Reference

A111D1 72TS2L

NAT'L INST. OF STAND & TECH R.I.C.

A1110S 031242

NBSIR 80-2003

Workplace Safety Symbols:

Current Status and Research

Needs

Neil D. Lerner

Belinda L. Collins

Building Safety and Security Group

Environmental Design Research Division

Center for Building Technology

National Engineering Laboratory

National Bureau of Standards

U.S. Department of Commerce

Washington, DC 20234

March 1980

U.S. DEPARTMENT OF COMMERCE —QC

100

,1156

80-2003

1980

NATIONAL BUREAU OF STANDARDS

National Bureau of Standards

Library, E-01 Admin. Bldg.

WORKPLACE SAFETY SYMBOLS:

CURRENT STATUS AND RESEARCH

NEEDS

NBSIR 80-2003 FEB 2 7 198)

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Neil D. Lerner

Belinda L. Collins

Building Safety and Security Group

Environmental Design Research Division

Center for Building Technology

National Engineering Laboratory

National Bureau of Standards

U.S. Department of Commerce

Washington, DC 20234

March 1980

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

Luther H. Hodges, Jr., Deputy Secretary

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

NATIONAL BUREAU OF STANDARDS. Ernest Ambler, Director

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ACKNOWLEDGMENTS

This work was supported by the National Institute of Occupational Safety

and Health under an agreement with the National Bureau of Standards. We

wish to thank James Lark and Roger Jensen of NIOSH for providing valuable

suggestions and technical coordination. Brian Pierman of the National

Bureau of Standards also provided valuable support. Finally we wish to

thank the personnel of the plants we visited for their generous help and

expertise.

iii
ABSTRACT

Although written signs are a common means of conveying safety information

in the workplace, pictographic symbols can be a more effective way of

providing the same information. Symbols are independent of a particular

written language, and can be more accurately and rapidly perceived than

the comparable word message. Despite the many advantages of safety

symbols, they can be ineffective or even dangerous if the intended meaning is not accurately communicated. As a result, there is a great need

for careful evaluation, consistent application, and eventual standardization for safety symbols.

This report documents an initial assessment of current symbol use and

future requirements. It includes a review of the technical literature

on symbol research; observation of safety sign and symbol use in the

workplace; compilation of commercially available symbol referents; and

review of national and international standards. Based upon these sources,

an initial list of 40 symbol referents is presented along with research

priorities for evaluating the effectiveness of symbols for these

referents

.

iv
EXECUTIVE SUMMARY

Signs are a common means of conveying warnings and information in the

workplace, and so play an important role in worker safety. Traditionally, signs have conveyed information through written messages. In

many instances, however, pictograms or symbols may be a superior means

of communicating safety information. As a result, there has been a tremendous growth of interest in the use of symbolic signs beginning

with highway information and now including product and workplace safety

applications.

Among the potential advantages of symbolic signs over comparable word

signs (researched mainly for highway signs) are: independence from

written language (which is important especially where foreign languages

or functional illiteracy occur), rapid and accurate perception, shorter

reaction time, perception at greater distances, rapid and accurate

learning of symbol meaning, and maintained effectiveness under conditions of stress, distraction, or visual degradation. However, if not

properly developed, symbols can be ineffective, and even dangerous, as in cases where a meaning opposite to the intended message is conveyed.

As a result, the need for careful evaluation, consistent application,

and ultimately standardization is critical for safety symbols.

In support of the development of effective workplace safety symbols,

the National Institute of Occupational Safety and Health (NIOSH) has

sponsored a project at the National Bureau of Standards (NBS) to evaluate the use of pictographic signs in the workplace. This project will

consist of three general tasks: (a) determination of the kinds of

safety or hazard situations which require symbols; (b) development of

a set of candidate symbols for each situation; and (c) experimental

evaluation of the effectiveness of the symbols in communicating the

intended meaning.

This report documents the findings from the initial phase of the project. This includes (a) a review of the technical literature on symbol

use; (b) observations on safety sign use documented at six site visits

to various factories representing diverse industries; (c) information

obtained from sign manufacturers; (d) information on commercially available symbolic signs, and (e) a review of national and international

standards for symbols.

Based upon these sources an initial list of 40 symbol referents (meanings) is presented. Examples of symbols for each referent are now

being collected. These referents and selected symbols will be

researched in the next two phases of the project. Finally, research

priorities for the investigation of safety symbols are discussed,

focusing on the determination of the meaningfulness of the symbols.

These priorities will be used to develop a testing program which will

be implemented during the next phases of the project. The outcome of

testing will suggest procedures for evaluation and a preliminary

set of symbols for further research and development. v
TABLE OF CONTENTS

Page

ACKNOWLEDGMENT iii

ABSTRACT iv

EXECUTIVE SUMMARY v LIST OF FIGURES viii

LIST OF TABLES viii

SI CONVERSION ix

1. INTRODUCTION 1

1.1 Need for Symbol Use 1 1.2 Requirements for Research on Workplace Safety Symbols ... 2

2. OVERVIEW OF SYMBOL RESEARCH LITERATURE 4

2.1 Background 4

2.2 Highway Symbol Research 6

2.2.1 Direct Comparison of Word and Symbol Signs 6

2.2.2 Assessment of Meaningfulness 9

2.2.3 Behavioral Observations of Symbol Effectiveness... 11

2.2.4 Visibility of Highway Symbols 11

2.3 Automotive and Machinery Symbols 12

2.4 Public Information Symbols 15

2.5 Product Labeling Symbols 17

2.6 Safety Symbols 18

3. DEVELOPMENT OF WORKPLACE SAFETY SYMBOL REFERENTS 20

3.1 Overall Procedures 20

3.2 Site Visits 21

3.2.1 Generic Hazards and Common Injuries 21

3.2.2 Use of Pictographic Signs 23

3.2.3 Alternatives to Signs 23

3.2.4 Sign Context 24

3.2.5 Most Frequent Signs 24

3.3 Sign Catalogues, Publications and Manufacturers 26

3.3.1 Catalogues and Publications 26

3.3.2 Information from Sign Manufacturers 26

3.4 Review of Symbol Standards 28

3.5 Symbol Referents Recommended for Study 32

vi
TABLE OF CONTENTS (Continued)

Page

4. NEEDS FOR RESEARCH ON WORKPLACE SYMBOLS 35

4.1 Effective Symbols: Research Focus 35

4.2 Procedures for Evaluating Understandability 35

4.3 Other Research Considerations in Determining Symbol

Effectiveness 38

5. CONCLUSION 38

REFERENCES 39

APPENDIX A 43

APPENDIX B 50

vii
LIST OF FIGURES

Page

Figure 1. Proposed ISO Symbol for "No Exit” (Blind Alley) 3

Figure 2. Symbolic Conceptualizations of "Restricted Entry" 5

Figure 3. Graphic Variation of a Single Conceptualization for

"No Smoking" 29

Figure 4. Further Examples of "No Smoking" Symbols (in addition

to those in Figure 3) 34

LIST OF TABLES

Table 1. Site Visits 22

Table 2. Common Generic Messages from Site Visits 25

Table 3. Symbols Typically Available from Sign Catalogues 27

Table 4. Symbol Referents Standardized by ISO and the EEC

for European Application 30

Table 5. Common International Referents for Symbols from the

Australian, British, Dutch and French Standards 31

Table 6. Selected List of Symbol Referents 33

viii
SI CONVERSION

The units and conversion factors given in this table are in agreement

with the International System of Units or SI system (Systeme International d'Unites). Because the United States is a signatory to the 11th

General Conference on Weights and Measures which defined and gave

official status to the SI system, the following conversion factors are

given.

Length

1 inch = 0.0254* meter

1 foot = 0.3048* meter

Area

1

1

/ A square inch = 6.4516* x 10 4 meterz square foot = 0.0929 meter^

Volume

1 cubic foot (ft^) = 0.0283 meter^

Exactly

ix

1.0 INTRODUCTION

1.1 NEED FOR SYMBOL USE

Written signs have traditionally provided information to guide, protect,

and inform people in buildings in the United States. Written signs are

common in the workplace, where they play an important role in worker

safety. More than 5.6 million people were injured, and at least 4500

were killed, in workplace accidents in the United States in 1978 (Bureau

of Labor Statistics, 1979). Injury is most likely during the first month

on the job, and the "incidence of injury or illness decreases with length

of service in all age groups" (National Safety Council, 1979, p. 26).

Signs may be particularly important in alerting the new worker, who is

less familiar with existing hazards and precautions. Despite the

prevalence of written signs, however, they may not be the best way of

conveying necessary information. As a result, there has been a tremendous

growth in the use of pictograms or symbols. With these, the information

is conveyed pictorially, often without word labels.

The modern use of pictograms began with the development of standardized

traffic symbols in Europe in the early part of this century. Currently,

there is increasing use of symbols within the United States for transportation systems, hazard warnings, fire safety, and public information.

For example, the Department of Transportation (DoT) successfully sponsored

the implementation of standard symbols for motorists, and has proposed

other symbols for public information in transportation facilities. Increased concern for worker safety and consumer protection has sparked

interest in the United States in the use of symbols as a viable means of

communicating safety information.

The increasing interest in symbol use can be seen from the various

national and international groups that are developing standards for symbols. At the national level, the American National Standards Institute

(ANSI) has recently chartered the Z535 Committee on Safety Colors, Signs,

Symbols, and Product Alerts while the National Fire Protection Association (NFPA) has sponsored a subcommittee on Visual Alerting Signs and

Symbols. Both of these committees are working toward the development

of voluntary standards for worker safety and fire safety symbols. The

Society of Automotive Engineers (SAE) has also sponsored the development

of a set of standard automotive symbols. In the international realm,

the United Nations (UN) has developed signs and symbols for labeling

hazardous materials for transport. Finally, the International Organization for Standardization (ISO) has three committees dealing with standards for symbols. These include the Technical Committee (TC) 21 on Equipment for Fire Protection and Fir^ Fighting; TC 80 on Safety Colors

and Signs; and TC 145 on Graphic Symbols. There are not yet any national

standards in the U.S. for workplace or worker safety symbols, however.

The reasons for developing symbols for use in workplaces lie in the

numerous advantages of symbols. The primary advantage, of course, is

1
that pictures communicate information without the use of written language (Mead & Modley, 1968; Modley, 1966). Symbols have been used in

Europe because the prevalence of international travel and trade created

the need to overcome language barriers (Kolers, 1969). Even within the

U.S., there are large numbers of people who do not read or speak English

well. Because there are no established criteria for functional literacy, estimates of illiteracy vary widely from about 2 million to about

64 million adult Americans (Kirsch & Guthrie, 1977-1978; Washington

Post, 1979). Furthermore, Bureau of the Census data, collected in 1976,

indicated that English was not the usual language for about 8 million

people in the U.S. Of these, about 5 million reported difficulty in

speaking or understanding English. (There were no reported data on reading skills). For those whose native language is not English or who

are functionally illiterate, symbols could be the only visual warnings

for preventing accidents and providing protection.

1.2 REQUIREMENTS FOR RESEARCH ON WORKPLACE SAFETY SYMBOLS

An overview of the research literature on symbols (presented in more detail in Section 2.0), underlines some additional advantages of symbols. Among the major advantages are that pictograms can, in some

cases, be perceived more rapidly (Janda & Volk, 1934), more accurately

(Walker, Nicolay & Stearns, 1965), and at a greater distance (Smith & Weir, 1978) than words. Reaction time may be shorter to symbols (Smith

& Weir, 1978), even under conditions of stress (Smillie, 1978). Symbol

meanings can often be rapidly learned and accurately remembered (Walker,

et al., 1965), with minimal confusion among alternatives (Green & Pew,

1978). Symbols may also be superior to words under conditions of interference either by distraction from another task (King & Tierney, 1970)

or by visual interference or degradation (Ells & Dewar, 1979). These

advantages of symbols over words may not be true under all conditions,

however.

Most of this research has focused on highway signs, with some attention

to applications such as automotive machinery and product labeling. Yet

these experiments have, for the most part, ignored the use of symbols to

convey safety messages within buildings. As a result, their effectiveness has rarely been evaluated.

Although symbols can be more effective than written signs, their effectiveness depends heavily upon selecting symbols which are readily understandable. Simply drawing a picture is not sufficient. The picture

must be evaluated in a systematic research program. Yet, this evaluative stage is rarely done, because symbols are typically developed and

implemented in response to an individual, specific need. Although the

creator of a symbol may understand its meaning perfectly, this message

may not be communicated to anyone else. Collins and Pierman (1979)

noted that several fire-safety symbols developed by ISO TC 21 failed to

communicate the intended meaning to a large percentage of U.S. subjects.

In fact, some of the symbols communicated a meaning which was the opposite of the intended message. Figure I shows a proposed ISO symbol to

2

indicate a blind alley (no exit). Not only did Collins and Pierman find

that few people identified this meaning correctly (2%), but one-third of

those tested thought it meant exit or safe area. A situation in which

a symbol communicates an opposite meaning illustrates the most serious

problem with the use of symbols. As a result, before symbols are standardized, particularly for safety situations, their effectiveness in

communicating the message must be evaluated.

Once a symbol has been developed to fill a specific set of needs and

researched to determine its effectiveness, it should be standardized for

a given application. A major problem currently is that anyone who feels

the need for a symbol develops one, often without reference to existing

symbol sets. Figure 2 shows an example of eight different conceptualizations, for symbolizing "restricted entry." Each of these basic forms

may have several graphically distinct renditions in use. This illustrates how the same message may have several different graphic images.

If the representation of each of these symbols is very different, the

potential for serious confusion is great. Therefore, there is a need

to develop consistent and ultimately standard sets of safety symbols for

use in workplaces. Because the signs currently used in workplaces provide critical information for preventing accidents and for providing

personal protection, failure to develop and implement consistent, wellrecognized symbols is potentially dangerous.

The task of developing effective workplace symbols is threefold. First,

a determination must be made of the kinds of situations which require

symbols. Exactly what messages, or referents, need to be conveyed and

for which hazards? Secondly, a set of candidate symbols must be

selected for each referent, particularly where there have been numerous

attempts to symbolize a given referent. Thirdly, the various proposed

symbols must be evaluated to determine if they, in fact, communicate the

desired meaning to the target audience. In this process, it is important to realize that because some situations are more difficult than

‘ others to symbolize, the process of developing effective symbols must

be an evolutionary one.

In the following pages we will review the research literature; describe

site visits and conclusions from visits to factories; review catalogues

and correspondence with numerous sign manufacturers; develop a list of

symbol referents for further investigation; review national and international standards for symbol use; and discuss requirements for assessing

the effectiveness of worker safety symbol evaluation methods.

2. OVERVIEW OF SYMBOL RESEARCH LITERATURE

2.1 BACKGROUND

Before symbols are implemented as part of a communication system, their

effectiveness in conveying information and producing the desired behavior

must be evaluated. For a symbol to elicit a behavioral response, a series of psychological processes must be completed. These include

4
Figure 2. Symbolic Conceptualizations of ’’Restricted Entry"

(Some of these symbols may be privately copywritten)

5
detection, discrimination, recognition, and understanding (or identification). (For a complete discussion of perceptual information processing, see Dember and Warm, 1979.) A symbol must be effective at each

stage of this process if it is to be a reliable means of communication.

Research on symbols has focused on various stages, asking such questions

as: How detectable is the symbol? How discriminable is it from all

other symbols? How recognizable is it when seen in a different context?

How well does it communicate the desired meaning? How effectively

does it alter behavior? In addition, some experimenters have assessed

people's attitudes toward, and preferences for, specific symbols.

In the literature review that follows, it will become apparent that some stages of the communication process have received relatively little

research attention. Furthermore., most symbol systems have not been

studied systematically. For the most part, researchers have concentrated on detectability and understandability as the major research

areas for symbols. Although the bulk of the research has concentrated

upon highway symbols, this review will discuss the application of

symbols in four areas: road and highway symbols; vehicle and machine

symbols; public information and directional symbols; and product hazard

symbols. Workplace safety symbols have received little research attention, although some relevant experimental results will be discussed at

the end of this review.

2.2 HIGHWAY SYMBOL RESEARCH

The bulk of the highway symbol research has centered upon a comparison

of the effectiveness of word and symbol signs, typically for response

accuracy or reaction time. In several other instances, a set of symbols

has been directly evaluated for its understandability. Finally, several

investigators have assessed the effectiveness of highway symbols in

terms of perceived meaningfulness, discriminability , or alteration of

behavior.

2.2.1 Direct Comparison of Word and Symbol Signs

One of the first highway symbol experiments was conducted by Janda and

Volk (1934) who assessed the speed of reaction to 20 signs and symbols.

They also assessed the correctness of response by having subjects push

a lever in the direction indicated by the various symbols and signs.

Reaction time was shortest for the symbols and greatest for the words

alone with a total difference of 200 msec. In addition, speed of

response increased with repeated trials. The authors claimed

consequently that word signs are a relatively poor way of conveying

information to people.

In a later comparison of word and symbol signs, Walker, Nicolay, and

Stearns (1965) compared both the accuracy of understanding and the ease

of learning for international highway symbols and U.S. highway (word)

signs. The authors presented seven black and white signs and symbols

for .06 sec tachistoscopically after five minutes of familiarization.

6
Subjects identified the nature of the sign or symbol in writing, after

it was presented briefly. This procedure was repeated using colored

stimuli for a new set of subjects. Finally, subjects defined the meaning of the symbols in a subsequent test of retention. In all cases, the

authors found that the international symbols were identified significantly more accurately than the word signs regardless of color and delay

before re-testing. They attribute the better performance of symbols to

their perceptual simplicity and visual integration.

A number of researchers have used a measure termed "glance legibility"

to assess the effectiveness of word and symbol signs. As defined by

King (1971, 1975), glance legibility is the percentage of correct

matches between a symbol (or word) stimulus and an answer chosen from

an array of symbols or words. The tachistoscopic presentation of the

test stimulus is limited to brief exposures. Both the time to make the

match and the accuracy of the match are recorded. Glance legibility

essentially measures the recognizability of a symbol.

King (1971) used the glance legibility procedure to compare the meaningfulness of two series of 10 symbols each with one series of 10 road

signs for 208 subjects. First, King had subjects give a definition for

each symbol. Then, King presented each symbol briefly (.05 sec and .3

sec) so that subjects could match it against an answer array of 9 symbols. King found that there were significant differences in the accuracy

of response for the two series of symbols; the series which contained

prohibitory symbols proved to be especially difficult to define. When

glance legibility was assessed, the percentage of correct matches decreased for word signs as presentation time decreased, but not for symbol signs. There were no differences in correct response between the

two series of symbols, however. Finally, 65 percent of King's subjects

claimed that the symbol signs were easier to match than the word signs.

Thus, although the word signs may have been initially more meaningful,

under short presentation times, symbols were more recognizable and more

accurately matched.

In a subsequent experiment, King (1975) used the glance legibility

approach to study the effects of delayed stimulus presentation, with

and without interference during this delay, upon the accuracy of symbol

recognition. Under actual driving conditions, there is typically a time

interval between observing a highway sign and acting upon it. In addition, the driver usually performs some other driving-related task during

this time interval. Consequently, King (1975) repeated his earlier

experimental procedure but delayed the subject's response for intervals

of 5 and 10 seconds and added an interference task during another 10

second interval. The symbols, signs, °r*d presentation durations

used in King (1971) were repeated. For the short (.05 sec) viewing

conditions, the percentage of errors increased for both the 10 sec delay and interference conditions. In addition, even more errors ocurred

for the word signs under interference conditions. King suggested that

his results indicate that symbols retain their superiority under difficult viewing conditions.

7
Plummer, Minarch, and King (1974) also used the glance legibility task

to compare reaction time and response accuracy for 10 highway word and

symbol signs. They presented a single word or symbol for 200 msec. Subjects selected an answer from an array containing either 3 words or

3 symbols which was presented for 6 sec. Each comparison was repeated

3 times for a total of 60 observations for each subject. In addition

10 subjects received special training on highway symbol signs. The

authors found that the reaction time, or time to select an answer from

the answer array and depress the correct button, was slower for symbol

signs than for word signs. The response to symbols was significantly

more accurate, however. Prior training decreased reaction time but did

not affect accuracy. Finally, individual symbols varied both in

response time and recognition accuracy.

Dewar (1976) used the glance legibility procedure to determine the

effects of a prohibitory slash upon symbol recognition. Fifteen symbols

were studied under four different ways of symbolizing prohibition:

slash superimposed on the symbol, symbol superimposed on the slash,

partial slash, and circular red surround. Both normal and degraded

viewing conditions were studied. In each, legibility was greatest for

symbols with a red surround and least for symbols with the symbol superimposed upon prohibitory slash. Nevertheless, because the use of a red

circle to indicate prohibition would not be effective for most color

defective people, Dewar recommended the use of a partial slash.

It is important to remember that Dewar's (1976) experiment was a recognition experiment in which he did not assess the meaningfulness of the

various prohibitory conditions or compare different permissive and prohibitory versions of the same symbols. Nevertheless, his results do

indicate that the slash can impair the detectability of the symbol

underneath. As as result, it is particularly important to ensure that

the underlying symbol is not overly complex. Resolving the issue of

complexity is, in itself, a difficult question which deserves further

research.

In a later experiment Dewar and Ells (1977) compared accuracy scores from a glance legibility experiment with the meaningfulness of the same

symbols using the semantic differential. The semantic differential

measures the meaningfulness of a word or idea by having subjects rate

the sign on a set of scales made up of bipolar adjective pairs. In a test of 20 traffic symbols, Dewar and Ells found that meaningfulness

as defined by the semantic differential was highly correlated with the

accuracy of a subject's definition of a symbol. In a second experiment,

Dewar and Ells were able to correlate glance legibility with semantic

meaningfulness only for word i.^is, not for symbol signs. The authors

did not explain this lack of correlation but suggested that both semantic

differential and glance legibility measures are needed to provide a complete picture of a symbol's meaningfulness and recognizability

.

In a reaction time experiment which did not use the glance legibility

procedure, Dewar, Ells and Mundy (1976) compared the effectiveness of

8
word and symbol signs for 3 tasks of increasing complexity. In the

first task, subjects were shown slides of 26 signs (half verbal and half

symbolic) and asked to classify 20 of these as either regulatory or warning. Reaction time was measured from the onset of the slide to the

onset of the verbal (classification) response. In a second task, Dewar

et al. introduced a "loading" task which required subjects to classify

and respond to specific numbers while classifying the signs. In both

tasks, reaction time was shorter for word signs than for symbol signs,

although this difference decreased for signs which occupied a smaller

visual angle. The authors suggested that the reaction time was faster

for word signs because the subject's response was the same as the

message on the word sign. Use of the loading task increased reaction

time for all signs. In the third task, visual distraction in the form

of a motion picture of a highway was added to the sign slides. Subjects

were also instructed to maintain a constant speedometer reading (which

the experimenter varied). In this task, with both visual distraction

and loading, the superiority of the word signs disappeared and the symbol

signs performed better. As a result, the authors suggested that the

verbal reaction time procedure validly predicts legibility distance for

symbols only under conditions of attention demands and visual distractions similar to those experienced during normal driving.

In a very recent assessment of reaction time for traffic signs and

symbols, Ells and Dewar (1979) used a measure designed to be less biased

toward verbal response. In this study, the experimenter first read a traffic sign message aloud. The subject then viewed a slide of a traffic sign and responded "yes" or "no" if the visual sign and the verbal

message were the same. The time to initiate the verbal response was

measured. Stimuli were viewed under both normal and degraded conditions.

In this experiment, reaction time was always shortest for symbolic measures. In addition, response time increased more for verbal signs than

for symbolic signs under degraded viewing conditions. Thus, the change

in response method enabled the more rapid detectability of symbolic

messages to be measured under all viewing conditions.

These experiments indicate clearly that symbolic signs can be more

effective than verbal signs, if the response measures and viewing conditions are chosen appropriately. Because the use of a strictly verbal

labeling response would appear to bias the reaction time data toward

word signs, Ells and Dewar's (1979) experiment offers an interesting

experimental approach alternative. Nevertheless, the use of reaction

time as a measure provides an index of some of the demands of actual

driving, where the speed of responding to a sign's message can be

critical.

2.2.2 Assessment of Meaningfulness

In a different experimental approach, highway symbols have also been

directly evaluated in terms of their understandability . Assessment of

meaningfulness has typically been made to determine if a set of symbols

9
is accurately understood. Speed of response has not been a critical

variable in these experiments.

In one of the first assessments of highway symbol meaningfulness,

Brainard, Campbell, and Elkin (1961) evaluated the effectiveness of 30

European symbol signs. Meaning was assessed first by having subjects

either give a definition for each symbol or select the correct answer

from an array. Following this, subjects received a brief training

period after which they again provided definitions for each of the symbols. Next subjects sketched their idea of an appropriate symbol for

each of 16 definitions. Finally, a new set of subjects gave definitions

for each of the new symbol signs.

Brainard et al. found a high correlation between the answers for both

the definition and selection answers, although there were fewer correct answers for the definitions (54% rather than 74%). Training improved

the percentage of correct answers to nearly 100 percent for both response

modes. The analysis of the drawings revealed common stereotypes for

at least 9 of the 16 definitions and common elements for the majority

of the symbols. Testing of symbols based upon these stereotypes revealed

that the percentage of initially correct answers to them was greater than

for the European symbol signs in all instances. The signs with the

lowest scores tended to be more abstract or to use a prohibitory slash.

Brainard et al. found that the meaning of prohibitory signs was frequently

reversed, although brief training on all symbols improved accuracy to near 100 percent. It should be remembered that this experiment was published in 1961, before the current extensive use of prohibitory circleslash signs by the Department of Transportation, so that more recent

studies might have not unearthed a similar problem.

Griffith and Actkinson (1977, 1978) also evaluated the understandability

of highway symbols. They determined the effectiveness of 128 road symbols used in Germany for U.S . Army personnel. They found that at least 10 of

the 128 signs were misunderstood by more than 50 percent of the subjects,

and that the overall percentage of errors upon first exposure was quite

high. In addition, they also found that memory cues and verbal elaboration were not significantly effective as training procedures, although

each reduced errors somewhat. As a result, these authors questioned the

ready interpretabi lity of many highway symbols and claimed that their

subjects had trouble with more abstract and less directly representational symbols.

Although Griffith and Actkinson did not comment upon it, the very large

number of symbols studied (128) may have caused problems—particularly

since some contradict U.S. pra^^ce. In some instances, for example, a red circle alone was used to indicate prohibition, with the slash used

to lift the restriction, so that the meaning became in essence a double

negative.

10
By contrast in the U.S., a red circle is used with the slash to indicate

prohibition. As a result, it is not surprising that Griffith and

Actkinson's subjects had problems with these symbols.

2.2.3 Behavioral Observations of Symbol Effectiveness

The meaningfulness of symbols has also been assessed directly by

determining their effectiveness in altering behavior. Forbes, Gervais,

and Allen (1963), for example, developed a lane-control symbol in a set

of laboratory experiments, and then tested its effectiveness on the

highway. In the initial tests, the authors determined that a red "X"

appeared to be most effective in controlling traffic lane use. This

symbol was then tested under actual highway conditions, in which a lane was closed off by a lightweight barrier. Presence of the barrier was indicated by the red "X" for some of the trials. The number of drivers

who made the correct lane change and the distance from the barrier at

which this change was initiated was improved by the red "X". Thus,

Forbes et al. found a symbol which tested well under both laboratory

and actual highway conditions.

In a similar experiment, Dewar and Swanson (1972) evaluated a set of

symbols in a laboratory setting and then tested one of these symbols

under actual driving conditions. Initially, they compared twenty-three

word and symbol signs by having subjects define each one when presented

under short viewing conditions (.04 sec). The signs were presented

first by themselves, and then in a picture of a road intersection. For

the most part, the symbols were recognized more accurately than the

words, although some combinations of symbols and wjrds reduced understandability compared with either alone. In a subsequent highway experi

ment, the relative effectiveness of positive (prescriptive) and negative

(proscriptive) symbols for "no left turn" was determined by counting the

number of cars making illegal left turns at an intersection. The positive symbol appeared to be more effective in altering behavior in the

desired direction than the prohibition symbol.

2.2.4 Visibility of Highway Symbols

In the final experiment to be reported on highway symbols, the discriminability of a symbol was determined for different visibilities. Smith

and Weir (1978) evaluated the effectiveness of eight different directional symbols under conditions of blur and low contrast. "Blur" simulated the effects of different visual acuities upon visibility, particularly for nighttime conditions, while "contrast" simulated the effects

of glare, as from bright sunshine. Eight levels of both blur and contrast were studied. In both experiment", subjects judged the direction

in which the symbols pointed. Smith and Weir also determined subjective

assessments of each of the 8 directional symbols. In this phase, subjects arranged photographs of the 8 symbols according to their suitability as a directional indicator. Smith and Weir found that although two

symbols tested particularly well in terms of visibility criteria, one

of these symbols was ranked as the least acceptable symbol. As a result

11
they suggested that criteria for symbol effectiveness must consider not

only detectability and discriminability but also subjective response.

The most effective symbol should perform well under all criteria.

2 .3 AUTOMOTIVE AND MACHINERY SYMBOLS

Pictograms and symbols are also used to mark controls and to provide

operating information in cars, trucks, and machinery. The impetus for

this application derives from the international sale of machinery and

equipment and the consequent need to convey equipment operating information accurately without the use of written language. Because symbols can be smaller than a comparable word phrase, they are preferred to

lengthy written instructions for providing operating information.

Unlike highway symbol research, research into automotive-machinery

symbols has focused on evaluating the effectiveness of one or more sets

of symbols for a particular referent. Rarely have researchers compared

symbols with words or evaluated reaction time. Rather, the focus has

been upon determining the meaningfulness of a set of symbols for a particular audience.

Cahill (1975, 1976) evaluated the interpretability of some of the

symbols proposed by Dreyfuss (1966) for use on farm vehicles and industrial machinery. She studied the effects of both context and previous

experience upon the understandability of ten selected symbols for 30

male subjects. Context was provided by using a drawing of the interior

of a cab for a piece of heavy equipment so that subjects could locate

the appropriate place for each symbol, and perhaps derive some meaning

from this "context". Half the subjects received context; half did not.

All subjects viewed slides of the symbols and provided definitions for

each. Subjects were considered "experienced" if they had operated,

designed, or serviced heavy industrial or farm equipment. Determination

of experience was made only after all subjects had completed the experiment .

Analysis of the results indicated that context and previous experience

facilitated accurate recognition of the symbols, although there was wide

variability in the understandability of individual symbols. Furthermore,

although context improved performance, it did not alter the relative

ranking of the understandable symbols. Cahill (1976) noted that the

understandability of the symbols appeared to be influenced by the kind

of graphic representation used. For example, symbols such as "fuel,"

"horn," and "turn signal" were understood by most subjects. Cahill com- mented that these symbols are fairly direct pictorial representations of

commonly encountered objects. '"'‘'her symbols such as "engage" and "choke" were understood by very few subjects; neither received a correct

response from the "no context" group. Cahill (1976) claimed that,

because these symbols are conceptual rather than pictographic representations, they are not at all familiar even to technologically sophisticated users. In these instances, although experience and context can

12
provide useful cues, symbol design is critical in determining the

understandability of a particular symbol.

In a study of automotive control symbols, symbol design was also found

to be a critical variable, Wiegand and Glumm (1979) evaluated the

effectiveness of a single set of symbols for automotive controls. They

tested a set of symbols proposed by ISO by having 125 U.S. subjects

match pictures of 25 symbols to a list of 35 definitions. The percentage of correct identification was above 80 percent for 20 of the 25

symbols. Yet, two of the symbols, "choke" and "master lighting switch"

performed poorly enough to warrant redesign. Wiegand and Glumm suggested that knowledge of the understandability of a set of symbols can

be used to indicate where additional design or education is needed.

One of the best ways of selecting a set of symbols for standardization

is to test several different graphic representations for each idea

(referent). Thus, Heard (1974) evaluated the effectiveness of three

different symbols for each of 24 referents for a very large number

(2593) of licensed drivers in four countries. She studied three age

groups as well: 16-25, 26-55, and over 55.

A total of 54 symbols were studied—three variations of each of 15 ISO

symbols and one variation of 9 other symbols. These symbols were tested

in the appropriate location in an actual automobile or an automotive

mock-up. As subjects were read a driving scenario which involved each

of the 24 symbols, they touched each control at the appropriate place,

using the symbol for identification. The time to find and touch the

correct symbol was measured to the nearest 0.5 sec- Accuracy of response

was also recorded.

Heard was able to select one symbol for each of twelve referents based

upon significant experimental differences between the symbols in the

three proposed sets. For recommendation, a symbol had to be understood

correctly by more than 75 percent of the subjects and be confused with

other symbols no more than 5 percent of the time. Based upon these

criteria, Heard (1974) recommended a set of symbols which performed

significantly better than all other symbols in an actual vehicle under

simulated driving situations.

Green and Pew (1978) also examined the effectiveness of 19 pictographic

symbols used in automotive displays. They employed fifty subjects in a series of five tasks. First, they determined the subjects’ familiarity

with the symbol, by having them circle those that they were "reasonably

sure" that they had seen before. Secondly, in a determination of "association norms” for each symbol, subject? were read driving scenarios similar to those used by Heard (1974) and asked to indicate which of several

symbols was appropriate for each scenario. In the third task, subjects

made estimations of the magnitude of the "communicativeness" of each

symbol, (or how well it conveyed the desired meaning). In the fourth

task, subjects were given training until they could associate each label

correctly with the appropriate symbol. Finally, reaction time was

13
assessed by recording the amount of time until the subject could

respond "same" or "different" to a picture of the symbol and a label

read by the experimenter.

Green and Pew found that education (technical vs. non-technical) , road

experience, and specific vehicle experience all affected a subject's

symbol knowledge. In addition, analysis of task 1, familiarity, indicated that most symbols were unfamiliar; the mean number of familiar

symbols was 2.6 out of a possible 19. The second task indicated that

only 6 out of 19 symbols tested met Heard's acceptance criteria of minimum 75 percent recognition and maximum 5 percent confusion. In fact,

many of the symbols which were confused with each other were also

rated as being very poor for communication. Nevertheless, subjects were

able to learn the symbol label pairs of the fourth task relatively

rapidly (usually in 3 trials). Results for the fifth task, reaction time,

indicated both a pronounced learning effect and variation in a subject's

ability to do the task rapidly.

When Green and Pew examined correlations between tasks, they found that

neither familiarity nor associative strength was strongly correlated

with reaction time measures. Rated communicativeness, however, was highly

correlated with associative strength and reaction time. Hence, this

measure could conceivably be used as an effective measure of the utility

of a symbol. The authors also noted that although sex and technical

ability affected the initial recognition of a symbol, these did not

appear to affect performance on the other tasks. Furthermore, although

reaction time decreased with learning, it was affected by the discriminability of an individual symbol. Finally, the authors concluded that

it is important to interview subjects to understand why specific symbols

are mistaken and confused. The numerous confusions and mistakes

reported by Green and Pew underline the need to research the understandability of specific symbols.

Because previous research had shown variability in the understandability

of symbols. Green (1979) explored the development of better symbols for

automotive controls and displays. First, Green had subjects draw

symbols for each of seven referents. Then another group rated the

meaningfulness of the six or seven most frequently drawn symbols for

each referent.

In the first phase, 43 subjects drew pictures of seven referents

heater, air conditioner, fresh air vent, radio volume, radio tuning,

tire pressure, and lamp failure. Three judges then scored these ratings

by giving them labels such as "fire" or "snowflake" or some similar

term. The drawings were then «_ ouped by label and the most frequently

suggested drawings were used as stimuli for the second phase. In the

second phase, 62 subjects gave estimates of the informativeness of the

newly drawn symbols. Subjects were given sheets upon which the referent

(label) appeared in the center surrounded by four to ten candidate symbols. Subjects made magnitude estimations of the informativeness of

each suggested symbol for the various referents. Analysis of the data

14
indicated that subjects were able to agree upon at least one symbol for

each referent. These symbols did not always agree with those in common

use, however. Green (1979) concluded that having people draw symbols

for proposed referents (the "production method”) should be the first

step in data collection for symbol research. Magnitude estimation

should then be used to select the "best" of these symbols for a given

referent for further study.

In a study of symbol discriminability , Green and Davis (1976) explored

the effects of variation in the orientation of automotive symbol controls.

Previous research, such as Heard (1974), evaluated the recognizability

of automotive symbols placed in an upright position only. Yet symbols

placed upon controls are often rotated away from upright, and consequently may not be rapidly or accurately identified.

Green and Davis presented ten subjects with three different symbols

which varied in orientation. Subjects were given a page with numerous

pairs of symbols, one of which varied in orientation. Half of the

varied symbols were also reversed (mirror image). Subjects judged

whether the symbol pairs were the same (S) or different (D) (mirror

image reversed). Analysis of the results indicated that increasing the

rotation of the symbol away from upright significantly affected response

time for deciding if both members of the pair were the same. Green and

Davis commented that this delayed reaction could be hazardous in an actual driving situation. As a result, because a driver could have

difficulty in responding appropriately in an emergency, control symbols

should always be mounted in an upright position. The problem of rotated

symbols is greatest for controls which themselves can be moved away from

a "normal" position.

2.4 PUBLIC INFORMATION SYMBOLS

The third application of symbols to be discussed is that of public

information symbols. These are symbols which provide primarily directional information to the general public. Intended to be understood by

a wide variety of people who do not speak a common language, they are

frequently used in transportation facilities.

Research in this area has typically focused upon the meaningfulness,

or understandability , of a set of symbols. For example, Easterby and

Zwaga (1976) assessed the meaningfulness of various symbols for six

informational referents under the sponsorship of the ISO. In a three

stage experiment, they determined the "best" symbol for the following

referents: drinking water, information, stairs, taxi, toilets, and

waiting room. First a small sample of subjects from the U.K. and the

Netherlands ranked a large number of symbols in terms of their

"appropriateness" for a given referent. Three symbols were chosen from

these rankings for each referent for further research. In the second

phase, subjects from six countries gave meanings for each of the three

symbol sets.

15
Easterby and Zwaga found that subjects were able to provide a more-orless accurate definition for some symbols. Other symbols, however,

received few correct definitions and a high percentage of "don't know"

answers. Symbols that were readily understood were highly pictorial

rather than abstract.

In the third phase, groups of subjects from six countries matched each

of six referents against a group of 24 symbols. Different groups

received one of three versions of the symbols being tested for the six

referents. (Eighteen of the symbols merely provided choice alternatives).

Each subject matched only one version of a symbol for each referent.

Easterby and Zwaga found that the matching test allowed them to select

a "good" symbol from a set of symbols, but was limited by the quality

of the symbol set. Thus, the matching test would not allow subjects

to indicate that none of the symbols was particularly effective. As a result, the authors recommended that a matching test be done after

recognition testing has indicated the most "meaningful" symbols.

Both the matching and recognition test data provided valuable insights

into the confusion between symbols, as well as the kinds of alternative

answers given by subjects. These data were instrumental in selecting

the set of public information symbols currently recommended by ISO.

The other major evaluation of the effectiveness of public information

symbols was commissioned by the U.S. Department of Transportation (DoT).

First, DoT sponsored the design of a set of 34 public information signs

by the American Institute of Graphic Artists (AIGA) . After compiling a list of existing symbols for each referent, the AIGA (1974) then designed

what they considered to be the best symbol for a given referent based

upon this compilation.

The list of symbols developed by the AIGA is currently under evaluation

by the Franklin Research Institute. In an interim report, Freedman,

Berkowitz, and Gallagher (1976) used a variety of both paper-and-pencil

and performance tests to assess the symbols. These tests were designed

to assess the recognizability of the symbols, elicit confusions, and

provide an indication of the relative difficulty of the symbols. While

the initial tests were designed as input to a subsequent, large-scale

testing phase, they did indicate that the symbols varied widely in

initial recognizability. For example, only eleven of the 34 symbols were understood by all subjects.

Following completion of the paper-and-pencil tests of appropriateness,

subjects completed a "walking rally." In this test, subjects followed

the symbols to various location^ within a building. Time to arrival

and correctness of the destination were monitored. Freedman and

Berkowitz (1977) also administered matching and multiple choice tests

at an airport and a subway station, and are in the process of a largescale test of the 34 symbols at a variety of transportation facilities.

16
Preliminary comparison of the paper and pencil data with the field data

indicated few differences in the subjects’ responses. Because about 9

symbols were missed by a large number of subjects, the authors proposed

several criteria for effectiveness. They suggested that symbols which

are recognized by 60 percent or fewer people are clearly unacceptable,

while those recognized by more than 80 percent are acceptable. Finally

those recognized by 60-85 percent need some improvement. The Franklin

Research Institute is currently testing these criteria and test

procedures

.

These two research projects have assessed the meaningfulness of public

information symbols with large groups of people—people who would likely

use these symbols. Unlike the highway symbol research, no assessment of

the speed of detection was made, nor were the symbol signs directly compared with word signs. As with automotive/machinery applications,

teaningfulness or understandability appears to be the most useful

characteristic by which to evaluate public information symbols, and

certainly is the most frequently used by researchers.

2.5 PRODUCT LABELING SYMBOLS

Another emerging application of symbols is that of product labeling.

While the Canadians, the British, and the Common Market (EEC) have all

proposed or adopted standards for warning consumers of potential hazards,

there is little if any research on the effectiveness of these symbols.

In addition, several controversial product labeling symbols have been

produced in the U.S. These include "Mr. Yuk," produced by the Pittsburgh

Poison Control Center, to replace the skull-and-c ossbones to warn

children of poisonous substances, and the lawnmower and CB antenna

symbols developed by the Consumer Product Safety Commission (CPSC) to warn consumers of potential accidents. While these symbols generated

much discussion, only the effectiveness of Mr. Yuk has been researched.

’Mr. Yuk" has been found to be understood by small children as indicating

a hazardous ("yuky") substance, although its effectiveness for adults

has not been determined.

One of the few extensive assessments of product labeling symbols was conducted in Great Britain by Easterby and Hakiel (1977a, 1977b, 1977c).

In their first study, Easterby and Hakiel (1977a, 1977b) had people

design signs to convey fire, poison, and caustic hazard information.

Subjects were provided with a selection of image forms and colors, background colors and shapes, enclosure shapes and colors, surround shapes

and colors, and supporting field colors.

Analysis of the results indicated that ved was the perferred color for

fire signs while black was preferred for poison. Both red and black were equally liked for caustic. Easterby and Hakiel (1977b) commented

that these colors appear to be chosen to indicate the identity of the

hazard, and, consequently, reinforce the function of the image. The

stereotypes generated in this series of studies were used to construct

17
signs for a subsequent study of the understandability of product-warning

signs.

In the final study, Easterby and Hakiel (1977c) evaluated productlabeling signs by first having students rank-order a set of symbols in

terms of their effectiveness in conveying a given message. This procedure reduced the large number of symbols found in a compilation of

existing symbols to 4 symbols for each of 3 hazards (fire, poison, and

caustic). The ordering experiment revealed that subjects preferred

symbols which described the hazard (descriptive) to symbols which

prohibited a hazardous action (proscriptive) or prescribed a course

of action to avoid a hazard (prescriptive). Furthermore, when there were several versions of a somewhat similar image, subjects preferred

the visually more complex image to a graphically simplified one. It is

not clear, from the authors' description, whether a complex image is

also more graphically representational.

The symbols selected from the pilot test were then studied in a nationwide survey of 4000 respondents in the U.K. The survey consisted of a recognition test in which each subject provided meanings for each of

17 signs—5 test signs and 12 contextual signs that might be found on consumer goods or in public environments. The five test signs included

the poison, caustic, and fire symbols developed earlier, as well as electrical and general hazard symbols. All 4,000 respondents judged

the 12 context signs, while only 500 respondents judged each variant

of each hazard sign.

Analysis of the results indicated that attributes of the sign (image,

color coding, and shape coding) and characteristics of the respondents

(age, sex, household composition, and experience with signs) all influenced the recognizability of the signs. They suggested that symbols

which have been extensively simplified from a graphic standpoint do not

perform as well as more complex images — which one can infer, resemble

the intended referent more closely.

Easterby and Hakiel (1977c) concluded, however, that the single factor

which primarily affects recognition performance is image content. Other

factors such as color and observer characteristics are important, but

ultimately the understandability of the sign will depend on the symbolic

image chosen.

2.6 SAFETY SYMBOLS

Although there do not appear to be any studies which have assessed the

effectiveness of symbols for \ kplaces, two studies have examined

aspects of safety signs. One (Collins & Pierman, 1979) evaluated

the meaningfulness of fire safety symbols. The other (Laner & Sell,

1960) determined the effectiveness of safety posters. Although Laner

and Sell did not assess symbol use, their work is of interest because

it measured the effectiveness of safety messages directly in terms of

changes in unsafe behaviors.

18
Collins and Pierman (1979) reported an experiment in which they determined the understandability of 22 "fire safety" symbols proposed by ISO.

They asked 143 subjects to provide a short definition for each symbol.

Three judges rated the answers as "correct," "incorrect," or "no

response." In addition a tally was kept of the number and kind of

incorrect answers. The percentage of subjects responding in each of

the three ways was calculated for each symbol.

The authors found that some symbols such as "fire extinguisher," "no

smoking" and the conventional U.S. "exit" sign were understood by almost

all the subjects tested. Yet other symbols such as "blind alley," "do

not block" and "break glass" were understood by less than 20 percent of

the subjects. In addition, several symbols were given a meaning opposite

to that which was intended. Thus, the "no exit" or "blind alley" symbol

was interpreted as "exit” or "safe area" by almost all subjects who gave

a definition for this symbol. Altogether over 95 percent of the subjects

either misidentif ied or did not respond to this particular symbol.

The authors commented that an instance in which a symbol is given a meaning opposite to that which is intended is potentially very dangerous. They recommended that before symbols are adopted, particularly

those which communicate emergency information, their effectiveness must

be evaluated. A safety symbol must be understandable before it can begin to alter behavior and prevent accidents.

Laner and Sell (1960) examined the effectiveness of safety messages in

altering unsafe behavior. Although safety posters with various sorts of

warning messages have typically been used in an effort to stop unsafe acts,

their effectiveness in actually modifying these behaviors has rarely been

assessed. Effectiveness could be measured by studying accident rate

reduction directly, except that the frequency of accidents is so low that

the experiment would be inordinately long. Laner and Sell also rejected

the idea of measuring poster effectiveness in terms of the extent to

which a poster could be recognized, remembered, or liked because these measures do not assess actual behavior.

Consequently, Laner and Sell (1960) selected a behavioral measure which

could involve an operation that was potentially dangerous, frequently

carried out, and readily measurable—namely, the hooking back of chain

slings onto a crane hook when not in use. Seven steelworks participated

in the experiment in which posters depicting safe steelworking practices

were developed and displayed. First a baseline of behavior was established over five weeks without poster display. Then the posters were

displayed. Behavior was measured for five weeks, followed by a lapse of

7 weeks without measurement, concluding with 2 additional weeks of measurement.

19
Laner and Sell found that the posters had a positive effect in the six

test steelworks (substantial for four of these) but no effect in the

seventh, or control steelwork. Furthermore, they noted that the behavior affected by the posters was at least maintained, if not improved,

following the seven week period in which behavior was not measured. The

authors suggested that these posters were effective either because they

acted as perpetual reminders or because they established or reinforced

working habits which were self-maintained. They also found that the

increase in safe behavior was greatest in those shops with low ceilings

where the unsafe practice constituted the greatest hazard to personnel.

They concluded that posters may be more effective if the message they

carry can be seen to be directly relevant to the situation. Such a conclusion may be extended to the use of safety symbols as well. In

addition, the use of a behavioral measure—reduction of unsafe acts—is

perhaps the ultimate measure of a sign or symbol's true effectiveness.

Its use should be explored more for all applications of symbols.

3. DEVELOPMENT OF WORKPLACE SAFETY SYMBOL REFERENTS

3.1 OVERALL PROCEDURES

The preceding review of research on symbols indicated that researchers

typically began their evaluative process with an existing set of symbols

for specific referents. These symbols were developed primarily by standards organizations, graphic designers, and manufacturers, so that the

role of the researcher was confined to evaluating these specific images.

The case for evaluating symbols for workplace safety is a bit different,

however, in that there is no single set of existing symbols. Rather,

numerous symbols abound for some referents while few symbols exist for

other referents. Further, the most important set of referents to

symbolize has not been determined. Because there are no complete standards in the U.S. for either symbols or referents for signs for workplace safety, the first task in an assessment of symbols for workplaces

is to determine the symbols that are currently used and the kinds of

general situations which appear to require hazard warnings. Secondly,

a list of symbol referents which is broad enough to be applicable to

most workplace situations must be developed. Finally, specific symbols

for these referents must be selected and evaluated experimentally. NBS

is following these 3 steps in its evaluation of worker safety symbols.

In this section the various sources used to develop an initial listing

of safety symbol referents are outlined. Three major sources were consulted. These included site visits, sign catalogues, and national and

International standards. Each T these will be reviewed in turn.

Finally a list of symbol referents based upon all of these sources is

outlined.

20
3.2 SITE VISITS

One source of information about current symbol use was observations made

during visits to six industrial sites. Six plants were visited to provide familiarity with sign usage in the field. The sites were selected

to represent as wide a range of industries as possible and included:

the manufacture and assembly of heavy equipment engines; the manufacture

of ceramic glass; the final assembly of aircraft; the chemical manufacture of vinyl acetate based resins; shipbuilding (manufacture, assembly,

and repair); and oil refining. These sites not only provided a range of

major industries, activities, and hazards, but also a spectrum of philosophies in workplace safety practices and sign use. Consequently, the

plant visits provided invaluable background for this project.

Table 1 summarizes some of the findings of the site visits. For each

plant, this table outlines plant size, activity, hazards, and comments

on sign usage. This information is based on our interpretation of

observations and conversations with plant personnel, and should not be

interpreted as reflecting official statements or policy of the company

or as critical evaluations on our part.

Appendix A presents a listing of signs observed, organized by type of

sign (prohibition, safety gear, etc.). Although many signs contained

more than one type of message (e.g., "caution-lead work—no eating,

drinking, or smoking"—"gloves and shoes required"), they are presented

in only one of the categories in Appendix B. For each generic referent

(e.g., "wear hearing protection"), every sample of specific wording was recorded to give an indication of the variability jf the signs and any

subtleties or differences in meaning. These observations were confined

to safety signs observed in the workplace, and exclude signs on vehicles,

machines, and tools. Posters and admonitions (e.g., "safety first") were not included.

3.2.1 Generic Hazards and Common Injuries

Each industry has a. unique set of major hazards associated with its

activities, such as explosion, extreme heat, caustic chemicals, fire,

etc. The most frequently reported injuries, however, usually appeared

unrelated to these major threats and were similar from plant to plant.

These common injuries included slips (especially where oil, ice, or chemical substances could be on the floor), hand and finger injuries,

back injuries, eye injuries, and cuts. Safety officers often expressed

the opinion that workers were cautious about major hazards and were more

likely to be injured where work was routine and repetitious. Somewhat

in contradiction, equipment maintenance workers appeared to have especially high injury rates relative to other employees, and this was often

attributed to the novel or unfamiliar tasks required of the maintenance

staff. As is obvious from Appendix A, safety signs seemed to be most

frequently related to potential hazards, or protective gear rather than

to common injuries.

21
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22
3.2.2 Use of Pictographic Signs

In general, the six plants relied heavily upon word signs. Because

employees were believed to be generally literate in English, there was little perceived requirement for pictographic signs. Nevertheless, the

DoT hazard warning symbols for material transport were in widespread

use, as were symbols for vehicle operating instructions and precautions.

Neither of these can be directly transferred to workplace safety symbols,

however.

One plant did deliberately use a large number of pictograms, primarily

to remind personnel to wear safety equipment. This plant had a noticeable number of illiterate employees as well as foreign visitors. Symbols were also believed to be "eye-catching." In other factories, some specific hazards were symbolized pictographically . These included "nosmoking" at one site where there were foreign visitors, and "high noise area—ear protection required" in another plant. Other than these

examples, however, the common practice was to use word signs —often quite

lengthy word signs.

3.2.3 Alternatives to Signs

Two alternative strategies to the use of safety signs were observed.

One strategy is to institute a general policy regarding some hazard, and

then only indicate where this policy is suspended. For example, in a chemical plant, where a threat of fire or explosion is prevalent,

smoking and matches may be generally prohibited except where noted.

The other common alternative to specific safety signs is to indicate

general information or warning by color coding of particular areas through colored lines on the floor or on definite hazards. (In contrast

to color coding of signs, here the color is the entire message.) For

example, yellow lines are commonly used to indicate a general hazard

area while red bands are used to indicate fire fighting equipment.

Such color coding contrasts with the more specific messages about

hazards or procedures contained in workplace signs.

The colors encountered were:

Red: fire related (equipment, sprinkler lines, alarm), emergency

alarms, hazard (e.g., cranes, flags or tags on dangerous or broken equipment)

Orange: explosives

Green: safety (protective equipment, eye wash, emergency shower),

delimit safe walkways

Yellow: hazard

White: delimit safe walkways

23
The yellow hazard warning was particularly frequent, and used in the

following ways:

- denote hazardous areas limited to knowledgeable personnel

- indicate moving parts, equipment, and guardrails

- indicate overhead hazards such as cranes

- denote areas where some safety equipment is mandatory

(hard hats, safety glasses, or hearing protection)

In some factories, because the use of color coded areas dominated safety

communication, signs were relatively infrequent. In contrast to signs,

this coding could be spatially precise, indicating the exact location

and extent of the hazardous area. While the prevalence of the yellow

hazard indication suggests the need to adopt a good pictogram indicating

a general hazard, the use of such a symbol as an alternative or supplement to simple color coding requires consideration (for some applications) .

3.2.4 Sign Context

One question addressed during the site visits was, how are signs

presented? In other words, where are they typically located, how are

they illuminated, where are they located with respect to the hazards

they represent, and what is the background against which they are presented? Although such details are expected to vary, there were highly

idiosyncratic practices and extreme variability in sign presentation

among the sites visited. Even the same message (e.g., eye protection

required) was presented in many different ways: signs were placed on stands in the aisles, or mounted on walls (sometimes well above eye

level and out of the usual visual field), or above entrance ways, or on fixtures and equipment. Often, signs were presented in clusters,

rather than singly. Lighting varied from signs poorly placed in shadow,

to ones placed in bright illumination. Warnings were sometimes placed

at entrances, sometimes located around the workspace, and other times

mounted on or near the hazard. Sometimes warning signs were difficult

to see due to clutter, poor maintenance, or blending into the background

color. (In some cases the predominant workplace color was yellow to

yellow-green, making yellow warning signs obscure). As a result, no "typical" or "representative" contexts were identified. What is a familiar context in one setting appears unusual in another plant, or even in another section of the same plant due to differences in hazards,

layout, and sign usage.

3.2.5 Most Frequent Signs

Table 2 indicates the types of generic safety messages that occurred

with high frequency across the various industries. The messages in the

table are given in general form (e.g., restricted admittance), even though the wording of individual signs may have varied (e.g., authorized

personnel only, positively no admittance, restricted area, do not enter,

etc.). While the messages in Table 2 represent commonly occurring and

24
Table 2: Common Generic Messages From Site Visits

Hazards;

General

Electrical

Flammable

Explosive

Heat

Caustic, acid

Overhead

Noise

Slip/Trip/Watch Your Step

Vehicles

Radiation

Safety and Emergency Gear ;

Eye Protection Required

Hard Hat Required

Foot Protection Required

Hearing Protection Required

Caustic-Handling Gear Required

Breathing Gear

First Aid

Emergency Shower

Eye Wash

Fire Alarm

Fire Extinguisher

Fire Hose

Prohibitions ;

No Smoking

No Flames, No Hot Work

Do Not Touch, Keep Away From

Egress, Access ;

Walkway

Exit, Emergency Exit

No Exit

Restricted Admittance

Keep Area Clear

Keep Door Open

Keep Door Closed

25
important workplace signs, they should not be viewed as a complete list

given the limited number of plants visited.

3.3 SIGN CATALOGUES, PUBLICATIONS, AND MANUFACTURERS

3.3.1 Catalogues and Publications

In addition to the site visits the following sources were reviewed for

information on symbol availability: sign catalogues, sign manufacturers, individual company guidelines, and compilations of pictorial signs

(Dreyfuss, 1972; Modley & Myers, 1976).

A list of the most frequently occurring kinds of symbols was compiled

from this review and is given in Table 3.

The review of catalogues and publications indicated many common symbols.

These fall into categories such as protective gear, hazard warnings,

prohibited actions and information about fire and safety instructions.

In addition, at least one catalogue offers an extensive list of unusual

symbols to fit most hazards. This report, however, concentrates upon

the most frequently occurring symbols as being representative of current

offerings from sign manufacturing catalogues.

3.3.2 Information From Sign Manufacturers

To assess the extent of the demand for and the use of symbolic signs,

twelve sign manufacturers were contacted. They were asked for any

available information on sign use, including the most frequently purchased signs, the most frequently requested symbolic signs, and the

perceived demand for symbolic signs.

Although the responses differed greatly in terms of the detail provided,

there seemed to be a feeling that the demand for pictorial signs was increasing. One manufacturer of both written and symbolic signs

observed a "very significant increase in the demand for pictorial

signs," estimating an increase of "about 10 percent or better per year

for the past five years." Another company still produced mainly written

messages because it felt some messages could not be adequately conveyed

symbolically. However, it added that this could change if there were

changes in the standards to accommodate symbols. In general, the

responses indicated industry interest in symbolic signs and concern over issues of standardization and effectiveness. Some sign manufacturers

expressed a need for some form of agreement, but also indicated concern

about proprietary rights for symbols developed by individual companies.

The manufacturers noted that many of the most widely requested pictographic signs were not safety related (e.g., men, women, handicap

access, etc.). Perhaps the most frequently cited symbolic safety sign

was "no smoking." While this pictogram varies somewhat, nearly all

examples provided used the familiar image of a burning cigarette with

26
Table 3. Symbols Typically Available From Sign Catalogues —

Prohibition;

No smoking

No open flame

Do not enter

Authorized personnel only

Keep out/no trespassing

Do not touch

Protection ;

Eye protection

Hard hat area Hearing protection/noise area Respirator required/self-contained breathing apparatus

Foot protection required

Hand protection required

Face protection required

Protective clothing required

Protective belt/harness required

Hazards ;

Radiation area Electric shock/high voltage

Corrosive /caustic /acid

Flammable

Fork lift trucks/vehicles

Explosive

Poison

General hazard

Overhead hazard

Slippery surface/danger of falling

Laser

Falling objects/flying objects

Hot surface/danger of burns

Biological hazard

Crushing /entanglement

Fire ;

Fire extinguisher

Fire hose and reel

Fire alarm

In case of fire, use stairway

Do not use water to extinguish

Fire exit

Fire hydrant

Information ;

First aid

Safety shower

Eye wash

Smoking area/smoking permitted

Direction

Exit

Keep door closed

Stretcher

No exit/door blocked

Pedestrian crossing/crosswalk

27
a prohibitory slash through it. Figure 3 presents collected examples of

this image to illustrate the range of graphic variation. Other frequent

symbolic signs included those for protective gear (glasses, ear protectors, hard hats), flammable hazards, and fire equipment (extinguisher,

hose). Although quantitative information on the use of these signs was

not available, many additional examples of pictograms were provided

during the review of sign catalogues (see section 3.2).

There appears to be only partial correspondence between the pictograms

that appear to be most in demand from manufacturers and the written

signs most frequently observed on plant visits. Although the pictograms — for "no smoking," "protective gear,” and "fire equipment" — do in

fact represent a subset of the most frequently encountered messages,

it is that subset that can be most plainly and literally represented by

a simple picture. Other frequent messages — related to egress, restricted access, general hazard, doorways — appear less in demand as pictographic signs. Correspondingly, the graphic representation of these

messages varies much more from company to company. This suggests that

developing an explicit consensus representation for such messages may

be an important step in increasing demand for these symbols. Such a consensus may arise through the ANSI Z535 subcommittee on safety symbols

which has begun to identify referents for further investigation.

3.4 REVIEW OF SYMBOL STANDARDS

Another source that was reviewed is that of national and international

standards for symbols. As noted earlier, there is no standard in the

U.S. for workplace symbols, although ANSI has recently chartered the

Z535.3 Subcommittee on safety symbols. The current OSHA standard does

not deal directly with workplace safety symbols except for those for

radiation and biohazard. DoT does use the international (U.N.) standard

for symbols for the transport of hazardous materials. Because these symbols appear upon containers used in factories, they should be reviewed

for consistency with workplace symbols. In addition, individual companies

and government agencies have developed their own standards (see the proposed Air Force Standard, DoT Transportation Symbols, Du Pont Symbols,

and FMC symbols). These symbols are applicable only upon a specific and

limited basis. Symbol and sign referents used within the U.S. are given

in Appendix B. In addition, referents from other countries in North and

South America are given for comparison purposes.

At the international level, the International Organization for Standardization (ISO) TC 80 has drafted a standard (DIS 3864.3) for worker safety

symbols which is currently under consideration. The EEC directive

(R/1455) provides a similar set of symbols and referents, as do many

other national standards: Great Britain (BS 5378), Australia (AS-1319),

Netherlands (NEW 3011), and France (NF X08=003). See Tables 4 and 5

for a listing of common referents from these international standards.

Symbol standards which tend to vary from the ISO norm are those from

countries outside Europe. The Canadian Standard (CAN 3-Z321-77) provides

28
Figure 3. Graphic Variation lor a Single Conceptualization for

No Smoking" (Some of these symbols may be privately

coywritten)

29
Table 4. Symbol Referents Standardized by ISO and the EEC for

European Application

ISO - DIS - 3864.3

Safety Signs

Prohibition Signs

1) Smoking prohibited

2) Fire, open light, and smoking prohibited

3) Thoroughfare prohibited for pedestrians

4) Water as extinguishing agent prohibited

Mandatory Action Signs

5) General mandatory action - exclamation point

6) Eye protection must be worn

7) Respiratory protection must be worn

8) Head protection must be worn

9) Hearing protection must be worn

10) Hand protection must be worn

11) Foot protection must be worn

Warning Signs

12) General warning, caution, danger, risk

13) Caution - risk of fire

14) Caution - risk of explosion

15) Caution - risk of corrosion

16) Caution - toxic risk

17) Caution - risk of electric shock

Information Signs

18) First aid

19) General indication of direction

The EEC Directive (R/1455) adds the following referents:

1) Not drinking water

2) Caution - radioactive material

3) Beware - overhead load

4) Beware - industrial trucks

5) Emergency exit with 3 '^mbols

30
Table 5. Common International Referents for Symbols from the Australian,

British, Dutch and French Standards

Prohibition

No smoking

No open flame

No pedestrians

Do not extinguish with water

Not drinking water

Warning

Flammable material - risk of fire

Explosive material - danger of explosion

Toxic matter - danger of poison

Corrosive matter - risk of corrosion

Radioactive material

Risk of electric shock

General danger

Danger - overhead load

Danger - industrial trucks

Caution - laser beam

Danger - biohazard

Slippery when wet

Danger - compressed gas

Danger - insufficient clearance

Safety Instruction - Mandatory Action

Eye protection required

Hard hat required

Ear protection required

Respirator required

Safety gloves required - hand protection

Safety shoes required - foot protection

Information

First aid

Direction

Emergency exit

No admittance

Fire extinguisher

Eyewash

Shower

Stretcher

No trespassing

31
a list of referents and suggested glyph (image) content for some 50

signs related to the occupational environment. The Uruguayian standard

lists 8 symbols warning of hazards (UNIT 131-58). The Bolivian standard

(NB20. 1-003) lists only 6 hazard-warning symbols. The Philippines do

not appear to have a standard for worker safety symbols although they

have adopted the U.N. (DoT) standard for symbols for the handling of

goods (621.798.7). Although the Japanese standard (Z9103-1965) provides

hazard warning signs and symbols for 8 situations. Table 2 of Appendix B

provides symbol referents from non-European standards.

3.5 SYMBOL REFERENTS RECOMMENDED FOR STUDY

After reviewing the wide range of symbol referents collected from sign

catalogues, sign manufacturers, site visits and sign/symbol standards

(both national and international), a list of 40 referents was compiled

for further experimental study. This list which is presented in Table 6

is based primarily upon the frequency of occurrence of a particular

referent in each of the sources. Additional referents will be added

as the need arises.

Table 6 represents the authors' judgment of the importance of the

specific referents for testing purposes, and should be viewed as an initial prioritization, which may be altered following consultation

with safety experts.

The referents are given in intentionally general form (e.g., "eye protection required”). At some point, further discrimination among referents may be required (e.g., "safety glasses," "safety glasses with side

shields," "safety goggles"), depending upon the need to provide information about a specific hazard or action.

Table 6 is, of necessity, an incomplete list of important workplace

safety messages. It contains messages that occur generally across

various industries, rather than ones of particular importance in specific

work areas. Nevertheless , the selected items should be widely applicable.

This list is a compilation of symbol referents, or the message to be

communicated, rather than a list of symbols. A compendium of different

symbol images for each of the referents identified in Table 6 is being

developed. The compendium will be based upon variations in image content

rather than upon sign shape or color. It Is intended to show some of the

differences in imagery within categories, and provide the basis of a set

of images for further testing. As an example, Figure 4 presents examples

of "No Smoking" symbols in addition to the variants already presented in

Figure 3. Thus Figures 3 and 4 together illustrate for one referent the

collection of images to be repr - "anted in a compendium.

32
Table 6. Selected List of Symbol Referents

Access/Egress;

Prohibition;

Protection;

Hazard;

Emergency;

Restricted access,

do not enter

Exit

No exit

Emergency exit

Pedestrian pathway

Direction

Keep area clear, do not

block

Keep door closed

Use stairs in case of fire

No smoking Do not use water to

No open flame extinguish

Eye protection

Ear protection

Head protection

Foot protection

Breathing

Hand protection

Face protection

Electricity

Fire

Explosion

General

Radiation

Corrosion

Poison

Overhead

Hot

Slips, trips, watch your

step

Entanglement

Fork lifts, vehicles

Starts automatically

Laser

Fire extinguisher Fire hose

Alarm call point Stretcher

First aid

Safety shower

Eye wash

33
Figure 4. Further examples of "No Smoking Symbols in addition to

those in Figure 3 (Some of these symbols may be privately

copywritten)

.

34
4. NEEDS FOR RESEARCH ON WORKPLACE SYMBOLS

4.1 EFFECTIVE SYMBOLS: RESEARCH FOCUS

Sections 2 and 3 reviewed research methods and results, and developed a list of referents for workplace symbols. In developing the list of

symbol referents, it became clear that there is no single set of existing workplace symbols. The number of images for each referent varies

from 2 to over 20. As a result, the development of effective symbols

for workplace safety will require selecting several plausible symbols

for each referent, testing the understandability of each symbol, and

selecting the most understandable symbol based upon experimental results.

To be effective, a symbol must be understood; it must communicate the

desired meaning to all those who encounter it. While understandability

is a critically important criterion by which to evaluate a symbol, it is

not the only one. A symbol must also be detectable at a given distance

under specific light levels. A symbol must be discriminable, or distinguishable from other symbols within a particular set. A symbol must be

recognizable, or be remembered and identified under different circumstances. A symbol must be graphically satisfactory and command attention. Finally, a symbol must alter behavior in the intended direction

and facilitate conformance with the message. A fully effective symbol

performs well in each of these areas. Understandability, however, is

the key which unlocks the whole process of conveying a safety message.

As a result, the priority for research on safety symbols is to determine

the understandability of the various images proposed for each referent.

In this way, the most understandable image can be selected for a given

referent. Determination of understandability is particularly critical

for workplace safety symbols, where the consequences of failure to

understand could lead to serious injury.

4.2 PROCEDURES FOR EVALUATING UNDERSTANDABILITY

As noted earlier, evaluation of understandability should proceed in

several stages. Where a large number of different images exist for a given referent, this number must be reduced if further research is to

be practical. The process of reduction is best done experimentally,

through the use of a ranking procedure. In a ranking procedure, subjects order a set of images according to how well they believe that each

image conveys the meaning of the referent. Easterby and Zwaga (1976)

followed this procedure with small groups of subjects in two countries

to select three sets of public information symbols. Similarly, Heard

(1974) and Green (1979) had subjects rank images for automotive displays

and controls according to meaningfulness. Use of rank-ordering can

reduce a large set of symbols to a more reasonably sized set for subsequent testing. It also ensures that the set of images tested is at

least somewhat meaningful. As a result, ISO TC-145-SC1 recommends rankordering as the best procedure for reducing the size of a set of images.

35
When a large number of images does not exist, or where no existing image

appears to be meaningful for a particular referent, use of the "production method" can be valuable. In this method, subjects are given a referent and asked to draw a symbol which conveys this meaning. Brainard

et al. (1961) used the production method to generate highway sign images.

Similarly, Green (1979) used this method to develop images for automotive

controls. In conjunction with a graphic artist, the production method

is advantageous in producing a large number of images which are meaningful to the subject group, and which can then be reduced through

rank-ordering. Once a set of symbols has been ranked according to meaningfulness, the highest ranked images must then be evaluated for their

understandability to a new, larger group of subjects. Because of the

large number of existing images for most workplace safety referents, the

production method may be needed only at a later stage where no image has

tested well for a particular referent.

Assessment of understandability has been done in several ways. The most common method is to ask subjects to provide a verbal definition of the

symbol. As examples, Brainard et al. (1961), Walker et al. (1965),

Dewar and Swanson (1972), Cahill (1975), Easterby and Hakiel (1972), and

Collins and Pierroan (1979) all asked subjects to provide definitions for

symbols in applications ranging from highway to automotive to safety.

Fewer researchers have used matching or multiple choice procedures,

among them Brainard et al. (1961), Freedman et al. (1976), and Lerner

and Collins (in preparation). In this procedure, subjects are given a list of meanings for each symbol and asked to select the correct one. Comparisons of multiple choice and definition methods have found that

although the the percentage of correct answers is typically somewhat

higher for multiple choice procedures which appear to provide some context and additional information about the symbol, the ordering of correct

responses for both methods is similar (Brainard et al. , 1961; Lerner and

Collins, in preparation). In a related "matching" type of procedure,

subjects are asked to select a symbol which "matches" the referent from

a larger set of symbols. Used by Freedman et al. (1966), and Easterby

and Zwaga (1976), this procedure provides information on the confusability of items within a set of symbols. Easterby and Zwaga (1976)

recommend its use as the final step in a complete evaluation of symbols

to eliminate confusion from a coordinated set of symbols.

Another general evaluation method involves the use of ratings, such as category scales and the psychophysical procedure of magnitude estimation, in which a subject is given the referent message and is asked to

provide a numerical estimation of how meaningful each symbol is. This

procedure has been used by Dewar and Ells (1977), Green and Pew (1978),

and Green (1979). Rating scales ty be less useful for determining

whether a subject knows precisely what a particular symbol means, since

no measure of response correctness is obtained.

Once a set of symbols has been tested for understandability, a decision

can then be made about each symbol's adequacy. However, there is no

36
obvious criterion for an "acceptable" symbol. Nonetheless, some consensus exists in the literature. Heard (1974) considered symbols to be

understandable if they were defined correctly at least 75 percent of the

time with only 5 percent confusion with other symbols. Freedman and

Berkowitz (1977) suggested that scores below 60 percent correct response

indicate an unacceptable symbol, scores above 85 percent correct indicate

an acceptable symbol, and scores between 60-85 percent correct indicate

symbols which require improvement. Brainard et al., (1961) suggested

that symbols which have correct responses over 85 percent fall into the

high recognition category. While these researchers agree that 75-85

percent correct recognition indicates that the symbol is meaningful,

this cut-off should be contingent upon the demands of the specific symbol set and method of evaluation.

In fact, since some methods (e.g. matching or multiple choice) could

produce a higher percent of recognition than other methods (eg, definition), the stringency of the criterion may need to vary with the procedure. Lerner and Collins (in preparation) have further suggested

using confidence ratings to supplement the percentage correct measure.

On the other hand, the relative performance of the various symbols,

regardless of absolute levels, also provides valuable information about

the effectiveness of the symbol set. As a result, the choice of criterion should depend upon the kind of evaluation procedure employed and

the eventual application of the symbol. Where context information is

given by the test format, the criterion for acceptance should perhaps

be higher.

In another approach to setting criteria, the latest draft of the ISO TC

145 addendum to ISO 7000/DAD 1 suggests the criterion should be based

upon the level of risk. It suggests that for small risks, an 85 percent

correct response for the ISO recommended matching test is desirable.

For larger risks, a level of 95 percent correct response is recommended

with no other referent greater than 1 percent (confusion). Unfortunately,

large and small risks are not defined. These two approaches suggest that

both risk level and evaluation procedure as well as the eventual application should be considered in setting criteria for symbol acceptability.

If none of the workplace safety symbols evaluated for a given referent

meet the predetermined criterion for understandability , then the symbol

must be redesigned, or an intensive educational program must be developed

and implemented. The production method could be profitably used at

this point to suggest new graphic renditions. Similarly, the confusions

generated by existing symbols can be reviewed to determine what graphic

features create problems. Once a symbol has been redesigned, it should

then be re-evaluated.

37
4.3 OTHER RESEARCH CONSIDERATIONS IN DETERMINING SYMBOL EFFECTIVENESS

Assessing the raeaningfulness of a symbol is a critical element in the

initial evaluation. However, a complete description of the performance

and usefulness of a symbol requires further considerations. One important test procedure is a behavioral one, in which subjects must perform

the action indicated by the symbol. This procedure, although rarely

used, can be one of the most critical, for it indicates not only that

subjects can define a symbol, but further that the symbol is effective

in eliciting the indicated action. The problem in using this technique

is to determine some measurable activity and then measure the frequency

or accuracy of its occurrence with and without the symbol. Thus, Janda

and Volk (1934) asked subjects to push a lever in the direction indicated by the symbol while Heard (1974) had subjects touch automobile

controls that were represented by symbols. Freedman et al. (1976)

observed whether subjects could correctly negotiate their way through a museum, following directions provided only by symbols. Forbes et al.

(1963) determined the lane position where motor vehicles swerved to avoid

a highway barrier with and without a lane change symbol, while Dewar and

Swanson (1972) counted the number of times that vehicles made illegal

left turns in full view of a "No left turn" symbol. Each of these

experiments determined whether a symbol effectively altered behavior in

the desired direction. Such a determination appears to be the logical

final step in an assessment of symbol effectiveness in a given situation. Unfortunately, in many cases, particularly with safety signs,

there is no explicit overt behavior associated with the message. While

actual reduction in accident rates could be measured, the rarity of such

events would require large scale, long term studies. Nevertheless, the use of protective gear and the avoidance of prohibited acts could more easily be studied as a function of the type of warning message or symbol.

Another set of considerations in determining the effectiveness of a symbol is its performance under special conditions. These might include

unusual physical environments such as smoke, dust, or poor illumination,

or unusual states of the observer such as haste, distraction, panic,

injury, drug or alcohol effects. Finally, such practical considerations

as manufacturing costs or the potential for disfigurement or other van- dalism must be taken into account before implementing a specific symbol.

Nevertheless the primary need for research on workplace safety symbols

remains the experimental determination of the relative understandability

of symbols proposed for each referent.

5. CONCLUSION

In support of the development of effective workplace safety symbols,

the National Institute of Occupational Safety and Health (NIOSH) has

sponsored a project at the National Bureau of Standards (NBS) to evaluate the use of pictographic signs in the workplace. This project

consists of three general tasks: (a) a determination of the kinds of

38
safety or hazard situations which require symbols and selection of

appropriate safety messages; (b) development of a set of candidate symbols for each situation; and (c) experimental evaluation of the effectiveness of the symbols in communicating the intended meaning. This

report documents the initial phase of the project.

In the preceding pages, we have reviewed the current use and status of

workplace symbols. At this point, there is no consistent use of

specific symbols to convey particular safety information. There is no agreement upon the referents or messages to be conveyed, nor upon the

images to depict these messages. There are, however, numerous proposed

and commercially available images for almost every common safety message.

As a result, there is a great need to determine which messages should

be standardized, and which images should be selected for these messages.

In this report we have presented a list of messages which have high

priority for initial consideration. In addition, we have discussed

and recommended a number of procedures for the experimental selection

and evaluation of workplace safety symbols. Throughout, the focus has

been upon the need to evaluate the understandability of safety symbols

because of the importance of accurate communication of the safety

message.

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1. American Institute of Graphic Arts (AIGA) , Symbol Signs . Report

prepared for the Department of Transportation. D0T-0S-40192,

November 1974.

2. Brainard, R. W., Campbell, R. J., and Elkins, E. H., Design and

Interpretability of Road Signs, Journal of Applied Psychology,

1961, 45, 130-136.

^

3 . Bureau of Labor Statistics, Occupational Injuries and Illnesses

for 1978, USDL 79-788; and Work Related Deaths for 1978, USDL

79-787, Nov. 7, 1979.

4. Cahill, M. C., Interpretability of Graphic Symbols as a Function

of Context and Experience Factors, Journal of Applied Psychology,

1975, 60, 376-580.

5. Cahill, M. C., Design Features of Graphic Symbols Varying in

Interpretability, Perceptual and Motor Skills , 1976, 4_2, 647-653.

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48-50.

7. Dember, W. N. and Warm, J. S., Psychology of Perception , 2nd

Edition, New York: Holt, Rinehart & Winston, 1979.

8. Dewar, R. E., The Slash Obscures the Symbol on Prohibitive

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39
9.

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(ed.) Sign, Image and Symbol , New York: George Braziller, 1966,

pp. 126-133.

13. Dreyfuss, H., Symbol Sourcebook , McGraw Hill, New York, 1972.

14. Easterby, R. S. and Hakiel, S. R., Safety Labeling of Consumer

Products - Interim Report on Shape and Colour Coding of Signs , AP Report No. 56, Applied Psychology Department, University of

Aston in Birmingham, Gosta Green, Birmingham, England, March

1977(a).

15. Easterby, R. S. and Hakiel, S. R., Safety Labeling of Consumer

Products: Shapes and Colour Code Stereotypes in the Design of Signs , AP Report 75, Applied Psychology Department, University of Aston

in Birmingham, Gosta Green, Birmingham, England, December 1977(b).

16. Easterby, R. S. and Hakiel, S. R., Safety Labeling and Consumer

Products: Field Studies of Sign Recognition , AP Report 76,

Applied Psychology Department, Univeristy of Aston in Birmingham,

Gosta Green, Birmingham, England, December 1977(c).

17. Easterby, R. S. and Zwaga, H. I. G., Evaluation of Public

Information Symbols, ISO Tests: 1975 Series , AP Report 60,

Applied Psychology Department, University of Aston in Birmingham,

Gosta Green, Birmingham, England, March 1976.

18. Ells, J. G. and Dewar, R. E., Rapid Comprehension of Verbal and

Symbolic Traffic Sign Messages, Human Factors , 1979 , 21^, 161-168.

19. Forbes, T. W., Gervais, E., and Allen, T., Effectiveness of Symbols

for Lane Control Signals, Highway Research Board Bulletin, 1963,

244, 16-29.

20. Freedman, M. and Berkowitz, M. S., Preliminary Report on Laboratory

and Pilot Field Testing: Testing Criteria and Techniques of Evaluation for Passenger/Pedestrian Oriented Symbols for Use in Transportation Related Facilities , DoT-0S-60071. FIRL No. C4448, January 1977.

21. Freedman, M., Berkowitz, M. S., and Gallagher, V. P., Symbol Signs : Testing Criteria and Techniques of Evaluation Passenger /Pedestrian

40
Oriented Symbols for Use in Transportation Related Facilities , Interim Report, U.S. DoT, September 2, 1976.

22. Green, P., Development of Pictographic Symbols for Vehicle Controls

and Displays," Society of Automotive Engineers: Technical Paper

(Warrendale, PA), #790 383, February-March, 1979.

23. Green, P. and Davis, G., The Recognition Time of Rotated Pictographic Symbols for Automobile Controls, Journal of Safety Research , 1976, 8_, 179-183.

24. Green, P. and Pew, R. W. , Evaluating Pictographic Symbols: An

Automotive Application, Human Factors , 1978, 20^, 103-114.

25. Griffith, D. and Actkinson, T. R., International Road Signs:

Interpretability and Training Techniques, Proceedings of the

Human Factors Society - 21st Annual Meeting , 1977, pp. 392-395.

26. Griffith, D. and Actkinson, T. R., International Road Signs:

Interpretability and Training Techniques , U.S. Army Research

Institute for the Behavioral and Social Sciences - Report 1202,

September 1978.

27. Heard, E. A., Symbol Study - 1972 , Society of Automotive Engineers, Automotive Engineers Congress, Detroit, MI, February 25 - March 1, 1974, 740-304.

28. Janda, H. F. and Volk, W. N., Effectiveness of Various Highway

Signs, National Research Council - Highway Research Board

Proceedings , 1934, _14, 442-447.

29. King, L. E., A Laboratory Comparison of Symbol and Word Roadway

Signs, Traffic Engineering and Control , No. 12, 1971, pp. 518-520.

30. King, L. E., Recognition of Symbol and Word Traffic Signs, Journal

of Safety Research , 1975, 7, 80-84.

31. King, L. E. and Tierney, W. S., Glance Legibility - Symbol Versus

Word Highway Signs, paper presented at the 1970 Annual Meeting of

the Human Factors Society, San Francisco, October 1970.

32. Kirsch, I., and Guthrie, J., The Concept and Measurement of Functional Literacy, Reading Research Quarterly , 1977-78, 485-507.

33. Kolers, P. A., Some Formal Characteristics of Pictograms,

American Scientist , 1969 , 57^, 348-363.

34. Laner, S. and Sell, R. G., An Experiment on the Effect of Specially

Designed Safety Posters, Occupational Psychology, 1960, 34, 153-169.

41
35. Lerner, N. D. and Collins, B. L., The Assessment of Safety Symbol

Understandability by Different Testing Methods, NBSIR in review.

36. Mead, M. and Modley, R., Communication Among All People Everywhere, Natural History , 1968, 77 , 56-63.

37. Modley, R., Graphic Symbols for World-Wide Communication, in

G. Kepes (ed.) Sign, Image and Symbol, New York: George Braziller,

1966, pp. 108-125.

38. Modley, R. and Myers, W. R., Handbook of Pictorial Symbols , New

York: Dover Publications, 1976.

39. National Safety Council, Accident Facts: 1979 Edition , National

Safety Council, Chicago, 1979.

40. Plummer, R. W. , Minarch, J. J. and King, E. L., Evaluation of

Driver Comprehension of Word Versus Symbol Highway Signs,

Proceedings of Human Factors Society 19th Annual Meeting , 1974,

pp . 202-208.

41. Smillie, R. J., Continuing Research in Job Performance Aids: The

Interaction of Speed Stress and Media, Proceedings of the Human

Factors Society 22nd Annual Meeting , 1978, pp. 502-506.

42. Smith, G. and Weir, R., Laboratory Visibility Studies of Directional

Symbols Used for Traffic Controls Signals. Ergonomics, 1978, 21,

247-252.

43. Walker, R. E., Nicolay, R. C., and Stearns, C. R., Comparative

Accuracy of Recognizing American and International Road Signs,

Journal of Applied Psychology , 1965, 49, 322-325.

44. Washington Post, "Reading and Writing Gap Widening as Needs Outdistance Skills in U.S.", September 9, 1979, p. 12.

45. Wiegand, D. and Glumm, M. M. , An Evaluation of Pictographic

Symbols for Controls and Displays in Road Vehicles, Technical

Memorandum 1-79, U.S. Army Human Engineering Laboratory, February,

1979.

42
APPENDIX A

LISTING OF SIGNS OBSERVED

Type of Message General Referent Specific Wording or Image

Hazards General hazard Caution—hazardous area

(NFPA hazard symbol)

(demarcation lines, usually yellow)

(yellow parts and rails)

(tags, pennants)

Electrical hazard Danger—high voltage

Danger— volts

High voltage

volts

(color coding of equipment for voltage—green

(lowest), yellow, red)

Heat Caution—hot, do not touch

HOT

Danger—burns

Caution—hot water

Hot water

Danger—hot

Danger—resin is packed hot.

Flammable and

Explosive

Flammable-keep fire away

Class B, C explosive

(Flammable liquid symbol)

(AF explosive symbol)

(orange doors indicate explosives)

Danger—propane

Danger—acetylene vent

Liquid nitrogen

Radiation Danger—radiation area—keep clear

Reactor plant controlled material

Caution—radioactive material

Pictogram of radiation symbol

Chemical, caustic,

acid

Caustic

Danger—acid

Danger—acid wastes

Caution—hazardous chemical

Danger—chemical unloading

Warning—mercury in use Mercury handling

Danger—caustic wash above

Danger—caustic methanol solution

Danger—phenol

Danger—phenol and formalin storage

Caution—nitric acid

Danger—sulphuric acids

Warning—mercury in use Danger—benzene—cancer hazard

(H2S area marked in magenta and yellow)

Do not touch. Material will not wipe off and

a severe burn will result

Noise Caution—high noise area

Caution—high noise level

Maximum exposure in this area hours

43
Type of Message General Referent Specific Wording or Image

Overhead, cranes Danger—men working overhead

Caution—watch crane Warning—watch for crane Caution—Keep clear of crane—no walking

Watch your boom

(Hooks and ends of cranes yellow)

Pressure Danger—high pressure air

HP valve

Traffic Caution—lift truck operating area Caution—pedestrian crossing

Automatic start Danger—starts automatically

Caution—conveyor automatically controlled

lock out before servicing

Other Caution—open pit

Caution—aircraft on jacks

Fragile—handle with care

Stop—tank car connected ("Blue Flag" rule)

Safety Gear General Gear Warning—use safety equipment

Think—wear proper safety equipment

Wear your safety gear

Head Hard hat area

Notice—hard hats required

Danger—hard hat area

Hard hats

(Yellow lines to denote hard-hat area)

Pictogram of head in hard hat

Eye Eye protection required in this switch room Notice—eye protection required beyond this

point

Safety first—eye protection required in this area Caution—eye protection required

Caution—do not enter without eye protection

Eye protection required when disconnecting

hoses

Caution—do not enter without wearing safety

glasses

Are your glasses on?

Eye protection required in this area Notice—safety glasses required in this area Safety first—safety glasses required

Caution—safety glasses required

Caution—safety glasses required in this area Notice—safety glasses required beyond this

point

(Lines on floor to denote safety-glasses area)

Wear your goggles when grinding

Safety first—wear goggles when grinding

Goggle area

Save your eyes—do not operate without safety

glasses and face shield

Pictogram of safety glasses

44
Type of Message General Referent Specific Wording or Image

Chemical, caustic Acetaldehyde—Flammable corrosive—wear face

shield, goggles, rubber gloves

Wear face shields and chemical goggles when

opening filter

Caution—contains sodium hydroxide (caustic)

wear gloves and face shield when working

around tank

Caution—chemical goggles, face shield, rubber

gloves and apron required when handling

phenol, caustic acid, or other corrosive

material

Caution—goggles, face shield, and rubber

gloves MUST be worn when drawing ammonia

(. . . when working in screen)

Hazardous raw materials list (matrix of

corrosivity, toxicity, required gear)

Foot Pictogram of shoe with deflected arrow

Hearing Caution—high noise area—ear protection

required

Hearing protection required

Notice—ear protection required in this area Hearing protectors must be worn inside yellow

lines in forming department

Caution—wear your ear protection in this area Engine testing—hearing protection required

Think—if high noise work starts, use your ear protection

Ear protection required—mandatory ear protection required beyond this point

Pictograms of ear protectors, and hard hat with

ear protectors

Heat, fire Asbestos suits only

Kiln suits

First aid station First aid

First aid room Dispensary

Clinic

To the dispensary

Pictogram of cross (usually in conjunction with

word sign)

Stretcher, blanket Hospital stretcher here

Stretcher

Safety blanket

Fire blanket

Eye wash and

shower

Eye wash station

Emergency eye wash

Emergency eye wash—relieve line pressure

before applying to eyes

Caution—emergency eyewash only

Safety first—eye wash fountain

Eye wash and emergency shower

Emergency shower—eye wash

Pictogram of cross, emergency shower

Emergency shower

(Green circles on floor and green lights used

to indicate location of shower)

45
Type of Message General Referent Specific Wording or Image

Breathing Gas mask inside

Breathing air

Air masks

Safety first-self contained breathing

equipment in this building

Caution—if FF 2 S alarm is blowing, fresh air

equipment must be used to enter unit

Alarm Fire alarm

Fire

Fire department will respond

Emergency alarm—for fire/crash—activate horn

Notice—if gong rings, notify

In case of emergency call

Emergency air horn—open air valve to summon

help

Emergency whistle

Phone, telephone

Caution—F^S alarm light

Caution—leave the area if the FF 2

S alarm horn

blows

Caution—leave the area if the H

2

S alarm siren

sounds

Warning—do not enter room when alarm sounds,

Flalon 131 being released

(red stripes on walls and columns)

(red bulbs)

Firefighting Fire extinguisher

Fire extinguisher here

Fire station

Use CO

2 extinguishers only in this building

h

2 o co

2 Fire hose

In case of fire, open door and pull lever (on

deluge system)

Water spray system

Entering sprinkler zone Sprinkler water

Water spray curtain

Water spray—fire protection valve

Foam truck inside

Foam 832 (numbers refer to foam lines)

(red stripes, columns, boxes, bulbs)

Other Ladder for emergency use only

Deluge system for vapor control

Emergency propane and oxygen cut off

Access, Egress Exit Exit

out

Pictogram of arrow

Emergency exit Emergency exit

Fire exit

Emergency exit—do not block

Fire door—do not block

No exit No exit

46
Typo of Message General Referent Specific Wording or Image

Prohibitions

Keep open, clear

Keep closed

Traffic

Restricted

Admittance

No Smoking

Keep door open at all times

Notice-Keep this doorway clear

Do not block doorway

Fire station—keep clear

Caution—keep this area clear

Keep this doorway free of obstruction so fire

door can close

Keep door closed

Keep fire door closed

Danger—this is not a walkway

Notice—No thoroughfare

Stop (on floor)

Use lined walkways only

(Use of lined walkways, usually yellow, but

also white, red, or green)

Do not enter

Caution—work and storage area—do not enter

Do not enter without #1 operator’s permission

Keep out—authorized personnel only

Danger—keep out

Danger—keep out—electrical hazards

Danger—construction area—Keep out

Danger—keep out of plate storage area

authorized personnel only—violators subject

to disciplinary action

No admittance—authorized personnel only

Positively no admittance

No admittance—paint factory employees only

Authorized personnel only

Authorized personnel—keep out

(Company) personnel only

Unauthorized persons keep out

Unauthorized personnel keep out

Unauthorized persons keep out at all times

Restricted area—authorized personnel only

Controlled area

No trespassing

Trespassing forbidden

Trespassing forbidden—for fire only

Fire permit required for entry into air

conditioning room Notice—persons with pacemaker—do not enter

this area—microwave oven in use Danger—pacemaker wearers do not enter this room Pictogram of horizontal bar inside of circle

No smoking

No smoking beyond this point

Positively no smoking beyond this point

No smoking—protect your job

Danger—No smoking in this area

No smoking—$25 fine

No smoking beyond this door

No smoking in catwalk or ramp

Equipment—-no smoking

Danger—fuel storage—no smoking

47
Type of Message General Referent Specific Wording or Image

No Smoking (cont.) Danger—restricted area—no smoking

no hot work

Smoking—carrying matches—open lights—

positively prohibited

Flammable—no smoking within 10 feet

Pictogram of circle, slash lighted

cigarette, and of diamond, X, lighted

cigarette

Other FlammableRelated

Flammable-—keep fire away

Danger—no welding

Other

prohibitions

Danger—do not open

Danger—do not open while in operation—high

velocity particles

Do not throw trash in this area Notice—No storage permitted

Butts only—no trash

Do not throw cigarette butts on floor

Place no objects on roof curbing

Do not park or place material under this

stretcher

- *.

. ;

'

' t

' 1 .

-

V

»•

. •• l

• v , y ,

• .';*•••••'.* . »

v

Danger—do not stand here

Do not park closer than 6 feet from tracks

Ride bus, no walking (words in 3 languages)

Caution—general purpose fork lift. Trucks not

permitted in this area Caution—battery operated vehicles not

permitted in this area Danger—do not start this machine

Do not turn off agitator

Caution—stay off furnaces

No liquids (water, coffee, tea) in this area Caution—lead work—no eating, drinking, or smoking—gloves and shoes required

Do not hump this car Caution—used lumber—do not use Caution—do not use (on lumber)

Pictogram of circle, slash, walking figure

Procedures Avoid entanglement Caution-Keep closed while in operation—moving

parts

Caution—do not operate this machine without

guards in place

Warning—keep guards in place while machine is

in operation

Keep hands out of moving equipment

Hands off

Fire use only—hands off

Danger—keep off

Caution—stay clear of rocker when using

Caution—tie back long hair before operating

buffer

48
Type of Message General Referent Specific Wording or Image

Authorized use only This machine to be used by qualified operators

only

Caution—authorized personnel only to operate

equipment

This shipyard is red tag country—If you don't

know, keep your hands off and ask—Danger

Falls Keep manhole covers closed

Before ascent secure platform locks

Caution—to avoid a fall, please use handrails

Be stair wise—(1) one step at at time,

(2) walk, don't run, (3) use handrail

Walk, don't run—safety first

Hose Keep lines and hose off ladder

Safety first-coil hose after using

Vent, valve Danger—vent to safe location

Caution—shut off N£ and open vent prior to

opening standpipe

All petcocks on engine must be open and water

valves shut off before moving hoses

Doors, lids Keep lid down

Caution—keep doors closed when spraying

Lock door if room unattended

Chock wheels Caution—chock wheels before loading

Chock trailer wheels while loading or unloading

Machines and

Equipment

Caution—operate automatic lubrication system

before starting this machine

Caution—shut down pumping operation before

entering

Lock out field disconnect before entering

Did you check this (with picture of a torch)

"Housekeeping"

related to

hazards

^2°2—Flush spills immediately

FOD--foreign object deposit

Safety—empty catalyst container must be

returned

Keep cylinders chained (with picture of

chained cylinders)

(Various signs indicating general housekeeping

responsibilities)

Other safety

procedures

Deposit all flame-producing devices before

entering this area Slow-sound horn

Asbestos material only

Maximum Limits Weight Caution—maximum floor loading, 150 Ibs/sq ft

This floor will safety sustain a load of

pounds

Maximum capacity tons

Persons Personnel limit - 10 persons

Maximum number of persons

Other Explosive limits—15 pounds

Danger—do not exceed rated capacity

49
APPENDIX B

Table 1. Sign Wordings or Symbol Referents Which Have Been Suggested as Standard for Various U.S. Applications

OSHA Standard 1910.145 Standardized Hazard Warning Symbols

adopted by DoT, U.N. and EEC

Examples of Wordings (1) Flammable liquids

(2) Flammable solids

(3) Flammable gas

(4) Toxic gas

(5) Compressed gas Danger Signs (6) Toxic substance

(7) Harmful substances - keep away from food

(1) Danger - keep off - electric current (8) Corrosive substance

(2) Danger - no smoking, matches, or open flame (9) Organic peroxide

(3) Danger - men working above (10) Oxidizing substance

(4) Danger - not room enough here to clear men on cars (ID General hazard - multi-load of different substances

(5) Danger - keep away (12) Dangerous when wet (substances which in contact

(6) Danger - men in boiler with water emit flammable gases)

(7) Danger - insufficient clearance (13) Spontaneously combustible substances

(8) Danger - 2,300 volts

(9) Danger - keep out

(10) Danger - crane overhead

(11) Danger •- keep out

(12) Danger - biological hazard

Caution

(1) Caution - do not operate, men working on repairs

(2) Caution - hands off switch, men working on line

(3) Caution - working on machines - do not start

(4) Caution - goggles must be worn when operating

this machine

(5) Caution - this door must be kept closed

(6.) Caution - electric trucks - go slow

(7) Caution - this space must be kept clear at all times

(8) Caution - stop machinery to clean, oil, or repair

(9) Caution - keep aisles clear

(10) Caution - operators of this machine shall wear

snug-:fitting clothing - no gloves

(11) Caution - close clearance

(12) Caution - watch your step

(13) Caution - electric fence

Safety Instruction Signs

(1) Report all injuries to the first aid room at once

(2) Walk - don't run

(3) Report all injuries no matter how slight

(4) Think, if safe go ahead

(5) Make your work place safe before starting your job

(6) Report all unsafe conditions to your foreman

(7) Help keep this plant safe and clean

Direction Signs

(1) This way out

(2) Fire exit

(3) Fire extinguisher

(4) To the fire escape

(5) To the first aid

(6) Manway

(7) This way to first aid room

Informational Signs

(1) No trespassing under penalty of the law

(2) This elevator is for freight only, not for passengers

(3) No admittance except to employees on duty

(4) No admittance

(5) No admittance, apply at once

(6) No trespassing

(7) Men

(8) Women

(9) Por employees only

(10) Office

50
APPENDIX B

Table 2. Non-European Standardized Symbols

Canadian Standard

Signs and Symbols for the Occupational Environment

REFERENT GLYPH CONTENT

(l) Alert - exclamation point

(2) Breathing protection required - front view of head with respirator

(3) Eus - front view of bus

(4) Cafeteria - knife and fork

(5) Car - front view of car

(6) Chemical burn - drops falling on hand - index and second fingers disintegrating

(7) Coffee shop - cup and saucer

(8) Compressed gas - view of gas cylinder

(9) Direction - arrowhead with stem

(10) Drain - funnel connected to an s-drain top

(11) Drinking water - human face with angled container

(12) Electrical hazard - zigzag line tapering vertically

(13) Elevator - box enclosing males and females with arrows pointing up and down

(14) Explosion hazard horizontal lines, sumounted by simulated explosion with radiating

particles and wedge shaped lines

(15) Eye protection front view of head with eye protection

(16) Eyewash drops spraying up to a side view of an eye

(17) Fire alarm - disc with hammer and convector lines on both sides of disc

(18) Fire axe H side view of a complete fire axe

(19) Fire extinguisher - side view of fire extinguisher showing cylinder and hose

(20) Fire hose - curled fire hose in form of a spiral with a nozzle at the bottom

(21) Fire hydrant - front view of a fire hydrant plug

(22) First Aid - Greek cross

(23) Foot protection - side view of foot protection

(24) Hair protection - front view of a head with a hair net

(25) Hand protection - front view of glove - fingers extended

(26) Head protection - front or side view of head with head protection

(27) Hearing protection - front view of head with ear protection

(28) Flammable - horizontal line surmounted by flames

(29) Man — front view of male figure showing head, 2 arms and 2 legs

(30) Men at work - side view of human with shovel

(31) Open flame - flaming match

(32) Overhead crane - side view of hook with safety catch and with pulley and cables above

(33) Parking - Sanserif capital "P"

(34) Phone - side view of a handset

(35) Poison - skull and crossbones

(36) Running side view of person running - 2 arms and 2 legs

(37) Safety lane - side view of human walking between 2 broken lines

(38) Security - policeman's shield

(39) Shower - drops spraying from a side view of shower head

(40) Slippery floor - horizontal line, with a human figure that has lost its balance

(41) Smoking & smoking cigarette

(42) Stair - side view of risers and treads

(43) Start hand, with index finger extended and almost touching side view of a button or switch

(44) Stretcher - view of a stretcher with Greek cross inside

(45) Touch Hand, with index finger extended and almost touching horizontal

plane or line

(46) Truck(s) - side view of a truck

(47) Valve 2 closed arrowheads pointing at each other sumounted by a capital

"T" as illustrated

(48) Vending ~ side view of hand holding the representation of a coin and

inserting same i ~ * o vertical slot

(49) Waste - hand throwing an object into a receptacle

(50) Woman

Categories

front view of a skirted female figure showing head, 2 arms (at

approximately 60° from the horizontal), and legs (together)

(1)

Regulatory - Prohibition

Mandatory

(2) Warning - Caution

Danger

(3) Information - Emergency-related

Miscellaneous
APPENDIX B

Chinese 7.1002

Red -

Orange -

Yellow -

Green -

Blue -

Purple -

Black - White -

All Colors -

Table 3. Non-European Safety Referents

Uruguay - UNIT-131-38

Fire protection equipment and apparatus

Fire exit signs

Fire alarm boxes

Fire buckets and pails

Fire hose location

Fire hydrants

Fire pumps Fire sirens Post indicator values for sprinkler system

Sprinkler piping

Safety cans Barricades

Danger signs

Emergency stop bars

Wire blocks

Flat work ironers

Stop buttons

Energized equipment

Switch box door

Unguarded hazards

Picker guards

Safety starting buttons

Pulleys

Tranmission guards

Rollers

Cutting devices

Power jaws

Stumbling

Tripping

Caught in between

Construction equipment - bulldozers, tractors Guy wires

Locomotives

Door ways

Low beams and pipes

Trucks, trailers, fork lift, cranes

Pillars, posts, columns

Freight car loading plates

Piping systems

Stretchers

Gas masks

Safety showers

Elevators

Ovens and vats Kilns

Valves

Vaults

Scaffolding

Ladders

Calor - heat

Comburentes - oxidizing

Corrosivos - corrosive

Electricidad - electricity

Explosivos - explosive

Inflamables - flammable

Radiaciones - radiation

Toxicos - toxic

Bolivia DGNT-NB-20. 1-003

Calor - heat

Electricidad - electricity

Explosivos - explosive

Inflammables - flammable

Radiaciones - radiation

Toxicos y corrosivos - toxic and corrosive

Japanese Standard Z9103-196J

No fire, no open flame

Danger

Attention - watch out First aid No entry, no trespassing

Under repair

Radiation

Arrow

Labels and tags

Traffic

Housekeeping

Aisles

Stairways

Food dispensing equipment

Follow Munsell System

52
NBS-114A (REV. 9-78)

U.S. DEPT. OF COMM.

BIBLIOGRAPHIC DATA

SHEET

1. PUBLICATION OR REPORT NO. NBSIR 80-2003

4. TITLE AND SUBTITLE

Workplace Safety Symbols: Current

Status and Research Needs

5. Publication Date March 1980

7. AUTHOR(S)

Neil D. Lerner and Belinda L. Collins

8. Performing Organ. Report No.

9. PERFORMING ORGANIZATION NAME AND ADDRESS

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, DC 20234

11. Contract/Grant No.

12. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (Street, City. State. ZIP)

NIOSH

944 Chestnut Ridge Road

Morgantown, W. Va. 26505

13. Type of Report & Period Covered

14. Sp&tsoriKg Agsecy Code

15. SUPPLEMENTARY NOTES

| | Document describes a computer program; SF-185, FIPS Software Summary, is attached.

16. ABSTRACT (A 200-word or teas tactual summary of moat significant information. If document includes a aignificant bibliography or

literature aurvey, mention it here.) Although written signs are a common means of conveying safety information

in the workplace, pictographic symbols can be a more effective way of providing

the same information. Symbols are independent of a particular written language,

and can be more accurately and rapidly perceived than 4_ he comparable word message.

Despite the many advantages of safety symbols, they can be ineffective or even dangerous if the intended meaning is not accurately communicated. As a result,

there is a great need for careful evaluation, consistent application, and eventual

standardization for safety symbols.

This report documents an initial assessment of current symbol use and future

requirements. It includes a review of the technical literature on symbol research;

observation of safety sign and symbol use in the workplace; compilation of

commercially available symbol referents; and review of national and international

standards. Based upon these sources, an initial list of 40 symbol referents is

presented along with research priorities for evaluating the effectiveness of symbols

for these referents.

17. KEY WORDS (six to twelve entries; alphabetical order; capitalize only the first letter of the first key word unleaa a proper name;

separated by semicolons)

communication; hazard; pictograms; safety; signs; standards; symbols;

visual alerting; warnings

18. AVAILABILITY [%} Unlimited

I | For Official Distribution. Do Not Release to NTIS

I | Order From Sup. of Doc., U.S. Government Printing Office, Washington, DC

20402, SD Stock No. SN003-003- Q Order From National Technical Information Service (NTIS), Springfield,

VA. 22161

19. SECURITY CLASS

(THIS REPORT)

UNCLASSIFIED

20. SECURITY CLASS

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PRINTED PAGES

61

22. Price

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