NUREGICR-0468

SAND78-1990

RP

Nuclear Power Plant Fire ProtectionFire Barriers

(Subsystems Study Task 3)

Earl E. Minor

Dennis L. Berry

Manuscript Submitted: January 1979

Date Published: September 1979

Sandia National Laboratories

Albuquerque, NM 87185

Operated by

Sandia Corporation

for the

U. S. Department of Energy

Prepared for

Engineering Methodology Standards Branch

Office of Standards Development

3 •U. S. Nuclear Regulatory Commission

Washington, D.C. 20555

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,* * * - Z"

:CO ieB %": r ir
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NOTIE

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NUREG/CR-0468

SAND78-1990

RP

NUCLEAR POWER PLANT FIRE PROTECTION -

FIRE BARRIERS (SUBSYSTEMS STUDY TASK •)

Earl E. Minor

Dennis L. Berry

Manuscript Submitted: January 1979

Date Published: September 1979

Sandia Laboratories

Albuquerque, New Mexico 87185

operated by

Sandia Corporation

for the

U.S. Department of Energy

Prepared for

Engineering Methodology Standards Branch

Office of Standards Development

U.S. Nuclear Regulatory Commission

Washington, DC 20555

Under Interagency Agreement DOE 40-550-75

NRC FIN No. A-1080

ABSTRACT

Standards currently used in the fire protection field are analyzed in

relation to their applicability to nuclear power stations and recommendations concerning their improvement are made. Results of mathematical

analyses of typical fire barriers are given. Based on the temperature

gradient established in the mathematical analyses, a stress analysis of

poured concrete walls is described. Recommendations are made for followup studies and experiments.

5
ACKNOWLEDGMENT

The authors thank D. W. Larson and C. E. Sisson of Sandia

Laboratories' Fluid and Thermal Sciences Department for their assistance

in defining and modeling the ASTM E 119 standard fire, and J. D. McClure

of Sandia's Engineering Analysis Department for stress analyses of the

concrete fire barrier.

6
CONTENTS

Page

1. Introduction 9

1.1 Task Description 9

1.2 General, Procedure 9

1.3 Technical Approach 10

2. Evaluation of Existing and Proposed Standards 11

2.1 General 11

2.2 Evaluation of ASTM E 119 11

2.3 Evaluation of ASTM E 152 18

2.4 Evaluation of IEEE 634 20

3. Thermal Modeling of Walls 22

3.1 Description of Walls Modeled 22

3.2 Thermal Analysis 24

3.3 Stresses Caused by Thermal Gradient 32

4. Literature Study of Penetration Seals 34

5. Conclusions and Recommendations 35

5.1 Walls 35

5.2 Doors 36

5.3. Penetration Seals 36

APPENDIX 39

Re ferences 47

7

NUCLEAR POWER PLANT FIRE PROTECTION -

FIRE BARRIERS (SUBSYSTEMS STUDY TASK 3)

1. Introduction

1.1 Task Description

Based on the need to support near-term regulatory and licensing

objectives for nuclear power plant fire protection, the Nuclear Regulatory

Commission (NRC) Office of Standards Development requested Sandia

Laboratories to develop the underlying logic and technical bases associated with four specific fire protection topics.1 The topics selected by

-the NRC were fire ventilation, fire-detection, fire barriers, and fire

hazards analysis. The third topic, fire barriers, is the subject of this

report; separate reports cover the other topics.

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

standards which govern the design and testing of fire barriers. •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. It was not an objective of this study, to predict the

actual conditions to which a barriei will be exposed during a fire or to

predict the response of a barrier under these actual conditions. These

problems are discussed as part of the fire hazards analysis topic. 2

1.2 General Procedure

To accomplish the study objective, it was necessary to become

familiar with the way in which fire barriers are presently tested and,

where possible, to 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:

9•
Study and evaluate the standards currently in force or proposed to

determine if the needs of firesafety in nuclear power stations are

satisfied by these standards.

e Evaluate thermal characteristics of typical 3-hr barriers and

calculate their thermal response when exposed to the standard ASTM E

119 furnace test, using a computerized mathematical model.

* Determine and recommend necessary follow-up action.

1.3 Technical Approach

The NRC has established the requirement that safety-related areas

shall be separated by 3-hr-rated barriers..3 Existing guidelines and

standards applicable to the testing of fire barriers (ASTM E 119, ASTM E

152, and IEEE 634)4-6 were reviewed to determine whether their test

methods and criteria satisfy the needs of nuclear power stations.

Using the test conditions defined in these standards, a mathematical

model was developed to investigate the thermal response of typical fire

barriers when exposed 'to standard test conditions. To establish limiting

barrier performance characteristics, thermal properties of the selected

barriers were then varied to determine those property limits for which

each barrier would just fail the thermal response criteria of the standard

tests.

A study of current available literature was conducted, especially in

the area of penetration fire stops. Reports of tests were evaluated

against the needs of nuclear power stations.

As a result of the above investigations, recommendations are made for

follow-up studies and experiments. (See Section 5.)

10
2. Evaluation .of Existing and Proposed Standards

2.1 General

Standards evaluated, in this study were limited to those specifying

fire tests of barriers,,doors, and penetration seals.

The following standards were evaluated:

" ASTM E 119-76, "Standard Methods of Fire. Tests of Building

Construction and Materials." This standard is similar to

NFPA 251. and UL 263 standards on the same subject.,

" ASTM E 152, "Standard Methods of Fire Tests of Door

Assemblies." This standard is similar to NFPA 252 and UL

10B.

* IEEE 634-78, "Standard Methods of Fire Tests of Cable

Penetration Fire Stops."

These standards were reviewed only for areas which present technical

difficulties or which are poorly defined in relation to the-requirements

of nuc-lear power stations. No attempt was made to do a comprehensive

critique of the standards.

2.2 Evaluation of ASTM E 119

Standard ASTM E 119, "Standard Methods of Fire Tests of Building

Construction and Materials," prescribes test methods and acceptance

criteria for the elements of construction such as walls, ceilings, floors,

beams, and columns. This standard had its origin in recommendations of

the International Fire Prevention Congress in London, 1903. The

recommendations were based on experience from actual fires and results

from fire tests conducted before 1903. Tests had been performed in

England using small brick huts and wood as a fuel. The fire was built

11
until it reached the desired temperature and maintained around that

temperature as an average for the duration of the test (commonly 4 hours).

The temperaturemost commonly selected was 1700°F (926%C).

In the United States the first attempt at establishing a national

standard was begun by the American Society for Testing and Materials

(ASTM) in 1907. This effort produced a national standard closely resembling therequirements of the New York building code of 1899 for testing

floor elements in a fire hut with a wood-fueled fire. As prescribed in

the.test procedure, an average temperature of 1700'F (926"C) was to be

maintained for 4 hours. In 1909 the ASTM added a separate test for walls,

to be performed in a manner similar to floor tests except that the test

duration was limited to 2 hours. Both the floor and wall tests made use

of a furnace to produce the high-temperature test conditions.

Although the ASTM efforts in 1907 and 1909 are recognized as the

first genuine attempts to establish a national standard for fire barrier

testing in the United States, it was not until 1917 that ASTM E 119 as it

exists today was adopted. In 1917 the ASTM standard was changed from an

average-temperature test-(at 1700 0 F or 926 0 C) to a better defined test

using a prescribed time-varying temperature test curve. Today this test

curve is often referred to as the standard time-temperature curve.

Origin of Standard Time-Temperature Curve -- Before the establishment

of the standard time-temperature curve, exposure in most fire tests had

been specified as a temperature, on the average, greater than some value.

In 1916 and 1917, two meetings were held to establish fire standards for

the United States. These conferences were attended by representatives

f rm eric Society for Testing and Materials, National Fic Protecti on

Association, Underwriters Laboratories, National Bureau of Standards,

National Bureau of Fire Underwriters, Factory Mutual, American Institute

of Architects, American Society of Mechanical Engineers,,American Society

of Civil Engineers, Canadian Society of Civil Engineers, and American

Concrete Institute. The new Standard, ASTM C'19 (later renumbered E 119),

was issued at the February 24, 1917, meeting.

12
The major accomplishment of the new standard was its.prescribed timetemperature curve. First published in a 1916 description of proposed UL

column tests, this curve has remained unchanged since.

It is important to realize that the standard curve was defined in

.1917 without the knowledge of what actual temperature profiles in building

fires might be. Although burnout experiments had been conducted in

Europe, none had been conducted in the United States at that time and

building fire parameters were essentially unknown. Following the adoption

in this country of the standard curve, however, the National Bureau of.

Standards conducted tests which showed that, while the temperature rise

during the initial stages of a test fire was more rapid than the ASTM

curve indicated, results as measured by the endurance of walls indicated'

that the ASTM curve approximated the maximum fire severity of the Bureau

of Standards tests.

However, the conditions under which these tests were performed differ

from conditions to be found in nuclear power plants. For example, the

first burnout building (constructed in 1922) was accoutered with furniture

and papers to resemble an office and it contained windows which supplied

ventilation for the fire. Such test fires, representative of offices and

residences, continued into the 1940s and, although no detailed test.

results of this work were published, it appears that none of the tests

were conducted using the conditions of limited ventilation, heavy construction, and synthetic combustibles found in nuclear power plants.

"Standard" Exposure -- It must be understood at the outset that, even

though a given barrier has received a 3-hr rating, this does not imply

that it will last 3 hrs in every fire situation. Nor does it imply that

it will last twice as long as a'barrier which has a 1-1/2-hr rating. It

means only that a representative barrier has been subjected to a specified

time-varying temperature test in a furnace under specified conditions of

restraint and has not failed the criteria in ASTM E 119. Many variables

enter into the endurance of a barrier, such as construction and loading

differences, fuel loading and ventilation (which primarily control the

burning rate and the removal of hot gases), fuel distribution and exposed

ýirface of the fuel, and even the volume into which hot ga ses are vented

13
from the fire chamber. Also, it is not clear that a comparative quality

rating is achieved between the "standard" exposure and endurance in a real

fire. Babrauskas 7 presents the argument as follows:

It is sometimes asserted that, even though under many conditions

the standard curve exposure will not be at all similar to the

expected realistic exposure, it is still justified to use the

curve. The argument usually runs, "we know the test results

will not be the same as endurance time in a fire, but so long as

the test exposure is fully standardized, all materials will be

tested fairly and adequate ranking established." It should be

adequately clear that such a viewpoint is untenable. Compare,

for instance, an assembly using materials which are good insulators and have low TC*, with one using poorly insulating, high

TC materials. When tested under appropriately low temperatures,

the first assembly will be superior, but at higher temperatures

the second will be better. In general, there is no way of

assuring that even relative rank will be preserved; in consequence testing under conditions greatly differing from those of

the expected fire is not a suitable design philosophy.

On the other hand, Kanury and Holve concluded that " there is no

reason to discard the standard time-temperature curve as a specified

exposure Isource for fire performance evaluation of materials, even though

superficially it fails to be a realistic duplicate of any one particular

full-scale enclosure fire exposure history." 8

Walls most commonly used in nuclear power plants are of poured

concrete. Other walls which could be used are concrete block or gypsum

board with appropriate structural support. The exposure provided by the

ASTM E 119 standard fire-exposure test is a reasonable method of assessing

these fire barriers when it is combined with a knowledge of expected fire

conditions to which a particular barrier-may be exposed.

Restraint -- Standard ASTM E 119 provides for bearing walls and

partitions to be tested with a load superimposed "in a manner calculated

to develop theoretically, as nearly as practicable, the working stresses

*TC is the critical temperature of the material. As an example, for

structural steel the critical temperature is usually considered to be

1000 0 F (538 0 C).

14
contemplated by the design." For bearing walls, the standard specifically

states that the test specimen shall not be restrained on its vertical

edges. Test specimens of nonbearing walls and partitions, on the other

hand, are specifically required by the standard to be restrained on all

four edges.

Restraint of walls during test has been debated for years with no

consensus reached. In view of the difficulty in determining a reasonable

restraint specification and in view of the fact that the furnace test is a

poor simulation of actual building fires, no change-is recommended in this

study. Of considerably more importance is the need to protect steel beams

and columns so that critical temperatures are not exceeded, thereby

causing structural failure.

Critical Temperature of Steel -- Steel structural elements must be

protected so that their critical temperature is not exceeded.

Columns and beams must be tested in a configuration simulating their

actual construction and loaded "'in a manner calculated to develop theoretically, as nearly as practicable, the working stresses contemplated by

the design." 4 The component is considered as passing the fire endurance

test successfully if it sustains the applied load for a period equal to

that for which the classification is desired.

An alternate method for testing the protection of structural steel

columns does not require that a load be applied. Instead, the column is

instrumented with at least three thermocouples located at each of four

levels to measure temperatures of the steel. The test is considered successful if "the transmission of heat through the protection during the

period of fire exposure for which classification is desired does not raise

the average (arithmetical) temperature of the steel at any one of the four

levels above 1000'F (538°C),or does 'not raise the temperature above 1200'F

(649°C) at any one of the measured points."

15
In actual situations, the failure temperature of steel is a function

of the stresses present in thesteel, 9 which are not really determinable

in a complex situation because the load-bearing contributions of the

associated structures (decking, etc.) are uncertain and may in fact change

as a fire progresses. The commonly accepted critical temperature for

steel of 1000°F (538 0

C) is a satisfactorily conservative figure. The

point must be stressed, however, that protection of steel beams and

columns must be provided so that barrier integrity is maintained.

Hose-Stream Test -- Section 9 of ASTM E 119 describes the hose-stream

test required of walls which have a rating of 1 hr or more. A duplicate

of the sample wall exposed to the fire endurance test shall be exposed to

a fire exposure test for a period equal to one-half of that indicated as

the resistance period in the fire endurance test, but not for more than 1

hr. Immediately thereafter it shall be subjected to the impact, *erosion,

and cooling effects of a hose stream directed first at the middle and then

at all parts of the exposed face wi-t-h--changes-in-d-i-rect-ion-being made

slowly. As an alternate, the specimen exposed to the fire endurance test

may immediately thereafter be exposed to the hose-stream test.

While it is apparent that the hose-stream test might eliminate

excessively flimsy structures by applying a horizontal load, the force

delivered by the hose stream and the application of that force to the wall

are not readily calculable or precisely controllable.

Under E 119 conditions, S. H. Ingberg determined that with 30 psi

water pressure the measured force against a test panel was 257 N (about 58

lb). 1 0 The area on which the stream impinges is about 56.7 cm2 (about 9

in.2), giving an average static stress of 4.53 x i04 Pa (6.6 psi). in

case of failure, an average stress value is meaningful only if a large

segment of the wall buckles. However, failure usually is caused by a more

puncture-like penetration of the hose stream.

16
Harmathy and Lie 9 have stated:

The results of the hose stream test and cotton waste test* are

very difficult to interpret in strict scientific terms. If

unbiased scrutiny were to indicate that there is need for tests

of this kind in the standard specification, they would have to

be respecified to yield well-defined, quantitatively expressible

results.

Babrauskas 7 has suggested that orthogonal loading be applied to walls

only and that the hose-stream test be eliminated in favor of "either a

pendulum impact test after the specimen is removed from the furnace (as is

done in Germany)", or a constant orthogonal loading applied throughout

the test."

The German specification (DIN 4102) to which Babrauskas refers

provides for a spherical impact in three equally-spaced locations on the

outside (unexposed) surface of the test specimen 3 min before the expiration of the rating period. The impacts are to be imparted by a pendulum

with a spherical mass of 15 to 25 kg displaced so that an impact of 20 Nm

(i.e., 20 J or 14.75 ft-lb) occurs at the point of impact.11 The obvious advantages of such a system are the capability of calibrating the

equipment and the ability to compute the impact force.

This report does not advocate any specific replacement for the hosestream test but does point, out that it is neither repeatable nor capable

of rigorous analysis.

ASTM E 119 requires that the wall or partition being tested "shall

have withstood the fire endurance test without passage of flame or gases

hot enough to ignite cotton waste, for a period equal to that for which

classification is desired."

17
Furnace Differences-- As explained earlier, ASTM E 119 tests are conducted using furnaces which are controlled to produce a specified timevarying temperature environment for each test wail. In practice, temperature control is accomplished by regulating fuel flow into a furnace in

response.to a fuel-demand. signal generated by thermocouples installed 6

inches from the test specimens. Because furnace configurations and construction materials can vary from one test facility to another, some investigators have questioned the validity of controlling furnace temperatures from thermocouple response signals without fir:s.t calibrating the

thermocouples in conjunction with the particular furnace environments to

ensure consistency among all test furnaces. This concern may be

unfounded.

Based on the analysis described in the Appendix, it appears that the

present use of thermocouples actually minimizes the effects of differentfurnace configurations on test results. The analysis shows that, for

thermocouples in two different furnaces to follow the same temperature

history, the severity of the test conditions must be equal for the two

furnaces. This result is supported by a set of measurements taken in the

University of California(Berkeley) wall test furnace and reported by

Babrauskas. 7 These measurements demonstrate that the effect of the thermal properties of a furnace on the heat flux to the test specimen is

slight and, indeed, may not be any more significant than the variation

between tests in the same furnace. In addition to the insensitivity of

test results to furnace properties, Babrauskas has found that, over a wide

range of thermocouple sizes and shapes, all thermocouples respond comparably after a lag period ranging from several seconds to about 10 minutes, depending on the thermocouple mass. For a 3-hr test, this lag is

negligible.

2.3 Evaluation of ASTM E 152

Standard ASTM E 152, "Standard Methods of Fire Tests of Door Assemblies," provides for both a fire endurance test and a hose-stream test.

The discussion of the standard time-temperature curve given in Section

2.2, Evaluation of ASTM E 119, is applicable to ASTM E 152 as well.

18
Criteria which must be met by a door assembly during the fire

endurance test are:

9 No flaming is allowed on the unexposed surface-during the first 30

min of fire exposure.

* Light (approximately 6-in.) flames are allowed along the edges of the

door on the unexposed side after 30 min for periods not exceeding 5

min.

* Light flaming, as defined.above, may occur on the unexposed surface

during the last 15 min if the flames are within 1-1/2 in. of a

vertical edge or within 3 in. of the top edge.

* A hose-stream test shall be performed after the fire exposure without

openings developing during the impact.

When hardware is to be evaluated for use on fire doors, it shall hold the

door closed in accordance with the conditions of acceptance throughout thd

exposure period and, in addition, the latch bolt shall remain projected and shall

be intact after the test. The hardware need not be operable after test.

Hose-Stream Test -- Perhaps the hose-stream test applied to door assemblies

is more defensible than the application of the hose-stream test to walls (see

discussion in Section 2.2) because of the elimination of excessively flimsy door

assemblies from consideration as -rated doors. However, the criticism mentioned in

the earlier section is still valid, insofar as inability to calculate the

resulting forces or control the application of those forces to the door.

The authors' view is that, although the hose-stream test is of value in

eliminating flimsy structures, an improved method which is more readily controlled

and capable of analysis would be desirable.

19
Furnace Pressure -- ASTM E 152 directs, "Maintain the pressure in the furnace

chamber as nearly equal to the. atmospheric pressure as possible." (The pressure

of a natural-draft furnace may be controlled by dampers in the exhaust flues,

while a forced-draft furnace may be controlled by controlling the blowers.)

In a compartment fire, a positive pressure difference between the room and

the surrounding environment is generated by the expansion of gases within the

room, and the pressure will vary according to the available ventilation to the

room and the density (and temperature) of the combustion gases. Unfortunately,

furnace tests of doors, as well as other building components, are consistently

performed with a slightly negative furnace pressure, apparently to minimize the

escape of toxic smoke and gases from the furnace to adjacent areas. Because of

this, the effectiveness of a door in limiting the spread of flame and smoke is not

fully tested. Heating of the door cracks, especially along both the top and the

door jam, will be significantly affected by the furnace pressure. If the furnace

pressure is positive, the cracks will be heated; conversely, if the furnace

pressure is negative, the cracks will be cooled by the inflow of-air. Obviously,

-a considerable advantage accrues to doors being tested under negative pressure

conditions.

Section 6.2.5, Part 2, of the German standard, DIN 4102, requires that, "when

testing building components whose function includes sealing a room, a positive

overpressure of 10 + 2 Pa must be maintained throughout the test, beginning 5 min

after ignition.''I Ten pascals is equivalent to 0.00145 psi or 0.04 in. of water,

a slight positive pressure. A positive pressure of at least that magnitude should

be incorporated into Standard ASTM E 152 to improve the evaluation of doors.

2.4 Evaluation of IEEE 634

Until very recently there was no standard to specify tests or criteria for

penetration seals. IEEE 634, "IEEE Standard Cable Penetration Fire Stop

Qualification Test," 6 is the first attempt to fill this need.

Before this standard appeared, tests had been performed using ASTM E 119

criteria. The new standard is also based on ASTM E 119, with the only apparent

difference being that the temperature rise on the unexposed surface is limited by

20
the self-ignition temperature of the outer cable covering, the fire stop

materials, or material in contact with the fire stop. For power generating

stations, the standard specifies a maximum temperature (not temperature rise) of

700'F on the unexposed surface.

The discussion of the standard time-temperature curve given in Section 2.2,

Evaluation of ASTM E 119, is applicable to IEEE 634.

Criteria which must be met by penetration seals are quoted below:

6.1.1 The cable penetration fire stop shall have withstood the

fire endurance test as specified without passage of flame or

gases hot enough to ignite the cable or other fire stop material

on the unexposed side for a period equal to the required fire

rating.

6.1.2 Transmission of heat through the cable penetration fire

stop shall not raise the temperature on its unexposed surface

above the self-ignition temperature as determined in ANSI

K65.111-1971 of the outer cable covering, the cable penetration

fire stop material, or material in contact with the cable

penetration fire stop. For power generating stations, the

maximum temperature is 7000 F.

6.1.3 The fire stop shall have withstood the hose-stream test

without the hose stream causing an opening through the test

specimen.

Hose-Stream Test -- As in the case of door tests, the hose-stream

test may have some validity as a method for eliminating inadequate

materials or poor installations. However, the criticism given in Section

2.2 of this report remains applicable to hose-stream tests of penetration

seals. The unevenness of forces resulting from the hose stream and the

lack of repeatability of the test complicate the performance of an

engineering analysis of test results. Therefore, the test represents only

a factor upon which a subjective judgment may be based.

Furnace Pressure -- See Section 2.3 for a discussion of furnace

pressure as it applies to tests of doors. The points mentioned there are

applicable to penetration seals as well. The fact that furnace tests are

commonly run with a slightly negative furnace pressure instead of a

positive pressure simulating an actual fire is probably a more serious

error for penetration seals than for any other construction component.

21
Penetration seals are commonly made of a foamed-in-place silicone

rubber compound which has the characteristic of burning slowly so as to

provide protection a prescribed length of time.

In contrast to the negative pressure of the furnace test, the

positive pressure of an actual fire will cause the following:

" Increased burning rate of the fire-stop material because of a better

supply of oxygen to the burning surface.

" Increased erosion of the char which normally forms on the surface of

fire-stop material exposed to the test fire. Increased erosion--or

less char--will allow easier access of oxygen to the burning surface

and also provide less insulation against heat penetration.

" Increased likelihood of hot gases or flame being emitted from cracks

or openings in the penetration seal.

Thus, it is apparent that a negative furnace pressure during the fire

exposure test of a penetration seal could result in an undertest and

consequent over-rating of a particular seal.

It is, therefore, the strong recommendation of this study that a

positive pressure be defined and incorporated into the standard for fire

exposure testing of penetration seals.

3. Thermal Modeling of Walls

3.1 Description of Walls Modeled

Three types of wall construction were chosen for analysis.

Predominant in the nuclear power industry is the concrete wall with steel

reinforcement. For this first case the analysis concentrated on a

thickness of 8 in. as representing the minimum thickness which might be

used as a 3-hr barrier.12

22
For the second wall type, a concrete block wall was selected as being

representative of a typical add-on (or backfitted) 3-hr configuration (see

Figure 1). Again, an 8-in. thickness (minimum 7-5/8-in. thickness) was

chosen to represent the minimum for a 3-hr barrier.12

To complete the analysis, a wall consisting of steel and gypsum board

was modeled. There are cases in older nuclear power plants where space

limitations dictate the use of this type of wall construction. Details of

the wall configuration were taken from design No. U603 in the UL Fire

Resistance Index, 1976.12 The "back face" was a duplicate of the "front"

or fire-exposed face so that a 3-hr rating from either side was obtained.

See Figure 2 for construction.

Though not necessarily defining all.possible 3-hr barriers, these

wail-s are t-ypical of those which might- be used as 3-hr fire barriers in

nuclear power plants. Conversations with representatives from a cross

section of nuclear power plants indicate that the steel-reinforced cast

concrete wall is the most commonly used.

16-

Figure 1. Typical Block Construction

23ý
Top View

No. 16 Swg Steel Both Sides

Vertical Cross - Section

Figure 2. Diagram of Composite Wall

3.2 Thermal Analysis

Description of Method -- Basic equations for radiative, conductive,

and convective heat transfer were solved to determine the temperature

profile through the typical walls described in Section 3.1. These

equations take. the form

qR 1 - T24) for radiation,

24
oC p IT ax ( (t k 'T) .. )x for conduction, and

-k ET h (T - T2) for convection,

ax 1 .2

where

a= the Stefan-Boltznann constant

C = emissivity

p = density of the material

Cp = specific heat of the material at constant pressure

k = thermal conductivity of the material

h = convection coefficient

T = temperature (K).

In general, these equations were solved by.using a computer program which

mathematically divided each of the three wall types being analyzed into

segments. By using small wall segments and small time steps, the

differential terms in the heat transfer equations could be treated as

finite differences. Once the heat transfer mechanism for the walls was

modeled in this way, the thermal response of the walls was calculated

using the controlled temperature conditions which exist in a test furnace

as defined by ASTM E 119. Then, by mathematically varying the thermal

properties of the walls (e.g., density, thermal conductivity, and heat

capacity) over a realistic range of values until the thermal response of

each wall "just failed" the criteria in ASTM E 119, limiting values for

each thermal property were calculated. The Appendix presents the details

of this approach.

Proceeding in this manner, it is possible to assess the relative importance of each thermal parameter and to judge whether a reasonable variation of the parameters from one installation to another could result in an

unexpected barrier failure. This knowledge, when combined with a knowledge

of the anticipated severity of a fire in particular power plant areas, can be

used to predict barrier response under installed conditions. 2

25
Cast-Concrete Wall -- Temperature gradients through an 8-in. concrete

wall were calculated by using the approach outlined above. The results of

this effort are shown in Figures 3 and 4. Figure 3 includes the temperature rise vs time for the test furnace flame, the furnace thermocouples, and

the wall's front face and back face. The curves in Figure 4 depict temperature gradients through the wall at 30 min and at each 30-min increment of

time through 3 hrs. The thermal responses shown correspond to those expected

to occur in a wall which "just passes" an ASTM E 119 furnace test for 3 hrs

(i.e., the back-face temperature increases 250'F during the test). To arrive

at this condition, the wall emissivity (EW), thermal conductivity (k), and

heat capacity (PCp) were adjusted as explained earlier. The adjusted values

p

are shown in Table I.

Based on a comparison of the limiting values shown in Table I with

typical literature values for concrete,13-16 it is concluded for this study

that the thermal performance characteristics of cast concrete barriers are

insignificantly affected by practical variations of wall thermal properties.

2500 -

2000

1500

4J

1000

500

0

0

Figure 3.

0.6 1.2 1.8 2.4 3

Time (hr)

Thermal Model Results for Fire Test

of Concrete Wall (8 in.)

26
2500

2000

1500

ý4.

a 1000

500

0

0 1.6 3.2 4.8 6.4 8

Depth in Wall (in.)

Figure 4. Thermal Model Results for Fire Test of Concrete

Wall (8 in.) - Profile Through Wall

TABLE I

Thermal Characteristics of Cast-Concrete Wall

Thermal Property

(footnote)

E W (a)

k (b)

pCp (c)

Value

0.65

2.043-0.001096T W/m-°C

2.02 x 1 0 b j/m 3 -K

aCalculations using 0.4 and 0.8 for emissivity (representing practical

lower and upper limits) for the 8-in. concrete wall resulted in a

back-face temperature difference of only 8.7 0 F (4.8'C) at the end of

3 hrs. On this basis, the use of an approximate midrdnge value of

0.65 was considered justified.

bThis value is based on work described in Reference 13. The

multiplying constant was adjusted to obtain a "just-passing"

temperature rise on the back face of an 8-in, concrete wall: T in

this formula is in degrees centigrade.

cAdapted from measurements by Harmathy and Allen. 1 4 This value

represents an effective heat capacity of the wall over the

temperature range calculated. The value includes latent heat

effects.

27
Concrete-Block Wall -- As done for the cast-concrete wall, the

thermal properties of a concrete-block wall were varied to yield a "just

passing" thermal response. The thermal property values used are

presented in Table II, and Figures 5 and 6 are graphs of the thermal

response results.

Except for the thermal conductivity (k), the values in Table II for a

block wall are the same as those in Table I for a cast-concrete wall. It

was found that an extremely high value of thermal conductivity (0.382

W/m-K) was needed to cause "just passing'.' conditions in the concrete-block

wall. In fact, this value is 73% higher than expected for block wall

material,15 and therefore represents a very conservative limiting case.

Based on this result, it is concluded for this study that the thermal

performance characteristics of concrete-block barriers are insignificantly

affected by practical variations of wall thermal properties.

TABLE II

Thermal Characteristics of Concrete-Block WallThermal Property Value

•W 0.65

k 0.382 W/m-K

pC 2.02 x 106 J/m 3 -K

Steel-and-Gypsum-Board Wall -- To complete the thermal analysis of

3-hr barriers exposed to the ASTM E 119 standard time-temperature curve, a

steel-and-gypsum-board wall was analyzed. In addition to the analysis

previously described, the latent heat of vaporization (which was included

in the value of pC for concrete) was modeled separately for gypsum. This

p

was necessary because gypsum typically consists of 20% water by volume.

28
2500

20001

'1500

ý4)

0 1000

Ow

500

I

Flame

Front Face

Back Face

A I I I I I A

0 0.6 1.2 1.8

Time (hr)

2-.4 3

Figure 5. Thermal Model Results for Fire Test of

Wall (8 in.)

Concrete Block

2500

2000

1500

1.000

E500

0

0 1.6 3.2 4.8

Depth in Wall(in.)

6.4 8

Figure 6. Thermal Model Results for Fire Test of Concrete Block

Wall (8 in.) - Profile Through Wall at Web

29
The thermal properties of steel and gypsum which were used (from

Reference 16) are listed in Tables III and IV.

TABLE III

Thermal Properties of Steel 1 6

Temp (°C)

0

100

200

300

400

600

800

1000

1200

k(W/m-K)

43.26

43.26

43.26

41.54

39.80

31.15

29.42

29.42

31.15

pCp

(j/m3-K)

3.688 x 106 0.8

TABLE IV

Thermal Properties of Gypsum1 6

k(W/m-K)

0.457

pCp

(j/m 3 -K)

6.027 x 105 0.8

Latent heat of vaporization was taken into account at each node of

the computer model as the node reached 212 0 F (100%C). According to-Kanury

and Holve, vaporization occurs abruptly at the boiling point of water. 8

Figure 7 shows the temperature-vs-time history of each element of the

wall. Temperature gradients at 30-min intervals are shown in Figure 8.

The "steps" occur, because of the loss of heat to the water vapor as the

nodes reach vaporization temperature. Density of the water was taken as

62.4283 lb/ft 3 (I g/cm3 or 1000 kg/m3 ) and the specific heat, Cp, as

4.184 JIg-°C.

30
'130

41

$4.

5 0o~

50

0

2500

1500'

412h

I112

5 0

00

1.6

Figure 

8. 7

Th ermal 

M1--

Of c 

Results 

fu

O t( Wall (8 .) Fire 

Test

- k1n.) 

V.4

Wa1

ermal 

Model

Wall 

(8 in.) 

Results 

o

Prorfi 

or Fire 

Tet 

Of 

Co 

site

fieThrough 

Waj tst

31
From Figures 7 and 8 it can be seen that, unlike the cast-concrete and

concrete-block walls discussed earlier, an 8-in. composite wall will pass

a 3-hr test with considerable thermal margin for the back-face temperature. This is because moisture vaporization from the gypsum board affords

considerable fire protection; to "just pass" the. 8-in. composite wall, an

unrealistically low (<20%) moisture content would have to be assumed.

Kanury and Holve has shown that increasing the moisture content to 50%

would afford the greatest protection; 8 however, the 20% value used in this

study is typical of commercially available materials. On this basis it is

concluded for this study that the thermal performance characteristics of a

composite gypsum board/steel fire barrier are insignificantly affected by

practical variations of bairier thermal properties.

3.3 Stresses Caused by Thermal Gradient

In addition to studying the thermal degradation of fire barriers

under test conditions involving prolonged, high-temperature exposures, it

was recognized that an evaluation of the material stresses within the

barriers also should be made. Unfortunately, a rigorous mathematical

assessment of the thermally induced stresses occurring within a fire

barrier presents a formidable problem whose solution lies beyond the scope

of this study. In particular, the following difficulties complicate the

stress analysis:

" The constraining loads which bound fire barriers during testing

and during an actual fire in a power plant are not readily

quantified.

" The degree of stressrelief afforded by localized cracking and

spalling of the barrier surface is a complicated function of the

barrier age, induced stress gradients, amount of reinforcement,

and constraining loads.

32
The significance of these factors was evaluated by performing a

finite-element stress analysis of an 8-in.-thick, reinforced concrete wall

when exposed to the temperature gradients predicted by the thermal analysis described above. It was found that, without allowing. some degree of

stress-relief cracking within the concrete wall, the barrier would be

expected to fail within 30 min. Since such test failures are not observed

for 8-in. concrete walls, it is clear that a simple stress analysis model

which ignores localized spalling or cracking is inadequate.

Despite these analytical shortcomings, however, several qualitative

conclusions can be reached. First, problems associated with calculating

the effects of various constraining loads can in part be avoided by

following standard ASTM E 119 requirements (to load test walls) ". . . in

a manner calculated to develop theoretically, as nearly as practicable,

the working stresses contemplated by the design." Second, as stated

earlier (page 26) and discussed further in Section 5.1, adequate barrier

performance can best be demonstrated by ensuring that the actual fire

conditions do not exceed the temperature or duration limits to which a

barrier originally is tested. Third, as will be discussed in the next

section, a survey of numerous test reports reveals that barrier

penetration seals, and not the barriers themselves, Are probably the

weakest element of nuclear power plant fire barriers.

On the basis of these observations and the limited scope of this

study, it appears that further evaluation of the stresses induced in

barriers during testing is not warranted at this time.*

*Work to refine the wall stress model discussed above to include the

effects of localized stress relief is proceeding at Sandia Laboratories in

conjunction with a nuclear power plant fire protection program being

funded by the U. S. Department of Energy.

33
4. Literature Study of Penetration Seals

A study of the available reports on fire tests of cable penetration

fire stops reveals a lack of sufficient data upon which to base an adequate conclusion. Of nineteen reports evaluated, four were of 1-hr

tests,17-20 fourteen reported 3-hr tests,21-34 and one was of a test

extended to 5 hr. 3 5 Two tests of 3-hr duration were performed with a

positive furnace pressure;21 26 other tests--where furnace pressures were

reported--were performed with a negative furnace pressure of 0.08 in. of

water. 2 4 29 32-34 Tests for which furnace pressures were not reported are

assumed to have been conducted with negative furnace pressures because

they are conventionally done in that way. One of the tests conducted with

a positive pressure is considered a severe overtest as the pressure was

controlled at 9 in. of water inside the furnace.21 Predictably, the fire

stop failed. Back pressure in the furnace for the test reported in

Reference 26 ranged from 0.25 to 0.5 in. of water, a reasonable value for

an actual fire. Although most of the penetration seals tested were of the

foamed silicone type, the-seal in the test just mentioned was constructed

with fireproof hardboard dams at both ends of- the penetration, the cables

sprayed with a hard-setting fireproof material, and the cavities and seams

packed with an insulating wool. No failure was observed.

The actual performance of commercial penetration seals in a realistic

fire environment has not been well demonstrated by most of the fire tests

reviewed.17-35 These tests have not been conducted in a consistent enough

manner to allow significant conclusions to be reached.

34
5. Conclusions and Recommendations

5.1 Walls

Capability of Walls Modeled -- The reinforced concrete, concrete

block, and gypsum walls modeled in this study represented configurations

with conservatively realistic thermal properties. On this basis, walls

of -these types used in nuclear power plants would serve as adequate

barriers, if exposed to actual fire conditions which do not exceed the

temperature and duration limits to which the walls were originally

tested.2

Standard Time-Temperature Curve -- Because the standard fire cannot

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

,given barrier has received a standard. rating-does not -mean that- i-t 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 large amount of experience has been gained using the

standard exposure,

e No "standard" exposure can be defined which will eliminate

all such objections, and

" 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.

In addition to this, it can be concluded that the present use of

thermocouples to control barrier exposure temperatures during testing

minimizes the effects of different test furnace configurations and,

therefore, represents an acceptable practice for ensuring standard

temperature test conditions.

35
Critical Temperature of Steel -- Of considerable importance is the

need to protect steel beams and columns so that critical temperatures are

not exceeded.

Hose-Stream Test -- It is recommended that the hose-stream testing of

walls be eliminated. If it is felt that an orthogonal load should be

applied to the wall, a more repeatable method which is amenable to either

analysis or measurement of forces should be developed.

5.2 Doors

Hose-Stream Test -- Because of an inability to accurately calculate

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

test, an improved method should be defined to replace that test. Such a

method should be suitable for analysis or direct measurement of the

applied forces.

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). 1 1 A positive

furnace pressure of at least that magnitude should be required for the

testing of door assemblies.

5.3 Penetration Seals

Hose-Stream Test -- The criticism of the hose-stream test in Section

5.2, Doors, is applicable to penetration seals also. it is recommended

that a repeatable method of loading the seals which is amenable to

analysis or direct measurement of forces be developed.

Furnace Pressure -- As discussed at length in Section 2.4 of this

report, the practice of testing with a negative furnace pressure is

especially inadequate for penetration seals. Therefore, it is recommended

that a requirement be added to Standard IEEE 634 for a reasonable positive

pressure in the furnace during fire exposure tests.

36
Definition of Test Specimens -- The ANSI/IEEE 634 standard should

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, tCne practice does

not appear to be documented as a requirement.

Recommendation for Further Investigation -- A series of controlled

fire tests are needed to gain sufficient information to evaluate

commercially available seals. The following steps are recommended:

1. Determine the magnitude of the steady-state pressure to be

expected in a burning area of. a nuclear power plant.

2. Determine the magnitude and duration of any pressure pulses

which may result from a sudden introduction of air into a

burning room deficient in oxygen (as when a door is opened).

3. Expose representative, commercially available penetration

seals to a standard ASTM E 119 furnace test, in the steadystate pressure defined by item 1 and the pressure pulse

defined in item 2.

4. Expose representative, commercially available penetration

seals to the worst-case temperature and pressure conditions

expected in nuclear power station fires.

During the tests outlined above, the effects of both steady-state and

impulse pressure differentials across the seals and the effects of thermal

expansion of penetration components such as pipes, conduits, and cable

trays would be investigated.

37

APPENDIX

Thermal Model-of ASTM E 119 Fire Exposure. Test

ASTM E 119 requirements for the furnace test of building construction

and materials were used as the basis for modeling the responses of the

three types of walls to the stancard fire. The following basic

assumptions were made:

e Blackbody radiation from furnace walls was assumed.

* Thermocouples 6 in. from the test wall are required to follow

the standard time-temperature curve. Thus, the fire

temperature and the wall temperature were computed based on

the view factors between the wall and the thermocouple and

the flame.

* Emissivity of the thermocouple was assumed to be 0.8. This

assumption was tested by holding other parameters constant

and calculating the thermal response of the 8-in. concrete

test wall with a thermocouple emissivity of 0.2. A back face

temperature difterence of about 3% resulted. Thererore the

more conservative (and probably more realistic) value of 0.8

was chosen.

" Thermocouples were idealized to massless spheres to simplity

calculations.

" Flames were assumed not to touch the test wall with a

significant velocity.

39
" Radiation was considered the means of transmitting heat to

the test wall. Convection was ignored as contributing 10% or

less of the energy reaching the wall. Other investigators

agree with this conclusion.7 8 Kanury and Holve agree, even

though convection was considered in their analysis. (Notice

that this assumption and the first one listed tend to be

compensating.)

" In the cavities of the block wall and the composite wall,

radiation was considered the means of transmitting heat and

convection was ignored.

An electrical analog of the energy "circuit" is given in Figure A-I.

TC

C

EC A

AA F AF F TRR C C-F F 'F-C ACc C -

1fF TW

FF

TW = ABSOLUTE TEMPERATURE OF WALL

F = V!EW FACTOR

A = AREA

= EMISSIVITY

SUBSCRI PTS:

C = THERMOCOUPLE

F =FLAME

W = WALL

Figure A-I. Electrical Analog of Energy Circuit

40
Energy exchange between the fire and the thermocouple is given by

qF L + C IFC F+ -TF C4 (1)

Similarly, energy exchange between the wall and the thermocouple is

given by

q C ý1- C

C A C

1

1

F

C C-W

+l-E

WA-

(2)

and between the fire and the wall by

qF-W 1=4I F. 1

1

AFc-w

+ TWA

(3)

For a zero-mass thermocouple, Eqs. (1) and (2) must be equal, since

the thermocouple cannot store energy. Therefore,

[ A + ACFCF -A

C C C C F F

(4 4) TF - C =

(4)

1-E C

SCAc

1

I

'A F - ,C C-W

(4 Tw_ -T )

E.A

41
or

C F L EC+ F C-F

4d T4)

(AC)/ IEFI C'

S1-C

1 (5)

1

+ FCFcW

Since the area of the thermocouple is very small,

AC

Aw

A.C

AýF

Therefore,

4 4) 4 '_

1- T IE ITC T )

+ F .7cF F

(6)

or

E . c-F C

-FCF (1-6 )±+s: I(4 4

(4TF T

CW F +EC

F C (1 -E )± + I-

(7)

42
where

T-4. 4 C F C-F F'CW E C)+Ei J(4 4)(8) TW FCW " F F ý'Ec) +E PTF -c

and

4 4 4\4 _W c-F(I- c) + Cl

TF T/tFC+ C T W) Fc + £3 (9) TFF =W T

or

T T4 4 T 4 fF CW [C-F(1-6 1 EC) 4-C] )1/4 (10)

F C TC W FC LC-W F (- C CJ)J

In the computations, TF lags TW by one time increment. However, the

error resulting from this calculation is insignificant when the time

increment is small. The thermocouple temperature, TC, is defined by the

standard time-temperature curve. There remains, then, the calculation of

view factors FC_w and FC.F to complete the information necessary to

calculate the energy impinging on the ,test wall.

View factor calculation was accomplished as follows. 2 5

Area WTall A2- 4 -

b - Thermocouple

Area =A

3m

43
Thermal modeling of the fire test represents a test wall which is.

three metres square (i.e., 3 m on each side). The flame temperature is

controlled by a single thermocouple near the geometric center of the'test

wall responding *to the standard time-temperature curve.,

The area designated A2 in the figure is the area of 1/4 of the test

wall, while the thermocouple area is designated by A1 . The thermocouple

is placed 6 in. (0.1524 m) from the wall. Thus,

c 0.1524 m

Dimensions a and b are the sides of 1/4 of the test wall area; therefore,

a b = 3/2 m, and

a/c b/c 9.8425

Letting x = a/c and y b/c, the following formula, taken from Reference

36, gives us

1 _______ *1 ___ _+_

dA1-A 2 2=r + 2tan- I +2x 1/2 +

Y 2/tan I x

(1 +y2) (11)

Since in our case a/c = b/c = x = y, Eq. (11) may be simplified to

Fd1 -A2 ( y 1 / t .1( Y 21/2 (12)

FdA 1 -A2 Tr(l + y 12~+2/) (12

44
Substitution .of numerical values, for the arguments gives us

Fd FdA A . 0. 2479 (for each of four such areas), -- A2

1.2

F 0. 9916 for the active side. dA A-A 1 2

Since the thermocouple is considered as sphere instead of a point (thus

only 1/2 of its area is viewing the test wall),

Fcwý 0.9916/2 = 0.496, and

FCF 1.000 - 0.496 = 0.504

With a knowledge of the test furnace flame temperature given by Eq. (10),

it is possible to determine temperature profiles through the test wall as

a func tion of time by using the following equation for heat conduction.

pp PC W (k aT) (13) a t ax8

where TW Tw(X, t) = wall temperature

k = k(T) = thermal conductivity

P = density of wall

C = C (T) = specific heat of wall.

Note: It is assumed that there is no heat generated in the types of walls

under consideration.

45
The governing initial condition is

Tw(x, o) TAMB,

and the boundary conditions are

(14)

aTW,

.a'x (/4 4

\.F W/~ .(15)

at x = 0 (fire side)

aTw B

-k, .-i-- = h [Tw(L) T [T4 ()o T4-

.ax LW AMBJ AB (16)

at the back face (x L)

h = convection coefficient

c = emissivity of back face

a- Stefan Boltzmann constant

The convection coefficient, h, was computed.using the quation,

h = 0.29(AT/L)

1 /4 (17)

which describes free convection over a vertical plate

L is the vertical dimension in feet,' AT is in degrees

Btu/hr-ft 2 -oF.

with laminar flow.

F, and h is in

By simultaneously solving Eqs. (10) and (13) and all governing

boundary.conditions, it is possible to calculate the wall temperature

profile as a function of time and position, given the test thermocouple

temperature as a function of time.

46
Re ferences

1. E. A. Bernard and G. L. Cano, Report onTask l, •,"Fire Protection

System Study," Sandia Laboratories, SAND76-0630 (NUREG 766516),

February 1977.

2. D. L. Berry and E. E. Minor, Nuclear Power-Plant Fire Hazards

Analysis Study, Sandia Laboratories, SAND79-0324 (NUREG/CR-0654), to

be published.

3. NRC Regulatory Guide 1.120, "Fire Protection Guidelines-'for Nuclear

Power Plants," November 1977.

4. ASTM E 119-76, "Standard Methods of Fire Tests of Building

Construction and Materials," 1976.

5. ASTM E 152, "Standard Methods of Fire Tests of Door Assemblies,"

1978.

6. "IEEE Standard. Cable Penetration Fire Stop Qualification Test," IEEE

634, .1978.

7. V. Babrauskas, Fire Endurance in Buildings, Report No. UCB FRG 76-16,

November 1976.

8. A. M. Kanury and D. J. Holve, "A Theoretical Analysis of the ASTM E

119 Standard Fire Test of Building Construction and Materials.".

Stanford Research Institute Final Report, August 1975.

9. T. Z. Harmathy and T. T. Lie, "Fire Test Standard in the Light of

Fire Research," Fire Test Performance, ASTM STP 464, pp 85-97, 1970.

10. S. H. Ingberg, Symposium on Fire Test Methods, ASTM STP 344,

Philadelphia', pp 57-68, 1962.

11. Standard DIN 4.102, Brandverhalten von Baustoffen und Bauteilen,

Deutscher Normenausschuss, Berlin, 1970.

12. Underwriters.Laboratories, Fire Resistance Index, 1976.

13. S. A. Meachem, The Interactions of Tennessee Limestone Aggregate

Concrete with Liquid Sodium, Clinch River Breeder Reactor Plant, TN,

WARD-D-0141, December 1976.

14. T. Z. Harmathy and L. W. Allen, "Thermal Properties of Selected

Masonry Unit Concretes," Journal of American Concrete Institute, Vol.

70, pp 132-142.

15. W. M. Rohsenow and J. P. Hartnett, Handbook of Heat Transfer, McGrawHill, 1973.

47
16. A. J. Chapman, Heat Transfer, 3rd, ed. Table A.1, MacMillan Pub. Co.,

Inc., NY, 1974.

17. A. Brown, Full-Scale Demonstration - Fire Testing of a System for

Penetration Sealing Based on Foamed Silicone Elastomer, Studsvik 77-

05-26, November 1977.

18. D. L. Orals, "Communication Cable 'Poke-Thru' Floor Fire Test,"

August 1976.

19. G. E. Commerford, "Fire Resistance Tests of Cables and Pipe

Penetration Fire Stop Material, NEL-PIA/MAERP Standard Method,"

Southwest. Research Institute Project No. 03-4380-505, February 1976.

20. A. Brown, Fire Test of Chemtrol CT-18 Silicone Foam and Flexible Boot

Penetration Seals, Studsvik 77-12-20, December 1977.

21. M. D. Pish, Fire Research Tests on Silicone Foam-Floor Penetration

Seals, Southwest Research Institute, October 1977.

22. Factory Mutual Research, Fire Endurance Test on Penetration Seal

Systems in Precast Concrete Floor Utilizing Silicone Elastomer

(Chemtrol Design FC 225), Ser. No. 26543, October 1975.

23. M. D. Pish, Fire Test on Floor Penetration Seals, Southwest Research

Institute, July 1977.

24. G. J. Jarosz, "Fire and Hose-Stream test of Penetration Configuration

sealed with Silicone Foam (15-23 lbs/ft 3 ) and Silicone Gel (75-95

lbs/ft 3 )'', TECH-SIL, Inc. Test Procedure TS-TP-0014, Final Report,

July 12, 1978.

25. M. D. Pish, R. McClintock, "Fire Qualification Test on Silicone Foam

Floor. Penetration Seal", SwRr Project No. 03-S174-001, Draft Final,

September 26, 1978.

26. R. C. Lawrence, "Report on Fire Stop Tests for Rancho Seco Nuclear

Generating Station--Unit No. 1," February 24, 1978.

27. M. D. Pish, "Fire Tests of Eight Floor Penetration Seals," Project

No. 03-4685-106-b, Southwest Research Institute, San Antonio, TX, May

1977.

28. G. E. Commerford, "Fire Tests of Floor Penetration Seals," Project

No. 03-4685-106, Southwest Research Institute, San Antonio, TX,

January 1977.

29. G. J. Jarosz, "Fire and Hose-Stream Test.of Penetration Configuration

Sealed with High Density iilicone Elastomer and High Density Leaded

Silicone Gel, (147 lbs/ft min.)," TECH-SIL, Inc. Test Procedure TSTP-0007, Final Report, July 10, 1978.

48
30. D. L. Orals, P. S. Quigg, "Firecode CT Gypsum Thermafiber Access

Firestopping for Walls," Des Plaines, Ill., undated (test data

5/24/78).

31. M. S. Abrams, "Qualification, Fire and Hose Stream Tests-Bisco Test

No. 1042-01," Construction Technology Laboratories, Skokie, Ill.,

February 1978.

32. Virginia Electric and Power Company, "Fire Endurance Test on Cable

Penetration Fire-Stop Seal Systems Utilizing Dow Corning Q3-6548

Silicone RTV Sealing Foam," Final Report, February 15, 1977.

33. G. J. Jarosz, "Fire and Hose-Stream Test of a Dual Conduit

Penetration Configuration (Cast Concrete Opening) Sealed with

Silicone Foam (15-23 lbs/ft 3 )," TECH-SIL, Inc., Test Procedure TS-TP0008-E, Final Report, Elk Grove Village, Ill., August 9, 1978.

34. M. S. Abrams, T. D. Lin, "Fire and Hose-Stream Tests of Penetration

Seal Systems," Skokie, Ill., April 1978.

35. Factory Mutual Research, Fire Test on Silicone Rubber Penetration

Seals in-Masonry Wall. Design'WP 374, Ser. No. 24963, August 1975.

36. E. M. Sparrow and R. D. Cess, Radiation Heat Transfer, pp 300-310,

Brooks-Cole Pub. Co., Belmont, CA, 1966.

37. A. J. Chapman,.Heat Transfer, 3rd Ed., p 385, MacMillan Pub. Co.

Inc., NY, 1974.

49

NRC FORM 335 1; REPORT NUMBER (Assigned by DDC)

(7-77) U.S. NUCLEAR REGULATORY COMMISSION NUREG/CR-0468

BIBLIOGRAPHIC DATA SHEET SAND 88-1990

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

Nuclear Power Plant Fire Protection - Fibre Barriers .

(Subsystems Study Task 3) 3. RECIPIENT'S ACCESSION NO.

7. AUTHOR(S) 5.. DATE REPORT COMPLETED

"MONTH_ I YEAR -Earl E. Minor, Dennis L. Berry September 1979

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

Sandia Laboratories MONTH IYEAR Albuquerque,.NwMxc New Mexico 87185 •.6 September Laebak 1979

6. (Leave blank)

8. (Leave blank)

12..SPONSORING ORGANIZATION NAME AND MAILING ADDRESS (Include Zip Code)

10. PROJECT/TASK/WORK UNIT NO.

Engineering Methodology Standards Branch

Office of Standards Development 11. CONTRACT NO.

U. S. Nuclear Regulatory Commission,

Washington, D. C. 20555 FIN No. A-1080

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

Final TechnicalI

15. SUPPLEMENTARY NOTES 14. (Leave blank)

16. ABSTRACT (200 words or less)

Standards currently used in the fire protection field are analyzed in relation to their

applicability to. nuclear power stations and recommendations concerning their improvement

are made. Results of mathematical analyses of typical:fire barriers are given. Based

on-.the temperature gradient established in the mathematical analyses, a stress analysis

of.poured'concrete walls is described. Recommendations are made for follow-up studies

and experiments.

17. KEY WORDS AND DOCUMENT ANALYSIS 17a. DESCRIPTORS

Fire

Fire Barriers

17b. IDENTIFIERS/OPEN-ENDED TERMS

i8o AVAILABILITY STATEMENT 19. SECURITY CLASS (This report) 21. NO. OF PAGES

UInrlasified

Unlimited 20. SE CU-RI TY CLASS -This page) 22. PRICE

Unclassified S

NRC FORM 335 (7-77)