NBSIR 80-2004

The Measurement of the Smoke

Leakage of Door Assemblies

During Standard Fire Exposures

Leonard Y. Cooper

Center for Fire Research

National Engineering Laboratory

National Bureau of Standards

U.S. Department of Commerce

Washington, D.C. 20234

June 1980

Final Report

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100 Prepared for: iU56 Occupational Safety and Health Administration (OSHA)

npi 9nn/i Department of Labor

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NBSIR 80-2004

» ^ < THE MEASUREMENT OF THE SMOKE

LEAKAGE OF DOOR ASSEMBLIES

DURING STANDARD FIRE EXPOSURES

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Leonard Y. Cooper

Center for Fire Research

National Engineering Laboratory

National Bureau of Standards

U.S. Department of Commerce

Washington, D.C. 20234

June 1980

Final Report

Prepared for: The Occupational Safety and Health Administration (OSHA)

U.S. Department of Labor

Washington, D.C. 20210

U.S. DEPARTMENT OF COMMERCE, Philip M. Klutznick, Secretary

Luther H. Hodges, Jr., Deputy Secretary

Jordan J. Baruch, Assistant Secretary for Productivity, Technology, and Innovation

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director
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PREFACE

This report on smoke leakage of door assemblies is one product of an ongoing joint

research program of the Occupational Safety and Health Administration (OSHA) of the

Department of Labor and the National Bureau of Standards (NBS) , Center for Fire Research.

The program is entitled: Key Elements of Emergency Escape Requirements for Employees in

Workspaces Under OSHA Jurisdiction. Other ongoing areas of research presently included in

this program are: Estimating safe available egress times for workspaces subsequent to the

ignition of hazardous fires; the relation of building design and human factors to emergency

evacuation of workspaces; and studies of building smoke control by means of open stairwellsprinkler systems.
TABLE OF CONTENTS

Page

PREFACE ill

LIST OF FIGURES vi

Abstract 1

1. INTRODUCTION 1

1.1 The Ability of Building Occupants to Achieve Safe

Egress or Refuge 1 1.2 Tne Effect of Compartmentation on the Phenomenon of

Smoke Migration 2 1.3 The Utility of High Temperature Smoke Leakage Measurements 3 1.4 An Overview of This Investigation 4

2. APPLYING THE HIGH TEMPERATURE TEST METHOD 4

2.1 The Proposed ISO Test Method for Measuring the Smoke

Leakage of Door Assemblies During Standard Fire

Exposures 4 2.2 The Original Objective of This Investigation 5 2.3 An Overview of the Results of Applying the Test Method 6 2.3.1 The First Test 6

2. 3. 1.1 Description of the Test 6

2. 3. 1.2 Results 7

2. 3.1. 3 Reflecting on the Results 7 2. 3. 1.4 Conclusions of the First Test 8

2.3.2 The Second Test 8

2. 3. 2.1 Description of the Test 8

2. 3. 2. 2 Results 9

2. 3. 2. 3 Overall Conclusions of the Two Tests 10

3. A CRITICAL ANALYSIS OF THE TEST METHOD 10

3.1 Preliminary Remarks 10

3.2 A Limitation of the Test Method . 11

3.2.1 The Distribution of Pressure 11

3.2.2 Capability of the Test Method to Simulate Effects

of a High-Rise Building Fire Scenario 11

3.2.3 The Limited Utility of the Concept of a (Constant) Orifice Coefficient . 12

3.2.4 Desirable Attributes of a Smoke Leakage

Test Procedure 12

3.3 Some Troublesome Theoretical Aspects of the Test

Method 13

3.3.1 General Remarks 13

3.3.2 The Two Components of Outflow 14

3.3.3 The Nature of the Steady State and Its

Implications 15

3. 3. 3.1 An Overview 15

3. 3. 3.

2

Flow Conditions During Times of Cool

Door Surface Conditions 15

3. 3. 3. 2.1 Flow Phenomenology Following

Vent Closing 15

3. 3. 3. 2.

2

Steady-State Position of the

Enclosure-to-Ambient Neutral

Plane - A First Estimate 17

3. 3. 3. 2.

3

A Refined Estimate for the

Level of the Neutral Plane

and Its Implications 20

iv
TABLE OF CONTENTS (continued)

3. 3. 3.

3

Flow Conditions Resulting From the

Combined Effects of Leakage and Hot

Door Surface Heat Transfer 22

3.3.4 A Summary of the Test Method's Shortcomings 22

4. AN ALTERNATIVE TEST CONCEPT 23

4.1 The Alternative Test Concept and Its Overall

Advantages 23

4.2 Significant Features of the Test Concept ..... 23

4.2.1 Continuous Quasi-Steady Operation 23

4.2.2 Accurate Simulation of Ambient Conditions 24

4.2.3 Universal Control of the Furnace-to-Enclosure

Pressure Differential 25

4.2.4 Accuracy of the Leakage Measurement 26

5. SUMMARY 26

6. ACKNOWLEDGEMENTS 27

7. REFERENCES 28

APPENDIX A. ISO/TC 92/WG 3 N 203. DP 5925 FIRE TESTS ~ SMOKE CONTROL

DOOR ASSEMBLIES. PART 3. HIGH TEMPERATURE TEST

(REVISION OF DOCUMENT N 189) A-1

APPENDIX B. AN ESTIMATE OF THE RATE OF GAS OUTFLOW DUE TO HEAT TRANSFER

FROM THE DOOR SURFACE B-1

V
LIST OF FIGURES

Page

Figure 1. Location of thermocouples in the enclosure 29

Figure 2. Location of thermocouples in the enclosure outlet 30

Figure 3. Location of pressure differential measurements 31

Figure 4. Various AP's during 840-900-second closed vent interval 32

Figure 5. Outflow velocity during 840-900-second closed vent interval 33

Figure 6. Various AP's during 2400-2520-second closed vent interval 34

Figure 7. Outflow velocity during 2400-2520-second closed vent interval .... 35

Figure 8. Various AP's during 4020-4140-second closed vent interval 36

Figure 9. Outflow velocity during 4020-4140-second closed vent interval .... 37

Figure 10. Venturi throat thermocouple temperatures during 4020-4140-second

closed vent interval 38

Figure 11. Enclosure temperature as a function of elevation during the

4020-4140-second closed vent interval .... 39

Figure 12. Estimates of outflow due solely to expansion for a door of

dimension lmx2m 40

Figure 13. Idealized model of flow within the enclosure shortly after vent

closure 41

Figure 14. A sketch of a vertical distribution of enclosure temperature and

plots of possible resulting distributions of enclosure pressure ... 42

Figure 15. Plot of (j)(X) defined in eq. (9) 43

• • Figure 16. Plots of m* and q* as functions of X with K as a parameter.

See c‘(|. (9) 44

2 1/2 Figure 17. Plot of q/fD /2)(gD) ] as a function of X with K as a parameter.

Plot of q as a function of X with AT as a parameter, for D = 0.3 m

and T , = 295°K 45 amb

Figure 18. Plot of V(Z^)/V as a function of X with K as a parameter 46

Figure 19. A test concept for measuring leakage of door assemblies during

standard fire endurance tests 47

Figure 20. Model for determining the rate of outflow, q, which is associated

solely with the heat transfer rate, Q 48

Figure 1(A) Measurement of air leakage during a high temperature test A-10

Figure 2(A) Enclosure for leakage rate measurement A-11

Figure 3(A) Enclosure and furnace surround A-12

Flgur< '•C^) Calibration of enclosure (see clause 6) A-13

vl
THE MEASUREMENT OF THE SMOKE LEAKAGE OF DOOR

ASSEMBLIES DURING STANDARD FIRE EXPOSURES

Leonard Y . Cooper

Abstract

A basis for relating overall Intrabuilding smoke migration dynamics

to high temperature, door assembly smoke leakage measurements is

formulated. The results of applying the tentative, high temperature,

ISO test method DP 5925 Part 3, which was developed to measure smoke

leakage of door assemblies during the course of a standard fire endurance

test, are reported. A critical analysis reveals that the basic objective

of the method is limited in its utility in the sense that fire scenarios

in high-rise buildings may not be adequately simulated. Consistent with

the above-mentioned experimental results, troublesome theoretical problems

with the test method and its procedures are identified. These lead to a conclusion that the test method as written is generally unreliable. An

alternate test concept which removes the above-mentioned DP 5925 Part 3 limitation and all of its problems is described and its development is

advocated.

Key words: Building fires; compartment fires; doors; egress; fire tests;

high-rise buildings; leakage; life safety; smoke; smoke movement; stack

effects; test methods.

1. INTRODUCTION

1.1 The Ability of Building Occupants to Achieve Safe

Egress or Refuge

Relative to the threat of fire in occupied buildings, life safety can be measured by

the ability of building occupants to achieve safe egress (or safe refuge) subsequent to a potentially hazardous Ignition. The overall safe egress capability of occupants is dependent

on two basic elements; namely, the time available for safe egress (i.e., the length of

time subsequent to fire detection and prior to the onset of untenable conditions) , and the

time required for safe egress.

Safe available egress time is basically a function of the building design, including

all active and passive fire protection systems, and the contained fuel loads which are characteristic of the building occupancy. Required egress time is a function of the

physical nature of the egress paths, of the occupant density distribution, and of the

physiological and psychological characteristics of the occupants. An excess of available

1
egress time over required egress time would generally indicate a safe condition vis-a-vis

life safety in fires. An excess of required over available egress time would indicate a hazardous condition.

If one follows the above approach, it is evident that estimates of the available and

required egress times are required for an analysis of life safety. This work addresses

itself to a specific aspect of building design which impacts most heavily on the safe

available egress time part of the "equation"; namely, the smoke leakage characteristics of

building partition penetrations during fully developed fire exposures. The closed door

assembly is taken here as the prototype of such partition penetrations. It should, however,

be stressed at the outset that the ideas developed in this work would be totally applicable

to arbitrary leakage paths of interest which may be characteristic to any particular wall

or floor construction practice.

1.2 The Effect of Compartmentation on the Phenomenon

of Smoke Migration

Depending on a given fire scenario in which hazardous conditions develop and in which

partial or total building evacuation is required, the actual paths of occupant egress can pass through a variety of different building spaces. These spaces will generally become

untenable at different times. Furthermore, the onset of untenability in a given space is

likely to result from the spread of the potentially hot, toxic, and/or obscuring products

of combustion (smoke) . And the significant physical mechanisms which govern this smoke

spread can vary from one space to the next.

Compartmentation has been classically used to impede the spread of fires from one

space to another. Thus by proper and proven construction practice one can anticipate

containment of a fire within a given compartment space of fire origin for a time interval

of, for example, two or more hours. Such compartmentation constructions will not necessarily

abate the spread of smoke to any significant degree. Nevertheless, compartmentation

remains a convenient and useful concept for the study of smoke spread phenomenology and

for estimating the onset of untenable conditions. Once smoke has passed from a compartment

of fire origin, through penetrations (e.g., leaks in a doorway assembly) in its barriers,

and into an adjacent compartment, new and different primary physical mechanisms of smoke

spread can come into play. In short, smoke compartmentation can be the major factor in

the switchover from one dominant smoke spread mechanism on one side of a barrier to a different mechanism on the other.

As a first approximation it is useful to identify two basic types of smoke migration

mechanisms. One of these would be associated with a compartment of fire origin, and the

other with all other parts of the building. Because of relatively high smoke temperatures,

buoyancy effects are likely to dominate the dynamics of the smoke migration in the compartment

2
of fire origin. Taking account of these effects, Cooper [1]^ has begun to develop a technique for estimating available egress time within such compartments of fire origin

(which can include "freely connected" multiple spaces). Assuming a limited rate of leakage

into adjacent compartments and anticipating rapid mixing and cooling of the smoke upon

entry therein, suggests the second, a "tracer gas" migration type of mechanism for the

smoke's continued transport throughout the building. In particular, one would expect that

continued migration and dilution of "cold" smoke outside of a compartment of fire origin

could be studied by dynamic building infiltration and ventilation models, i.e., by assuming

that continued intrabuilding smoke movement and dilution is driven by active forced

ventilation systems and, if appropriate, by building stack effects.

Note that the definition of compartmentation in the present, smoke migration, context

is keyed to the above words, "assuming a limited rate of leakage into adjacent compartments.

The problem of quantifying such a definition so that a particular enclosure of building

space can be rated as a bona fide compartment in the above sense for some length of time

following ignition will not be addressed here.

1.3 The Utility of High Temperature Smoke Leakage Measurements

The compartment of fire origin is the source of smoke for the rest of the building.

From the above discussion it is evident that a dynamic analysis of the development of

untenable conditions outside of this compartment would require estimates of the rate of

leakage across various paths in its bounding partitions. For example, if a door assembly

provides the major leakage path, then its rate of leakage while being exposed to a characteristic threatening fire would provide the necessary input data for such an analysis.

For life safety evaluation and design purposes, the leakage data of such a door assembly

during the course of a standard fire endurance test would be useful in this regard. And

such door assembly leakage data need not be used only for the relatively sophisticated

task of estimating the actual time to untenability in the various building spaces. Indeed,

it is likely that such quantitative leakage data would also be useful in a simple ranking

of door assemblies relative to their smoke stopping capabilities. For example, some practical utility could be potentially extracted from the notion that: the "tighter" the

door assembly, the greater the available egress time throughout the building (outside the

fire compartment). A quantitative measure of door assembly "tightness" is required to

invoke even this simple idea.

Presently accepted methods for measuring the response of door assemblies to fully

developed fire exposure conditions are typified by ASTM E 152/NFPA 252, Fire Tests of Door

Assemblies. Following that procedure, door assemblies are tested and rated for ability to

stay in place when exposed to fire (and to a water hose stream) until a limiting gap size

’Numbers in brackets refer to literature references lifted it the end of this report.
is formed. The test does not require simulation of any particular real fire, cross-door

pressure differential, and it does not measure the air (or gas or smoke) flow across the

door assembly. Therefore, having received a rating by virtue of its performance during

this test procedure, the leakage characteristics of a particular door assembly are still

unknown. If leakage characteristics of door assemblies are to be measured then an alternate

or revised test method is clearly required.

1.4 An Overview of This Investigation

It was the original objective of the present investigation to measure the leakage

rates of various common, (ASTM E 152) rated door assemblies during the course of standard

fire exposures, and, ultimately, to place the results of these measurements into the

perspective of the above discussion on successful egress from buildings. The vehicle

chosen to perform the high temperature leakage measurement was the proposed International

Organization for Standardization (ISO) test method ISO/TC 92/WG 3 N 203 - DP 5925 Fire

Tests, Smoke Control Door Assemblies Part 3, High Temperature Test. Although this test

method was still under development at the time of this choice, it was the only test method

available for the task at hand. The test method was implemented and was found to have

both limitations and significant basic shortcomings. The investigation eventually focused

in on an analysis of these shortcomings. Finally, an alternate test concept which removes

the limitations and shortcomings of the present high temperature DP 5925 Part 3 test

method was formulated. The details of all of this are reported in the sections to follow.

2. APPLYING THE HIGH TEMPERATURE TEST METHOD

2.1 The Proposed ISO Test Method for Measuring the Smoke

Leakage of Door Assemblies During Standard Fire Exposures

The ISO Technical Committee ISO/TC 92, Fire Tests for Buildings and Structures,

is preparing three different methods for testing the leakage characteristics of door

assemblies. These are all documented under the title "DP 5925 Fire Tests, Smoke Control

Door Assemblies." Each of the methods is being designed to test leakage under a different

simulated condition of building smoke and fire exposure. The tests are to be identified

as Part 1 - Ambient Temperature Test; Part 2 - Medium Temperature Test; and Part 3 - High

Temperature Test. An introductory document which discusses the relevance of these test

methods is identified as "DP 5925 Part 0 - Commentary." To date. Part 0 and only two of

the three test methods. Parts 1 and 3, have been formulated to the point of being documented.

The tentative test method of Interest here is Part 3. A copy of the most recently revised

version of this is included in appendix A.

The basic idea of the high temperature test is rather simple. A sketch of the test

setup is Included in figure 1 of the appendix A document.

4
A door assembly to be evaluated is mounted in a wall assembly. This is integrated in

a wall furnace as if the door assembly were to receive a standard fire resistance rating,

for example, by ISO 3008 or ASTM E 152. A large collection enclosure covers the entire

unexposed portion of the door assembly. A circular opening of diameter 30 cm (11.8 in)

penetrates the enclosure opposite the door surface. The enclosure is carefully attached

to the wall which contains the door assembly in a manner to minimize the leakage of gases

from the enclosure through these attachment points. During the course of a test the

furnace gases pass through the door assembly leakage paths under evaluation, into the

enclosure, and out through the circular duct-like opening. The leaking furnace gases

simulate the smoke laden gases that would leak across the assembly during an actual

threatening fire scenario. Velocity measurements of the enclosure outflow gases are made

at one point on the axis of the opening. Assuming quasi-steady flow and uniform gas

velocities at a section of the outflow duct, conservation of mass is invoked and the

velocity measurement is used to deduce a time varying rate of door assembly leakage.

So as not to continuously subject the unexposed surface of the door assembly to an unrealistic environment due to trapped hot furnace gases, an upper and lower vent (water

sealed to prevent spurious leakage) is added to the enclosure structure. These vents are

left open for 4-minute intervals during the course of the test procedure. Following every

one of these 4-minute intervals the vents are closed for 1 minute during which time the

quasi-steady flow condition described above presumably establishes itself. At the end of

each 1-minute interval the above-mentioned outflow velocity is recorded, the vents are

then opened, and the next 4-minute open vent interval is initiated.

The driving force for smoke (furnace gas) leakage during the high temperature exposure

simulation is the distributed pressure difference across the door assembly, i.e., from

inside to outside of the furnace. This must be specified in the test method. Toward this

end the procedure specifies that the furnace pressure be controlled to maintain a zero pressure differential at the door sill. Taking the door height to be H, and the absolute

temperature of the furnace at time t into the test to be T^(t), the effective result of

this specification is a positive pressure differential across the door assembly which

linearly increases the elevation, with rising from AP = 0 at the sill to

AP - 11.5 (H/meters)[l - ^ pascals at the top of the door.

Other than the usual data on furnace performance, the measurements called for in the

test procedure are limited to the pressure difference across the door at its sill, and the

velocity and temperature of the gases at the axis of the circular outflow port of the

enclosure.

2.2 The Original Objective of This Investigation

As discussed in section 1.3 the original objective of this investigation was to

subject several different door assemblies to the high temperature ISO test method described

5
above. The plan was to build an enclosure and to test four different door assemblies of

the types tabulated below.

Tests

to be

Conducted Door Type

UL

Classification

Glass

Size

2 UL Classified Hollow Metal Type

Stiffner Design

1-1/2 hr

(B)

No Glass

1 UL Classified Hollow Metal Type

Stiffner Design

1-1/2 hr

(B)

100 sq in

Vision

Light

1 UL Classified Hollow Metal Type

Stiffner Design

3/4 hr (C) 30 by 40 in

Vision

Light

1 UL Classified Kalemin Type 1 hr (B) No Glass

An initial "shakedown" test was alloted for the first of the door types listed in

this table. Thus, a total of five different high temperature door assembly tests were

planned, where the first and second of these would be done on a 1-1/2 (B) UL classified

hollow metal type door assembly of Stiffner design and with no glass.

The tests were to be run at the Underwriters Laboratories (UL) in Northbrook, Illinois.

2.3 An Overview of the Results of Applying the Test Method

2.3.1 The First Test

2. 3. 1.1 Description of the Test

In accord with the above objectives the first test was run on the hollow metal door

in accordance with the DP 5925 Part 3 test procedure. Besides the measurements called for

in the procedure, data was also acquired on the temperature and horizontal displacement of

the unexposed door surface, the air temperature in the enclosure near the upper vent, and

the temperature at a point on the outside surface of the enclosure.

All channels of data were recorded on paper tape every 30 seconds during the course

of the test. The enclosure vents were designed to be operated by a hydraulic system which

would be activated manually.

The prescribed 4-minute open; 1-mlnute closed vent sequence was followed initially,

but later into the test the closed vent intervals were increased to 1-1/2 and then 2 minutes.

The test was terminated after approximately 55 minutes because of a breakdown of the

hydraulic vent control.

6
2. 3.1. 2 Results

It is sufficient for the purpose of the present report to briefly describe the

significant results of the first test at UL. The results of a second, similar test will

be presented in considerably more detail in section 2.3.2.

The major measured results were related to the center line outflow duct gas velocities

as measured toward the end of closed vent time intervals. With regard to this it appeared

that these velocities had not reached quasi-steady values as would be required if the

fundamental philosophy of the test method is to be valid.

Besides the above-measured result there was also a significant visually observed

result, namely, between 1 and 1-1/2 minutes following vent closure a stratified smoke

layer started to flow out of the upper part of the outflow duct. (The painted surfaces of

the door and frame were the likely sources of this smoke.) This continued until the end

of the closed vent time interval. It was noteworthy that the above-mentioned measured

values of outflow velocities approached inordinately small values (the order of tens of

feet per minute— sometimes smaller) compared to the visually observed velocities (of the

order of hundreds of feet per minute) in this smoke layer.

As a point of information, toward the end of the closed vent time intervals and

toward the end of the test the recorded temperatures of fire gas in the upper part of the

enclosure approached 200°F (93°C) . Also, at these later times the unexposed door surface

temperature reached the order of 750°F (399°C).

2. 3. 1.3 Reflecting on the Results

The above results clearly called for some reflection regarding the likely overall

nature of the transient gas flows within and through the enclosure subsequent to the

initiation of the closed vent test intervals. This resulted in a conjecture that the

phenomena in question were analogous to those produced by a heat source in a ventilated

enclosure. In this analogy the outflow opening in the present experimental setup would

correspond to the enclosure ventilation opening. The hot leakage furnace gases and the

hot unexposed surface of the door, both of which must have been generating buoyant plumes near the door surface in the present experimental setup, would correspond to the enclosure

heat source. Just as would occur upon switching on the heat source in the ventilated

enclosure, it was therefore conjectured that upon closing the vents during the present

experimental procedure these latter plumes would result in a filling of the enclosure with

an upper, growing layer of hot gases. Eventually the nature of the steady state would be

one where the flow of gases at the circular ventilation opening would be outward (hot

gases) at the upper portion of this section, inward (cool ambient air) at the bottom

portion of the section, and with a neutral plane (zero velocity) somewhere near the

elevation of the outflow duct axis.

7
If the above conjectured phenomenology does indeed occur while carrying out the test

procedure and/or if steady-state flows do not establish themselves fairly rapidly, say,

within a minute or two following vent closing, then it is evident that there would be

serious questions about the basic validity of the test method.

2. 3.1.4 Conclusions of the First Test

In view of all the above it was concluded that at least one further test, identical

to the first but with more instrumentation and data collection, should be carried out.

Note that this conclusion was compatible with the original test plan which called for two

tests on the same hollow core steel door design. More important, however, it was compatible

with a new and clear requirement that the above questions raised by the first test be

answered

.

Another conclusion of the test was that a careful analysis of the phenomena occurring

during the test procedure should be carried out. After a review of the second UL door

test in the remainder of this section, a presentation of the results of this analysis

basically an in-depth critique of the proposed DP 5925 high temperature test method— will

follow in section 3.

2.3.2 The Second Test

2. 3. 2.1 Description of the Test

A second test was run at UL which was essentially identical to the first except for

greatly Improved instrumentation.

Figures 1 and 2 indicate the locations of most of the thermocouples. Most of these were located within the enclosure so that the transient development of the gas temperature

distribution could be studied, e.g., for the purpose of establishing the potential compatibility of data with the conjectured stratification phenomenology discussed earlier. Those

few thermocouples which were located in the outflow duct were to provide an indication of

the validity of the cool lower inflow — hot upper outflow velocity distribution which was conjectured to occur during latter parts of closed vent time intervals.

Figure 3 indicates the locations where pressure differentials were measured. One of

the main reasons for these, i.e., APj and AP 5 , was to provide an indication of the variation

In time and in elevation of the enclosure-to-ambient pressure differential, e.g., for the

purpose of establishing the compatibility of data with the conjectured quasi-steady

position (near the outlet duct axis) of the enclosure-to-ambient neutral plane.

All data channels were scanned and recorded on magnetic tape once every 5 seconds.

8
For the first 40 minutes of the test the 4-minute open; 1-minute closed vent sequence

was maintained. After this time the closed vent interval was increased to 2 minutes. The

test was terminated after approximately 80 minutes at which time the vents became stuck in

the closed position.

2. 3. 2. 2 Results

The results of the second test generally corroborated those of the first test.

Additional insight into the flow phenomena was provided, however, by the more detailed

instrumentation capability.

The pressure differential data and the outflow velocity data which cover three

representative closed vent time intervals, 840-900 seconds, 2400-2520 seconds, and 4020-

4140 seconds, are presented in figures 4-5, 6-7, and 8-9, respectively. The temperature

history at the three thermocouples located in the throat of the outflow venturi for the

latter of these closed vent intervals is presented in figure 10. The enclosure temperature

distribution at seven different, equal spaced times during this time interval is presented

in figure 11. The temperature values plotted in this latter figure are an appropriate

average of the temperatures measured by thermocouples located within the enclosure at

identical elevations.

All of the above data support the general conjecture, briefly presented above in

paragraph 2. 3. 1.3 regarding the gas flows within and through the enclosure. The analysis

of these flow phenomena to be presented in the next section will place this data into

proper perspective. For the present, the following brief observations will suffice:

Figures 4, 6 and 8 indicate that quasi-steady enclosure-to-ambient pressure differentials

APi (top of door) and AP5 (bottom of door) were attained within 1-2 minutes following vent

closure. From the fact that these quasi-steady AP^ and AP5 values are of different sign,

it is also evident that in each of these three closed vent sequences a neutral plane

(i.e. , the elevation where AP = 0) must have been formed somewhere between the top and

bottom of the door. From the fact that AP^ consistently approaches the approximate value -

AP5, one also learns that the quasi-steady positions of these neutral planes were near the

mid-door elevation (i.e., near the elevation of the outflow duct axis).

If the neutral plane elevation is in the vicinity of the duct axis, then the net

outflow through the duct can change significantly with relatively small variations (e.g.

,

a few tenths of a duct diameter) in this neutral plane elevation. (This fact will be

substantiated below in the analysis of section 3.3.3.) Accordingly, when the neutral

plane reaches the vicinity of its quasi-steady elevation, say, to within a few inches, the

artual net flow through the duct will still deviate significantly from its quasi-steady

v.iliK’. The lag between the establishment of the quasi-steady neutral plane position

9
(i.e., quasi-steady APi and AP5) and the establishment of quasi-steady net outflow is

indicated by comparisons of the velocity histories of figures 5, 7 and 9 and the

.'P, and AP5 histories of figures 4, 6 and 8. For example, whereas figure 4 indicates that

quasi-steady AP's are attained by 1 minute following vent closure it is not clear from

the data of figure 5 that a quasi-steady duct axis velocity is at hand at this time. As

another example, figure 8 indicates that near-steady AP's are attained by 1 minute following

vent closure. However, the corresponding data of figure 9 suggests that even at 2 minutes

following vent closure, quasi-steady velocities in the duct cross section may not have

been attained. The enclosure gas temperature histories of figure 11 also indicate that

full quasi-steady conditions had not yet occurred by the end of the 4013-4132-second test

interval. Finally, the duct temperature data of figure 10 strongly support the contention

that, even as quasi-steady pressure conditions begin to be established, a highly transient

lower inflow of cool ambient air and upper outflow of hot enclosure gases are in evidence

at the venturi throat cross section.

2. 3. 2. 3 Overall Conclusions of the Two Tests

The results of the two tests at UL indicated that the proposed high temperature test

is not likely to provide the door assembly leakage measurement for which it was designed.

As will be seen, the analysis to follow in section 3 strongly supports this result.

Because of this it was concluded that the remainder of the UL test program, as delineated

in paragraph 2.2, be postponed until a satisfactory alternate door assembly leakage test was developed. Such an alternate test concept is proposed below in section 4.

3. A CRITICAL ANALYSIS OF THE TEST METHOD

3.1 Preliminary Remarks

This section is devoted to a critical analysis of the proposed high temperature ISO

test method DP 5925 (appendix A) for measuring smoke leakage past door assemblies. As

noted in section 2. 3.1.4 the need for this analysis became evident after reflecting on the

unexpected results of the first UL test. The results of the analysis to follow, although

compatible with the results of both the first and second UL tests, will be seen to stand

independent of them.

As will be seen, the analysis reveals that the basic objective of the test method is

limited in its utility in the sense that fire scenarios in high-rise buildings may not be

adequately simulated. More significant, troublesome theoretical problems with the test

method and its procedures are identified. The presentation to follow first discusses the

test limitation. Following this is an analysis of the more basic theoretical problems.

10
3.2 A Limitation of the Test Method

3.2.1 The Distribution of Pressure

The basic idea of the test in question is to measure the rate of gas leakage across a subject door assembly during the course of a fire exposure which simulates a fully developed

flashed-over fire. At any time during the test this leakage rate will clearly depend on

the distribution of pressure difference, Ap, across the door assembly. As delineated in

sections 3 and 7.2 of DP 5925 Part 3, the actual distribution modeled is the one where

the pressure in the furnace (representing the room of fire origin) is controlled in such a manner as to result in a zero (0-1 pascals) Ap at the bottom of the door assembly (i.e.,

the neutral plane is fixed at the door sill). By maintaining a zero Ap at this level, the

vertical variation in Ap is automatically determined by the then current temperature

(density) of the furnace gases.

The idea of the particular pressure distribution specified in the test is that it

presumably leads to conservative results in the sense that a higher leakage rate will

result in the test than would occur if, say, the neutral plane (the level of zero Ap) were fixed at a level above the door sill. Indeed, for one particular door gap assumption

Dekker and Haffmans [2] have estimated that almost twice as much gas would flow from the room of origin, in the case of the present Ap distribution, than in the case of a modified

distribution where the neutral plane was one third of the door height up from the door

sill. As it turns out, the conservative nature of this result only holds up when one considers use of the door assembly in low to moderate height buildings or in tall buildings

under moderate climate conditions, and under low to moderate wind conditions.

3.2.2 Capability of the Test Method to Simulate Effects of

a High-Rise Building Fire Scenario

In considering use of the door assembly in high-rise buildings, or, more directly, in

buildings where the stack effect is significant, the singular pressure distribution specified

by the test method no longer leads to conservative results. This becomes clear from the

following considerations: The source of smoke which infiltrates a high-rise building is

the room (smoke zone) of fire origin. The rate at which this source passes smoke into the

overall building air supply is determined by 1) the geometry of partition penetrations (in our case, door assembly penetrations) and by 2) the distribution of Ap across these

penetrations. The Ap that would exist in practice could be of the order of several tens

of pascals — several times larger than the Ap being considered in the present test method.

In short, while the test method may lead to conservative estimates of smoke leakage when

the door assembly was used in low buildings, it could lead to significant underestimates

of smoke leakage rate when the door assembly was used in high-rise building applications.

And it is precisely the "fire in the high-rise building problem" that has drawn so much

attention to the general problem of smoke movement.

11
Before leaving this section, it is appropriate to briefly describe a typical fire

which would result in a relatively high over-pressure Ap of the type referred to above.

Such a scenario might look as follows: Fire breaks out in a room on a low floor in a highrise building during cold winter climate conditions. The room flashes over and a ventilation

or fuel controlled fire develops where ventilation is from broken windows on exterior

walls. From this time on the fire room pressure is substantially maintained at the outside

pressure. This room of fire origin is connected to adjacent rooms by partitions with

relatively small penetrations, e.g. (closed) door assemblies. The pressure in these

adjacent rooms is substantially at an inside pressure which is characteristic of the (low)

floor under consideration. The AP across all these partitions is therefore maintained at

levels which are of the order of magnitude of several tens of pascals, i.e., at levels

which are of the order of magnitude of inside to outside stack effect, pressure differentials.

3.2.3 The Limited Utility of the Concept of a (Constant) Orifice Coefficient

In addition to the observations in the last paragraph it is timely to point out that

there is no good technical basis for obtaining required "high over-pressure" results by

scaling up valid "low over-pressure" data (which would presumably be acquired by following

the present test method). This is the case for two reasons: 1) The AP distributions are qualitatively different. Thus, the leakage rate in the present test method is a result of

a strongly varying vertical AP distribution (nominally zero at the door sill, and increasing

linearly with height to the order of 10 pascals at the top of the door) , whereas the high

over-pressure type of loading to be simulated would be relatively uniform over the entire

assembly, e.g., several tens of pascals + the order of 10 pascals. The flow coefficient

for the leakage cannot be characterized as an orifice coefficient in the usual sense. The

(constant) orifice coefficient concept can be valid when the flows involved are mostly

turbulent (i.e., are at relatively high Reynolds number. Re). However, for the present

case of long gaps (cracks) which act like moderately long two-dimensional ducts, the flows

will be of relatively small and highly varying Re. Besides that, these flows are not

likely to be fully developed for much, if any, of their duct lengths. In short, flow

coefficients associated with a given (narrow) door gap of interest will be strongly

dependent on gap geometry and on the AP across the gap (or on the gap Re)

It Is noteworthy that the above AP dependent flow coefficient phenomenon, which would

be exhibited in cold gas flows as well as in hot gas flows, has been observed in the

present context by Keough [3]. The added problem in the high temperature test is, of

course, the fact that gap geometry is changing during the course of the test due to

expansion, warpage, etc. of the door assembly.

3. 2.Desirable Attributes of a Smoke Leakage Test Procedure

The remarks In the above paragraphs lead to the following conclusions:

12
Flexibility in achievable AP distributions would be an attractive feature of a test

method for measuring leakage characteristics of partition assemblies. This flexibility

should include a AP distribution which is reasonably uniform and of the order of 100 pascals,

as well as a AP type of distribution characterized by a neutral plane (AP = 0) somewhere

near the door sill.

The present test method does not have the former, high pressure capability, and this

is a significant limitation in the evaluation of door assemblies for high-rise building

usage. This limitation could be overcome by following an alternate test concept to be

discussed below in section 4.

3.3 Some Troublesome Theoretical Aspects of the Test Method

3.3.1 General Remarks

There are two basic theoretical aspects of the test method which lead to serious

questions regarding its usefulness. The first of these has to do with the fact that the

gas outflow from the enclosure (during the closed vent phases of the test) has two,

inseparable components. One component, the one which the test sets out to measure, is the

actual leakage gases. The other component, which is of no interest, and which cannot be

physically separated from the first, is the result of expansion of enclosure gases due to

heat transfer from the hot, unexposed surface of the door assembly under test. As will be

seen, this latter expansion component can be of the same order as the former leakage

component

.

The second aspect has to do with the complicated nature of the steady-state flows

which develop in and through the enclosure following closure of the vents. It is after

this steady state is reached that the test procedure actually calls for outflow measurement^.

In the remainder of the paragraphs under section 3.3, an analysis of the impact and

implications of these two aspects of the test method is presented. At first it would

appear that several seemingly influential factors may have to be directly taken account of

during the course of such an analysis. A partial listing of such factors would include.

The actual test procedure does not directly call for measurement at the steady state,

c.f., 7.3 Operating Procedure of DP 5925. Rather it is assumed that this steady state

will occur by 1 minute following vent closing, and the procedure explicitly calls for

measurement at this time. The actual time to reach steady state will be a strong

function of the specific door assembly under test and the time into the test, and the

indirect, 1-minute prescription for steady-state definition can lead to serious error. This is borne out by the test results of section 2, for example, where the velocity data

of figure 7 suggest that an effective steady state may be at hand by 1 - 1-1/2 minutes

following vent closure at 2400 seconds, and where the velocity data of figure 9 suggest

that even 2 minutes following vent closure at 4200 seconds steady state may not have

been reached.

13
for example, furnace pressure, geometry and position of the gaps in the door assembly,

volume of the enclosure, and elevation and diameter of the enclosure exhaust port. As it

turns out, however, there are only four factors that are, in fact, required for such an analysis, namely, the overall leakage of the door assembly (which would, of course, be a complicated and apriori unknown function of furnace pressure and gap geometry) , the diameter

of the exhaust port, the outer door surface temperature, and the temperature of the enclosure

gases near the elevation of the exhaust port axis. At appropriate places in the discussion

below, these factors will be reintroduced.

3.3.2 The Two Components of Outflow

As mentioned above, one component of the outflow gas flow rate is the actual leakage

rate. It is, of course, the entire purpose of the test to measure this leakage rate.

Unfortunately, there is another component to these outflow gases, which can be small or large compared to the first. This added component comes into play once the temperature on

the unexposed surface of the door assembly starts to become significantly larger than the

ambient temperature. Thus the expansion component will be small relative to the leakage

3 component very early in the test, and may remain relatively small for a longer period of

time in the case of doors with relatively higher insulating properties. Indeed, even for

uninsulated doors, and late into a test, the expansion component of the outflow may (again)

be eventually masked by the leakage component if door warpage and resulting increasing gap

dimensions proceed far enough along.

In general it is difficult to make apriori estimates of the relative significance of

the expansion component for a given door assembly system. But an order of magnitude

estimate of this flow rate is achievable. Such an estimate was obtained, and it is presented

in appendix B. The result of this is plotted in figure 12. As can be seen there, for a door of dimension 1 m x 2 m and for AT = T ^ - T of the order of hundreds of °C, surface gas

the outflow due to expansion will be of the order of tens of m^/hr. It is evident from

leakage rate data of [3] and [4], for example, that such rates of outflow could completely

mask the leakage phenomenon under study. In such circumstances (which are, apriori, not

evident) the present test method may be totally inadequate.

The qualifier "may" is important. It is used here for the following reason: Whereas the

actual expansion effect will be smaller at all times in the case of a better insulated

door, the Insulated door may deform in such a manner as to significantly decrease the rate

of leakage as the test proceeds. Thus, in the case of well insulated doors, it may not be

unusual if the ratio of expansion component to leakage component increased from zero with

reasonable rapidity. Indeed it is very difficult to generalize regarding the outcome of

the potentially complicated Interplay of in-depth door temperature distribution, thermal

deformation, and unexposed surface heat transfer which would develop during the course of

a test. This Interplay would be a custom feature of any specific door assembly system.

14
In the special case of the tests described above in section 2, and toward the end of

these tests, the expansion component of the outflow is estimated from figure 12 to vary

from approximately 45 m^/hr to approximately 30 m^/hr during the course of a 2-minute

closed vent interval.

3.3.3 The Nature of the Steady State and Its Implications

3. 3. 3.1 An Overview

Upon closing the vents at a given time during the course of the test, the procedure

4

is to wait until a steady state is reached, and then to measure the outflow from the

enclosure. By applying the principle of conservation of mass in its steady-state formulation,

this measured rate of mass outflow is presumably equal to the rate at which mass leaks

through the door assembly. As it turns out, a description of the nature of this steadystate is elusive. However, whatever the steady state temperature and flow fields within

the enclosure, it is likely that at the time of steady state the original, pre-vent closure,

AP distribution (and the resulting leakage flow rate) will have been significantly altered.

Besides this, an additional problem may manifest itself in that a uniform slug flow

description of the outflow velocity distribution at steady state may not be adequate,

i.e., a single point velocity measurement may not permit a reasonable estimate of the

outflow rate.

The considerations of the previous paragraphs under section 3.3.2 strongly influence

the quantitative aspects of the phenomena voider discussion here. Yet, the above qualitative

remarks are independent of these considerations as will be clarified below. The situation

will first be discussed in the absence of hot door surface, expansion phenomena. Following

that, a hot door surface zero leakage scenario will be discussed. Finally, the phenomena

of combined effects will be presented.

3. 3. 3. 2 Flow Conditions During Times of Cool Door Surface Conditions

3. 3. 3. 2.1 Flow Phenomenology Following Vent Closing

For the purpose of this paragraph we assume that the unexposed door surface is

effectively at ambient temperature (i.e., the outflow from the enclosure is solely due to

door leakage). This assumption will always be valid early in the test. For well insulated

doors it will remain valid until later into the test.

Attention is focused on the time immediately following vent closure. The enclosure

is filled with cool ambient air, and it is assvimed that the Ap distribution across the

4

See the footnote at the bottom of page 13 regarding the specification of the time of

measurement (steady state)

15
assembly at this instant is substantially as it was prior to vent closing^ (i.e., the

AP is as prescribed in the test procedure) . By virtue of this AP distribution no leakage

occurs at the horizontal door sill gap. There will, however, be leakage gases entering

the enclosure in the form of hot, line jets through the vertical gaps and through the

upper horizontal gap of the door assembly. The horizontal momentum of these jets is

quickly diffused and masked by strong increases in upward momentum.

This upward momentum is a result of the relatively strong buoyancy forces which come into play. For the case of the vertical gaps, for example, a substantially vertical,

buoyant, half-plume develops, where the plume axis is coincident with the gap itself. In

this case, the flow field is analogous to the flow field in a plume formed from a vertical

line source of heat (buoyancy)

.

The unsteady phenomena related to a buoyancy source in an enclosure which is initially

at uniform gas temperature have been studied by Baines and Turner [5], Zukoski [6], Zukoski

and Kubota [7] and others. The steady state for this problem, when there is a ventilation

opening to the outside (as there is in the present case with the outflow venturi) , has

been studied by a host of other authors (e.g., Kawagoe [8], Prahl and Emmons [9], Quintiere

[10], and Rockett [11]. These latter studies are mainly in the context of fires in

enclosures. And indeed, the flow phenomenology of interest here is very much analogous to

the flow phenomenology of fires in enclosures.

Applying the ideas developed in the above referenced studies, it is likely that the

following scenario will unfold immediately following vent closure:

The plumes driven by the hot furnace gases rise upward in the enclosure, laterally

entraining cool ambient air all along their height. The lateral velocity of these cool

gases is relatively small compared to upward velocity in the plumes, and, away from these

plumes, the gases in the enclosure remain essentially in a quiescent state. The total mass flow in the plumes increases with height. The increase is due mainly to the entrained

air (i.e., the ratio of entrained air to furnace gases in the plume is relatively large).

Thus the average temperature in the plume decreases with height, remaining somewhere

between the temperature of the hot furnace leakage gases and the temperature of the cool

ambient air. Upon reaching the top of the enclosure the plume gases rapidly spread across

it in a relatively thin (compared to the height of the enclosure), hot, buoyant layer.

As time goes on, the upper, hot, plume gas layer starts to increase in thickness

replacing, from above, the lower cool gases which are continuously entrained into the

Upon closing of the vents there will actually be a relatively small and uniform increase

in enclosure pressure. This is due to the fact that all the enclosure outflow is now

through the relatively small constriction of the outflow port.

16
plume. A complete analysis of the phenomenon would also indicate the requirement of a net

outflow from the outflow port^. The entire situation at early times is depicted in figure 13.

As time goes on the interface between the upper and lower layers continues to drop, soon reaching the general level of the enclosure outflow port. Whether or not the steady

state is at hand is not immediately clear. As will be seen, the basic question in this

regard is whether the effective position of the interface continues to drop to the bottom

of the enclosure or settles in a steady state somewhere above the bottom, but below the

axis of the outflow port. In order to address this question a result will first be deduced

concerning the steady-state level of the enclosure-to-ambient neutral plane (i.e., concerning

the level at which P . = P i.. ..)• enclosure ambient

3. 3. 3. 2. 2 Steady State Position of the Enclosure-to-Ambient

Neutral Plane — A First Estimate

A general result for the steady state position of the enclosure-to-ambient neutral

plane will now be obtained. As it turns out, a direct calculation for this neutral plane

position is beyond the intended scope of this analysis. The following indirect approach

will be seen to yield the desired result for the enclosure outflow dynamics under review.

In figure 14 is a sketch of the enclosure, and, for a relatively late time into a closed vent phase, a vertical temperature profile for the enclosure gases (away from the

plume). The uniform and)lent temperature is also indicated in the figure. Corresponding

to these temperature profiles are plotted the vertical ambient and enclosure pressure

distributions. These latter pressure profiles are the result of vertical integration of

the temperature dependent density profiles. Thus

‘’anb<^n>

‘ n

P Az) = -P , (z ) - r p(T ,) g dz end end n z end

n

( 1 )

where z is some arbitrary reference level, and where P .,T .,P ,,T , are pressures

n

' amb amb end end

and absolute-temperature of the ambient and within the enclosure, respectively. The

different possible uniformly separated distributions in the figure indicate the fact

that with the second of eq. (1) and from the known distribution of T , (z) P , (z) can end end

be computed only to within an undetermined constant, P , (Z )

end n

The idea of a net outflow of the enclosure gases, uniform across a section of the outflow

port for some initial time following vent closure, is compatible with the figure 10 plot

of the section 2 test results.

17
Now let z be the unknown position of the enclosure-to-ambient neutral plane. Thus

n we define z as the position where P ,(z)=P ,(z). Also define

n end n amb n

AP (z) = P t(z) - P , (z) e-a end amb ( 2 )

Thus

AP = g / [P(T ,)-p(T ,)] dz e-a ^ z amb end

n

(3)

In this last equation and throughout this entire work all enclosure gases are taken

to have the properties of air. Furthermore, a constant absolute pressure, perfect gas

model for air is assumed. Thus, pT is assumed to be a single constant at all elevations

within the ambient and throughout the enclosure.

In terms of comparison between eq. (3) and the section 2 tests, recall that histories

of measured at the top and bottom positions of the door assembly have been plotted

in figures 4, 6, and 8. For the specific time 4132 seconds into the second test (figure 8)

the theoretical value of the bottom AP has been computed using the measured top AP

6“3 6"“3 value, the measured temperature profile of figure 11, and eq. (3). The excellent agreement

between the computed (-0.0150 in ) and measured (-0.0160 in ) AP values can be seen in w w e-a

figure 8.

It is noteworthy that the latter calculation also led to an estimate of the neutral

plane position at the time in question. This was found to be somewhere near the outflow

port axls^.

The volume rate and mass rate of flow through the outflow port, q and m, respectively,

can be written as

z + D/2

q

= /^ w(z) v(z) dz

z - D/2

P

(4)

z + D/2

m = P (z) w(z) v(z) dz

z - D/2

P

The precise estimate for the neutral plane elevation at 4132 seconds was found to be

6 inches above the outflow port axis. Anticipated experimental error does not, however,

allow precision in this regard better than the order of a foot.

18
where D and w(z) are the height and width of the outflow port, respectively, is the

vertical elevation of the midheight of the outflow port, v(z) is the velocity of the flow

measured positive in the enclosure-to-ambient direction, and p^(z) is the density of the

flow-through gases. Then

v(z) = [2 |aP^_^|/p^(z)]^/2aP^_^/|aP^_^| (5)

and

Pj.(z) = «

"'e-a

> <> > 0)

p(T .) If < 0 (v < 0) amb e-a

( 6 )

Referring to eq. (3) it is now assumed that, in the z range of interest, the maximum

variation of relatively small in magnitude compared to the minimum of

llenci^^) - I • This would clearly be the case for the sketched profiles of figure 14

provided z^ was in the proximity of the axis of the outflow port, e.g., provided

z - z n p

< D. Under these conditions, under the integral of eq. (3) can be

approximated by

^^e-a approximated by

""e-a

= SP(^amb> " ^amb/^encl<^p>

(7)

( 1 ) ( 2 ) The AP ’s that would be formed from the P , profile and from the P , and P , e-a amb end end

profiles sketched in figure 14 are indicative of the anticipated validity of the fact that

AP^_^ does indeed linearly with Z in a manner consistent with eq. (7) in the Z range

of interest. The P , profile is for z somewhere near the elevation of the outflow port

^ 2 ^ end n

axis, and the profile is for slightly below the outflow port opening.

Using the result of eq. (7) in eq. (5) the following estimate for v(z) is eventually

obtained

v(z)

(z-z z-z > 0 n n

(z-z z-z < 0 n n

( 8 )

Using this last result in eq. (4), and taking the outflow port as in figure 14 to be

circular in section and of diameter D, the following result is obtained for the total

volume flow rate and mass flow rate through the port and out of the enclosure:

19
(9) q* = V[(D^/2)(gDK)^^^] = <{>(X) - [1/(1 +

m* = m(l+K)/[p , (D^/2)(gKD)^/^] = 4.(1) - <^(-X) (1+K)^''^

amb

where

K =

4>(X) =

[T -(z )/T , - 1]; X = (z^ - z )/(D/2) end p amb n p

,/_];[ (l-?2)(^-X)]^/^ dc; X < - 1

/^[(1-^2)(^-X)]^/2 dc; -1 < X < 1

'O ; 1 < X

4i(X) is plotted in figure 15. q* and m* are plotted in figure 16 as a function of X with

1/2

K as a parameter. The corresponding values for q* K are plotted in figure 17. For

D = 0.3 m (the diameter of the outflow port prescribed by DP 5925) the dimensional values of

q are also presented in figure 17 as a function of X with ^gncl^^p^'^amb ^ parameter.

For the present purposes, these plots yield the significant results of this paragraph.

For example:

If T , (z )-T . is between 60°C and 1200°C, and the volume rate of flow from the end p amb

outflow port is less than 275 m^/hr, then the level of the neutral plane, z^, is in the

relatively narrow range

-2. < X < 0.25 or z-D<z<z+ D/8

P n p

3. 3. 3. 2. 3 A Refined Estimate for the Level of the

Neutral Plane and Its Implications

The results of the previous paragraph indicate the possibility of a neutral plane

(somewhat) below the bottom of the outflow port (i.e., X < -1.). Under these circumstances

the velocity across the entire section of the outflow port would be outward. This is

clearly not possible as a steady-state configuration for the phenomenon under consideration.

Indeed, If the outflow port velocity was uniformly outward at steady state, then all of

the gases within the enclosure would have had to have entered therein as hot leakage gases

from the furnace. Thus, a steady state with the neutral plane anywhere below the outflow

8 port Implies a bulk enclosure gas temperature which is essentially at furnace temperature .

Steady heat transfer from enclosure gases to enclosure surfaces, and then to outside air

cannot be expected to drop the temperature of these gases significantly below their

original furnace levels.

20
From figure 17, it is clear that with the present outflow port diameter, with enclosure

temperatures of the order of several hundreds of °C or greater (say K > 1) , and for X < -1,

outflow volume flow rates will exceed 400 m^/hr. This is inconsistent with the anticipated

flow rates which are not likely to exceed 100-200 m^/hr.

From the latter inconsistency it is now evident that a neutral plane elevation, z^,

which satisfies z < z - D/2 (with corresponding uniformly positive outflow velocities)

n p

must be discarded as a possible steady-state scenario in the present DP 5925 test method.

In view of the above, the following conclusions result:

In the steady state configuration the enclosure-to-amb lent neutral plane must satisfy

-1. < X < 0.25 or z - D/2 < z < z + D/8

P n p

As a result of this neutral plane position, the steady velocity of the flow in the cross section of the outflow port will be a strong function of elevation. In the lowest

portion of this section there will actually be a layer of air which flows into the enclosure.

It is, in fact, this cool, ambient, inflow air which (by mixing with the plumes of the hot

leakage gases) would maintain steady-state enclosure temperatures at characteristic levels

significantly below furnace temperatures.

Note that the above theoretical conclusions are compatible with the experimental

results of section 2 and with the observations below eq. (3).

The DP 5925 procedure for estimating the volume rate of flow out of the enclosure is

to measure the velocity at the outflow port axis, v(z^), and to multiply this by the area

of the port. Using eqs. (8) and (9), and defining the average flow velocity through the

port as V, where

V = 4 q/(nD^),

the following experimental estimate, for ^ can therefore be anticipated

|qest/4i = l^(%>/^l = (^/2) lx|^^^/lct.(X)-4,(-X)/(l+K)^^^l (10)

Using eq. (10), 9gg^/q been plotted in figure 18 as a function of X with K as a parameter. It is evident from this that the experimental estimate for q can be in significant

error.

21
3. 3. 3. 3 Flow Conditions Resulting From the Combined

Effects of Leakage and Hot Door Surface Heat Transfer

The previous paragraphs of 3. 3. 3. 2 developed a scenario for enclosure flow dynamics

that are to be anticipated solely as a result of door assembly leakage (i.e., during test

times when cool door surface conditions prevail). As it turns out, a hot door surface,

zero leakage scenario would follow much the same lines.

In 3. 3. 3. 2, line plumes of hot leakage gases were considered to be the driving mechanism

for the flow. In contrast to this, for the case of a zero leakage hot door surface a purely convective type (i.e., no mass injection), two dimensional plume would be formed.

This would start at the bottom of the door and rise in a boundary layer flow all along the

hot door surface. The net outflow from the enclosure would be the result of enclosure

gases expanding from hot door surface heat transfer. All results and figures discussed in

3. 3. 3. 2 would be entirely relevant.

The scenario anticipated in a real, DP 5925 door assembly test would, of course,

involve the combined effects of leakage driven outflow and expansion driven outflow. The

actual flow dynamics would be the result of a complicated combination and interaction of

leakage line plumes and a two dimensional, vertical surface, wall (door) plume. The

results and conclusions of 3. 3. 3. 2 would again be relevant.

3.3.4 A Summary of the Test Method's Shortcomings

As a result of the above investigation the following shortcomings of the DP 5925 test

method have been identified.

A. The net rate of outflow from the port of the enclosure is a result of two, unknown,

time-varying and Inseparable components, namely, actual leakage from the furnace and

enclosure gas expansion due to hot door surface heat transfer. In general these two

components can be of the same order of magnitude.

B. The time to approach quasi-steady-state conditions within the enclosure (subsequent

to vent closing) will depend on the door surface temperature and on the door assembly

leakage characteristics. In contrast to the suggestion of section 7.3 of DP 5925,

this time will not generally be less than 1 minute. For example, in the present

NBS/UL tests even 2 minutes was not generally ample for the development of quasisteady conditions. In this regard, the situation would have been even worse if the

door had been specifically designed for "tightness" and/or it had been insulated.

C. Afcsumlng that a quasi-steady-state condition is reached within the enclosure at a

r asonably short time following vent closure (e.g., within a time short enough so

f 't the unexposed side of the door assembly was not subjected to inordinate heating

22
by hot enclossure gases) , 1) the velocity distribution in the outflow port cross section will be highly nonuniform with zero velocity occurring somewhere in the lower

half; 2) a one point velocity measurement for estimating the net (leakage plus expansion)

port outflow can lead to significant errors; and, 3) the vertical distribution of

furnace to enclosure pressure differential may be significantly different from that

distribution maintained during the open vent portions of the test. For example, if

the door sill pressure difference is maintained at zero during the open vent phase,

then it will not be zero during the closed vent phase. As a result of this overall

variation in pressure distribution, the total leakage flow rate across the assembly

can vary significantly depending on whether an open or closed vent condition prevails.

In view of these shortcomings it appears that the DP 5925 test method will not yield

reliable estimates for the desired leakage characteristics which it sets out to measure.

4. AN ALTERNATIVE TEST CONCEPT

4.1 The Alternative Test Concept and Its Overall Advantages

This section will introduce an alternate test method concept for measuring door

assembly leakage characteristics. The test method has neither the limitations discussed

in section 3.2, nor the shortcomings described in section 3.3. While requiring reasonably

steady furnace operating conditions, it does not require furnace pressurization. The test

concept represents a universal test method in the sense that a single door assembly test

setup could lead to leakage data at low, moderate and high furnace (room of fire origin)

temperature and under conditions ranging from small to large pressure differentials.

A sketch of the proposed test concept is presented in figure 19. Various features of

this concept are noted on this figure and the most significant ones are discussed below.

4.2 Significant Features of the Test Concept

4.2.1 Continuous Quasi-Steady Operation

The most important feature of the test concept is the fact that it involves a continuously

quasi-steady operating procedure. Thus, to a good approximation and at all times during

the course of the test, steady-state mass balance can be correctly applied to the enclosure.

In particular, the rate at which furnace gases leak past the door assembly, can be

computed from

*leak

' ‘exit' *In

where, as indicated in figure 19, A and m, are the measured mass rates of gas flow exit in ^ into and out of the enclosure.

23
4.2.2 Accurate Simulation of Ambient Conditions

In order for the test to provide a reasonably accurate simulation of the door assembly

response to a real fire scenario, the temperature history of the unexposed surface of the

assembly must be properly simulated. This temperature history will, of course, depend on

the history of the rate of heat transfer from the assembly surface. But the rate of heat

transfer is controlled by the ambient conditions. Thus, simulation of the door assembly

response requires simulation, in the enclosure, of the significant features of typical

adjacent room ambient conditions.

Independent of any specific door assembly of interest and independent of the pressure

difference across it, the ambient condition characteristics which will lead to an appropriate simulation of the desired heat transfer are 1) maintaining the enclosure surfaces

at room temperature, and 2) maintaining zero to low velocity room temperature air at

positions away from the immediate vicinity of the door surface. The first of these

characteristics is to ensure simulation of radiant energy exchange between the hot door

surface and the cool bounding surfaces of an adjacent (to room of fire origin) space. The

second of these characteristics is to ensure simulation of natural convection heat transfer

from an elevated temperature door surface to a (relatively) quiescent, ambient temperature,

adjacent room atmosphere.

With regard to the second of the above characteristics, low velocity is intended to mean a velocity which is, at most, characteristic of normal room draft velocities. It is

also intended to mean a velocity that is small relative to characteristic velocities in

the convective door surface boundary layer at times when convective heat transfer becomes

significant. In general, air velocities of the order of 0.1 m/sec or less will satisfy

the low velocity criteria. Thus, for the present purposes, no significant variation in

convective heat transfer is anticipated if the ambient velocities vary with this range.

As will be seen, the allowable flexibility (0 - 0.1 m/sec) in upward air velocity would be

taken advantage of in the design of enclosure ventilation control.

As indicated in figure 19, both of the above ambient condition characteristics are a design feature of the enclosure test fixture. Enclosure surfaces are maintained near room

temperature by forced cooling, either air (from fans on the outside) or water. The enclosure

environment is continuously and slowly flushed from bottom to top by clean, cool, low

velocity air.

Besides performing the prime function of door assembly heat transfer simulation, cool

operating conditions for the enclosure structure would lead to its general endurance and

long life.

24
4.2.3 Universal Control of the Fumace-to-Enclosure

Pressure Differential

The proposed test method is conceived in a manner as to permit continuous and precise

control of the fumace-to-enclosure pressure differential during the entire course of a

test, and this without any adjustment or control of furnace pressure. As indicated in

figure 19, this pressure control is accomplished by varying the flow resistance of the

upper fan-duct system. The control would be done either manually or automatically and in

a manner as to continuously maintain the enclosure pressure (i.e. , the fumace-to-enclosure

pressure differential) at any desired value.

Assume, for example, that one wished to study leakage resulting from a configuration

where the elevation of the neutral plane is at the door sill (as is the objective of the

DP 5925 Part 3 test method). Then, throughout the course of the test, the upper duct

valve would be continuously adjusted in a manner as to maintain this pressure differential

condition. (Valve adjustments would definitely be required as the door assembly leakage

characteristics were altered due to continued fire exposure.) Alternatively, by a proper

(large) opening of the valve, the enclosure pressure could be easily maintained at a negative pressure relative to ambient. In this manner, a relatively large fumace-toenclosure pressure differential could be imposed across the door assembly, thereby simulating

the characteristic, high-rise building over-pressure phenomenology discussed in section 2.

By proper component selection, the lower fan-duct-flowmeter system at the enclosure

inlet would be designed so that the mass flow rate of air passing into the enclosure would

be relatively insensitive to the above-mentioned variations of enclosure pressure. That

this can be easily achieved is evident from the following observations. First notice that

the enclosure pressure would always be required to stay within the bounds, say.

-0.4in < P w

-100 Pa < P

end

end

amb

amb

0

0

Now assume that the lower flowmeter and duct is designed so that the fan delivers a desired rate of inlet air, from the ambient while overcoming a pressure drop of, say,

5 to 10 in = 1250 to 2500 pascals. If P - is maintained within the above relatively w end

narrow range, it is evident that with the use of such ventilation components the mass rate

of air actually delivered to the enclosure would vary by a relatively small amount from

the design m^^ value. As noted in the previous paragraph, moderate variations in the mass

rate of air flow (i.e., in the upward enclosure air velocity) do not upset the desired

simulation of the door assembly response.

In view of all the above, it is evident that, with proper design the single upper

valve actually provides both rapid response and universal control of the fumace-toenclosure pressure differential. The significant implication of all this is contained in

25
the following summary conclusion:

A device of this design Is capable of providing a predetermined , rapid response

furnace-to-enclosure pressure differential during the course of a standard, door assembly

fire endurance test. With such a capability, a total evaluation of the subject door

assembly leakage characteristics could be obtained .

4.2.4 Accuracy of the Leakage Measurement

Having described the basic test concept and some of the rationale for the design of

the test enclosure, attention is again refocused on the basic measurement of This

is embodied in eq. (11). Thus, the accuracy of determining at any instant of time

is dependent on the accuracy of measuring “ TMin’

Within reasonable limits, the basic test configuration is such as to permit m

exit

and m^^ measurements of any desired accuracy. The key to this capability lies in the fact

that the pressure drop in both the upper and lower flowmeter-duct systems can be designed

to be arbitrarily large. (Whatever the magnitude of the desired pressure drop, an appropriate fan would be selected to overcome it.) With the availability of a large pressure

drop, an appropriate flowmeter (and associated pressure measuring instrumentation) can be

selected which would provide any reasonable desired degree of accuracy in the measurement

of the mass flow rates.

5. SUMMARY

This Investigation of the measurement of door assembly smoke leakage has been presented

in four major sections.

In the first section a basis for relating overall intrabuilding smoke migration

dynamics to high temperature compartment partition smoke leakage measurements was formulated.

The approach taken was to develop the concept of smoke compartmentation, and to identify

and discuss the implications of the two different smoke migration phenomena that would be

in effect on each side — the fire side and the protected side — of the leaking compartment

partition.

The second section presented the results of applying the tentative, high temperature

ISO test method DP 5925. This test method was designed to measure the smoke leakage of

door assemblies during the course of a standard fire exposure. As was seen, these results

led to unanswered questions regarding the validity of the test method. In order to answer

Liifcsfc questions, further testing and an in-depth analysis of the test method was carried

"t . The results of the further testing were reported in section 2.

26
The analysis of the DP 5925 Part 3 test method was presented in the third section.

As concluded in section 3.2, the basic test method as written was found to be limited in

practice. In particular, the test objective, even if attained, would not result in a clear evaluation of the performance of door assemblies during fire scenarios where standard,

high-rise building, stack effects come into play.

Perhaps more significantly, serious theoretical problems with the test and its procedures were identified in section 3.3. Taken all together, these latter problems led to the

following conclusion: For door assemblies where enclosure gas temperatures during quasisteady conditions do not approach the level of furnace temperatures, and where such quasisteady conditions are attained within a few minutes of vent closure, the basic DP 5925

Part 3 test method can potentially yield rough estimates for the desired smoke leakage

characteristics which it sets out to measure. However, to accomplish this, significant

additional data would have to be acquired. For example, once quasi-steady conditions

prevail, the net enclosure outflow could be estimated from figure 17 once the elevation of

the neutral plane (i.e., the position of zero velocity) within an outflow duct cross section and the temperature of the enclosure gas near the general vicinity of this elevation

was determined.

An alternate test concept has been formulated which removes the limitation and

theoretical problems of the DP 5925 Part 3 test method. This concept was presented in

figure 19 and in section 4 wherein several of its significant features were identified and

briefly discussed. The concept holds promise as a universal type of test method in the

sense that a single door assembly setup would lead to reliable leakage data throughout the

entire course of a fire endurance test, and under conditions ranging from small to large

pressure differentials. Moreover, the test concept is not restricted only to the evaluation

of door assembly leakage characteristics. Indeed, it could also be used to evaluate the

leakage characteristics of overall wall and floor assemblies. In short, it is strongly

recommended that the alternate test concept be developed to the point where its apparent

potential promise can be evaluated in a more tangible manner.

6. ACKNOWLEDGEMENTS

IT;*:, author gratefully acknowledges Mr. Lionel A. Issen of Construction Fire Research,

CFR/NBS who provided all liaison between UL and NBS during the course of the test program

and who transmitted and decoded all of the data that was acquired. Also acknowledged are those members of the UL staff, notably Mr. Robert M. Berhinig, Engineering Group Leader,

vho carried out the tests described herein with the flexibility that was required by

mture of the task at hand.

27
7 . REFERENCES

}

[1] Cooper, L. Y., A method for estimating safe available egress time from a workspace,

Nat. Bur. Stand. (U.S.), to be published as NBSIR.

[2] Dekker, J. and Haffmans, L., Comments on ISO DP 5925 Parts 2 and 3 Received from TNO,

ISO/TC 92/WG 3 N 209, Sept. 1978. (unpublished committee report)

[3] Keough, J. J., Air Leakage Through Doors, Report of the Department of Works, Commonwealth

Exp. Bldg. Sta., Chatswood, NSW, Australia (Nov. 1972).

[4] Dekker, J., Results of Air Leakage and Fire Tests on Doors, ISO/TC 92/WG 3 (Finland-2)

106 (March 1973). (unpublished committee report)

[5] Baines, W. D. and Turner, J. S., Turbulent Buoyant Convection From a Source in a Confined Region, J. Fluid Mech., Vol. 37, Part I (1969).

[6] Zukoski, E. E., Development of a Stratified Ceiling Layer in the Early Stages of a Closed Room Fire, Fire and Materials, Vol. 2 (April 1978).

[7] Zukoski, E. E. and Kubota, T., A Computer Model for Fluid Dynamic Aspects of a Transient Fire in a Two Room Structure, Cal. Inst, of Tech. Jet Propulsion Center

Report, NBS Grant 5-9004 (June 1978).

[8] Kawagoe, K., Fire Behavior in Rooms, (Japan) Bldg. Res. Inst., Report No. 27

(Sept. 1958).

[9] Prahl, J. and Emmons, H. W., Fire Induced Flow Through an Opening, Combustion and

Flame, Vol. 25, No. 3 (Dec. 1975).

[10] Quintiere, J., Growth of Fire in Building Compartments, Fire Standards and Safety,

ASTM STP 614, A. F. Robertson, ed., American Society for Testing and Materials (1977).

[11] Rockett, J. A., Fire Induced Gas Flow in an Enclosure, Combustion Science and Technology,

Vol. 12 (1976).

[12] Eckert, E. R. G. and Jackson, T. W., Analysis of Turbulent Free Convection Boundary

Layer on Flat Plate, NACA Technical Note 2207 (1950).

28
NORTH

29

Figure

1.

Location

of

thermocouples

in

the

enclosure
ANEMOMETER

30

Figure

2.

Location

of

thermocouples

in

the

enclosure

outlet
Figure 3. Location of pressure differential measurements
.09

.08 A

O

Ap2

Ap4

Api

Ap5

FURNACE TO ENCLOSURE : TOP OF DOOR

FURNACE TO ENCLOSURE : BOTTOM OF DOOR

ENCLOSURE TO AMBIENT : TOP OF DOOR

ENCLOSURE TO AMBIENT : BOTTOM OF DOOR

.07 -

.06 -

a

° _ „ ° n

.05

^ .04

Z

a

<1 .03

.02 -

Z

LU>

UJtoO

z

LU>

z

LU

Q.

o

.01

-gt A ^

. •••

• • A • • •• •

fc * • **

O O O D ** O O O O O °°Oooooooo o o o o O oo o O o

D

-.01 L 840 900 960

TIME/SECONDS

Figure 4. Various AP's during 840-900-second closed vent interval

32
TIME/SECONDS

•itflow velocity during 840-900-second closed vent interval

33

|<^est|/(m3/HR)=|([_VELOCITY|xAREA/(m3/HR)
.09

.08

,07

,06

05

,04

.03

02

.01

0

.01

02

Fi

Ap2 - furnace to enclosure : TOP OF DOOR

• Ap4- FURNACE TO ENCLOSURE : BOTTOM OF DOOR ^ Api - ENCLOSURE TO AMBIENT : TOP OF DOOR i! O Ap5 -ENCLOSURE TO AMBIENT : BOTTOM OF DOOR

ZUJ>

UJtoO

u

z

UJ>

z

UJ

a.O

I I

I I 1 2400 •

J I I L ^ ^ A

0*8° • o

8 ®

2460 2520

TIME/SECONDS

o o

•O

•

O •0 9

O

•O •o

•o

o

• OoOqoO •

•

• ^ • o

•

•

•

are 6 Various AP's during 2400-2520-second closed vent interval

1

'34
Figure 7. Outflow velocity during 2400-2520-second closed vent interval

35

Iqest

/(m3/HR)|=|^VELOCITY|

x

AREA/(m3/HR)
,09

.08

07

,06

.05

.04

,03

02

.01

0

.01

02

Ap2 - FURNACE TO ENCLOSURE : TOP OF DOOR

• Ap4 - FURNACE TO ENCLOSURE : BOTTOM OF DOOR ^ Api - ENCLOSURE TO AMBIENT : TOP OF DOOR

o Ap5

. ENCLOSURE TO AMBIENT : BOTTOM OF DOOR

z

UJ>

Ui

(/> o

u

z

lU>

z

UJ

o.o

A A A o °

J I L*-J I L J I L 4020 o 4080

0 o o o CALCULATED FROM

EQUATION 3 AND

DATA OF FIGURE 11

4140

°°°°OOOooOo(S^

OO

CALCULATED

MEASURED

• • • O

• •

' igure 8. Various AP's during 4020-4140-second closed vent interval

36
|([^

VELOCITY)

/(FT/MIN)

Figure 9. Outflow velocity during 4020-4140-second closed vent interval

37

|qest|/(m3/HR)

=)<[

VELOCITY)

x

AREA/(m3/HR)
TEMPERATURE

/

°C

125

ANEMOMETER ^ THERMOCOUPLE 89

O THERMOCOUPLE 90 • THERMOCOUPLE 91

50

25 ^ I 4020

J I I I I 4080

TIME/SECONDS

• O

• o

•••

2.0

J I i 1 L

4140

rigure 10. Venturi throat thermocouple temperatures during

4020-4140-second closed vent interval

38
ELEVATION

RELATIVE

TO

DOOR

A 4013 SEC. INTO TEST - IMMEDIATELY BEFORE VENT CLOSE • 4040 SEC. INTO TEST - 27 SEC. FOLLOWING VENT CLOSE

4073 SEC. INTO TEST - 60 SEC. FOLLOWING VENT CLOSE

4105 SEC. INTO TEST - 92 SEC. FOLLOWING VENT CLOSE

O 4132 SEC. INTO TEST - 119 SEC. FOLLOWING VENT CLOSE

A •

^ %

m

A •

^ 0 BO

A BO

^ • B O

J I I \ l_J I I I I L 50 100

ENCLOSURE TEMPERATURE / °C

O

B O

B O

B O

O

-L_L

150

Figure 11. Enclosure temperature as a function of elevation

during the 4020-4140-second closed vent interval

39
80

60

40

20

0

)

Tsurface “ TEMPERATURE OF UNEXPOSED

DOOR SURFACE

Tend -AVERAGE TEMPERATURE OF

ENCLOSURE GASES

200 400

( Tsurface — Tend ) / °C

600

Figure 12. Estimates of outflow due solely to expansion

for a door of dimension 1 m x 2 m

AO
Figure 13. Idealized model of flow within the enclosure

shortly after vent closure
POSSIBLE

Pend

(Z)

A2

Figure

14

. A

sketch

of

a

vertical

distribution

of

enclosure

temperature

and

plots

of

possible

resulting

distributions

of

enclosure

pressure
- 2-10 1 k

Figure 15. Plot of <}'(^) defined in eq. (9)

43
A* = ifi(l+K)/[(D2/2)(gDK)!^2 panb]

q* = q/[|D2/2)(gDK)!^2]

Figure 16. Plots of m* and q* as functions of A with K as a parameter. See eq. (9)

44
q/(rti3/HR)

FOR

D

=

0.3m

o

SIXV laod QNV

W0U09 mod dO

S13A31 N33M139

3NV1d 1Vdin3N

woiioa mod

dO 13A31 A^0^39

3NVld lVdin3N

45

Figure

17.

Plot

of

q/[(D^/2)

(gD)

V^]

as

a

function

of

X

with

K

as

a

parameter.

Plot

of

q

as

a

function

of

X

with

AT

as

a

parameter,

for

D

=

0.3

m

and

T

,

=

295

®K.
V(Zp)/V

46
VALVE

FLOW METER

E.G., ORIFICE

mieak

'AP exit

T exit

I

. HEAT TRANSFER / I FROM HOT DOOR

0 Pk

I SURFACE

hN I A * '| ~4 i I'

Tfu rnace

DOOR

T

•^BOUNDARY LAYER

/ FROM HOT DOOR

FLOW METER

E.G., ORIFICE

nriexit

COMPUTE rflexit FROM

^Pexit and T exit

. APenclosure

DURING COURSE OF TEST VARY VALVE

OPENING TO MAINTAIN APenclosure AT

DESIRED VALUE. THEN COMPUTE;

mieak () = rflexit (t) - rfl in (t)

COOLED ENCLOSURE SURFACE

SIMULATE NATURAL DRAFT VELOCITY PLUS MASS

THAT WILL BE ENTRAINED IN B.L.

• PACKING ”, MESH, OR FILTER TO DISTRIBUTE

min UNIFORMLY OVER ENCLOSURE AREA

Tin I COMPUTE min FROM

( APjn AND Tin

m in

SELECT FAN, (HIGH IMPEDANCE) ’PACKING”, AND FLOW METER SO THAT WHEN

Ap enclosure AS REQUIRED {WITHIN A RELATIVELY WIDE RANGE) THE min

PRODUCED WILL SIMULATE REALISTIC COOLING CONDITIONS FOR THE DOOR.

Figure 19. A test concept for measuring leakage of door assemblies

during standard fire endurance tests

47
Figure 20. Model for determining the rate of outflow, which is

associated solely with the heat transfer rate, Q

48
APPENDIX A

ISO/TC 92/WG 3 N 203. DP 5925 FIRE TESTS — SMOKE CONTROL

DOOR ASSEMBLIES. PART 3. HIGH TEMPERATURE TEST

(REVISION OF DOCUMENT N 189)
Docurm*.nt No

iSO/TC 92/VC 3

'3TVa.i\'4 197 3

international organization for standardization

I S 0

organisation I N T £ r n a T I o n a l e d e normalisation

froin: BRITISH STANDARDS INSTITUTION

J fKRK STREET LONDON wiA :as

T<Uphnt<t: 01 •429 9000

T<Utrams: STANDARDS LONDON wi

J I HciU O'^ctl k Accoma««)

92j'>iC 3 Fire resiacance doors

shucccrs and ’i^zed | elenciics (oc TC 92 | fire cescs on building • aacsrials and scruczurs:

SecrcuriM - Unicfld Xincdom

DP 5925 FIRE TESTS - SMOKE CONTROL CCCR ASSEMQLIES

PART 3. HIGH TEMPER.ATURE TEST (RevisLcn of documenc N 139)

CONTENTS Pa-e

Foreword

2.

Scope and field of applicacion

2. Definitions

3 . Test princip 1

4. Apparatus

5. Prcoaracion of test spccinens

6 . Cal ibrac ton

7. Procedure

8 . Test results

9. Tesc report

FIGURES

1. Mcasureacnc of air leakage during the high tenperauore test 9 2. Enclosure for leakage rate cieasureRent 10

3. Enclosure and furnace surround 11 Calibration of enclosure 11

7,2 1

•') 9 7 V A-2
ISO/TC 9:/VG J S 203

CRZyORD

(The firsc ?arc oc the forevord Is prepared by ISO Central Secretariat giving

details of the member bodies which approved the proposal.;

This standard method of test is one of a series being prepared by ISO/TC 92

' 1-ire tests on buildinv; materials anc structures' for the assessment and

evaluation of the performance of door assemblies intended to act as barriers to smoke in fire.

The severity of the heat exposure ana test conditions governs the smoke control

performance of doors and has led to the preparation of the standard in Parts,

further explanations and guidance on this and other considerations are given in

D? 5925: Part 0. Laboratories are advised to acquaint thenseives with the

concents of the commentary before using any of Che tests in this series.

This standard specifies a method of testing and evaluating the performance of

door and shutter assemblies intended to act as barriers to smoke under high

temperature conditions. Tne test is designed to be carried out using the same furnace and generally unoer the conditions of the test specified in

ISO 300dl). Ic coes not, however, adopt the same pressure conditions as ISO 3UU8, and seme aspects of the ISO 3C08 test (e.g. cotton pad test) are

omitted. Further tests in the secies arc being prepared as follows:

DP 5925 Fire tests - Smoke control door asoembiies

Part 1. Ambient temperature test.

DP 5925 Fire tests " Smoke control door assemclies

Part 2. Medium temperature test.

NOTli - So Chat suitable precautions to safeg-uari health of test person:'iel

may be taken, the attention of all concernca fire tests is drawn to the

possibility chat toxic or harmful gases may be evolved in combustion of

test elements.

1. scops: and field of applicaticn

Tliis International Standard specifies a method of testing and evaluating the

performance of door asse;obiies Incluoing roiling shutter and other closure

assemblies Intended to control the passage of smoke in conditions of high

temperature. Tills test measures the flow of air tiirough the test assembly at one pressure level.

This test -procedure does not -or-ovide o means of determining criteria to ISO 3CC3 nor mechanical damage to a door asse-.soly, and these should be assessed

sc-,)a cutely

1 ) ISO 300S Fire resistance test, door one shutter assemblies.

ir. i6‘)7v 78/ i 1^10 2 A-3
ISO/TC 3

1 . D^riNITICNS

ror die purpose of ciiis Lncerna.:.ioruiI Standard, the definitions i^iven in

ISO IS0“1), ISO 326i-) and Ut* 3925: 9art 0 together '^th the following

arc applicable:

2.1 door asscnslv (doorsoc) : .\n assembly including a fixed part (the door

franej, one or aore covaoie parts ( tne ccor leaves) and tncir hardware, the

function of vnich is to aJLLow or to prevent access,

2.2 .sao<>» control door : A door assembly whose pciaary Tuncticn is to resist the

passage of smoice as cetemincd. by 01* 3925.

2.3 high te-.r.ocrature : A temperature rcprcscncacive of a fully develped fire

according to tnu standard temperature time as specified in ISO 3313).

3. IE3T ?RI.NCI?L£

In a building fire, there will generally be an increase la pressure on the

exposed face of a door inducing smoltc to be transact tea from the high to the' low

pressure side of the ccor, Ac high temperatures, not only will there be an increase in pressure but a pressure gradient will ceveiop over the height of tee

door and the severity of the exposure conditions aay cause some doors to suffer

damage and distortion increasing the site of gaps through wnich smoke can pass.

The test procedure exposes a door to the heating conditions specified In tne

standard iire~cesistance test (ISO 33^) and simulates standard pressure

conditions, ftovisiun is made cor 'the collection and measurement of tne

rate of flow and temperature of hoc gases passing from the high to the low

pressure sice of the door.

ATPAiC\rJS

4.1 Furnace

Tl;c furnace snail be capable of subjecting one side of the specimen to the

heating ana pressure conditions specified in ISO 334.

Means shall ce provided for increasing ana .tiaincaining the pressure conditions

within the furnace to chose required by 7.3.2.

1 ) ISO 1804 doors terainoiogy.

2 ) ISO 32bi Fire tests, vocabulary.

3 ) ISO 834 Fire resistance tests - elements of building construction.

lo97v 3 A-4

73/ 1 1*,^:
iso/TC 92/wc 3 :i :oi

4 .2 Znclosura

The enclosure (see figures 1 and 2) shall conpcisc the foiiowingi )

a) A light rjecal frame shall be clad with chin oecal sheet (for example

approximately 1.3 mm thicx)

.

b) ;\11 faces of the enclosure shall have a non- ref lent ive black finish.

c) Gla;:cd Inspecciun panels shall be provided, as necessary.

d) Closable vents shall be provided in the top and bottom, naving an area

as large as is possible. If required, additional vents may be provided. 7ne

design of the vent shall not allow leakage under test conditions.

e) Handles shall be provided on the vent shutters together with a mechanism

CO enable simultaneous closing.

£} The overall dimensions shall be appropriate to allow it to be firmly

fixed to Che vail in which the door assembly is installed and to cocplotely

cover Che exposed face. The depth shall be between 6(J0 am ana 7 CO xm.

g) A circular opening, of diameter 300 + 5 am, shall be provided at

mid-height In die back face of the enclosure to which a shaft of

300 lU mm in length and circular* cross section shall be attached to

accommodate the thermocouple and anemometer.

h) A sheet metal radiation shield with reflective surfaces for the

protection of the .'incinomccer with a diameter 430 + IG xm shall be actachec

to the underside of the box witn straps at 230 ^ iO am from the back.

4 , 3 Method of attachment of enclosure to furnace surround

When a door is to be tested in a wall surround made of material containing free

moisture, the inside of the enclosure shall be sealed from the concrete surrounc

by aeans of copper foil (see figure 3) or by ocher accepcaole methods to prev-int

moisture from the concrete entering the enclosure. The foil shall be cementec at

the corners to eliminate air leaks.

The enclosure shall norraaiiyZ) 5© attached to the furnace surrouna by means

of thick sceoi angle sections as shown in figure 3. However, this does not

preclude Che use of other suitable methods if desired.

1 )Working drawings will be available from the secretariat of ISO/TC 92 at the

time of public.it ion.

2 )An alternative method of fixing may be necessary for testing double doors.

i o9 7v

4 A-5
ISO/TC 92 /WG 3 N

a . i Insc.r*^».or.c::cion

i.4.1 Therr.ocouple

A chermocoupia. shall be located in the axis of the taeasurin? shaft to measure. Che cenipcracure of the sasas anproaching che anemomecer. Additional

thermocouples may be used at other points la Che enclosure..

4 . A , 1 Hrussuro mcas»r*uo. couipncnc

The mea.surcments of pressu'^e to an accuracy of ^ L Pa shall be made ac a minir-:rr or three ixisitlons located along a verical nxi.s on one side of and close to

door as.sombly In line with the top and bottom edges of che door opening and at one third of cite height from the sill level (see ISO 3003, 7. 1).

4.4.3 Anemometer

A high cemnerature anemcmecer shall be fitted in a venturi tube as shown la

figure 1. Tals shall be capable of measuring gas flows from 20 n-^/h to

7 50 3^/h at temperatures up to 120 *C, and wlchia a velocity range or

0.2 a/s to 20 m/s.

5. PRE?Ail,\7I0N OF TEST SPECL'IENS

5 . 1 Construction-^ ^

The test sh.all be* perenened on a cociplece door assembly as intended to be uscc

in practice. Incorporating ail hard-ware and ocher equipment^K The finish

and fora of the specimen shall be represencacive of che finish and fora of the

door as InstalleU. in its intended position of use.

Tlic mounclnr, of the test s-pecimcn shall be represenen civc of its use in prnctiso

so chac appcopclace clearances exist between door and its frame.

When che specimen is tested in a surround^ ^ intended for the determination

of fire— resistance che requirements of ISO 3003, 5.2 shall also apply.

1 ) See ISO 3C08, page I, note 3.

1)

The performance of a door assembly is influenced by the mechanical features ;f

construction. The re.sults of a fire test riay not always be valid for a construction having overall dimensions larger or much smaller chon chose of zr.± test specimen (see 1)1* 5925: Parc 0).

3)

During the developncnt of che test Che specimens should be mounted in a concrete surrou.md other materials may be used provided chat adequate scalir.g :a."i dc ensured.

221b97v 5 A-6

/b/1
ISC/TC 92/ VC j N 20

j

5.2 Conciiiior.ir.-',

cpeciaens concaini.''.^ hydroscopic materials or ocher cuceriais which can be

affecccd by aoiscur? shall be condicioned co e-quilibriuc: v;ich che prevailing

condicions in die laboratory which snail be vichin che following liaacs:

cempecacure (dry bulb) 298 ^ 15 *K

rclacivc huinidicy ^0 “ co 65 Z

Doors or shuccers made cncirely of aec.ii or of mecal and glass do noc require

conaicloning

6. CALIBllATION

In phase one of the calibracicn, che gas flow race, (mJ/h) , ciirough the test

door assembly shall oe measured at amcienc temperature wnc.n a pressure

‘a^^ncial , aPoviPa), exists betw.2 -r. the test furnace ana the enclosure

(see figure 4), ~;e pressure ei: ferer.t lal oeeween tne enclosure anc tne test

laboratory snail be small when coaparea with aPo(ua). -ne flow race is

too s.Tiall, the door can be opened a little and if it is coo large, Che door can

be sealed with cape.

In phase two or che calibration, che mccsuremenc opening in the enclosure shall

be tightly seaiec. Tne pressure in the furnace siiali be increased and the

pressure dif f e rent t.ila between che furnace ana che enclosure, fi.l>i.(t^a), and

between che enclosure and Che test iaocacory, ip2(?a), shall be measured.

The tightness of che enclosure, K, shall be calculated from che formula

Q lPoi?2

where: Q gas flow race (m3/h)

and shall noc exceed the value of uiiity.

7 . .wROC'iDURii

7 . 1 Mounting and nro-vT ra to rv routine

7.1.1 For a full asscss.mcnt , tests si^all be performed on two spcci.Ticns oy

e.xposiiig opposing faces to die furnace; ciiis may be done simultaneously or separately, depending on the equipment avaiiablel).

1 ) To meet special circumstances or if

the lea*<.vige diroug.n tne door from one

ts liiuiy to be signif icancly nigner

may deciae to test a single asaemo-/

one direction only.

ddi o5 7v

it can be ascertainee by observation ..-.nc stce to the ocher from tne one dirsctirn

tnen from tne ctner, the testing auto.orif/

with the direction of air flow from ;r.*o

6 A-7

I'll \
»3C/iC 9 2/Vi'G 3 ZC-j

7.1.2 Prior Co ci.xinf; Che er.clocur®, Che door shall be ooened anc rloseb ac case cen cimes Co check Che adequacy ot che opening orr ari^e'nenc s . A door

equipped 'jicl' an aucomacic closing device shall be allowec cc close oy xec.-.s o: ch is dcv.ee ‘ ^

7.1.3 The enclosure sha 1 I be actnehed Co che furnace surround in accordance Ji:r;

4,3.

7.1.4 Tlie air leakage race of Che enclosure sIjjI! be decerxin-a according ro

c 1 ause 6

7 , 2 Tesc cundi cions

7.2.1 Tlic door shall be subjecced co che heacing condicions required by

ISO 3008.

7.2.2 A positive pressure gradienc shall be applied in accordance vich 130 3CC5,

buc shall be .idjusced so chac che pressure difference, in cne range cero co -1 ?s

exiscs ac Che boccom of che cesc specimen,

7 . 3 Ooeracing procedure

n»e CesC shall be scarced with che venCs open. After 4 min, che vents s.hal '. be

closed and cue pressure differencial regulated Co che specified value. A pence

of 1 ain shall Chen be allowed for condicions wichin cne enclosure co scsoilice

AC Clic end of this period, the following shall be recorded:

• a) Che pressure ac Cop and boctom of Che door;

b) che ceniperacure i.n cne enclosure;

c) che cenperacure of chc hoc gases within cne .'ne a s u r i .n g shaft;

d) chu flow race of che hoc gases.

The vencs shall be reopended and che procedure repeated ac i.ncervals of

S ainuces.

7.4 Tesc duration

The Cest shall be Cemunaced

a) when che specimen no longer -neecs Che criteria under uhicn c.he per formonci: is being judged; or

b) when the operacional li.-nics for Chc measuring system are exccedea 1 )

I ) This procedure is nor intended Co be a durabilicy '•esc repr esenc ing :ne -ear

and tear normally found in use.

•J “or che type of inscrumcnci usee in

jund ':o be JC > C.tmperaCure noc nec greaCer Chan 7^0 mj/h.

che deve I oomenc of chr C!sc :r. e greater cl’.an 313 or uc a f'.o- :•

::: o97-y 7 A-8
ISO/TC 9 2 /VC 3 .‘i :03

e) ac a time mucually agreed between the sponsor and Che testing laboratory

8. TEST RESULTS

The temperatures and tates of How of hoc gases Ca-^/h) aC time intervals as specified in 7.3 shall be rect'rded in tabular fcrai.

9. TEST REPORT

The test report shall include Che following information:

a ) name

b ) name

c) date

d ) name

of testing laboratory;

of sponsor;

of test;

of manufacturer and trade~name (if any) of product;

e) details of the construction, physical characteristics and conditioning

of Che specimen together with drawings; clearances and gaps between the

door and frame shall be fully recorded;

f) description of the test apparatus and if applicable Che direction of the

heating conditions with reference to the door or shutter assembly;

g) details of fixings of the specimen Co the surrounding wal I and of any

joints between Che door assembly and the surrounding wall;

U) the side of the door which was tested;

j) test results;

k) description of glazing, if any.

7.2109

8

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APPENDIX B

AN ESTIMATE OF THE RATE OF GAS OUTFLOW DUE TO

HEAT TRANSFER FROM THE DOOR SURFACE

Bl. THE MODEL

The purpose of this appendix is to present an estimate of the order of magnitude of

outflow that is to be anticipated solely as a result of heat transfer to and expansion of

enclosure gases. We assume that the door assembly is without any leakage paths. We assume further that the unexposed (to the furnace) door surface is of height H and width W.

The simplest possible model of the phenomenology under study is depicted in figure 20.

Here we have assumed that all significant heat transfer, Q, to the enclosure gases is from

the door surface. As a result of this energy input there is a net rate of expansion of

gases in the enclosure, and some of the enclosure gases are pushed out of the single

opening at a volumetric outflow rate, q, to be determined.

B2. THE RELATIONSHIP OF RATE OF OUTFLOW TO RATE OF HEAT TRANSFER

In reference [6] Zukowski has presented a result for heat addition to gases in a fixed volume enclosure with leaks. This is directly and generally applicable to our present model. Thus, assuming uniform exit gas (air) properties,

P q C T = Q (B-1)

e p e

where p^, T^, and are the density, absolute temperature and specific heat at constant

pressure, respectively, of the air which is actually exiting from the enclosure opening

(i.e., from the "leak").

With a determination of the heat transfer rate, the desired outflow rate is Immediately

at hand by using the above result.

B3. AN ESTIMATE FOR THE HEAT TRANSFER RATE

For the purpose of estimating the heat transfer rate we assume that the door surface

is at a uniform surface temperature, T^, which is reasonably constant during a given

closed vent phase of the test. We also assume that away from the door surface the temperature

of the gases ] (e.g. , T^ = T__,).of the gases in the enclosure, at a given instant of time is substantially uniform

end

The above assumptions and the outflow estimates to follow are very good all through

the test at early times following vent closure. In fact, at such times

B-1
where w 1 1 C 1. tr TA. , is the ambient (laboratory) temperature. At later times following vent closure

^

i o CIIW CAIUL/ j. t-ii A. v-4- u»i. ^ • / k «- A, u I- A u A.iU^o A A.T VCiiC I^XL^oLlLc: (e.g., at the approach of steady state), the uniform assumption may not be a particularly

good one. However, even then the results below will provide a reasonable estimate of the

order of magnitude of q.

With the above in mind we consider convective cooling of the door surface by means of

a buoyant, two dimensional, boundary layer which grows from zero thickness at the bottom

of door*. This boundary layer will be entirely laminar, (mostly) turbulent, or in a transitional state, along the height of the door depending on whether [12]

boundary layer and 6, v, u, and k are characteristic values for the coefficient of thermal

expansion, dynamic viscosity, viscosity, and thermal conductivity, respectively, of the

fluid -.n the boundary layer.

For air, the average Nusselt number for the entire range of Gr can be computed from

the air properties, 6, v, p, k, and C at the average boundary layer temperature

*Note that the effects of radiant heat transfer are not taken account of here. Radiant

transfer from the hot door surface to the facing vertical enclosure surface would tend

to maintain that latter surface at an elevated temperature. During the closed vent

phases under consideration this hot surface would transfer additional energy to the

I Insure gases thus yielding a net q which was larger than that to be computed.

Q

Gr Pr < 10 - laminar

8 10

10 < Gr Pr < 10 - transitional (B-2)

10^^ < Gr Pr - mostly turbulent

where

3 2 Gr = Grashoft number = g S (T -T )H /v

s g

Pr = Prandtl number = C y/k (=.72 for air)

P

[ 12 ]

Nu = h H/k

ave ave

0.511 Gr^^^; Gr < 4.2 (10^)

,0.0184 Gr^^^; 4.2 (10^) < Gr

(B-3)

where h is the average heat transfer coefficient. In the above we will evaluate all ave

B-2
Using the above results we can now compute the total heat transfer rate from

Q

= HWh

ave

(T - T J = Wk (T - T ,) Nu

s end 8 end ave

where Nu is computed from eq. (B-3)

ave

B4. THE RATE OF OUTFLOW

(B-4)

Using eqs. (B-1) and (B-4) we obtain our desired result

q

= Wk(T -

s Tend,)/(p endT end

= W V 6(T - T ,)Nu 1.11

s end ave

(B-5)

In order to get actual estimates on q for our problem we have used this equation to

estimate q as a function of T -T , for a door of dimension H x W = 2 meters x 1 meter and

s end

for the two values 20°C, and 100°C. These results are presented in figure 12.

B-3
NBS-114A (REV. 9-78)

U.S. DEPT. OF COMM. 1. PUBLICATION OR REPORT NO. BIBLIOGRAPHIC DATA NBSIR 80-2004

SHEET

4. TITLE AND SUBTITLE

THE MEASUREMENT OF THE SMOKE LEAKAGE OF DOOR

ASSEMBLIES DURING STANDARD FIRE EXPOSURES

7. AUTHOR(S)

Leonard 'i

.

Cooper

9. PERFORMING ORGANIZATION NAME AND ADDRESS

NA-^iONAL BUREAU OF STANDARDS

P';PARTMENT OF COMMERCE

(•WASHINGTON, DC 20234

12. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS fStreef. city, stste, ziP)

Prepared for;

The Occupational Safety and Health Administration (OSHA)

U.S. Department of Labor

Washington, D.C. 20210

15. SUPPLEMENTARY NOTES

I I Document describes a computer program; SF-185, FIPS Software Summary, is attached.

16. ABSTRACT (A 300-word or less factual summary of moat aighificant Information. If document includes a significant bibliography or

literature surrey, mention it here.)

A basis for relating overall Intrabulldlng smoke migration dynamics

to high temperature, door assembly smoke leakage measurements is formulated. The results of applying the tentative, high temperature,

ISO test method DP 5925 Part 3, which was developed to measure smoke

leakage of door assemblies during the course of a standard fire endurance

test, are reported. A critical analysis reveals that the basic objective

of the method is limited in its utility in the sense that fire scenarios

in high-rise buildings may not be adequately simulated. Consistent with

the above-mentioned experimental results, troublesome theoretical problems

with the test method and its procedures are identified. These lead to a conclusion that the test method as written is generally unreliable. An alternate test concept which removes the above-mentioned DP 5925 Part 3 limitation and all of its problems is described and its development is

advocated.

17. KEY WORDS to twelve entries; alphabetical order; capitalize only the first letter of the first key word unless a proper name;

separalad by semicolons)

Building fires; compartment fires; doors; egress; fire tests; high-rise buildings; leakage; life safety; smoke; smoke movement; stack

effects; test methods.

II. AVAILABILITY [ '^Unlimited

I I For Official Distnbution. Do Not Release to NTIS

Order From Sup. of Doc., U.S. Government Printing Office, Washington, DC

20402, SD Stock No. SN003-OO3- X ' From National Technical Information Service (NTIS), Springfield, 22161

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(THIS REPORT)

UNCLASSIFIED

20. SECURITY CLASS

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