NBSIR 77-1313

An Assessment of the Technical

Literature on Emergency Egress

from Buildings

Fred I. Stahl

John Archea

Center for Building Technology

Institute for Applied Technology

National Bureau of Standards

Washington, D C. 20234

October 1 977

Prepared for the Center for Fire Research, in support of: OSHA-NBS Emergency Escape Requirements Project

Sponsored by:

Occupational Safety and Health Administration

U.S. Department of Labor

Washington, D.C. 20210

and

HEW-NBS Fire/Life Safety Program

Sponsored by:

U.S. Public Health Service

Department of Health, Education and Welfare

Washington, D.C. 20203

NBSIR 77-1313

AN ASSESSMENT OF THE TECHNICAL

LITERATURE ON EMERGENCY EGRESS

FROM BUILDINGS

Fred I. Stahl

John Archea

Architectural Research Section

Center for Building Technology

Institute for Applied Technology

National Bureau of Standards

Washington, D C 20234

October 1977

Prepared for the Center for Fire Research, in support of: OSHA-NBS Emergency Escape Requirements

Project, Sponsored by:

Occupational Safety and Health

Administration

U S. Department of Labor

Washington, D C. 20210

HEW-NBS Fire/Life Safety

Program, Sponsored by:

U.S. Public Health Service

Department of Health, Education

and Welfare

Washington, D.C. 20203

U.S. DEPARTMENT OF COMMERCE, Juanita M. Kreps, Secretary

Dr. Sidney Harman, Under Secretary

Jordan J. Baruch, Assistant Secretary for Science and Technology

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Acting Director
CONTENTS

CONTENTS ii

LIST OF FIGURES iii

LIST OF TABLES iv

ACKNOWLEDGEMENTS v

EXECUTIVE SUMMARY vi

1. INTRODUCTION 1

1 . 1 Purpose 1 1.2 Significance, and Specific Objectives of the Study 1

1 . 3 Scope 2 1.4 General Problem and Overview. 2

2. METHOD OF STUDY 7 2 . 1 Approach 7 2 . 2 Procedure . 7

3. THE EMERGENCY EGRESS TECHNICAL LITERATURE 10

3.1 Historical Development of Emergency Egress Literature 10

3.2 Evaluation of the Empirical Research Base: Investigations

of "Carrying Capacity", Based on Physical-Science Models 10

3.3 Investigations of "Carrying Capacity" Which Question

of the Physical-Model Foundation 18

3.4 Investigations of Egress Signage, Emergency Lighting,

and Visibility through Smoke 21

3.5 Investigations of Occupants' Responses to Actual

Fire Emergencies 24

3.6 Summary 28

4. ANALYTICAL ASSESSMENT OF THE EMERGENCY EGRESS TECHNICAL

LITERATURE 30

4.1 Field Based Quasi-Experimental Designs 30

4.2 Laboratory-Experimental Designs 33

4.3 Post-Hoc Survey Research Designs 35

5. SUMMARY OF RECOMMENDATIONS 40

5.1 Recommendations Concerning the Technical Adequacy

of the Available Empirical Literature 40

5.2 Recommendations Concerning Specific Applications

of the Available Technical Literature... 42

5.3 Recommendations Concerning General Directions

and Methodological Requirements for Future Research 43

5.4 Conclusions 45

FOOTNOTES 46

EMERGENCY EGRESS BIBLIOGRAPHY 47

FIGURES 54

TABLES..... 57

ii
LIST OF FIGURES

Figure 1. "Geneology" of Emergency Egress Research 54

Figure 2. Analytical Assessment Matrix 55

Figure 3. Theoretical Distribution of Fire-outcomes, for a Given Occupancy 56

iii
I

Table 1

i

LIST OF TABLES

Egress Research and the OSHA Regulations:

Exemplary Issues.... 57

IV
ACKNOWLEDGEMENTS

The NBS-OSHA Emergency Escape Requirements Project is directed at

identifying the data base, assessing the capabilities of selected elements,

and providing the technical basis of hazard assessment as each relates to

emergency escape from the workplace. The HEW-NBS Life/Fire Safety Program

involves a series of interrelated projects in the areas of decision analysis,

fire and smoke detection, smoke movement and control, automatic extinguishment, and the behavior of institutionalized populations in fire situations.

This project, an important part of the overall Emergency Escape Requirements

Project, was conducted within the Architectural Research Section of the

Center for Building Technology, IAT, National Bureau of Standards.

The authors* extend their thanks to Dr. Robert Wehrli, former Chief

of the Architectural Research Section, for his editorial recommendations

on the manuscript. Dr. Bernard Levin and Mr. Harold Nelson of the Program

for Design Concepts, Center for Fire Research, NBS, are also acknowledged

for their editorial assistance. Mrs. Candace Roat, formerly of the Architectural Research Section is gratefully acknowledged for her special editorial

contributions. Finally, the authors thank Miss Cheryl Talley and Miss Terry

Ahalt for typing various versions of the manuscript, under the pressures

of a very heavy workload.

*John Archea is currently Associate Professor of Architecture, College of

Architecture, Georgia Institute of Technology, Atlanta, Georgia 30032

v
EXECUTIVE SUMMARY

A technical assessment was made of the literature on research, and

the data base related to current emergency egress regulations promulgated

by the Occupational Safety and Health Administration (OSHA). The purposes

of this assessment were to ascertain the extent to which these regulations

were based upon empirical research, and to determine the adequacy of available

research findings from which OSHA emergency egress regulations may be developed.

Three distinct areas of research on emergency egress were identified:

(1) research on the carrying capacity of exitways, (2) research on signage,

lighting, and visibility through smoke, and (3) research on occupant responses

to, and experiences in building fire emergencies.

Only research on the carrying capacity of exitways appears to have had

direct impact on current OSHA regulations, which are based largely on empirical

findings reported in 1935. These findings are currently under challenge by

J.L. Pauls, of the National Research Council of Canada. Pauls found that, during

fire drills in high-rise office buildings, the flow capacities and discharge

rates of stairs and exit doors were significantly lower than statistics

reported earlier, and assumed by current regulatory authorities. Aside from

the usual discrepencies among available research data, however, the scientific

merits of this data base remains an open question. Moreover, no single approach

to the study of carrying capacity seems sufficiently comprehensive to account for

the egress problem taken as a whole. Where various methodological shortcomings

of the original carrying capacity research are taken into account, this portion

of the egress data base may be appropriately applied to design problems in

which direct, immediate, and well-staged exiting behavior can be anticipated.

Much of the available data on egress signage, lighting, and visibility

through smoke has appeared since the adoption of standards by OSHA, and

consequently this area of research has had minimal impact on OSHA egress

regulations. Although most of this research has involved well controlled

laboratory experimentation, this portion of the data base suffers problems

which arise whenever we try to generalize from controlled laboratory experiments

to actual fire environments and experiences.

Recent post-incident studies of occupants responses in real fire situations

have appeared after the adoption of emergency egress standards by OSHA. At

present, this portion of the literature seems the most limited in its applicability

to design or regulation. This is due to the general failure of investigators

to consider the role of building layout and exit arrangement in their research.

However, the importance of these studies lies in their delineation of emergency

egress scenarios, their identification of response patterns, and their exposure

of frequencies with which such patterns have actually occurred during building

fires. Explication of these issues is believed essential to any future program

of regulatory development in the emergency egress area.

vi
On the basis of the technical literature assessment, the following categories

of research are recommended for intensive investigation:

(1) Research on access to exitways;

(2) Resolution of the discrepencies between findings by Pauls and other

investigators of the carrying capacity of exitways;

(3) Continued research on egress signage, lighting, and visibility through

smoke (e.g., the work at the Center for Building Technology, IAT,

National Bureau of Standards, which is currently under the sponsorship

of OSHA); and

(4) Definitive identification and description of emergency egress scenarios

and response patterns.

Specific recommendations concerning research strategy and technique are also offered.

VI 1

1. INTRODUCTION

1 . 1 Purpose

The overall purpose of the investigation was to carry out an in-depth literature study, leading to an assessment of the data base

underlying current standards for emergency egress facilities in occu- pancies regulated by the Occupational Safety and Health Administration

(OSHA)

.

The present report represents a critical assessment of the technical

literature pertaining to emergency egress. As only small portions

of this literature have been specifically applied within the regulatory

process, the review should not be construed as an evaluation of current

regulatory policy.

1 . 2 Significance, and Specific Objectives of the Study

1.2.1 Significance

The method of generating standards and including them in legislation

or regulation is complex, subject to wide variation, and at times quite

controversial. A major element in the development of standards, and in

the adoption and implementation of building regulations, lies in the breadth

and depth of research data available to support the reasonableness of the

standards. It is not always feasible for regulatory agencies to support

design standards through reference to research. The inability to argue

the efficacy of regulatory standards on the basis of relatively unbiased

technical support has, moreover, added tc the difficulty inherent in enforcement. It is believed that this problem can be mitigated through the accumulation

of a well-founded base of technical literature.

This report provides an assessment of the supporting technical base

for emergency egress regulation provisions in current building codes. This

assessment is intended to aid regulatory officials in judging the credibility

of currently promulgated codes, and to guide development of research programs

leading to any needed changes in standards that would be more effective

in actual conditions.

1.2.2

Specific Objectives

The following objectives guided the conduct of the study:

(a) to identify the technical literature relevant to emergency

egress from buildings housing work environments;

(b) to evaluate the validity and usefulness of the available

technical research as a supportive basis for building regulation;

(c) to identify key knowledge gaps concerning emergency escape, and

to recommend useful avenues for futher research.

1
1 . 3 Scope

The specific focus of the technical literature study was on emergency

escape arrangements for individual workers or groups of workers.

Investigations of egress width, flow rates, travel distance, and the

physiological and psychological capabilities of humans under deteriorated

environmental conditions were taken into account.

1 . 4 General Problem and Overview

1.4.1 The Occupational Safety and Health Act: Purposes and Mechanisms

The fundamental intent of the Occupational Safety and Health Act

of 1970 (1)* is to insure safe and healthful working conditions for men

and women, through the development, promulgation, and enforcement of

reasonable standards. The Act specifically directs the Secretary

of Labor to "promulgate as an occupational safety or health standard

any national consensus standard, and any established Federal Standard

unless he determines that the promulgation of such a standard would not

result in improved safety or health for specifically designated employees" (2).

Toward the achievement of these ends, the Act specifically provides

for the conduct of research relating to occupational safety and health.

This includes the study of toxic and harmful environmental agents, and

of pertinent psychological factors, for the purpose of establishing bases

for the adoption and enforcement of regulations.

1.4.2 State-of-the-art of Egress Research

Throughout this century, investigators seeking to gather data

relevant to the problem of emergency exiting from buildings have relied

upon conventional research techniques. For example, the early NFPA and

NBS studies of crowd-flow in various occupancies utilized the basic

technique of counting numbers of persons passing by a fixed point

in space during an arbitrarily defined time unit. The primary intention

of the early investigators was to measure the "carrying capacity" of

egress route components (corridors, doors, stairs) of various dimensions

and designs. Occupants were studied during periods of normal building

usage, while they were clearly in no danger. However, research findings

have been assumed to generalize to cases of emergency egress, for the

purpose of developing or evaluating life safety standards.

The same general approach to egress research continued into the

1930's most notably by K. Togawa (1955) in Japan (who developed elaborate

mathematical models of building egress from his data). Even by the

1970's, studies of egress carrying capacity, based on the traditional

assumptions, were in progress. Examples of the most recent work

include research by I. Peschl (1971), J.J. Fruin (1971), and S.J. Melinek

and S. Booth (1975).

*Footnotes appear at the end of the paper.

2
It is important to note, however, that not all investigators concerned

with the measurement of carrying capacities found results compatible with

current building regulations. J.L. Pauls (1975), for example, demonstrated

that the true carrying capacity of stairways may be substantially smaller than

that generally assumed by code writing bodies. Observing high-rise building

occupants on stairs during fire drills, Pauls noticed a swaying motion

and a staggered distribution of persons on the stair treads. Such

evidence called into question the traditional practice of assessing

stair adequacy on the basis of the 22-inch linear file, and the related

assumption that on stairs, persons can be expected to walk two abreast.

Through the same series of drill investigations, moreover, Pauls suggested

that total evacuation time for tall buildings may be erroneously estimated

if one merely employs mathematical models of the type developed earlier

by Togawa. According to Pauls, egress management and staging may be

as important as the provisions of adequately sized corridors, doors, and

stairs for the evacuation of critical areas, although the former

are not presently specified in building codes and standards.

A second category of empirical research includes work in issues

directly relating to emergency egress, though outside the context of

buildings. Experiments on egress route signage and emergency lighting have

been conducted by the U.S. Navy. These studies focused on the problem

of fires and other emergencies on board aircraft carriers and other

large vessels. Additional research has been under way at the Federal

Aviation Administration's Office of Aviation Medicine. This experimental

work has emphasized the study of exit sign and marker visibility through

smoke, and the effects of brightness and contrast on sign perception.

Finally, a small number of researchers have departed substantially

from the experimental and quasi-experimental approaches discussed above

and have relied instead upon social-survey techniques. Their

principal concern has been to gather useful data on occupants' experiences

during actual fires, and to cover not just egress movement, but a more

general and broader range of behaviors. The first comprehensive

investigation of this type was conducted in 1972 by P.G. Wood in

the United Kingdom, who interviewed victims from more than 1,000

incidents (mostly residential fires). Modeling his study after Wood's,

J.L. Bryan (1976) also interviewed victims of residential fires, in the

Washington, D.C., vicinity. A major objective of both researchers was

the reconstruction of actual behavioral sequences, reported to have

transpired during fires. Along similar lines, the National Bureau of

Standards has undertaken a sociological investigation of fires in

several nursing homes (G.M. Haber, in progress). Emphasis is focused

on understanding participants' feelings about, and emotional responses

toward, their fire experiences.

In summary, several general observations on the state-of-the-art

of egress research can be made:

(a) Three distinct areas of research on fire egress have been

undertaken. These are:

(1) studies of carrying capacities within protected exitways;

(2) studies of signage, lighting and visibility under fire

conditions; and fire emergencies.

3
(3) studies of occupant responses to, and experiences in,

fire emergencies.

(b) Investigations which yielded numerical data on exiting capacity

were conducted either under ideal laboratory-like conditions,

or in real buildings during periods of normal occupancy. In

such studies, subjects were not under any threat of injury or death, and didn t believe they were. Findings from such

investigations, have often been, however, assumed to generalize

to egress during real emergencies.

(c) Most investigations of egress capacity report similar trends,

although interpretations appear to vary somewhat widely.

(d) Investigations of egress facility capacity emphasized the

"safe end" of the evacuation system (i.e., fire resistive

corridor and fire stair design), while ignoring the "threatened

end" (spaces on buildings' floors where life-threatened stimuli

are likely to be first experienced, and where information is

likely to be most ambiguous).

(e) Social survey research in which fire victims were interviewed

has not emphasized issues peculiar to the design of exits.

Rather, the reconstruction of social and behavioral action

systems has been stressed.

(f) In general, empirical research on emergency egress has considered

various narrowly defined aspects of the problem. For instance,

those investigators concerned with the carrying capacity of

stairs or doorways usually ignored psycho-social factors.

Similarly, those who questioned victims about their response

patterns generally failed to correlate these findings with

meaningful measures of the threat-laden environment.

1.4.3 Emergency Egress Scenarios

A variety of diverse emergency egress behavior patterns may occur

in such large-scale work environments as department stores, plants,

or multi-story office buildings. In many instances, such facilities

consist of complex arrangements of functional spaces and circulation

ways, and are designed with varying degrees of fire or smoke retarding

compar Imentation . In other cases, entire floors may be open, and may be

separated from each other by fire-resistive construction. As a result

of such spatial organization, fire products often never spread beyond

resistive barriers (where these are provided), before they are extinguished.

It is rare that an entire facility would become engulfed by flames or smoke. Even where this might occur however (as in the tragic office

tower fires in Brazil, or in the recent Beverly Hills nightclub disaster

in Kentucky), environmental conditions will deteriorate progressively,

and some spaces within the building will remain minimally affected

longer than will others.

Empirical research on human behavior in fires has only begun

to explicate the relationship between occupants' egress patterns and

specific degrees of exposure to a life-threat. For the purposes of our discussion, however, it seems reasonable and appropriate to assume

that a person's actions in time of fire will depend upon the quality of

the emergency experience.

4
For example, occupants located far from the involved zone may take

no emergency actions at all, if they receive no information indicating

the existence of danger, or if they perceive their situation to be safe.

Other individuals, though not actually in the hazardous zone, may have

received specific information about the fire's location and intensity, as well as instructions on what to do or where to go. Many of these persons

are likely to proceed directly from their work stations to protected

exit ways, refuges, or to the outdoors. Others may be less immediate

in their escape actions, and may gather belongings, assist or alert

other occupants, etc.

There may be other situations, however, in which emergency egress

behavior is even less likely to be deliberate, immediate, or adaptive.

Persons in the building, remote from the involved areas, may receive

ambiguous information about the status of the fire and of their own relative

safety. Similarly, individuals may be misinformed as to the facts about

fire and smoke migration, or as to the life-protecting capabilities of

fire-resistive building construction. Such factors may contribute to an inaccurate perception of danger, or to a false sense of security. These

may in turn delay emergency evacuation activities, or evoke non-adaptive

or misguided emergency behavioral patterns.

Finally, a person may respond even to the most unambiguous life

threat on the basis of incorrect information or training, and habit.

A case in point is the direct, unimpeded movement of persons from work

stations to elevators (the egress route with which they are probably

most familiar), rather than to the specifically designated and protected

fire stairs.

1.4.4 Emergency Egr ess Response: Generic Patterns, and their Support

in the Technical Literature

The foregoing scenarios illustrate several factors which we may

presume influence the quality of an individual's emergency egress

response. These factors include: (a) accuracy of threat perception;

(b) quality of cues and quantity of information about the life-threatening

environment; (c) familiarity with building layout; (d) familiarity with

emergency procedures and egress routes; (e) immediacy and purposefulness

of the egress response; and ( f) location within the building. On the

basis of these factors, we may derive a set of generic emergency egress

responses. These include:

(1) direct egress behavior on a building floor, along an appropriate

route ;

(2) direct egress behavior in a fire stair or other protected exitway;

(3) direct egress behavior along an inappropriate route (e.g., path

leading toward an elevator rather than a stair);

(4) indecisive egress behavior (e.g., non-adaptive or indiscriminate

route-shifting during evacuation);

5
(5) indecisive pre-egress behavior (e.g., investigation);

(6) delayed egress behavior (due to e.g., warning or assisting

others, or collecting personal articles prior to actual

egress movement);

(7) re-entry behavior (after having left the threatened zone).

Emergency egress behaviors and scenarios of the kind described

above are quite likely to occur during the various stages of a building

fires in an occupational occupancy. Important questions, then, concern

not only the quality of the emergency egress data base, but also the

degree to which empirical research has specifically explicated each

generic response category. We noted earlier that three distinct foci were found in the empirical literature on egress. But to what extent

has this expansive data base actually addressed the unique problems

peculiar to various emergency egress scenarios?

1.4.5 Problem Summary

Briefly stated, then, the problem in this report was to determine

the extend to which the available technical literature on emergency

egress is capable of supporting design standards promulgated by OSHA.

6
2. METHOD OF STUDY

2 . 1 Approach

This report's technical literature evaluation was organized about two

distinct phase:

(a) a "descriptive" phase, and

(b) a "critical" phase.

In the descriptive phase, items were abstracted and the authors' hypotheses,

findings, inferences and recommendations were taken at face value. Our

results are documented in Chapter 3. The critical phase provided an opportunity to delve analytically into each item. Here, the usefulness

of the research to the egress state-of-art , and to the concerns of OSHA,

was assessed, as was the validity of research findings, and the appropriateness

of research methods. Moreover, an attempt was made to evaluate specific

inferences drawn by the investigators. This assessment is detailed in

Chapter 4.

Finally, principal content areas within the literature were assessed

to determine their contribution to the explication of specific emergency

egress scenarios. Appropriate recommendations concerning the applicability of various segments of the technical literature are offered in

Chapter 5

2 .2 Procedure

2.2.1 The Literature Search

An effort was made to cover a wide spectrum of materials dealing

with the problem of emergency egress from buildings. After a cursory

inventory, it was decided not to limit the review to materials specifically

involving OSHA-regulated facility types. The decision to approach the

egress literature more broadly was based on the considerations that:

(a) the egress literature itself is not neatly partitioned in terms

of building types or hazard classifications, and

(b) the Life Safety Code, from which OSHA's exiting regulations were adopted, carried implications for virtually all building types

in common use. Moreover, the broader search strategy permitted

the inclusion of salient research lying outside the general

building literature. Studies conducted by the U. S. Navy, and

by the Federal Aviation Administration are chief examples.

Literature identified as appropriate to the objectives of the study

generally clustered into four distinct categories, including:

(a) materials which specifically report empirical data on exiting

behavior, carrying capacities of pedestrian ways, or the attitudes

and beliefs of fire victims;

7
(b) background or supporting materials from cognate areas, particularly

the behavioral sciences, which assist in the interpretation and

evaluation of the available empirical evidence;

(c) materials which suggest or illustrate the shortcomings or assets

of current regulations, either by reference to case studies or design solutions, and not on the basis of empirical data;

(d) materials which illuminate the process through which research

findings are incorporated into building regulations.

2.2.2 Criteria for Evaluation

The critical phase of the technical literature review was accomplished

by evaluating each item against various issues:

The relevance of findings or conclusions to the egress state-of-art

,

and to the concerns of OSHA, was first considered. Of principal interest

was whether the material had potential value in improving our understanding

of the emergency egress problem. In addition, the degree to which authors'

conclusions were cast in language compatible with the writing of regulatory

statements, was assessed.

Increasingly, research on emergency egress has raised questions concerning

the reasonableness of assumptions which underlie life-safety regulations. Of

special interest, then was the identification of assumptions implicit in example:

of such research. This process focused upon investigators' conceptualization

of research problems, wherein assumptions about the relevance of variables,

or about systemic interrelationships among certain factors, frequently

operate. It was often found that such assumptions were either ignored (or

at least omitted from authors' reports), or else inadequately considered in

the development of research strategies.

When commenting upon their data, researchers often drew inferences con- cerning safety policy, building design, or regulations. In many cases,

however, authors attempted to generalize their findings to real-world contexts

not adequately simulated by their investigations. Examples include inferences

about corridor width and staircase adequacy during fire emergencies, drawn

solely on the basis of data gathered during periods of normal occupancy.

The rese arch design itself was also evaluated, in order to determine

the validity of findings , and the extent to which authors' conclusions were

just i f ied

.

Other aspects of the critical evaluation involved tracing the degree

of corroboration among investigators , and comparing research findings with

current design practice .

Finally, an attempt was made to assess the value added by specific

investigations to the emergency egress literature. Occasionally, for example,

items were found which provided the only known data base for an issue. A

8
case in point is the work of Johnson and Jones (1976), who provided data on

the manuever ability of stretchers through corridors, around corners, and

through elevator doors. In other examples, investigators employed new methods

of gathering data. Pauls, for instance, replaced earlier methods of headcounting during normal occupancy periods with video recording and motion

picture filming during evacuation drills. The tapes and films could then be

replayed later in the laboratory, as many times as necessary. Still others

contributed theoretical schemes useful in conceptualizing the egress problem

(e.g., Henderson, and Breaux, et al . )

9
3. THE EMERGENCY EGRESS TECHNICAL LITERATURE

3 . 1 Historical Development of Emergency Egress Literature

In addition to abstracting materials during the "descriptive" phase

of the review, the principal sources cited by investigators were recorded.

This permitted tracing the history of research methods and approaches to

the egress problem. Figure 1 illustrates the results of this exercise.

Several key points are suggested by the geneological analysis. The

first is the lack of empirical research input into egress code development

after 1935, when the NBS conducted its studies on the carrying capacity

of exiting facilities. NPFA-101, and consequently OSHA's exiting standards,

have not taken advantage of investigations conducted any more recently.

The geneological analysis also demonstrates that by the 1970's, two

distinct schools of egress research had emerged:

(a) the "carrying capacity" school represents those investigators

who emphasize the importance of providing properly designed

exit facilities in adequate numbers. Their research has

generally involved the measurement of flow rates through

various pedestrian ways in buildings.

(b) the "human response" school recognizes that the provision of

properly designed and located exiting facilities is a necessary,

but not sufficient, condition for the assurance of life-safety

from fire. Studies by these investigators have stressed the

need to model human spatial movement patterns and decisionmaking behavior, in an emergency situation which often provides

highly ambiguous perceptual cues.

The dichotomy seems amply supported by our historical analysis, which

also revealed a critical lack of c ross- fer t il iza tion between the two

schools

.

Our analysis further suggested that Pauls' work may have bridged

across the two schools through research concerned with both carrying

capacity and human response. Pauls, as was mentioned earlier, measured

flow capacities and evacuation time during fire drills in tall buildings.

Moreover, his interpretation of findings reflected a concern to relate

physical design parameters with the psycho-social phenomena believed to

operate during building emergencies. Melinek and Booth cited Pauls'

work for its value in carrying capacity measurement; Canter, et al .

,

valued its implications for understanding behavioral processes (human

response) during building fires.

3 . 2 Evaluation of the Empirical Research Base: Investigations of "Carrying

Capacity", Based on Physical-Science Models

As suggested elsewhere above, it may be useful to think of the

empirical research on exit carrying capacity as representing two viewpoints.

These are:

10
(a) The acceptance of a physical-science model (e.g., the "hydraulic"

model) as an explanation of human movement in buildings. Such

acceptance may be either implicit or explicit.

(b) A re jection of the physical model as sufficient (either by

itself, or in its traditional form) for the conceptualization

of egress behavior.

The former view shall be considered first, by presenting in detail

investigators' objectives, methods, findings and conclusions.

In general, it was found that the carrying capacity research focused

on the measurement of flow velocities and rates in buildings of various

types, as well as in stadia and train stations. Two overall objectives

included the construction of predictive models of building egress, and

the establishment (or evaluation and acceptance) of egress facility

design standards. Accordingly, researchers concentrated on the various

components of egress routes, and evaluated differences in flow characteristics

between level versus inclined paths (stairs, ramps), along corridors

versus through doors, upward versus downward travel on stairs, etc.

Consider the following investigations:

3.2. 1 NFPA (pre-1920 )

During the immediate pre-1920 period, the NFPA's Committee on Safety to Life was organized (see NFPA, 1917). In response to several

disasterous fire incidents, in which the deaths of large numbers of

persons were attributed to inadequate exit design, the Committee was charged with the task of developing recommendations for the number of

occupants permitted on the floors of buildings. The earliest deliberations

focused on the exiting problem in factory buildings, and attempts were made to account for construction type, hazard category, maximum allowable

escape time, and stair capacity.

It should be noted that the Committee did not, itself, conduct

empirical research, per se; but it was apparently the first professional

body to organize specifically for the purpose of systematically evaluating

anecdotal accounts of emergency egress activities, in relation to informal

studies which were being conducted at the time in various occupancies.

It should be further noted that the Committee's work came in the wake of

the Nation's earliest legislation specifically devoted to life-safety

from fire in buildings: the New York State Factory Laws (1914), and the

Wisconsin Building Code (1914).

Although NFPA's initial involvement in life-safety design regulation

included neither the conduct of specific empirical investigations, nor

the development of a comprehensive research program, its inclusion here

seems justified for two reasons. First, the early meetings of the

Committee on Safety to Life appear to have formally adopted a physicalscience approach to building egress in which building occupants, like

11
water, gas particles or ball bearings, were assumed to respond immediately,

and to be effected only by spatial configuration and density, during the

actual evacuation process. Moreover, since interpersonal influences on

an occupant's behavior, and the influence of affective responses to emergency cognition in humane were ignored, the philosophy further

legitimized consideration only of the "safe end" of the fire event

(i.e., the specially protected segments of evacuation routes).

Second, by legitimising its conceptualization of the emergency

egress problem in relatively specific terms, the Committee set the stage

for future research on all aspects of life-safety in buildings. That

this has indeed been the case is amply born out by other research reviewed

in this section of the current report.

Several conclusions relative to the pre~1920 egress state-of-art

resulted from the early Committee deliberations, and have been critical

to the formulation of the present day posture toward exiting regulation

and research. These include the notions that:

(a) for non-fire resistive buildings without horizontal exits, only

so many persons shall be permitted to occupy any floor as can

find refuge within stair enclosures;

(b) for fire-resistive buildings, the number of persons allowed

per floor may be in excess of stair capacity;

(c) maximum escape time may be assumed to be a function of the

number of persons passing out of the exit door, as follows:

ET^ = 4/3 [# of persons/ 2 2" unit*]

+ [time required to get to stairs, in seconds]

* above the first floor

(d) a useful guideline for stair design is to assume an average flow

rate of 45 persons/minute/22" width unit (1.35 persons/sec/m)

.

3.2.2 NBS ( 1935)

The principal objectives of the 1935 exit review conducted at the

National Bureau of Standards were to study exit requirements, develop

code provisions, and gather facts about exit conditions found in actual

buildings. The resulting comprehensive assessment was a direct outgrowth

from the foundation laid earlier by the NFPA, with the NBS effort attempting

to validate the original recommendations, and to expand egress research

beyond the domains of factories and schools.

The NBS effort primarily involved of two types of investigation:

First, a field study was conducted in a wide variety of occupancies in

12
an effort to record exit conditions actually found, and to measure flow

rates through doors, corridors, and on stairs. Measurements were made

under non-emergency conditions, during periods of normal occupancy. The

field study yielded the following results:

(a) detailed exit conditions, and dimensions in examples of the

occupancies surveyed were reported;

(b) discharge rates (as measured at doors, and at arbitrarily

selected points along stairs and corridors during periods of

normal occupancy) were found to vary somewhat across occupancies;

(c) discharge from ramps was found to be faster than from stairs;

(d) the rate of discharge was found to be relatively high in narrow passages as compared to wide ones;

(e) discharge rates were also found to vary as a function of story

height, riser-to-tread ratio, and the walking habits of occupants.

Second, an opinion survey was undertaken. This involved the distribution of questionnaires to building professionals, and a content analysis

of relevant articles in architectural magazines. The general objective

of the opinion survey was to assess design professionals' feelings about

the severity of fire safety regulations. It was found, almost without

exception, that architects considered the egress regulations of the time

to be much too severe and restrictive. When explaining their opinions,

many architects mentioned their belief that building regulations were

too arbitrary, and not based upon sound scientific evidence.

The general recommendations of the NBS report reaffirmed, and implied concurrence with, the building regulations promulgated earlier by the NFPA.

and 60 persons/min/22 inch exit unit (1.35 and 1.79 persons/sec/m) down stairs

and through doorways, respectively. Moreover, the general applicability of

these regulations to a wide variety of occupancies was implied.

3.2.3 K. Togawa (1955 )

The seminal work of Togawa in Japan is the most detailed and comprehensive

analysis of egress carrying capacity based on a physical-science model.

Togawa' s objective was to survey walking velocities and flow rates on stairs, through doors, and along corridors in department stores, apartment

houses, theaters, museums, hotels and commuter train stations.

Togawa conducted field studies at the various sites, observing inhabitants during periods of normal occupancy. Both individual and group movement

patterns were observed to measure the number of people passing between two

arbitrarily fixed points in space, as well as the time required for travel

between the two points. Major findings included the following:

13
(a) Flow rates often varied as a function of occupancy; but such

other factors as t irne of day, the age and sex of occupants, and

the type of footwear worn, appeared to have little meaningful

influence

.

(b) For individuals walking on stairs, stair width was found to be

an ineffective measure of flow rate. However, the tread-depth

dimension appeared to be most critical, and the individual's

pace was the only effective measure.

(c) For group movement on stairs: (1) travel time was found to be

an inverse function of staircase angle and story height; (2)

travel velocity was generally estimated to be 0.5 m/sec;

(3) walking time up or down stairs was estimated at "4H"

[i.e., 4 x (story height), in seconds]; and (4) flow rates

were approximately 1.5 persons/ sec/m through doorways, and 1.3

persons/sec/m on stairs.

Togawa derived predictive equations from the field data he gathered,

and demonstrated for a commuter rail station during rush-hours that his

mathematical model could estimate actual egress times.

Finally, Togawa was the first to describe "arch formation", the

process by which a large group gathered at a doorway begins to admit

persons through the opening,.

3.2.4 J.J. Fruin (1971 )

The above paragraphs maintain that a small number of studies,

particularly those by the KBS in 1935, and by Togawa in 1955, were influential in establishing an attitude toward research on egress. This

attitude influenced Fruin, who studied pedestrian movement on stairs,

along corridors, and through doors. His specific goals were the measurement

of pedestrian volume (i.e., density), walking velocity and flow rate,

spacing, conflict and queuing.

Methodologically, Fruin' s work may be construed as a replication of

the earlier studies on carrying capacity. In particular, he conducted

field studies in public buildings of various types, where actual users

were observed during periods of normal occupancy. Pedestrians were timed during their journey between arbitrarily fixed points along various

paths, as had been done by Togawa. In addition, Fruin included more general observations of pedestrian movement behavior.

For level passages and doorways, Fruin found that:

(a) reverse and cross-flow traffic conflicts did not substantially

reduce either pedestrian volume or speed;

(b) pedestrians tended to remain between 1 and 1.5 feet (.305 to .457 m) from the sidewalls of passageways;

(c) maximum average peak flow volumes were approximately 25 persons/

min/ foot (1.367 persons/sec/m);

14
(d) hands-on-shoulders evacuation yielded better flow characteristics,

and a better "psychological climate";

(e) maximum average flow capacities were attained when the pedestrian

volume approximated 5.0 sq . ft. /person (0.467 sq. m/person);

(f) as traffic density increased, pedestrians were more likely t o close

their ranks by reducing their longitudinal, rather than their

lateral spacing;

(g) queues developed when the flow-rate through a door was less than

that of the passageway;

(h) for freely-swinging doors, 40-60 persons passed per minute (0.67-

1.0 persons per second).

Concerning movement patterns on stairways, Fruin found that:

(a) movement velocities were faster going down than going up;

(b) males traversed stairs more rapidly than did females;

(c) for both upward and downward travel, velocity decreased as the

angle of incline increased;

(d) density appeared to have little effect on traffic flow;

(e) for "normal" movement patterns on stairs, 7-8 sq. ft. /person

(0.651-0.744 sq. m/persons) was required;

(f) as the density decreased on stairs, so did the variability of

movement velocity;

(g) crowding on stairs was inferred when the flow rate reached 18.9

per sons/min/ f t . (1.033 per sons/ sec/m) , by which point queuing was extremely likely.

3.2.5 I. Peschl (1971 )

Another recent example of carrying capacity research based on the

traditional physical-science model was provided by Peschl, who investigated

the capacity of door openings during simulated "panic" situations.

Peschl' s work, however, differs from that of other researchers in that

he conducted a laboratory, rather than a field experiment.

Peschl simulated various doorway conditions in the laboratory, and

then asked groups of varying numbers to press against the doors until

all persons moved through. Subjects were student volunteers, and large

group experiments were assumed to be analogous to, and representative

of, "panic" conditions in real building emergencies.

Peschl found that:

(a) often, after passing through the doorway, persons fell or stumbled (this was most acute in the large group experiments);

15
(b) the wider the doorway, the smaller was the probability of arch

formation, and the greater was the variability in flow rate;

(c) stable arches formed at openings of 1.2 in, and the frequency

of arch formation increased for narrower door widths;

(d) openings of 0.86 m produced very stable arches, and crowd passage

was almost impossible;

(e) for a 0.6 m doorway, the rate of exit for groups was nearly zero,

due to the very frequent occurrence of arch formation;

(f) movement through the doorways was found to be 3 times as fast for an "exponentially" curved outlet design, and 2.5 times as fast

for a rounded wall, as compared with a doorway in a straight wall;

(g) rapidity of movement through doorways decreased as the numbers

in a group increased;

(h) the probability of arch formation decreased, the smaller the group;

(i) the rate of exiting for a group was a linear function of doorway

width ;

(j) "pulsating" flow often resulted, since arches were self-dissolving;

a plot of exit rate as a function of time yielded a saw-tooth form.

On the basis of his findings, Peschl concluded that human beings may

be assumed to behave, in egress during panic, as granular particles flowing

from bins. Accordingly, he recommended that floors in egress ways be

sloped toward exit doors, and that a safe minimum door width would be

1.2 m.

Peschl' s approach and conclusions represent the strongest reliance on

a particle-behavior explanation of human behavior in building emergencies

to be found in the literature.

3.2.6 L.F. Henderson (1971 )

While Peschl advocated the "granular", or particle model, Henderson

introduced a far more rigorous form of analysis. Henderson suggested,

priori, that the movement of human crowds should be analogous to the

propogation of gas particles. Accordingly, he sought to demonstrate

that crowd movement could be described by the classical Maxwel 1-Boltzman

ga s model

.

Henderson distinguished between low- and high-density crowd flow,

and suggested that each has a counterpart in a model of particle movement.

In particular, while low-density crowd flow could be treated as a gaseous

medium, high-density flow could be construed as a fluid. His application

was confined to an experiment in "low-density" human crowd movement.

Henderson's investigation primarily involved two phases. First, he

observed human movement patterns in actual settings, and made measurements

of directional and velocity vectors. He studied several settings to

16
test various implications of the gas theory: College students on a campus thoroughfare, adults in a traffic intersection, and children in a playground

.

Second, he ran computer-simulations using the Maxwel 1-Bol t zman equations to generate "particle behavior". He then analyzed his data by

testing for agreement between movements in real environments, and those

predicted by the model.

Interestingly, the Maxwell-Boltzman gas model did predict realworld crowd measures rather accurately. Of greater interest is the fact

that Henderson attributed much of the variance between the two sexes to

differences in their walking habits (males were found to move faster

than females)

3.2.7 S.J. Melinek and S. Booth (1975 )

The principal objective of these investigators was to review and

interpret crowd movement and building evacuation data, for the purpose

of modeling evacuation time. This primarily involved existing data

bases, and focused on emergency egress from health-care facilities.

Melinek and Booth made the following observations on the basis of

their review of the carrying capacity literature, and as a result of

their modeling experience:

(a) escape becomes more difficult as visibility is reduced due to

smoke

(b) evacuation time depends upon how alert occupants are, and their

ability to respond to an alarm;

(c) the age and sex of individuals in a crowd has little bearing on velocity (in contrast with Henderson's observations), since the

speed of a group is determined by pressures exerted among all its

members

(d) there is less variation in the speed with which stairs are ascended,

than descended;

(e) the normal capacity for corridors appears to be 1.5 persons/sec/m

(for corridors between 1 and 3 m wide);

( f ) for unimpeded movement ( "f ree-f low) , a velocity of 1.3 m/sec may

be assumed;

(g) for densities of up to 1 person/m , the speed of an individual is

equal to the "free-flow" velocity;

(h) flow-rate maxima appear at densities of between 1-5 persons/m , and at higher densities, congestion results and flow rates decrease;

17
(i) for upward-sloping passages, velocity is reduced by 2 / per degree

of grade;

(j) for downward-sloping passages, velocity increases for small

grades, and decreases for larger grades;

(k) maximum downward velocity is generally found to occur with gradients

of approximately 7%;

(l) normal capacity on stairs appears to be 1.1 persons/ sec/m;

(m) as crowd density on stairs increases, the flow-rate reaches a maximum level, and then decreases;

(n) bends and corners do not appear to reduce flow-rate on stairs;

(o) arch-action becomes conspicuous when the flow-rate at an exit

reaches 1.8 per sons/ sec/m

;

(p) the frequency of arch formation is inversely proportional to the

square of the exit width.

On the basis of their reviews, Melinek and Booth developed equations

for the computation of evacuation time, which are essentially similar to

those offered earlier by Togawa. They also offered several design recom- mendat ions

:

(a) panic may be reduced by: (1) facilitating smooth egress flow,

(2) providing places of safety within buildings, (3) providing

emergency communication systems within buildings, and (4) providing

emergency lighting;

(b) the smallest recommended exit width is 0.76 m (as compared with

0.53 m required by British codes, and 1.2 m recommended by Peschl);

(c) the installation of mirrors should be avoided along exit routes,

where they could seriously mislead and confuse evacuees.

3.3 Investigations of "Carrying Capacity" wh ich Question the Physical-Model

Foundation

We shall now discuss studies of egress carrying capacity which tend to

reject the physical-science models as sufficient conceptualizations. In

general, research in this category was conducted in such real-world settings

as subway stations, office buildings, and hospitals. As in the case of those

investigations examined above, the studies reviewed here emphasize the measurement of flow-rates, velocities, and evacuation time in facilities of various

configuration. Again, the participants were not exposed to life-threatening

toxants and other stimuli of actual fires. However, attempts were made to

1$
structure field experiments, rather than to simply observe flow patterns

under the routine conditions of normal occupancy.

In not every instance did the authors cited below overtly suggest that

their data call into question the physical-science foundations for design

regulation. However, where this did not occur, it is reasonable to infer

from their findings that they questioned the traditional conceptualization of

the emergency egress problem.

3.3.1 London Transport Bo ard (1 958)

The flow of passengers in London subway stations was studied by means of observations made of the normal use of these facilities. The

numbers of passengers passing through selected footways within a fixed

time period were recorded. In addition, population densities and movement

velocities were measured. In a parallel study, controlled experiments

were conducted at a boys' school, in which rate-of~flow was measured

under conditions of varying density in corridors.

The following results were reported:

(a) in general, flow-rates on level passageways approximated 1.48

persons/ sec/m;

(b) flow-rates on stairs approximated 1.04 persons/ sec/m (ascending),

and 1.15 per sons/ sec/m (descending);

(c) for footways wider than 4 ft (1.22 ib) , the “lane" effect was of

little importance;

(d) flow was often 50% greater through short passageways (corridors

less than 10 ft long ! 3.05 ml), than through longer ones of equal

width

(e) two-way traffic flow yielded no substantial reduction in total

flow;

( f ) after the installation of a center handrail, the velocity on a 6 ft (1.83 m) stairway was reduced from 2.17 persons/sec. to 1.75

persons/ sec

(g) although the installation of center handrails effectively reduced

the number of available lanes from 3 to 2, actual flow was not

reduced by this ratio.

(h) queues did not tend to form at bends or corners;

(i) minor constrictions in passageways had no effect on capacity, but

tended to increase overall journey time for individuals;

19
Two conclusions resulted from observations made during this study,

which specifically questioned the traditional particle models of egress

behavior. First, the London Transport Board investigators concluded

that pedestrian systems must be studied in their entirety, since different

segments may contribute differential degrees of constriction. This

clearly contrasts with most carrying capacity research, which designates

arbitrarily selected segments for detailed analysis, and then generalizes

results to a wider range of conditions.

Second, the researchers concluded that the mechanism of crowd-flow

(albeit in subway stations) could not be considered analogous to either

liquid or gaseous flow in pipes. Instead, they found the speed of passenger

flow, with respect to density, to be represented by an equation which, in

the important middle ranges of density, reduces to the form:

(velocity) x (density) = a constant.

The investigators argued that this is not analogous to liquid flow,

since a liquid is virtually incompressible, and its density may be considered

as a constant independent of velocity.

3.2.2 J.L. Pauls (1975 )

Pauls documented the movement of people on exit stairs and other

egress facilities under various circumstances. Of major importance is

his study of some 40 evacuation drills in high-rise office buildings in

Canada. Pauls distinguished between two types of evacuation: total

evacuation, in which all occupants are presumed to attempt egress

simultaneously via the exit stairs; and phased evacuation, in which the

various floors are cleared according to some prearranged sequence.

The principal variables evaluated by Pauls included density and personal

space utilization on stairs, speed of descent, and evacuation time. Data

collected during fire drills included voiced-taped observer comments, taped

background sounds, and visual records of stair and corridor activity. It was generally assumed that the drills occurred without the prior warning of

building occupants.

On the basis of his field studies, Pauls urged that the traditional

assumptions which govern stair design in building regulations be reconsidered.

He found, for example, that:

(a) Evacuees did not walk in a highly regimented fashion, shoulder-toshoulder, nor even in staggered files. Side-to-side body sway,

individual concern for interpersonal separation, and varying need

for handrail support all influence the utilization of exit stairs

by evacuees

.

(b) Speed of descent on stairs tended to be more variable, and generally

lower, than architects had been led to believe by the traditional ly20
assumed flow-rate of 45 per sons/min/22 " stair width unit (1.35

persons/sec/m)

(c) Evacuation time in total-evacuation drills appeared to depend

upon (1) total building population and (2) available stair width.

A 10-story building with 100 occupants per width unit could be

evacuated in less than 5 minutes (+/- 20%). By contrast, a 30

story building with 1,000 occupants per width unit might take more than 30 minutes to evacuate.

These estimates derive from studies in which evacuees had prior drill

training, and were allegedly unaware of the reason for the evacuation

(i.e., that it is only a drill). In addition, trained supervisory personnel ("floor wardens") were present on each floor.

Pauls' analysis of phased-evacuation methods diverges even further

from the "particle" approach to emergency egress. According to his

observations, phased evacuation required trained supervisors and emergency

communications systems. The efficient use of exit stairs was seen to depend not only upon evacuees' movements, but also upon the organization

and management of the evacuation.

3.3.3 I. Appleton and P. Quiggen (1976)

These investigators simulated emergency egress procedures at a British hospital. Data gathered from the mock evacuations included

patient-preparation times, travel times, and travel speeds. The chief

objectives of the study were to recommend improvements to decrease total

evacuation times, and to develop a general model of evacuation for

hospitals

During the simulations, professional actors roll-played both ambulatory

and non- ambulatory patients. Two potential fire situations were evaluated:

a daytime incident, with ail staff members on hand, and a nighttime

fire, during which only a skeletal staff was present. The simulated

escapes were filmed, and special attention was paid to such activities

as: patient preparation, travel across the ward, shunting patients

through the exit, movement on stairs, and the staff members' return to

the ward to assist other patients.

As did Pauls, Appleton and Quiggen suggested factors operating

during fire situations which cannot be adequately explained by particle

models. Examples include stress and fatigue, which influenced the

performance of staff members under emergency stress, as well as indecision,

which occurred when alternative exits were necessary.

3 . 4 Investigations of Egress Signage, Emergency Lighting, and Visibility

Through Smoke

Focusing on neither emergency evacuation

capacity of various facility designs, a small

behavior nor the carrying

body of experimental

21
literature has dealt with the problems of exit sign perception, egress

path lighting, and visibility through smoke. Examples of this research

generally cluster into three categories: Japanese research on human

behavior in smoke-filled environments, U. S. Naval investigations of emer- gency evacuation procedures on board Naval vessels, and experiments con- ducted by the Federal Aviation Adminstration' s Office of Aviation Medicine.

Several examples are considered below.

3.4.1 Y. Watanabe, K. Nayuki and K. Torizaki (1973 )

These researchers observed the actions of firemen in smoke. Experiments

were performed in mine safety training pits. In a variety of smoke

densities, subjects (equipped with breathing apparatus and a portable

light) walked along designated courses, which included horizontal and

inclined paths. During the experimental period, subjects' walking

speeds and respiratory rates were measured. In general, it was found

that

:

(a) walking speed decreased as smoke density increased, until a point

was reached at which speed was nearly constant, and equal to that

in total darkness,

(b) as walkers became experienced with the course, their walking

speeds increased by up to 0.5 m/ sec on the horizontal, and by up

to 0.3 m/sec on a stair,

(c) walking speeds were lower at corners than along straight portions

of the course ,

(d) when subjects fell down in the smoke, they tended to lose their sense of direction,

(e) subjects least accustomed to both smoke and the route showed the

highest respiratory rates.

3.4.2 S. Tashida (1975 )

Tashida conducted further experiments on the effects of smoke

densities on human walking performance, employing subjects thoroughly

familiar with the interior space used for the experiments. Tashida

found that

:

(a) As smoke density increased, walking speed decreased. But as smoke density reached a certain point, the walking speed reached

a fixed level, and was no longer affected by smoke density.

Consider these subjects' reports: "...even when a portable light was used, observations became difficult, until it finally was a matter of shining the light at one's feet, and the speed was reduced accordingly." "Finally, when the smoke density reached

22
Che point where the light would barely illumine one's feet, I proceeded by reaching out to feel the wall at my side." At that

point, walking speed was influenced more by the use of the wall,

than by smoke density, per se.

(b) Subjects occasionally stopped along the path in order to search

for the lighted objective.

Tashida posited (quite believably) that persons making emergency

escapes in a smoke-filled environment become anxious, especially when the

visibility of wall and floor surfaces is reduced beyond a certain level.

In cases where occupants are not familiar with the environment, this is

believed to contribute to "panic".

In another similar experiment, Tashida found that:

(a) where visibility was approximately 5 m, some 20% of the subjects

returned to the starting point,

(b) where visibility was estimated to be 10 m, however, only 10%

returned

On the basis of these results, 10 m was recommended as the minimum

visibility range for persons in novel environments.

3.4.3 P.M. Edmondo and H.T. Macey (1968 )

These researchers conducted investigations into the use of illuminated

directional markers for emergency egress from ship compartments. Their

objectives were to determine the visibility of various light intensities

in dense smoke, and to evaluate the effectiveness of lighted devices as directional markers.

Two experiments were conducted. In the first, the visibility of different light-emitting units through varying smoke conditions was measured.

These units included quartz-iodine lamps, standard Navy hand lanterns , xenon

flashers, and illuminated exit signs.

The second experiment was designed to simulate

ditions, and to determine the optimum placement and

of light sources.

On the basis of these experiments, it was found that:

(a) The quartz-iodine lamp had the shortest detection distance of the

various lamps tested. The handlantern and xenon flasher were nearly equal in detection distance.

(b) The handlantern was found to be the best directional device. The

2 ft. (0,61 m) mounting height above the floor level, with a 6

actual emergency con- directional capabilities

23
(0.61 m) mounting height above the floor level, with a 6 ft.

(1.83 m) separation between lanterns, and with the light beam

aimed parallel to the direction of oncoming traffic.

3.4.4 J.D. Garner and D.L. Lowrey (1976 )

A laboratory experiment wad conducted in order to compare a variety

of commercially available exit signs and markers for aircraft cabins.

Both the light output and smoke penetration characteristics of such

units were evaluated.

Ten different signage units were obtained, and measures were made of

their average background brightness, average letter brightness, and letterto-bac kground contrast ratio. Measurements for each light were recorded at

one-foot (0.305 m) intervals, up to 6 feet (1.83 m) , in clean air and in

smoke, in a specially constructed chamber. Light transmittance over a 6 ft. distance was used as the smoke density criteria.

Garner and Lowrey found that:

(a) all examined light units diminished in output in smoke at a proportionate percentage drop in their initial brightness;

(b) higher initial brightness resulted in higher levels when measured

through a 90% smoke medium;

(c) at some point, however, there appeared to be a diminishing return,

since the increases in power requirements did not appear to be

justified by the slight increases in illumination.

3 . 5 Investigations of Occupants' Responses to Actual Fire Emergencies

Quite recently, several investigators have attempted to account for

human psycho-social parameters, and to examine emergency behavior in the

context of real fire emergencies. In these studies, facility design per se was not at issue. Rather, researchers emphasized the need to understand

the behavioral patterns which account for the variance in egress success

rates (Wood, 1972; Haber, 1977; Bryan, 1976; Lerup, 1976). Principal

examples of this literature are explored below.

3.5.1 P.G. Wood (1972 )

Wood had fire department personnel interview victims at the scene

of fire incidents. Nearly 1,000 fires were investigated in the United

Kingdom. Approximately 50% of these occurred in single-family dwellings,

and another 22.7% occurred in factories and shops. About 2% involved more than 250 occupants.

In preparing his interview schedule, Wood was concerned with the

following issues:

24
(a) how occupants first became aware of the fire;

(b) the location of occupants at the time of ignition;

(c) the first, second, and third actions taken by occupants, after

being alerted to the fire;

(d) whether, and how, occupants attempted to leave the building;

(e) whether occupants had difficulty moving through smoke;

(f) the location of occupants upon arrival of the fire department.

Wood found that most persons interviewed became aware of the fire's

existence either when they actually saw smoke, or through having been

alerted by others. A few respondents indicated that they were initially

alerted by the sight of flames, or by hearing distant shouts. Still others

said that vague noises, fire alarm signals, and increases in ambient heat

accounted for their initial alerting.

The following accounted for about 80% of all first actions reported:

Fire-fighting, calling the fire department, investigating the fire, warning

others, evacuating oneself, and evacuating others.

Fighting the fire, "inaction", calling the fire department, leaving

the building, and shutting doors accounted for about 60% of all second

actions, and approximately 73% of all third actions reported.

Most actions were found to be similarly distributed across the three

sequential categories. An interesting exception is "inaction". This

activity was virtually absent as a first action, was found to account for some 15% of the second actions taken, and was finally noted to account for

nearly half of all third actions reported.

Actions taken were also evaluated against various other factors. For

example

,

Wood found that:

(a) significantly more people left the building when

and confusing than when cues were unambiguous;

cues were ambiguous

(b) fire-fighting was more likely to occur as a first cues were clear;

action when

(c) investigation increased in direct proportion with

the fire;

proximity to

(d) calling the fire department was less likely the farther one was from the fire.

Moreover, it was noted that:

25
(e) leaving the building as a first action was more likely when the

fire was judged to be serious;

(f) fire-fighting became less likely when the fire was judged to be

serious

;

(g) there was a greater tendency to warn others, when the fire was judged to be serious.

It was also found that familiarity with the building did not correlate

with the directness and immediacy with which a person left the building.

However, persons who were familiar with the building;

(a) were more likely to call the fire department;

(b) were more likely to fight the fire.

More people were found to leave the building immediately when smoke

levels were minimal. In contrast, immediate egress was less likely for

persons who had previously experienced building fires.

Sex differences were also found to influence emergency actions taken.

For example, women were less likely than men to fight the fire, or to take

other steps to minimize the actual danger. They were more likely than men

to warn others, leave immediately, or request assistance.

3.5.2 J.L. Bryan (1976 )

Replicating Wood's field study, Bryan attempted to describe the

behaviors of fire victims in incidents in the Washington, D. C., vicinity.

As with Wood, Bryan focused upon reports of action patterns, and correlated

them with such other factors as sex differences, mode of initial alert,

and prior experiences in building fires.

Bryan generally corroborated Wood's findings on issues concerning

mode of initial alert, reasons reported for not leaving the building,

reasons reported for re-entry into the burning building, and sex differences

in re-entry behavior.

However, findings reported by Bryan failed to corroborate Wood's

concerning first action as a function of previous fire experience, and

first action as a function of sex. Regretably, data reported by Bryan

were not always presented in a format consistent with Wood's. Consequently,

opportunities for comparison along the widest possible variety of factors,

were lost.

3.5.3 G.M. Haber (1977 )

A similar research strategy was employed by Haber, who interviewed

victims of fatal fires in total-care institutions. These included

26
hospitals, nursing homes, and a home for the aged. Haber's principal

objective was to determine how social organizations behave before,

during and after fires in such facilities.

It was found that most of the buildings surveyed met all the applicable

construction codes, and that they had not been criticized as fire hazards.

In addition, no relationships were found between building size, firefighting equipment available, and the number of fatalities.

Rather than building or floor "size", the social structure and

institutional organization of floors emerged as critical factors. In five of the seven fires investigated, the room of origin was in the

extreme corner of the fire floor, far removed from the nurses station.

It was also found that the occupants of such corner rooms tended to be

the most deviant and chronically ill patients on the floor. Haber

suggested that since these individuals tend to be ignored and neglected,

a causal relationship between point of fire origin and certain institutional

policies may exist. Further support for this argument stems from the

additional findings that:

(a) "undersirable" patients were often assigned to rooms far distant

from nurses' stations;

(b) the least attention tended to be paid to the most distant patients,

in terms of surveillance and supervision.

While it was difficult to reconstruct the pre-fire socio-environmental

structures in a post-hoc survey, Haber found some indication that the

fires she studied were preceded by changes in normal routine, or the occurrence of some highly unusual problem in the building.

Concerning fire casualties, Haber found that:

(a) most deaths resulted from the inhalation of smoke and toxic

gases, and not from burning;

(b) "panic" did not occur, and no deaths were attributable to paniclike behavior;

(c) those who died were exposed to smoke for at least five minutes;

(d) fatalities were found either opposite or near the room of origin,

with no barrier between them and the smoke;

(e) several of those who died, though initially safe, delayed their

evacuation to collect personal possessions, then opened their

doors, and died in the smoke (according to reports).

In summarizing the human response to the fire environment, Haber

further noted that:

27
(a) The fire was usually first noticed by a patient or nurses' aide,

who actually saw flames or smoke. This person then alerted a nurse, and began shutting doors and evacuating patients.

(b) Male personnel, upon arrival at the scene, usually began fighting

the fire themselves.

(c) Persons located outside the fire area usually responded with disbelief. This response changed, with the eventual confirmation of

the fire.

(d) After the fire, all staff members were emotionally upset. Discussing the event with the interviewer seemed to relieve them.

(e) In general, staff members felt guilty about the fatalities.

However, they believed that there was nothing different they

could have done during the emergency.

3.5.4 L. Lerup (1975 )

Lerup did not conduct empirical research, perse. Instead, he

sought to identify patterns of human behavioral responses to fire situations,

and of interactions between human behavior and fire migration.

As in the case of Haber, Lerup studied fires in health-care facilities.

Unlike Wood, Bryan, or Haber, however, he was concerned with the "mapping"

of relationships between human behavior and the spread of the fire. His

mapping was based upon anecdotal accounts of fire events, such as the type

frequently presented in Fire Journal. He considered fire spread in terms

of discrete phases, or "realms' 1 (internally consistent fire states which

remain relatively stable over time), and critical events (discrete changes

in fire development which mark the termination of one realm, and the onset

of the next). Lerup also classified the behavior of building occupants in

terms of decision points, or "episodes", such as fire-fighting, rescuing

patients, seeking help, or escaping. Fire spread and occupants' movement

patterns were shown superimposed on floor plans of the buildings in com- posite drawings, each of which represented one realm/episode combination.

Many of the ideas for this approach were supplied by H. E. Nelson, of the

National Bureau of Standards.

According to Lerup, the maps are useful in giving a pictorial representation of a fire, and might be used as a general means for recording and

reporting information about fires.

3 . 6 Summary

In Part 3, we have described various kinds of empirical research on emergency egress. This was done to provide a basis for assessing the

validity of past research as a foundation for exit design regulations.

Accordingly, an effort was made to present investigators' objectives,

methods, and findings.

28
Also, we have pointed out a dichotomy between research assessing the

so-called "carrying capacity" of building exits, and research attempting to describe human responses under actual fire conditions.

In Part 4, we shall present evaluations of the empirical studies,

which included:

(a) field studies of carrying capacity which implied particle-model

explanations of human movement;

(b) field studies of carrying capacity which questioned such physicalscience foundations;

(c) survey investigations of occupants' responses in actual fire

sit uat ions ;

(d) experimental investigations of exit signs, emergency lighting,

and visibility through smoke.

29
4, ANALYTICAL ASSESSMENT OF THE EMERGENCY EGRESS TECHNICAL LITERATURE

The technical literature on emergency egress confronts those who

wish to use it with a dilemna. On the one hand, the literature contains

important and pertinent information. On the other hand, the information

must be applied with considerable care, due to various methodological

problems inherent in this area of research.

Perhaps the most pervasive caveat stems from the fact that data has

been collected on human responses and capabilities in non-fire situations.

The question therefore arises as to what extent these data can be used in

the prediction of behavior in stressful fire situations? Unfortunately,

there is little empirical evidence to help us. While we can be confident

that egress behavior will be affected by the added stress, we cannot

confidently predict the magnitude or the direction of the change. For

example, in predicting pedestrian flow down a stairway, we might expect

a decreased need for personal space during an emergency. This could

increase the overall capacity of the stair. On the other hand, we might

expect more eratic behavior on the stair, which could have the effect

of decreasing its overall capacity. A possible hypothesis might be that

the two effects balance each other. This would imply the use of flow rate

data obtained quite easily during non-stress ful situations. But this

approach is neither supported nor refuted by available empirical data.

Each of the investigative approaches found in the emergency egress

literature has its own set of methodological problems. Let us consider

each of these approaches, which include:

(a) field based quasi-experimental research designs;

(b) post-hoc survey research designs,

(c) laboratory based experimental and quasi-experimental research

designs .

The general assessment strategy is illustrated by the "analytical

assessment matrix" (Figure 2). The assessment of the investigative

modes includes a discussion of general premises underlying the approach,

of advantages associated with the approach, and of potential limitations

to the utility of findings . Finally, a critique of specific egress

investigations is provided.

4 . 1 Field Based Quasi-Experimental Designs

These chiefly include the various

which were conducted in real buildings

normal occupancy, or during evacuation

investigations of carrying capacity

either under conditions of

drills .

30
4.1.1

General Premises

For field-experimental designs, some testable model of the system

under study is often presumed to exist. Togawa , for example, described

egress from buildings in terms of fluid or gaseous media which travel,

according to deterministic physical principles, through pipes, ducts,

and the like.

When inferences are drawn from the experimental data about the

operation of real systems, it is further assumed that the model tested

contains most relevant variables, and the correct interrelationships

among these variables.

Similarly, it is assumed that variables studied have been properly

defined operationally , and that it is technically possible to carry out

such operations when making measurements in the field. In the literature

on carrying capacity, for example, "egress behavior" has been quite

narrowly defined in terms of such easily conducted operations as velocity

and flow rate measurement

Finally, a frequent general assumption is that the use of actual

field settings as "laboratories" increases the external validity of the

findings

4.1.2 Advantages of Field Based Quasi-Exper imental Designs

Depending upon the nature of experimental controls established in

the field, moreover, data collected from field studies may be amenable

to statistical analysis. Such analyses would clearly enhance the value

of experimental results.

4.1.3 Limitations to the Utility of Findings from Field Based QuasiExperimental Designs

In general, if an experimental situation differs appreciably from

an actual situation, then generalizations from the experimental results

to actual phenomena need to be justified. Thus, Pauls' research on fire

drills may be generalized to similar fire drills, but not necessarily to

real fires.

Many variables may be difficult to define operationally (e.g.,

"panic", anxiety, motivation, or even "safety"). When dealing with

these, it must not be assumed automatically that measurements accurately

or consistently reflect some universal notion of the construct in

question (the problem of "construct validity"). Some investigators

defined "egress behavior" velocities and flow rates. Certain observable

performance characteristics were assumed to describe the entire complex

behavioral system labeled "egress behavior". Broader studies of the

egress problem (e.g., Breaux, et al., 1976), as well as anecdotal accounts

of actual fires, suggest that this behavioral system involves perceptual

and cognitive processes which could lead to quite different velocity and

31
flow rate outcomes. But the flavor and implication of such complexity

is totally lost when so complex a construct as "egress behavior" is

defined merely in terms of a few accessible performance measures.

Similarly, while other variables may be appropriately defined,

their measurement may be extremely costly, difficult, or even dangerous

if human subjects were used in actual building fire experiments.

4.1.4 Critique of Specific Investigations

In referring to the field investigations of carrying capacity as "quasi-experimental " , the intention has been to emphasize their universal

lack of either experimental controls or procedures for the random

assignment of subject to conditions. While these features detract from

the validity of any causal inferences drawn from research results, they

may not seriously challenge the usefulness of non-causal correlations

or trends suggested by the data. There are, however, issues of much

greater concern in the evaluation of this segment of the technical

literature

.

For example, although some investigators made specific references

to the applicability of certain models to the study of building egress

(e.g., references to particle-models by Togawa and Peschl), they neither

viewed their research as mechanisms for validating the particle-behavior

assumption, nor did they otherwise question its validity. These models

were in fact used, however, as a framework for conceptualizing the

egress problem, and for explaining experimental results. But without an acceptable demonstration of the models' plausibility, the potential for

drawing erroneous conclusions about the behavior of people in real fire

situations is great.

In attempting to evaluate the findings and conclusions of the NBS

(1935) research, the fact that the investigation did not simulate lifethreatening conditions must be considered. The research methodology was

also weak in its arbitrary selection of measurable discharge points,

which bore little connection with a building fire "system", in which

all segments of egress routes are interrelated, and in which building

layout, fire phenomena, and occupants' response patterns may be presumed

to interact continuously.

While there is no denying that Togawa' s analysis of human flow

rates in building was comprehensive, all the reservations discussed

in connection with the carrying capacity literature apply to his analysis.

In particular, it must be remembered that building inhabitants were observed only during periods of normal occupancy, and that they were not

responding to 1 i fe-threat ing environmental stimuli of any kind.

Attempts to generalize Togawa' s results to emergency egress during

building fires (as has been suggested) requires the assumption that the

stresses of the fire threat do not significantly hinder or facilitate

egress performance.

32
In contrast, Henderson specifically sought to validate the MaxwellBoltzman gas model as an explanation of human crowd movement. When

interpreting Henderson's findings, however, it is essential to bear in

mind that the humans observed were neither confined to the rigid environmental structure of building interiors, nor were they exposed to lifethreatening elements. These, however, are factors which may be presumed

to influence performance during building emergencies. As the MaxwellBoltzman model was never empirically confirmed against real-world observations

made under such circumstances, its use in the prediction of emergency

egress behavior requires untested assumptions.

Equally serious difficulties stem from the fact that while meaningful

trends may indeed reside within the data base, few attempts were made to

employ analytical techniques capable of confirming their existence.

Moreover, research strategies not truly amenable to sophisticated statistical

analysis were frequently employed.

In summary, then, an analysis of the carrying capacity literature,

based on certain investigative principles, yields little evidence supporting

the application of this segment of the technical base to the development

or evaluation of design regulations for emergency egress from areas directly exposed to fire and smoke. Instead, an important contribution

of this literature appears to lie in the questions it has raised about

the problem of emergency egress from buildings, and in the hypotheses

and future research it may generate. In some cases, recent research on carrying capacity has led to an erosion of the traditional, narrowlydefined approach to research on this problem.

4 . 2 Laboratory-Experimental Designs

Within this category, the various investigations of visibility

through smoke, and of emergency lighting and signage are addressed.

4.2.1 General Premises

For the most part, the premises underlying the conduct of laboratoryexperimental research parallel those which guide their counterparts in

naturalistic field settings (see Section 4.1.1). Of primary importance

is the notion that experiments are usually designed for the purpose of

testing models or theories about real-world phenomena. It is further

assumed that;

(a) the model under test contains most relevant variables and

relationships

,

(b) the variables are properly defined operationally,

(c) these operations may be readily achieved, technically.

One factor which clearly distinguishes field-based from laboratorybased experimentation, however, concerns the question of external validity,

as follows: When a field experiment is properly designed, such that

environmental conditions during the experiment approach those inherent

in the natural phenomenon, then the experimental results may usually be

33
assumed to generalize to real-world populations. However, when environmental

conditions are set up in a laboratory, they are necessarily simplified,

and essential components of the natural phenomenon may be sacrificed.

The greater the discrepancy between the natural and laboratory environmental

systems, the more likely it will be that generalizations from laboratory

findings to real-world events are erroneous.

4.2.2 Advantages of Laboratory-Based Experimental Designs

Both theoretical and methodological advantages potentially accrue

from laboratory experimentation. For example, this form of research

permits the greatest opportunity for strict experimental control, whether

accomplished through the pre-conditioning of subjects, their random

assignment to experimental groups, etc. Much of the indeterminacy

inherent in the emergency egress technical base stems from the virtually

universal lack of just such experimental controls.

In addition, data obtained from well designed and tightly controlled

experiments are readily amenable to statistical analysis. Again, the

almost universal failure to develop a data base amenable to such analysis

has contributed to the current inability to draw conclusions which are sufficiently unequivocal for regulatory purposes.

Finally, laboratory experiments are convenient. In comparison with

field settings, laboratories usually are safer and more comfortable, and

processes may often be scheduled to suit the experimenter's personal

needs

.

4.2.3 Limitations to the Utility of Laboratory-Based Experimental Findings

Again, these limitations generally parallel many of the issues

addressed earlier in the context of the field-based experimental designs.

As suggested above, the generalization of findings from experimental

samples to real-world populations may also become problematic, especially

when there is a questionable degree of verisimilitude between the

laboratory and real-world systems.

4.2.4 Critique of Specific Investigations

In general, the experimenters discussed here did not explicitly

describe their investigations as attempts to assess particular models of

human perception or behavior. Rather, they attempted to deal on a piecemeal basis with various questions or hypotheses.

This tack is exemplified by the Naval and aviation experiments on signage systems, which sought to measure such quantities as detection

level, without ever describing the phenomenon in terms of, say, the

well-known "signal detection theory". Similarly, while the Japanese

experiments on pedestrian movement through smoke appeared to suggest

visibility maxima for corridors, no attempts were made to evaluate

their findings against current psychophysical or physiological models.

As a result, it becomes extremely difficult to determine the limitations

on the applicability of such findings. Moreover, while such efforts

34
have added various bits of knowledge to the emergency egress data base,

they contribute very little to the overall organization and strength of

this base.

Even the validity of findings produced through these efforts may be

called into question, when one considers Important differences between

the laboratory-experimental environments, and those of actual building

fires. In one such experiment, human subjects were never actually

employed. In those which did employ humans, moreover, performance measures were made on simplistic and relatively unrealistic tasks. In no cases did subjects believe that their lives were in any real danger, nor were they required to respond quickly to ambiguous or conflicting

environmental cues. Moreover, no subjects were ever "taken by surprise."

Very often, however, these are the kinds of factors and events which

surround participation in actual building fires.

Needless to say, the issue of employing humans in building fire

experiments or of subjecting persons to an actual injury or life threat

is undesirable for a wide variety of reasons. Even exposing them to

simulated threats might result in stress or psychic injury. This type

of experimentation on emergency egress has not been undertaken in the

United States. But to a very limited extent, such work has been done in

Japan. However, the mere fact that humans were utilized does not in and

of itself enhance the validity and usefulness of the research findings.

Indeed, this could only result when well controlled experiments, in

which the complexities of the real-world phenomenon are adequately

simulated in the laboratory, are conducted.

In summary, there are two major difficulties with this segment of

the technical literature. First, the validity of the findings is called into

question because of the unrealistic qualities of experimental settings.

Second, no advantage was taken of opportunities to relate experimental paradigms to

the evaluation of explanatory models or theories of human responses in lifethreatening situations. Although the aviation research conditions least

simulated those which might actually be encountered in buildings, the

Naval studies on board large ships appeared considerably more realistic.

Neither approach, however, rivaled the Japanese work in building corridors

and other similar situations. While results from these studies seem

somewhat suggestive of occupants' behavior in smoke-filled environments,

it must be reiterated that many other aspects of the life-threat were

not simulated at all. Consequently, future research may derive considerably

more benefit from the Japanese findings than might the design regulatory

process, at least in the short run.

4 . 3 Post-Hoc Survey Research Designs

This category primarily includes investigations of actual fires, in

which victims were interviewed.

4.3.1 General Premises

Post-hoc survey methods are often applicable both to analytical

research programs in which formulated models are subjected to test, and

to holistic studies which contribute to the preliminary phases of model

construction.

35
In those cases where models have been formulated and are under

examination, post-hoc case-studies of particular historical incidents

are often considered useful for gathering supportive (or challenging)

data. This is especially true in situations which, for practical purposes,

preclude the conduct of well controlled experiments in field settings.

Where no models of the real-world system have been formulated,

field surveys and post-hoc case-studies may be valuable in the identification

of relevant parameters, conditions, and relationships which underlie and

define such systems. This approach is exemplified somewhat by the

investigations of Wood, Bryan, Haber, and Lerup . Wood and Bryan, for

instance, operated under certain assumptions about the importance of

such factors as differences in age, sex, prior fire experience, etc.

They conducted lengthy post-incident case-studies at hundreds of sites

in an effort to knit these factors into a more unified "picture" of

emergency action sequencing. Eventually, a well formulated version of

this picture, or model, may be formulated and subjected to more rigorous

forms of empirical analysis.

4.3.2 Advantage of Post-Hoc Survey Designs

In the case of holistic research, where model construction (versus

model confirmation) is at issue, field surveys and case-studies may be

relatively informal. Since the strict logic required for the deduction

and testing of hypotheses must often be relaxed or even bypassed, controlled

environments need not be contrived, nor must "task performance", per se

,

be operationalized and measured. Rather, hypotheses are often formulated,

tested, reformulated, and then re-evaluated, under "unclean" field

conditions. The identification of trends is usually the desired outcome

of holistic work.

4.3.3 Limitations to the Utility of Post-Hoc Survey Designs

Several problems inherent in the survey research approach are particularly relevant in the study of occupants’ responses in actual

building fires. In particular, the following should be noted:

Much of Haber's data was obtained in the form of open-ended verbal

reports (as distinguished from scalar scores) . Such reports may be

adequate if the primary intention is to produce a narrative report on a particular historical event. However, where any form of tabulation or quantitative analysis is required, the intermediary task of translating

qualitative statements into some numerical code must be performed. If

this problem is not considered and solved during the early stages of

research design and planning, when techniques for data acquisition and

analysis are first developed, then specific evaluations of findings may

be of questionable utility. For example, do the quantitative trends

reflect occupants’ perceptions and verbal reports, or do they rather

mirror the researcher's biases, as these are built into his/her translation

mechanisms? It would be interesting and extremely useful to note, for

example, whether various other "experts" would draw inferences and

conclusions similar to those of Haber, on the basis of the same raw data

.

36
In addition, where case-studies or surveys involve either verbal

reports or scalar responses, any interpretation of the results must

recognize the potential for confusion likely to arise from diverse and

often conflicting perceptions of given words, phrases, questions, etc.

In the absence of validated questionnaire instruments (presently a key

problem in the fire area), the data analyst may well wonder: whether

the victim was responding to the question, as asked? Whether the respondent

viewed the event in the same light as did the researcher? Whether the

respondent’s internalized subconscious model of the fire incident, based

on his/her actual experience, was the same as the researcher's intellectualized

(though often also subconscious) model?

Other difficulties are more tactical in nature. For example, if

too long a time period is allowed to lapse between the occurrence of the

actual event, and its investigation through post-hoc techniques, memory

decrement may operate to reduce the validity of the data gathered.

Similarly, if victims have had ample opportunity to think about the

event, to discuss it openly with others, or to read the anecdotal accounts,

then the mediated version which is reported to the researcher may well

differ from the actual occurrence. While investigators may take care to

identify potential sources of such mediation (absent from the current

technical base) , it is not likely that they will successfully determine

their actual impact on victims' reports. Again, Haber's findings may

suffer from this problem, as might Lerup's analysis. In these cases,

while it might be tempting to infer certain behavioral trends from the

data, the actual validity and usefulness of the findings are themselves

virtually indeterminate.

Conversely, if the event was traumatic or painful, too short a time

lapse between the incident and its reporting may adversely influence

validity, as well. In particular, emotional controls over victims'

perceptions may act to produce erroneous, or distorted reports. This

problem becomes especially acute in cases where the reports are solicited

before respondents have had adequate time to "sort things out" in their

minds. Examples of this threat are likely to be found in the studies by

Wood and Bryan, who had fire-fighters question victims at the scene. Unfortunately, no attempts were made to assess the potential influence

of this "shock factor," nor to accommodate the inconsistency of its

effect across the population surveyed. For these reasons, the usefulness

of data obtained by these investigators, except in the identification of

the most general (and least informative) trends, may also be indeterminate.

A. 3. 4 Critique of Specific Investigations

In evaluating Wood's findings, several caveats must be considered.

First, procedures used for gathering data during the immediate postincident period are extremely sensitive to the emotional effects of the

fire experience upon the reliability of the victims' reports. Also, if

a period of time is permitted to lapse between the incident and the

interview, memory decrement and cognitive distortion may impact on reliability quite similarly.

Second, while various behaviors were tabulated as being first,

second, or third actions, Wood failed to assess interactions among these

37
actions. The more important (yet unasked) question would appear to be

how, for example, a particular first action influenced the selection of

subsequent behaviors?

Finally, it should be noted that the fires reported were primarily

those in single-family dwellings, and Wood's original analysis made no attempt to distinguish among occupancies.

When considering the application of these findings to the design of

egress facilities, it should be further noted that Wood didn't correlate

occupants' behavior with physical aspects of either the building layout,

or the dynamic qualities of the fire threat (as Lerup, 1975, has since

accomplished). Thus, it is difficult to apply Wood's findings to building

regulations or to building design criteria.

In general, Bryan made the same methodological errors that Wood

made. One exception, however, was the reconstruction of action sequences

during fires. Although Bryan also failed to assess interactive effects

among behavioral increments, he did infer from his data patterns of

action sufficient to aid in the formulation of hypotheses for future

research

.

Even though Haber, Wood, and Bryan dealt with somewhat different

concerns, there appears to be some agreement among their findings (for

instance, with respect to the issue of sex differences). Each of these

investigators employed essentially similar techniques, and these are generally subject to the same caveats. As a result, the question arises

as to whether their corroborative findings are indeed accurate reflections

of actual events (and are consequently of value), or whether they are merely artifacts of the research methodology. The usefulness of this

data base would be greatly served if such issues were addressed through

diverse techniques. Post incident surveys, for example, could be cross- validated by means of experiments of the type conducted by Appleton and

Quiggen.

Lerup 's mapping procedure is more than just data-plotting, and it

embodies a model of person-fire relationships. It implied that discrete

transformations in patterns of human behavior are keyed to changes in

the state of the physical environment, and that critical events which

launch the fire system into a new realm will simultaneously generate

decision points to which human occupants must respond.

Although Lerup appears to take this one-to-one relationship for

granted, it remains an empirical issue. For example, it may be argued

that decision-making behavior is somewhat stringently determined by

environmental events when the latter are highly proximate, unequivocal,

and salient. In building fires, however, it is apparent that many

occupants are outside the immediate vicinity in which the critical

events are unfolding, but are nevertheless receiving cues which vary

quite widely in terms of their information content. It is also becoming

more widely believed that where information is ambiguous, cognitive

processes operate to create distorted perceptions of events within

occupants' minds.

38
Since occupants may, therefore, potentially differ in terms of

their perceptions of reality, a data-categor izing technique which is

founded on the assumption that human behavior in fires is largely environmentdetermined seems somewhat unrealistic. Indeed, the resolution of this

issue deserves high priority in any future research program.

Methodological difficulties of the type outlined above clearly

detract from the utility of this segment of the technical literature

base. Questions also arise, however, concerning the efficacy of applying

knowledge about historical fires to the prediction of future situations,

and to the solution of concommitant life safety problems.

When a fire occurs in a building, both the physical and human

behavioral aspects respond in particular ways, forming a unique building

fire system. Should a fire ever occur in the same building again, the

various behavioral components are likely to unfold somewhat differently,

creating a new, somewhat different, unique system. Theoretically then, no two fires in the same building will produce identical behavioral

outcomes, and some distribution of events probably exists for the building.

The fire which actually does occur in this building, therefore, may be

viewed as a particular behavioral system sampled from the distribution

of all possible systems .

Whether the actual fire produced among the most or the least likely

outcomes is, at present, an indeterminate question. If it was among the

most likely (and hence, most likely to occur again ) , then lessons learned

from this fire may still be inadequate for dealing with future fires in

similar buildings which occur at more extreme ends of the distribution.

Or, if the outcomes were among the least likely, then such lessons may

be of relatively little value, in terms of wide-scale design regulations

for a building type. Although currently indeterminate, the future

mitigation of this problem will depend upon the large-scale acquisition

of reliable and valid data which explicate the fire-outcome distributions

for various building types. Refer also to Figure 3.

In summary then, it must be first noted that the research conducted

on occupants' responses in actual fires has produced very few data

relating directly to the design of exit facilities in buildings. Rather,

such studies have focused on the identification of sequential response

patterns, virtually independent of physical design parameters. The

analyst must further bear in mind that certain methodological and theoretical

constraints associated with the post-hoc case-study approach may render

the evaluation of such data interminate. Finally, when attempting to

plan for future fires on the basis of historical cases, one must assume

that

(a) the outcome probability distributions are similar for all

examples of the building type, and either:

(b) the case outcomes were the most likely, or

(c) all outcomes are sufficiently similar, regardless of their

likelihood

.

39
5. SUMMARY OF RECOMMENDATIONS

5 . 1 Recommendations Concerning the Technical Adequacy of the Available

Empirical Literature

5.1.1 The Literature on Egress Facility Carrying-Capacity

Considering their restricted view of building evacuation, various

investigators sought a rational way to measure or model the manner in

which exiting facilities are in fact utilized by building occupants.

The investigators assumed that the dimensions of exit path elements were

the dominant controlling factors. This has resulted in a variety of

recommendations relating to door and corridor width, maximum escape

distances, and minimum stair provision. All researchers measured essentially

the same egress parameters (e.g., flow rate), and while their interpretations

occasionally differed, most presented similar data. All things being

equal, this segment of the technical base should be useful in formulating

or supporting regulations for egress facility design.

The obvious discrepencies between the work of Pauls and other

investigators of carrying capacity should be taken into account. It

must be noted, however, that Pauls' data have not as yet been replicated,

while the other researchers have effectively replicated each others'

findings since 1935. Moreover, studies by all these individuals share

similar methodological and inferential caveats, as presented in Chapter 4 of this report.

On the basis of our assessment of the carrying-capacity research,

we conclude that this literature is technically adequate for those

applications in which the following assumptions are acceptable:

(1) pedestrian movement may be conceptualized in terms of physical

models which describe the flow of gaseous or fluid material;

(2) the measurement of walking velocity, flow rate, and escape

time sufficiently describes "emergency egress behavior."

Psychological and social factors which might influence the

emergency behavior of people need not be considered;

(3) investigation of the dimensional adequacy of exit facilities

is not enhanced by the consideration of factors which dispose

fire victims to actually utilize these facilities effectively;

(4) pedestrian behavior during periods of normal building occupancy,

during drills, or in a laboratory situation sufficiently

represents such behavior during an actual fire emergency;

(5) the measurement of pedestrian flow over selected paths (e.g.,

stairs, or corridor lengths) or bottlenecks provides a sufficient

representation of occupants' behavior for evaluating

entire egress routes.

40
5.1.2 The Literature on Emergency Visibility, Signage, and Lighting

The most serious limitation to the utility of this data base is

that it cannot be generalized from controlled experimental settings, to

real-world fire environments and experiences. Certain trends in the

data do seem to suggest, however, that the limited application of particular

findings, at least on a trial basis in actual buildings, may be useful.

In this context, standards might be developed, validated, or advocated

which concern exit sign lighting, coloration and contrast, minimum

visibility distances in smoke-filled spaces, etc. These appear to

involve the much more stable psycho-physical characteristics of humans,

which are likely to cut across wide variations in social or cognitive

structure. We conclude that this segment of the literature is technically

adequate for applications in which the following assumption is acceptable:

all the vital characteristics of real building fires are sufficiently

replicated in contrived laboratory settings; subjects' responses in the

laboratory therefore provide the experimenter with realistic impressions

of occupants’ behavior under actual fire conditions.

5.1.3 The Literature on Human Responses in Actual Fires

Although there have been a number of recent post-incident studies

on the sequences of actions taken by fire victims while attempting to

evacuate the premises, none of these have proven applicable to the

generation of OSHA egress regulations. These studies have failed to

adequately account for either the validity of the behavioral sequences

reported by victims, or for the environmental and fire development

factors upon which such sequences were dependent. The absence of an explicit concern for the channeling of evacuees to the exitways, or for

the arrangements of alternate exit routes, leaves a gap in the availability

of data to support regulations in these areas.

While many insights on the experiential qualities of the critical

early moments of the building egress process are emerging from this

research, the role of the environment, and the basis upon which it could

be more effectively regulated, remains unknown. Consequently, we

conclude that this portion of the emergency egress literature is technically

adequate only for those applications in which the following assumptions

may be accepted:

(1) case-study data may be extrapolated between diverse occupancy

categories

(2) case-studies of specific historical fire incidents are useful

in the prediction of future fire outcomes, for a given occupancy;

(3) the design of exit facilities requires knowledge of how people

respond to a fire alert, how they interact with other people,

and of the development of decision sequences;

(A) unconfirmed trends apparent In data from non-experimental

studies are applicable to the development of exit facility

design standards;

41
(5) available interview data collected from fire victims are useful even though the potential impact of confounding affects

(e.g., emotional distress, memory decay, the erroneous interpretation of victims' remarks) has not been determined.

5 . 2 Recommendations Concerning Specific Applications of the Available

Technical Literature

Within the limits imposed by the assumptions discussed above,

various segments of the emergency egress technical literature may prove

applicable to specific problem areas. Let us consider such applications

in terms of the egress scenarios and generic response patterns outlined

in Chapter 1 of this report.

5.2.1 The Literature on Carrying-Capacity

Of the three major focal points in the egress literature, the

empirical research on exit facility carrying-capacity appears to involve

the most judgment and assumptions when applying the data. In particular,

we recommend application of this data base only to those emergency

egress design problems in which occupants may be expected to demonstrate:

(a) unambiguous threat perception;

(b) a high degree of familiarity with the building's circulation

system and exit locations;

(c) a high degree of familiarity with emergency procedures; and

(d) an immediate, purposeful, and well-staged exiting response.

The more proximate the threat is to a group of occupants, the more

likely we would expect failure in flow estimates derived from "hydraulic"

or "gaseous" models. We therefore suggest that applications of the

carrying-capacity data base be limited to situations in which building

occupants are outside the immediately threatened zone, and removed from

fire bi-products which might cause confusion or evoke non-adaptive

emotional response.

5.2.2 The Literature on Egress Signage, Emergency Lighting , and

Visibility Through Smoke

Not only is this segment of the empirical base more technically rigorous than that dealing with carrying-capacity, but it also appears more readily applicable over a broader domain of occupants' response patterns.

Clarity of directional cues, and quality of other emergency information

can make the difference between unambiguous direct egress behavior, and

the more indecisive and delayed forms of exiting response. This data

base has the potential of helping to reduce such ambiguity.

It must be emphasized that building designers and code officials

cannot predict the exact course of events during any specific building

fire. Consequently, designs based solely upon carrying-capacity data

may fail whenever:

\

42
(a) threat perception is not as unambiguous as expected;

(b) many more untrained or new occupants, and visitors, inhabit

the facility than were originally planned for; and

(c) the immediacy of the life-threat evokes non-adaptive behavioral

responses

.

In our view, the technical state-of-the-art of this segment of the

egress literature seems sufficiently adequate to justify its application

to the problem of reducing perceptual and cognitive ambiguity during the

emergency exiting process.

5.2.3 The Literature on Occupants 1 Responses to Actual Fire Emergencies

When considering its technical adequacy, this portion of the emergency

egress literature proved least applicable to problems of exit facility

design or regulation. Its greatest potential, however, may lie in the

description of emergency scenarios, the identification of response

behaviors, and the exposure of frequencies with which these actually

have occurred during building fires. We recommend the application of

this data base not to emergency exiting design per se , but rather as a guide to the application of the more design-oriented research, and as a groundwork for continued exploratory investigations of the nature of

human behavior during building fires.

5 . 3 Recommendations Concerning General Directions and Methodological

Requirements for Future Research

5.3.1 General Directions for Research

On the basis of the detailed assessment of the existing data base,

four general categories are recommended for definitive research applicable

to the development of more responsive OSHA regulations for emergency

egress. These are:

(a) Research on access to exitways, including considerations of

travel distances and the spatial separation of alternative

exits

(b) Resolution of the discrepancies between findings by Pauls and

other investigators of the carrying capacity of exitways;

(c) Continued research on egress signage, lighting, and visibility

through smoke (e.g., the work at the Center for Building

Technology, IAT, National Bureau of Standards, which is currently

under the sponsorship of OSHA) ; and

(d) Definitive identification and description of emergency egress

scenarios and response patterns.

In order to guide the development and conduct of specific investigations,

additional recommendations are offered concerning research strategy and

technique, methods of data analysis, and the validation of findings.

43
5.3.2 Strategy and Technique

(a) In reviewing case-study results, it is presently impossible to

determine whether the specific outcomes of the actual fire were among the most or the least probable, nor whether the

incident studied was truly "typical" of the type which might

be expected more generally in the occupancy. Consequently,

the degree to which case-specific findings are useful to

occupancy-wide regulatory policy is questionable. A first

step toward mitigating this problem will be the development of

a data base which yields probability distributions for key

fire-outcomes, as these are reflected for various occupancies.

In this regard, it will be essential that "fire-outcomes" are construed to involve not merely egress time and exit utilization

statistics, but events more telling of occupants' decisionmaking behavior, as well.

(b) Where investigations shall involve measurements made on human

subjects, it is extremely important that the most salient

qualities of actual building conditions are replicated accurately.

If pedestrian movement is to be measured during periods of

normal occupancy, then generalizations will rightfully be

limited to the general case of "normal occupancy." Similarly,

observations made during fire drills may be somewhat telling

of human behavior during such drills, while shedding virtually

no light on the effects of an actual life-threat upon

occupants' responses. If ethical and moral codes ultimately

preclude the conduct of realistic experiments utilizing human

subjects, then such experimentation cannot be considered at

all. But, experimental results derived from poor replications

of actual building fire conditions may yield falacious and

misleading conclusions far too often, rendering such an approach

largely ineffective.

5.3.4 Validation

(a) Since the objective of empirical research will usually be to

accumulate useful data, "reasonable attempts" should be made

to replicate experiments and to validate, or to otherwise

cross-check, the data. Particularly, the investigator must

have some confidence that the variables named are indeed those

that are measured, and that the research setting sufficiently

simulates the kinds of experiences which would be expected in

actual fire situations.

(b) Interpretations and inferences drawn from experimental or quasi-exper imental research should be based on statistical

analyses of the data. This should extend beyond the identification

of trends, offering some measure of confience that variations

are not merely methodological artifacts, nor chance occurrences.

(c) Where the data do not lend themselves to the more rigorous

statistical tests, the evaluation of a given set of findings

might involve the inferences and opinions of a panel of experts.

44
5.4 Conclusions

Current OSHA regulations governing the design of emergency exit

facilities in buildings are based almost exclusively on carrying-capacity

research reported in 1935. However, this segment of the empirical

literature on exiting seems relevant to only a small, but vital, portion

of the emergency egress problem.

Wherever a fire situation is rendered confusing and ambiguous for

any building occupants, the direct egress patterns presumed by carryingcapacity researchers may occur with decreasing frequency. In these

situations, ambiguity may be decreased through the provision of adequate

directional information. While a technically adequate body of data

addressing this subject has begun to emerge, current OSHA exiting regulations

are not based on these recent findings.

No validated data were found pertaining to the role of the environment,

nor of the development of the fire, in shaping the critical decisions

that a person must make when responding to an initial fire alert.

Moreover, no suitable technical data was found that supported current

OSHA regulations on the maximum distances to protected exits, or on the

provision of alternative means of egress (these regulations appear to be

based upon the judgment of engineering experts) . This lack of research

exists despite the fact that a major portion of all fire deaths in

buildings seem to occur while people are trying to reach a protected

exitway or place of refuge.

Finally, an effort was made to consider various OSHA regulations in

the light of available data bases. This analysis represents an initial

attempt to key our recommendations for future research directly to

specific problem areas within the regulations. This analysis is outlined

in Table 1.

45
FOOTNOTES

(1) Public Law 91-596, 91st Congress, S.2193, December 29, 1970. The

complete text appears in Appendix C of P.S. Hopf's useful handbook,

Designer's guide to OSHA: a practical guide to the occupational

safety and health act for architects, engineers, and builders (New

York : McGraw-Hil 1 , 1975 )

.

(2) Occupational Safety and Health Act of 1970, Section 6(a)

46
EMERGENCY EGRESS BIBLIOGRAPHY

Including References Cited

Appleton, I. and Quiggen, P. Hackney hospital fire precautions project,

FRS contribution: an evacuation model . Boreham Wood, U.K. : Building

Research Establishment, Fire Research Station, Operations Research

and Systems Studies Section, 1976.

Associate Committee on the National Building Code. Measures for fire

safety in high buildings. Ottawa: National Research Council of

Canada, 1973.

Bazjanac, V. Another way out? Progressive architecture, April, 1974,

88-89.

Best, G. Direction finding in large buildings. In Canter, D. V. (ed.),

Arcitectural psychology . London: R.I.B.A. Publications, Ltdl,

1970, 72-75.

Bird, E. L. and Docking, S. J. Fire in buildings . London: A & C Black,

1949.

Breaux, J. , Canter, D. V. and Sime, J. Psychological aspects of behavior

of people in fire situations. Surrey, U.K. : University of Surrey,

Fire Research Unit, 1976.

Brend, H. J. Means of escape in case of fire . London: Sir Isaac Pitman

and Sons, Ltd., 1952.

Bryan, J. L. Human behavior in fire situations. Presented at the 2nd

Joint Panel Meeting on Fire Safety and Research, Tokyo, Japan,

October 19-23, 1976.

Caravaty, R. D. and Haviland, D. S. Life safety from fire: a guide for

housing the elderly . Troy New York: Rensselaer Polytechnic Institute,

Center for Architectural Research, 1967.

Cathey, B. H. A technique for analyzing building evacuation plans and

facility designs. Am. Soc . of Safety Engineers Journal , August,

1974, 26-28.

Chandler, L. T. Automatic recall of elevators by smoke detectors in

high-rise buildings. Fire journal , 1974, 6J3, 6, 79-82, 88.

47
Daniels, I. Experiencing a high-rise fire. Skyscraper management , July-August, 1975, 26.

Degenkolb, J. G. Exits and the building code. Am. Bldg, code news-analyst , October, 1963, 4^ 10.

Degenkolb, J. G. The evolution of high-rise fire protection. Bldg, official

and code administrator

and code administrator . Sept., 1974, 26-32; October, 1974, 20-31.

Dept, of Employment and Productivity. Means of escape in case of fire in

offices, shops and premises . London: H.M.S.O., Safety, Health and

Welfare: New Series #40.

Dominion Fire Commissioner. Emergency lighting systems . Ottawa: Dept,

of Public Works, Dominion Fire Commissioner, April, 1966.

Dowling, J. R. High-rise building code requirements available for

adoption. A. I. A. J. , January, 1973, 35.

Edmondo, P. M. , Hahin, R. and Sinay, J. P. Emergency egress from ships'

compartments. Phase II: a systems analysis

compartments. Phase II: a systems analysis . Annapolis: Naval

Ship R & D Laboratory, Report #2303, (ELECLAB 67/69), November, 1969.

Edmondo, P. M. and Macey, H. T. An investigation of lighting directional

Markers for emergency egress from ships compartments. Phase I study:

lighting investigation . ANNADIV NAVSHIPRANDCEN, Report #2661,

November, 1968.

Edmondo, P. M. , Musson, R. , and Sinay, J. P. Emergency egress from ships'

compartments. Phase III: installation and evaluation of a directional

marking system and lighting system . ANNADIV NAVSHIPRANDCEN, Report

#3561, February, 1972.

Ferguson, R. S. Towards a knowledge-based code. Presented at the Ottawa

Life Safety Systems Conference, National Research Council of Canada,

Div. of Building Research, Ottawa, Canada, July 23-24, 1974.

Fruin, J. J. Traffic and space characteristics of pedestrians. In

Fruin, J. J. Pedestrian planning and design . New York: Metro.

Ass'n. of Urban Designers and Environmental Planners, Inc., 1971.

Galbreath, M. A survey of exit facilities in high office buildings . Ottawa: National Research Council of Canada, Div. of Building

Research, Research Note #64, Sept. 1968.

Galbreath, M. A survey of exit facilities in high office buildings . Ottawa: National Research Council of Canada, Div. of Building Research,

Fire Research Note #8, May, 1969.

Garner, J. D. and Blethrow, J. G. Emergency evacuation tests of a crashed

L-1649 . Washington, D.C.: Fed. Aviation Admin., Off. of Aviation

Medicine, August, 1966.

48
Garner, J. D. and Blethrow, J. G. Light levels required for recognition

of five color contrasts for escape routes from aircraft. Washington,

D.C.: Fed. Aviation Admin., Off, of Aviation Medicine, unpublished

ms., January, 1968.

Garner, J. D. and Blethrow, J. G. Evacuation tests from an SST mock-up . Washington, D.C.: Fed. Aviation Admin., Off, of Aviation Medicine,

AM 70-19, December, 1970.

Garner, J. D. and Lowrey, D. L. Exit sign comparisons in clean air and

smoke. Washington, D.C. : Fed. Aviation Admin., Office of Aviation

Medicine, unpublished ms., December, 1976.

Haber, G. M. Fire as environment: study of human interaction with fire

as environment, in health care institutions. Washington, D.C.:

National Bureau of Standards, Center for Fire Research, IAT, Program

for Design Concepts, 1977.

Harrison, G. A. The high-rise fire problem. CRC critical reviews in

environmental control , October, 1974, 4_, 4, 483-505.

Hasbrook, A. H. , Garner, J. D. and Snow, C. C, Evacuation pattern

analysis of a survivable commercial aircraft crash . Oklahoma City:

Fed. Aviation Admin., Aviation Medical Service, Research Div. , Civil

Aeromedical Research Inst., Protection and Survival Br., May, 1962.

Henderson, L. F. The statistics of crowd fluids. Nature , 1971, 229 , 381-383.

Ide, K. The causes of death in fires. Resume of symposium reports.

Symposium of the physical, psychological and behavioral aspects of

fires, Japan Fire Science Ass'n.. November 20-21, 1975.

Inst, of Traffic Engineers. Pedestrian characteristics and space

requirements. Inst, of Traffic Engineers, Committee 8F, 1964.

Jensen, R. (ed.). Fire protection for the design professional . Boston:

Cahners, 1975.

Klein, J. (ed.). Emergency lighting handbook . Newark, N.J.: Electric

Cord Co . , 1961

Langdon-Thomas , G. J. Fire safety in buildings . London: A & C Black,

1972.

Lefer, H. Where there's fire there's smoke. Progressive architecture . Sept., 1976, 58-63.

Lerup, L. Mapping behavior: the case of fire (Working Paper No. 5) . Berkeley, Ca.: University of California, College of Environmental

Design, 1975.

49
Loftus, E. L. and Keating, J. P. The psychology of emergency communications.

In: G.S.A., P.B.S., 1974 international conference on fire safety in

high-rise buildings , Seattle, November 18, 1974.

London Transport Board. Second report of the operational research team

on the capaci ty of footways . London: London Transport Board, Research

Report #95, August, 1958.

Marchant, E. W. (ed.). A complete guide to fire and buildings . New York:

Barnes and Noble Books, 1973.

Marchant, E. W. Escape route identification. Fire Journal , December, 1970,

324.

Melinek, S. J. Methods of determining the optimum level of safety

expenditure . Boreham Wood, U.K. : Building Research Establishment,

Fire Research Station, October, 1974.

Melinek, S. J. and Baldwin, R. Evacuation of buildings: some effects of

changes in performance standards . Boreham Wood, U.K.: Building

Research Establishment, Fire Research Station, October, 1975.

Melinek, S. J. and Booth, S. An analysis of evacuation times and the

movement crowds in buildings . Boreham Wood, U.K. : Building Research

Establishment, Fire Research Station, CP 96/75, October, 1975.

Miura, T. Human physiology in high heat environments. Resume of

Symposium reports. Symposium on the physical, psychological and behavioral

aspects of fires, Japan Fire Science Ass'n., 1975.

Mohler, S. R. , Swearingen, J. J., McFadden, E. B. and Garner, J. D. Human factors of emergency evacuation . Oklahoma City: Fed.

Aviation Admin., Office of Aviation Medicine, Cvil Aeromedical

Resarch Inst., Sept., 1964.

Naka, Y. Study on simulation of complicated passenger flow in a railway

station. Presented at the 2nd Joint Panel Meeting on Fire Safety

and Research, Tokyo, Japan, October 19-23, 1976.

Nakamura, K. and Yoshioka, M. A simulation model of pedestrian flow

and its investigation. Summary of papers on general fuzzy problems,

The Working Group on General Fuzzy Systems, Report #1, November, 1975.

National Bureau of Standards. Design and construction of building exits

Washington, D.C.: U.S. Department of Commerce, National Bureau of

Standards, Misc. Publication M151, 1935.

National Fire Protection Association (N.F.P.A.). Employee organization

for fire safety . Boston: N.F.P.A. 1942.

N.F.P.A. Guide to O.S.H.A. f ire protection regulations . Vol. 1: N.F . P.A.

annotated O.S.H.A. regulations . Boston: N.F.P.A., 1971.

50
N.F.P.A.

1972.

High-rise buildings and fire safety . Boston: N.F.P.A., SSP-18,

N.F.P.A. Life Safety Code (101) . Boston: N.F.P.A., 1973.

N.F.P.A. Proceedings of the 21st Annual Meeting . Boston: N.F.P.A.,

1917.

N.F.P.A. Taiyo Department Store Fire. Fire journal , 1974, 68_, 3, 42-43.

National Safety News (staff). O.S.H.A. 's impact on fire protection.

National safety news , July, 1972, 47.

Patton, R. M. Life safety fire suppression system. The Minnesota fire

chief , July-August, 1976, 14-15.

Pauls, J. L. Movement of people in buildings. Presented at the Symposium

on Human Response to Tall Buildings, Chicago, July, 1975. Ottawa:

National Research Council of Canada, Div. of Building Research, June,

1975.

Peschl, I.A.S.Z. Passage capacity of door openings in panic situations.

Bown (Construction), January 9, 1971, 2^, 62-67.

Phillips, A. W. Human behavior in high-rise fires. Fire chief magazine , March, 1974, 30-31.

Phillips, A. W. The physiological and psychological effects of fires

in high-rise buildings. Factory Mutual record , May-June, 1973, 8-10.

Roytman, M. Ya. Principles of fire safety standards for building construction . Moscow, USSR: Construction Literature Publishing House, 1969. Translated

and published for N.B.S. New Delhi: Amerind Publishing Co., Pvt.,

Ltd., 1975.

Rubin, A. and Cohen, A. Human behavior in building fires . Washington, D.C.:

National Bureau of Standards, Technical Note #818, 1974.

Saito, F. Toxicity of combustion products during fires: determination

methods. Resume of symposium reports, Symposium on the Physical,

Psychological and Behavioral Aspects of Fires, November, 1975.

Schadt, A. C. High-rise life safety . Minnesota fire chief , July-August,

1975, 7.

Sf intesco , D. Points to consider: fire. A. I. A. J, , January, 1973, 31-35.

Skilling, G. B. The case for evacuating high-rise buildings. Fire

j ournal , 1972, 66_, 3, 25-26.

51
Snow, C. C., Carroll, J. J. and Allgood, M. A. Survival in emergency

escape from passenger aircraft . Washington, D.C.: Fed. Aviation

Admin., Off. of Aviation Medicine, AM 70-16, October, 1970.

Spehler, R. and Peissard, W. The evacuation of premises. The architect , September, 1972, 80-81.

Stevens, R. E. Exits in core-type office buildings. Fire journal . May,

1970, 64, 3, 68-70.

Stevens, R. E. The high-rise building dilemma. In High-rise building

fires and fire safety . Boston: N.F.P.A., SSP-18, 1972, 71-73.

Stevens, R. E. Movement of people. Fire journal , January, 1969, 63 , 1, 27-29.

Tashida, Shin. Walking in the midst of smoke. Symposium on the physical,

psychological and behavioral aspects of fires. Tokyo: Japan Fire

Sciences Ass'n., November, 1975.

Templer, J. A. Stair shape and human movement. Unpublished Ph.D.

dissertation. New York: Columbia University, 1974.

Togawa, K. Study on fire escapes based on the observations of multitude

currents . Tokyo: Ministry of Construction, Building Research Inst.,

1955.

Tsukamoto, K. A study of the nature of the causes of accidental death

in fires. Resume of symposium reports. Symposium on the physical,

psychological, and behavioral aspects of fire, November 20-21, 1975.

U.S. Congress. Occupational safety and health act. Public Law 91-596,

91st Congress, S.2193, December 29, 1970.

Wadey, W. J. Principles and means of escape in case of fire. The builder . August 8, 1965, 788.

Watanabe, Y., Nayuki, K. , and Torizaki, K. Actions of firemen in smoke . Tokyo: Fire Research Inst, of Japan, Report #37, 1973.

Williams, M. B. Topical report: fire safety for high-rise buildings . Silver Spring, Md. : The Johns Hopkins Univ. , Applied Physics Laboratory,

APL JHU , FPP TR7 , November, 1971.

Williams-Leir , G. Multiple regression analysis of fire deaths from burning . Ottawa: National Research Council of Canada, Research Note #58.

Willman, M. W. Updating the latest for early warning fire detection:

Toronto-Dominion Centre. Skyscraper management , July-August, 1975,

21-23.

52
Wood, P. G. The behavior of people in fires . U.K.: Dept, of the Environment

and Fire Officers' Committee, Joint Fire Research Organization, November,

1972.

Wooliscroft, M. J. The hospital fire problem: towards a rational approach.

Fire , 1976, 511-512.

Yamada, S. and Takeshi, G. Human walking and sense of panic during times

of disaster. Resume of symposium reports, Symposium on the physical,

psychological and behavioral aspects of fires, Japan Fire Sciences

Ass'n., Tokyo, November 20-21, 1975.

53
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II

t'

U.S. DEPT. OF COMM. BIBLIOGRAPHIC DATA

SHEET

1. PUBLIC ATTON OR REPORT NO. NBSIR 77-1313

2. (iov*t Accession

No.

3. Recipient’s Accession No.

4. TITLE AND SUBTITLE

An Assessment of the Technical Literature on Emergency

Egress From Buildings

5. Publication Date

6. Performing Organization Code

7. AUTHOR(S)

Fred I. Stahl and John Archea

8. Performing Organ. Report No.

9. PERFORMING ORGANIZAT ION NAME: AND ADDRESS

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

10. Project /Task/ Work Unit No. 4632470

11. Contract /Grant No.

12. Sponsoring Organization Name and Complete Address (Street, City, State, ZIP)

Same as item 9

13. I ype of Report & Period Covered

Final

14. Sponsoring Agency Code

15. SUPPLEMENTARY NOTES

16. ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a significant

bibliography or literature survey, mention it here.) An assessment was made of the literature on research related to current emergencyegress regulations promulgated by the Occupational Safety and Health Administration

(OSHA) . The purposes of this assessment were to ascertain the extent to which

these regulations were based upon empirical research, and to determine the adequacy

of available research findings from which OSHA emergency egress regulations may be

developed. Three areas of research on emergency egress were identified: research

on (1) the carrying capacity of exitways, (2) signage, lighting, and visibility

through smoke, and (3) occupant responses to, and experiences in building fires.

Only research on the carrying capacity o^ exitways appears to have had direct

impact on current OSHA regulations, which are based largely on empirical findings

reported in 1935. Much of the available data on egress signage, lighting,

visibility through smoke, and occupants' responses in real fire situations have

appeared since the adoption of standards by OSHA. Consequently, these areas have

had minimal impact on OSHA egress regulations. This study provides specific recom- mendations concerning the technical adequacy and range of applicability of the

available empirical literature on emergency egress from buildings. In addition,

it provides specific recommendations concerning directions and methodological

requirements for future research.

17. KEY WORDS (six to twelve entries; alphabetical order; capitalize only the first letter of the first key word unless a proper name; separated by semicolons) Architectural psychology; architectural research; building

codes; building design; building fires; building regulatory standards; emergency

egress; exit capacity; fire safety; human performance; regulatory data; occupational

safety.

18. AVAILABILITY [x] Unlimited

| For Official Distribution. Do Not Release to NT IS

[ J Order From Sup. of Doc., U.S. Government Printing Office Washington, D.C . 20402, SD ( at . No. ( 15

[X" Order F rom National T echnical Information Service (NT IS) Springfield, Virginia 22151

19. SECURITY CLASS

(THIS REPORT)

21. NO. OF PAGES

62

UNCLASSIFIED

20. SECURITY CLASS 22. Price (THIS PAGE)

$ 5.25

UNCLASSIFIED

OMM- D 29042
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