JCT A111D7 3TDE5E NBSIR 83-2732(^^ Use of Hazard Pictorials/Symbols in the Minerals Industry i f r U S. DEPARTMENT OF COMMERCE National Bureau of Standards Center for Building Technology Illuminating Engineering Group Building Physics Division Washington, DC 20234 September 1983 !i Sponsored by ^^reau of Mines tQC' S. Department of interior 100 Washington, DC 20241 .U56 83-2732 1933 I 1 1 '] f 4 a» rrA.m>iJua umiAmy Cj> f c Cl C/0 o . W£ C 83-2732 NBSIR no. USE OF HAZARD PICTORIALS/SYMBOLS /m IN THE MINERALS INDUSTRY Belinda Lowenhaupt Collins U S. DEPARTMENT OF COMMERCE National Bureau of Standards Center for Building Technology Illuminating Engineering Group Building Physics Division Washington, DC 20234 September 1983 Sponsored by Bureau of Mines U S. Department of Interior Washington, DC 20241 U.S. DEPARTMENT OF COMMERCE, Malcolm Baldrige, Secretary NATIONAL BUREAU OF STANDARDS, Ernest Ambler. Director . MS ffv- V ^ IT'J •v^'% 'X'- . = 0 " ' ^4 ' '-W ' * . .k? t ._.___ , U#^„ ' '/\'i ' '• , I' i,v ip/1 M v'^jNv J a! i'" ^ iM I w? -V D'< >? ^ * ^*-1 >r-fi ifc. *'' - • >.,/> M Vf.7 A .^'1 'V -. z.. J A ^’’ ’s#- ?,# tViiW’ ' ^,- '..I't^ .-a '»’ ' ^1 li i^T:V 4* j 5^' i-, I 't-1 ^ryii.ji ' 1 _ 4’5 » y . .iZ» 4 . K'^' .lui. I'm " fr * #•>. ft', " «\- V ‘tfl >i!»j B4-- 1C Ft>'" ,.^{t^.’‘ ib :'A>-^4 m M'l‘i ‘^C HiPWSivaBBi r A a; ^ 1; . % ."vf ' .' 3T<i ’' **-*»»%> •."-'i*"' *-- .i>P ~fl i . iU ’ Xj|^ Sir.V«»^>' \ r- ‘ i . 4T < f.~/ 'V' '1, . ij4.', .'.dlMidl. .r, < isart ABSTRACT This report documents a three-phase research effort on the evaluation of the effectiveness of safety symbols and hazard pictorials for use In mining and milling operations. In the first phase, applicable codes and standards were reviewed, along with documentation of typical mining hazards, to determine relevant safety messages. This phase included site visits to eight mine sites to document existing sign practice and common mining hazards. In the second phase, the effectiveness of two sets of symbols for 40 different safety mes- sages was evaluated with 267 miners from 10 sites at disparate geographical locations. This evaluation also included an assessment of the effectiveness of six different symbol surround shapes and colors. Symbols which were the most effective, according to the suggested criteria, were those which depicted both the person and the hazard or protective gear, and which were more repre- sentational, rather than highly abstract. Based upon this research, a set of 40 symbols was suggested for further graphic refinement, additional evaluation, and eventual use. In the third phase, these symbols were assessed in an in- mlne evaluation at 2 sites. This evaluation indicated that the symbol signs were generally well understood and conspicuous, with no problems of durability, or poor contrast arising during the three-month evaluation. A Handbook for using symbol signs in mines concludes the report. Key words: communication; hazard; mining; plctogram; safety; signs; standards; symbols; visual alerting; warnings. iii FOREWOEID This report Is one of a series documenting National Bureau of Standards research and analysis efforts In support of the Bureau of Mines (BoM)/ National Bureau of Standards (NBS) Hazard Plctorlal/Saf ety Symbol Evaluation Program, This report Is a deliverable product under BoM Contract Number JOl 13020 entitled, "Use of Plctorlals/Symbols In the Minerals Industry,". It was administered under the direction of Twin Cities Mining Research Center, Minneapolis, Minnesota with Guy Johnson acting as the Technical Project Officer. Phil Silas was the contract administrator for the Bureau of Mines. This report summarizes the research completed as part of the contract during the period of January 1981-January 1983. ACKNOWLEDGEMENTS The author wishes to acknowledge the help of the many people who were essential to the completion of this report. The cooperation of the many miners who parti- cipated so willingly Is deeply appreciated, along with the mining companies who allowed the use of their personnel and facilities. In addition, the following people furnished Invaluable support during the course of the project: Guy Johnson, Bob Mattes, and Mike Sapko, of the Bureau of Mines, provided con- tinuing support and use of mine facilities; Dr. Nell Lerner contributed exten- sively to the research planning, code review and documentation, and statistical analysis; Dr. Austin Adams also provided Invaluable assistance during the statistical analysis; and Ms. Karen Lister, Mr. Albert Hattenburg, Dr. Mary Natrella, and Mr. George Turner, of the National Bureau of Standards provided Insightful and helpful comments on the document. Finally, I would like to thank the Word Processing Unit for their competent Job In typing the many versions of the final report. Iv EXECUTIVE SUMMARY Extensive highway research has demonstrated that, when chosen appropriately, symbols can communicate information more rapidly and often, more effectively, the words. Greater use of symbols for safety and hazard warning messages, however, requires that they be understandable to the intended audience. The present project was designed to assess the effectiveness of safety symbols and hazard pictorials for mine-safety communication. In the first phase of a three-phase evaluation, requirements for safety signs in mines were determined by a series of site visits which assessed existing practice, a hazard analysis which reviewed mine accident and fatality statistics, and a code review which tabulated symbol and sign requirements in existing national and international codes. From this first stage, a set of 40 messages (referents) applicable to mine safety signs was developed. At the same time, one to two symbols were selected for further evaluation for each message, (based upon previous research and code recommendations). In the second phase, the understandablllty of the selected symbols was assessed with 267 miners at 10 different mine sites in the United States. Miners indi- cated their understanding of a symbol's meaning by completing a four-choice multiple response form. At each site, miners were split into two groups so that the performance of more than one symbol for a message could be compared. In addition, the degree of danger (perceived hazardousness) indicated by six different surround shapes was determined by a ranking procedure for several different Interior images. The results from the second phase indicated that statistically significant differences in performance occurred between symbols for 72 percent of the referents for which 2 symbols were studied. An analysis of variance revealed significant site and age differences as well. For 34 referents, at least one symbol was identified correctly by 85 percent or more of the miners participating. Symbols which performed below this level Included: Laser, Radiation, General Warning, Flammable, Fire Alarm Call Point, and No Exit. Many of these latter symbols are either highly abstract or represent unfamiliar concepts. Correctly identified symbols can be characterized as more pictorial, often depicting a person plus an action, or piece of gear, or hazard. Although problems emerged for some of the more abstract hazard-warning symbols, symbols for personal protective gear, prohibited actions, and fire/ safety equipment were generally correctly identified. The results of the rankings for the perceived hazardousness of surround shape indicated that the diamond and octagon were seen as most hazardous and the square and circle as least hazardous. Red, yellow, and orange were ranked as the most appropriate colors for hazard warning. In the third phase, a subset of 20 symbols was selected for an in-mine evaluation, based upon the results from the second phase. This evaluation, which took place at 2 mine sites in the Eastern United States, included further assessment of the understandablllty of the 40 "best" symbols, determination of confusions within, and conspicuity of, the subset of Installed symbols, and determination of physical parameters such as contrast and durability. Although the in-mine evaluation revealed continuing problems with the Flammable symbol. V the overall performance of the symbol signs was generally good. The need for additional word messages on some hazard-warning signs was Identified. Based on the three evaluation phases, a handbook was written for using symbol signs In mines. This handbook, which concludes the report, provides suggestions for symbol sign configuration, location, and testing at mine sites. In summary, the overall evaluation of safety symbols In mines Indicated that symbols are a generally effective means of communicating safety and hazard Information. A set of some 25-30 symbols Is suggested, along with a handbook containing general guidelines for the use of symbol signs In mines. Vi J TABLE OF CONTENTS Page ABSTRACT iii FOREWORD iv ACKNOWLEDGEMENTS iv EXECUTIVE SUMMARY v 1. INTRODUCTION 1 1.1 FRAMEWORK FOR THE STUDY OF SAFETY SYMBOLS AND HAZARD PICTORIALS 1 1.1.1 Background Research 2 1.1.2 Methods of Evaluation 3 1.2 WORKPLACE SAFETY SYMBOL RESEARCH 4 1.3 MINE SAFETY SYMBOL RESEARCH 5 1.4 CODE REVIEW 6 1.5 HAZARD ANALYSIS 10 1.5.1 Overview 10 1.5.2 Detailed Hazard Analysis 14 1.6 SITE VISITS 18 1.6.1 Hazard Information from Site Visits 18 1.6.2 Sign Usage 18 2. SELECTION OF REFERENT MESSAGES AND CANDIDATE SYMBOLS 25 2.1 SELECTION OF REFERENT MESSAGES 25 2.2 SYMBOL SELECTION PROCEDURES 25 2.2.1 Symbols Selected 25 2.2.2 Rationale for Specific Symbol Selection 27 2.2.3 Surround Shape Concerns 28 2.3 EXPERIMENTAL RATIONALE 29 2.3.1 Evaluation of Understandablllty 29 2.3.2 Perceived Hazardousness of Surround Shape 31 3. METHOD 32 3.1 PROCEDURE 32 3.2 PARTICIPANTS 32 3.3 STIMULUS MATERIAL 32 3.4 PROCEDURE4.4.1 34 3.5 SCORING OF RESPOJSE SHEETS 35 4. RESULTS 36 4.1 ANALYSIS OF COMPREHENSION DATA 36 4.2 DEMOGRAPHIC DATA 38 4.3 PERFORMANCE OF INDIVIDUAL SYMBOLS 44 4.4 RESULTS AND DISCUSSION OF INDIVIDUAL SYMBOLS 48 Individual Symbol Data 48 4.