacturer to develop installation

test and maintenance procedures primarily

geared to the nuclear power plant market.

Major Findings

Current design and regulatory guidelines alone are

insufficient to ensure satisfactory fire detection system

performance; the use of in-place testing of detectors under

conditions expected to occur normally in areas being

protected is recommended.

-83-
111.2.3 Fire Barriers

It was the objective of this study to assess the adequacy of

current standards which govern the design and testing of

fire barriers. 4 9 Specific areas of investigation included

the severity of test conditions, the ability of test procedures to represent actual fire conditions, the repeatability

of test results, the amount of safety margin afforded by

current tests, and the sensitivity of barrier performance to

specific design details.

To accomplish the study objective, it was necessary to

become familiar with the way in which fire barriers are

presently tested and, where possible, they mathematically

model the response of barriers under test conditions. Where

a clear definition of certain test conditions was lacking

or, because of physical complications, the conditions could

not be accurately modeled, a qualitative assessment of the

test requirements was made. The study procedure can be

generally described as follows:

1. Study and evaluate the standards currently in

force or proposed to determine if the needs of

fire safety in nuclear power stations are

satisfied by these standards.

2. Evaluate thermal characteristics of typical

3-hour barriers and calculate their thermal

response when exposed to the standard ASTM E119

furnace test, using a computerized mathematical

model.

3. Determine and recommend necessary follow-up

action.

Based on this study, a number of important conclusions and

recommendations were made:

1. Capability of Walls--Based on analysis using

heat transfer models, it was determined that

walls constructed of reinforced concrete,

concrete block, and gypsum are adequate fire

barriers if exposed to actual fire conditions

which do not exceed the temperature and

duration limits to which the walls were

originally tested.

-84-
2. Standard Time-Temperature Curve--Because the

standard fire connot be considered as representative of compartment fires, the fact that a

given barrier has received a standard rating

does not mean that it will last for the rated

duration in every fire situation or that a comparative quality rating is achieved. Nevertheless, it is recommended that no change be made

to the standard time-temperature exposure

because

a. A large amount of experience has been

gained using the standard exposure.

b. No "standard" exposure can be defined

which will eliminate all such objections.

c. Utilities are expected to assess the types

of fires to which a given barrier may be

exposed and evaluate the barrier in the

light of such knowledge.

3. Hose-Stream Test--Because of an inability to

accurately calculate or control the forces applied to a test specimen during the hose-stream

test, and improved method should be defined to

replace that test. Such a method should be

suitable for analysis or direct measurement of

the applied forces.

4. Furnace Pressure--To ensure that the test

realistically represents compartment fires and

the response of doors to these fires, it is

recommended that fire exposure tests be performed with a slight positive furnace pressure. The German standard DIN 4102 requires a

positive furnace pressure of 10 + 2 Pa (0.00145

psi or 0.04 in. water). 5 0 A positive furnace

pressure of at least that magnitude should be

required for the testing of door assemblies as

well as penetration seals.

5. Definition of Test Specimens--The ANSI/IEEE 634

standard on penetration seal testing should

-85-
specify that the configuration tested be

representative of the assembly as it is

installed in the power plant, not only duplicating the penetration seal itself, but

also providing the same layout among cable

trays with the same suspension and

restraints as will be incorporated into the

power plant barrier. While it is presumed

that the NRC has consistently required that

this be done as a condition of licensing,

the practice does not appear to be

documented as a requirement.

Major Findings

A number of changes should be made to the current methods of

testing fire-rated walls, doors, and penetration seals. In

particular, the hose-stream test should be improved, the test

furnace should be maintained at a positive differential

pressure, and commercial penetration seals should be tested in

a more realistic fire environment.

111.2.4 Fire-Hazards Analysis

The major objective of this particular study was to assess the

adequacy of existing fi':e-hazards analysis techniques in the

context of nuclear power plant safety.5 1 It was concluded

early in the study that a viable fire-hazards analysis for

nuclear power plant application should (1) be derived from,

but not necessarily duplicate, available and proven analysis

techniques; (2) be defendable in terms of being conservative

and technically sound; and (3) be easily used by both

designers and regulators. With these criteria established, a

large number of analysis methods were reviewed. By limiting

this review to only those methods which have received at least

some practical scrutiny, the first criteria automatically is

satisfied; only the second two criteria remained to be met.

For ease of understanding, it proved convenient to assign each

candidate analysis method to one of three categories depending

on whether a particular method was based on subjective

judgments, deterministic calculations, or probabilistic

logic. Since it was found that all of the available analysis

methods reviewed proved deficient in meeting at least one of

the analysis criteria, it was decided to select and combine

from available analyses those attributes most responsive to

the needs of nuclear power plant designers and regulators.

-86-
The analysis method which resulted from this approach relies

initially upon conservative assumptions and deterministic

calculations of fuel load and ventilation conditions to

bound expected fire severity. If such bounding conditions

are found to be acceptable to plant safety, the analysis is

terminated. If, however, plant safety cannot beensured

under conditions of a conservative bounding analysis, other

supplementary fire protection measures (e.g., detection,

manual suppression, and automatic suppression) are evaluated

in a probabilistic fashion to assess what level of fire

protection can be derived from these measures. If the

results of a probabilistic analysis also are found to be

unsatisfactory or inconclusive, a subjective analysis is

finally performed. Figure 30 places in perspective the

model arrived upon which is most suitable for assessing fire

severity in nuclear power plants.

Major Findings

On the basis of this study and a review of the fire-hazards

analyses performed to date for several nuclear facilities,

it is concluded that improvements can be made in most of the

analysis techniques presently used. These improvements are

important in eliminating the lack of both conservatism and

technical merit inherent in many traditional analysis

approaches.

-87-
COMPARISON OF MODELS

FOR ASSESSING FIRE SEVERITY

A

INSTANTANEOUS

COMBUSTION OF

EVERYTHING

COMBUSTION AT

SURFACE-CONTROLLED

BURN RATE

VENT I LATI ON-CONTROLLED

BURNING WITHOUT

HEAT LOSS THROUGH

OPENINGS

4

ACTUAL SEVERITY

FOR VENTILATIONVENT ILATI ON-CONTROLLED CONTROLLED FIRES

BURNING WITH HEAT

LOSS DIRECTLY TO

OUTI SDE

Figure 30

Comparison of Models for Assessing Fire Severity

in Nuclear Power Plants

-88-
IV. Summary

This report has summarized all of the test results and

research findings of the fire protection research program at

Sandia National Laboratories for the past 7 years. Altogether, some 30 reports and 75 tests are described. For

each test series conducted, the purpose of the tests and

results are described, and the major findings are summarized

for easy reference. A comprehensive reference list is provided which includes every major report released through the

end of 1981. A list of important papers presented at workshops and conferences is given for additional reference.

The executive summary describes the objectives of the research program, the major areas of testing, major findings,

and the interaction of researchers at Sandia National

Laboratories with the general fire protection community.

It is found that a number of test results have had a

measurable impact on fire protection guidelines for nuclear

power plants. In particular, the July 6, 1977 full-scale

exposure fire test clearly indicated that the cable tray

spacing as designated in Regulatory Guide 1.75 was inadequate for exposure fires. The small-and large-scale

penetration seal tests also raised the important issue as to

whether penetration seals should be tested under furnace

conditions of positive differential pressure or not. The

Browns Ferry Replication Test confirmed the survivability of

one redundant safety train during a postulated fire at one

important location in the Unit 1 reactor building. The

Halon tests have confirmed that for the configurations

tested, Halon 1301 can suppress deep-seated cable tray fires

provided that there is adequate Halon concentration and soak

time. And finally, fire retardant coatings and fire shields

were found to offer a measure of additional protection,

although there was a wide range in the performance of the

coatings.

-89-
V. References

1. "Recommendations Related to Browns Ferry Fire,"

NUREG-0050, NRC Staff, February 1976.

2. US Atomic Energy Commission Regulatory Guide 1.75,

Physical Independence of Electric Systems, February

1974.

3. NFPA 13-1980, "Sprinkler Systems, Installation,"

National Fire Protection Association, Boston, MA, 1980.

4. NFPA 15-1980, "Water Spray Fixed Systems," National

Fire Protection Association, Boston, MA, 1980.

5. "Fire Tests of Building Construction and Materials,"

ANSI/ASTM E119-80, American Society for Testing and

Materials, Philadelphia, PA, 1980.

6. Ronald Feit, Meeting Notes for the US Nuclear

Regulatory Commission Fire Protection Review Group,

Albuquerque, NM, September 7, 1978.

7. "Regulatory Investigation Report of the Browns Ferry

Fire on March 22, 1975," US NRC, Report Numbers

50-259/75-i and 50-260/75-1, June 1975.

8. Report on Cable Failures-1968 at San Onofre Nuclear

Generating Station, Unit I, Southern California Edison

Company.

9. James Gaffney, "The Significance of the New FR-I Flame

Test, "Wire Journal, October 1973, pp 82-84.

10. IEEE Standard for Type Test of Class IE Electrical

Cables, Field Splices, and Connections for Nuclear

Power Generating Stations Std. 383-1974.

11. H. Schonbacher and M. H. Van deVoorde, "Radiation and

Fire Resistance of Cable-Insulating Materials Used in

Accelerator Engineering," CERN European Organization

for Nuclear Research, April 15, 1975.

12. L. J. Klamerus, "Quick Look Report on Fire Protection

Research," Sandia National Laboratories, July 1976.

13. L. J. Klamerus, "Quick Look Report on Fire Protection

Research," Sandia National Laboratories, August 1976.

-90-
14. L. J. Klamerus, "Quick Look Report on Fire Protection

Research," Sandia National Laboratories, October 1976.

15. L. J. Klamerus, "Quick Look Report on Fire Protection

Research," Sandia National Laboratories, November 1976.

16. L. J. Klamerus, "Quick Look Report on Fire Protection

Research," Sandia National Laboratories, December 1976.

17. L. J. Klamerus, "Quick Look Report on Fire Protection

Research," Sandia National Laboratories, February 1977.

18. L. J. Klamerus, "Quick Look Report on Fire Protection

Research," Sandia National Laboratories, March 1977.

19. L. J. Klamerus and R. H. Nilson, "Progress Report on

Fire Protection Research," SAND77-0303, NUREG-0206,

Sandia National Laboratories, June 1977.

20. L. J. Klamerus and R. H. Nilson, "Cable Tray Fire

Tests," SAND77-1125C, Sandia National Laboratories,

Albuquerque, NM, July 1977.

21. L. J. Klamerus, "Quick Look Report on Fire Protection

Research," Sandia National Laboratories, July 1977.

22. L. J. Klamerus, "A Preliminary Report on Fire

Protection Research Program (July 6, 1977),"

SAND77-1424, Sandia National Laboratories, Albuquerque,

NM, October 1977.

23. L. J. Klamerus, "A Preliminary Report on Fire Protection Research Program Fire Retardant Coatings Tests

(December 7, 1977-January 31, 1978)," SAND78-0518,

Sandia National Laboratories, Albuquerque, NM, March

1978.

24. L. J. Klamerus, "Fire Protection Research Quarterly

Progress Report October-December 1977," SAND78-0477,

NUREG/CR-0366, Sandia National Laboratories,

Albuquerque, NM, August 1978.

25. L. J. Klamerus, "A Preliminary Report on Fire

Protection Research Program Fire Barriers and Fire

Retardant Coatings Tests," SAND78-1456, NUREG/CR-0381,

Sandia National Laboratories, September 1978.

-91-
26. L. J. Klamerus, "Cable Tray Fire Tests," SAND78-1810C,

PES-IEEE 1979 Winter Power Meeting, New York, NY,

February 1979.

27. L. J. Klamerus, "A Report on Fire Protection Research

Program Corner Effects Tests," SAND79-0914, Sandia

National Laboratories, Albuquerque, NM, May 1979. (Not

published.)

28. L. J. Klamerus, F. R. Krause, "Fire Protection Research

Quarterly Report January-March 1978," SAND79-0879,

Sandia National Laboratories, Albuquerque, NM, May

1979. (Not published.)

29. L. J. Klamerus, "Fire Protection Research Program

Corner Effects Tests," SAND79-0966, NUREG/CR-0833,

Sandia National Laboratories, December 1979.

30. W. J. Christian and T. E. Waterman, "Ability of

Small-Scale Tests to Predict Full-Scale Smoke

Production," Fire Technology, Vol. 7, No. 4, 1971.

31. G. Cruz and R. Corlett, "Enclosed Fire Smoke and Toxic

Gas Studies," University of Washington, August 7, 1974.

32. T. E. Waterman, "Scaling of Fire Conditions Supporting

Room Flashover," DASA 2031, December 1967.

33. L. J. Klamerus, "A Preliminary Report on Fire

Protection Research Program Fire Barriers and

Suppression .(September 15, 1978 Test)," SAND78-2238,

NUREG/CR-0596, Sandia National Laboratories,

Albuquerque, NM, December 1978.

34. L. J. Klamerus, "Electrical Cable Fire Suppression

Tests with Halon 1301," SAND81-1785, Sandia National

Laboratories, Albuquerque, NM, August 1981.

35. Thermodynamic Properties DuPont Halon Fire

Extinguishant, E. I. duPont de Nemours Company,

Wilmington, DE, 19898, Copyright 1966.

36. Halogenated Extinguishing Agent Systems: Halon 1301,

National Fire Protection Association, Boston, MA,

02210, Copyright 1977.

37. NFPA 12A-1980, "Halon 1301 Systems," National Fire

Protection Association, Boston, MA, 1980.

-92-
38. L. J. Przybyla, "Investigation of Fire Stop Test

Parameters," SAND81-7144, NUREG/CR-2321, Underwriters

Laboratories, Northbrook, IL, April 1981.*

39. "IEEE Standard Cable Penetration Fire Stop

Qualification Test," IEEE 634-1978. Available for

purchase from the Institute of Electrical and

Electronics Engineers, Inc., 345 East 47th Street, New

York, NY 10017.

40. R. B. Williamson, F. L. Fisher, "Tests and Criteria for

Fire Protection of Cable Penetrations," SAND81-7160,

NUREG/CR-2377, University of California, Berkeley, CA,

June 1981.*

41. L. J. Przybyla, Quick Look Report, "Replication

Experiments for Fire Protection Systems," Underwriters

Laboratories, Inc., Northbrook, IL, August 1981.*

42. L. L. Lukens, "Nuclear Power Plant Electrical Cable

Damageability Testing at the Radiant Heat Facility,"

SAND82-0236, Sandia National Laboratories, Albuquerque,

NM, January 1982.

43. L. W. Hunter, "Cable Tray Fires:, On the Mechanism of

Upward Fire Spread Through a Stack of Horizontal Cable

Trays," Applied Physics Laboratory, Johns Hopkins

University, Laurel, MD, May 19, 1978.

44. F. R. Krause, W. H. Schmidt, "Burn Mode Analysis of

Horizontal Cable Tray Fires," SAND81-0079, Sandia

National Laboratories, Albuquerque, NM, December 1981.

45. E. A. Bernard, G. L. Cano, "Report on Task I--Fire

Protection Study," SAND76-0630, NUREG76-6516, Sandia

National Laboratories, Albuquerque, NM, February 1977.

46. J. A. Milloy, "Nuclear Power Plant Fire ProtectionVentilation (Subsystems Study Task 1)," SAND79-0263,

NUREG/CR-0636, Sandia National Laboratories,

Albuquerque, NM, August 1979.

*Prepared under contract with Sandia National Laboratories.

-93-
47. D. L. Berry, "Nuclear Power Plant Fire Protection-Fire

Detection (Subsystems Study Task 2)," SAND78-1373,

NUREG/CR-0488, Sandia National Laboratories,

Albuquerque, NM, March 1979.

48. J. L. Boccio, "Requirements for Establishing Detector

Siting Criteria in Fires Involving Electrical

Materials," SAND81-7168, NUREG/CR-2409, Brookhaven

National Laboratory, Upton, NY, November 1981.*

49. E. E. Minor, D. L. Berry, "Nuclear Power Plant Fire

Protection-Fire Barriers (Subsystems Study Task 3),"

SAND78-1990, NUREG/CR-0468, Sandia National

Laboratories, Albuquerque, NM, September 1979.

50. Standard DIN 4102, "Brandverhalten von Boustoffen und

Bauteilen," Deutscher Normenausschuss, Berlin, 1970.

51. D. L. Berry, E. E. Minor, "Nuclear Power Plant Fire

Protection-Fire Hazards Analysis (Subsystems Study Task

4)," SAND79-0324, NUREG/CR-0654, Sandia National

Laboratories, Albuquerque, NM, September 1979.

52. R. K. Clarke, "Analytical Model for Cable Tray Fires,"

SAND75-0288, Sandia National Laboratories, Albuquerque,

NM, September 1975.

*Prepared under contract with Sandia National Laboratories

-94-
VI. Conference Reports

1. G. L. Cano, L. J. Klamerus, and E. A. Bernard, "Nuclear

Power Plant Fire Protection Research," SAND77-0389A,

ANS Topical Meeting, Chattanooga, TN, August 1977.

2. L. J. Klamerus, "Cable Tray Fire Tests," SAND77-1125C,

National Academy of Sciences Conference on Electrical

Insulation and Dielectric Phenomena, Albany, NY,

October 1977.

3. L. J. Klamerus, "Fire Protection Research Project,"

SAND77-1768C, Fifth Water Reactor Safety Research

Information Meeting, Gaithersburg, MD, November 1977.

4. L. J. Klamerus, "Status of the Fire Protection Research

(FPR) Program," SAND78-2025C, Sixth Water Reactor

Safety Research Information Meeting, Gaithersburg, MD,

November 1978.

5. L. J. Klamerus, "Cable Tray Fire Tests," SAND78-1810C,

PES-IEEE 1979 Winter Power Meeting, New York City, NY,

February 1979.

6. L. J. Klamerus, "Fire Research on Grouped Electrical

Cables," SAND79-0031, Sixth Annual Energy Conference

and Exhibition, WATTec, Knoxville, TN, February 1979.

7. L. J. Klamerus, "Status of Fire Protection Research

Program," SAND79-0882A, Nuclear Power Industry

symposium, Houston, Texas, June 1979.

8. L. J. Klamerus, "Fire Protection Research Program,"

SAND79-1593A, Institute of Electrical Engineers of

Japan, October 1979.

9. L. J. Klamerus, "Status of the Fire Protection Research

(FPR) Program," SAND79-2020, Seventh Water Reactor

Safety Research Information Meeting, Gaithersburg, MD,

November 1979.

10. L. J. Klamerus, "Fire Protection for Grouped Electrical

Cables,", SAND80-0244A, Seventh Annual Energy Conference

and Exhibition, WATTec, Knoxville, TN, February 1980.

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11. L. J. Klamerus, "Fire Protection Research Program at

Sandia Laboratories," SAND80-0880C, ANS/ENS Topical

Meeting, Thermal Reactor Safety, Knoxville, TN, April

1980.

12. F. R. Krause, "Burning Characteristics of Horizontal

Cable Trays," Seventh Water Reactor Safety Research

Information Meeting, Gaithersburg, MD, November 1979.

13. L. J. Klamerus, "Fire Protection Research Program at

Sandia National Laboratories," SAND80-2422C, Eight

Water Reactor Safety Research Information Meeting,

Gaithersburg, MD, October 1980.

14. W. H. Schmidt, F. R. Krause, "Nuclear Power Plant

Electrical Cable Burn Modes," SAND80-2816C, American

Nuclear Society Annual Meeting, Miami, FL, June 1981.

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Distribution:

US NRC Distribution Contractor (CDSI) (265 copies)-

7300 Pearl St.

Bethesda, MD 20014

240 copies for RP

1513 D. W. Larson

1513 D. D. Cline

1513 A. C. Ratzel

2165 J. E. Gover

3141 L. J. Erickson

3151 W. L. Garner

3154-3 C. W. Dalin

8214 M. A. Pound

9400 A. W. Snyder

9414 D. L. Berry

9440 D. A. Dahlgren

9441 M. Berman

9442 W. A. Von Riesemann (5)

9442 J. M. Chavez (25)

9443 D. D. Carlson

9444 S. L. Thompson

9445 L. 0. Cropp

9446 B. Bader

-97-
NRC FORM 335 1. REPORT NUMEER (Assignedby DDC) -U.S. NUCLEAR REGULATORY COMMISSION NUREG/CR-2 607

BIBLIOGRAPHIC DATA SHEET SAND82-0431

4. TITLE AND SUBTITLE (Add Volume No., if appropriate) 2. (Leave blank)

Fire Protection Research Program for the

U.S. Nuclear Regulatory Commission 3. RECIPIENT'S ACCESSION NO.

1975-1981

7. AUTHOR(S) 5. DATE REPORT COMPLETED

Donald A. Dube MONTH YEAR

April 1983

9. PERFORMING ORGANIZATION NAME AND MAILING ADDRESS (Include Zip Code) DATE REPORT ISSUED

Sandia National Laboratories .MONT" April YEA1983

PO Box 5800 6, (Leave blank)

Albuquerque, NM 8u185

8. (Leave blank)

12. SPONSORING ORGANIZATION NAME AND MAILING ADDRESS (Include Zip Code) TO. PROJECT/TASK/WORK UNIT NO.

Division of Engineering Technology

Office of Nuclear Regulatory Research 11. FINNO.

US Nuclear Regulatory Commission

Washington, DC 20555 NRC FIN No. A1010

13. TYPE OF REPORT j PERIOD COVERED (Inclusive dates)

Technical 1975-1981

15. SUPPLEMENTARY NOTES 14. (Leave olank)

16. ABSTRACT (200 words or less)

Since early 1975, Sandia National Laboratories has been conducting

fire protection research for the U.S. Nuclear Regulatory Commission.

Testing has been done on grouped electrical cable fires including

electrical initiation, fire propagation, the effects of fire retardant

coatings and barriers, suppression, and characterization of the

damageability of electrical cables. In addition, several studies of a

more generic nature such as fire detection, ventilation, and

fire-hazards analysis methodologies were performed.

This report condenses all of the test results, reports, papers and

research findings of the past seven years. Research conducted by

contractors to Sandia National Laboratories is also summarized.

17. KEY WORDS AND DOCUMENT ANALYSIS 17a. DESCRIPTORS

Fire Protection

17b. IDENTIFIERS/OPEN-ENDED TERMS

18. AVAILABILITY STATEMENT 19. SECURITY CLASS (This report) 21. NO. OF PAGES Unclassified

Unlimited 20. SECURITY CLAS,.Th,spage) 22. PRICE

Unclassl led S

NRC FORM 335 m11-8ni

* U.S. GOVERNMENT PRINTING OFFICE: 1983-0-676-026/540 -98-