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Final Yea Role o
U
CITY UNIVERSITY OF HONG KONGFaculty of Science & Engineering Department of Building & Construction
r Project (2001-2002)
f Construction Practitioners’ Characteristics in
nderstanding Safety Symbols in Hong Kong
Submitted in fulfillment of the requirement for the Master of Engineering in Building Engineering
Supervised by: Dr. Tam, C. M. Associate Head and Associate Professor
CityU Hong Kong
Submitted by: Yeung Chung Lai
MEng in Bldg Eng
April,2002
Table of Content
Declaration ………………………………………………………………i
Abstract ………………………………………………….……………....ii
Acknowledgements ……………………..……….……..…………..........iii
Table of Contents …………………………………..…….………..…….iv
List of Tables ……………………………………….….……………..….ix
List of Figures ……………………………………….……...…….……..xi
CHAPTER 1 INTRODUCTORY CHAPTER…………………………..1
1.1 An Overview of Construction Industry in Hong Kong…….….1
1.2 An Overview of Construction Safety in Hong Kong…………..3
1.3 Background………………………………………………………9
1.4 Objective……………………………………………………..….11
1.5 Methodology…………………………………………………….12
1.6 Scope and Limitations………………………………...………..13
CHAPTER 2 LITERATURE REVIEW……………………….……….15
2.1 Introduction…………………………………………………..…15
2.2 A Review of Construction Site Safety in Hong Kong ……. ….16
2.2.1 Current Problems……………………………….. .……….16
2.2.2 Workers Attitude and Safety Strategies………… ………17
2.3 A Review of Traffic Signs and Road Accidents………… ….…19
2.4 A Review of Warning Label and its effectiveness……… .…....22
2.5 A Review of Safety Symbol and its effectiveness…… …….….27
iv
2.6 Chapter Summary……………………………………………...31
CHAPTER 3 RESEARCH METHODOLOGY & HYPOTHESES….32
3.1 Introduction…………………………………………….…….…32
3.1.1 Symbol Selections and Settings……………… .……….…33
3.1.2 Adoption of Multiple Choice format…………. ………...34
3.1.3 Demography Survey…………………………..……..……35
3.2 Statistical Analyses………………………………..……………35
3.2.1 Data Description…………………………………………..35
3.2.2 Inferential statistics…………………………………….…36
3.3 Pilot Study……………………………………………………....38
3.4 Research Hypotheses……………………………………..…….39
3.5 Chapter Summary…………………………………………...…40
CHAPTER 4 REPORT FINDINGS…………………………………....42
4.1 Introduction…………………………………………………….42
4.1.1 Pit…………………………………….……………….....…46
4.1.2 Symbol…………………………………………..…………46
4.2 Overall Performance of Symbol Comprehension……….……47
4.2.1 Mandatory Symbol…………………………………..……47
4.2.2 Warning Symbol…………………………………………..48
4.2.3 Prohibition Symbol…………………………………..……50
4.3 Descriptive Statistics for Different Respondent Group………50
4.3.1 Age and Marital Status……………………………...…….51
4.3.2 Education Level………………………………….………..52
4.3.3 Monthly Income………………………………..………….53
v
4.3.4 Smoking and Drinking Habit………………….…………53
4.3.5 Job Position………………………………………….…….54
4.3.6 Involvement in Safety Related Activities…………….…..55
4.4 Chapter Summary…………………………………………...…55
CHAPTER 5 DATA ANALYSIS & DISCUSSION……………......…..57
5.1 Introduction……………………………………..………………57
5.2 Correlation between Symbols in Three Categories……….….58
5.2.1 Pearson Correlation Coefficient……………………...…..59
5.2.2 Discussion on Relationships between Three Symbol
Categories………………………………………………………..60
5.3 Compare the Comprehension Scores between Practitioners with
Different Characteristics by T-test……… ……….………….60
5.3.1 Comprehension of Symbols by Drinking Habit… ………62
5.3.2 Discussion on Comprehension of Symbols by Drinking
Habit…………………………………………………..…62
5.3.3 Comprehension of Symbols by Safety Activities…….….65
5.3.4 Discussion on Comprehension of Symbols by Safety
Activities………… ……………………………………...67
5.3.4.1 Risk Perception……………………………..……...67
5.3.4.2 Safety Management of the Companies…………...70
5.3.4.3 Learning and Cognition…………………….……..70
5.4 Compare the Comprehension Scores between Practitioners with
Different Characteristics by ANOVA………………………..72
5.4.1 Comprehension of Symbols by Job Positions…………....73
5.4.2 Discussion on Comprehension of Symbols between Site Staff
vi
& Workers……………………………………...………….75
5.4.2.1 Direct and Indirect Labour………………………..75
5.4.2.2 Cultural and Linguistic Background… …………..77
5.4.2.3 Locations of Safety Symbols…………… ………....77
5.5 Chapter Summary…………………………………… ……..….78
CHAPTER 6 RECOMMENDATIONS……………………………..…79
6.1 Introduction…………………………………………………….79
6.2 Recommendations for Construction Practitioners and Labour
Department………………………..…………………………….….79
6.2.1 Design the Symbols……………………………………….80
6.2.2 Trainings and Educations……………………….………..80
6.2.3 Drinking Habit…………………………………….………81
6.2.4 Locations of Safety of Symbols……………………..…….82
6.2.5 Standardization……………………………………………82
6.3 Recommendations for Further Studies…………………..……83
6.3.1 Shape and Colour…………………………………………83
6.3.2 Signal Words and Placement……………………………..84
6.3.3 Compliance Test……………………………………..…….84
6.4 Chapter Summary…………………………………..………….85
CHAPTER 7 CONCLUSION…………………………………………..86
vii
References…………………………………………………………..……..89
Bibliography………………………………………………………..……..95
Appendix…………………………………………………...…………….100
Appendix I Sample Questionnaire Appendix II Statistic for Data Description Appendix III Statistic for Data Analysis Appendix VI Previous Research
viii
List of Figures
Figure 1: Industrial Accidents in Construction Industry (1991-2000) .. 7
Figure 2: Safety Symbols Commonly Used in Construction Sites ........11
Figure 3: Tested Warning Labels Used in Chapanis Study .................. 24
Figure 4: Warning Labels Tested in Frantz Study................................. 26
Figure 5: Tested Safety Symbols in Questionnaire ................................ 45
Figure 6: Overview of Information Processing System in Human
Beings..............................................................................................72
List of Tables
Table 1: Gross Value of Construction Work Performed by Main Contractors
Analysed by Broadtrade Group (in Nominal Terms)...............................2
Table 2: Numbers of Industrial Accidents in Construction Industry
(1991-2000) .................................................................................................7
Table 3: Comprehension Percentage for Symbols in Three Categories ....45
Table 4: Comprehension Percentage for Prohibition Symbols...................45
Table 5: Comprehension Percentage for Mandatory Symbols....................46
Table 6: Comprehension Percentage for Warning Symbols .......................46
Table 7: Comprehension Percentage for Warning Symbols .......................46
Table 8: Comprehension of Symbols by Age ...............................................51
Table 9: Comprehension of Symbols in Three Categories by Age .............51
Table 10: Comprehension of Symbols by Marital Status.............................52
Table 11: Comprehension of Symbols by Education Level.........................52
Table 12: Comprehension of Symbols by Monthly Income.........................53
Table 13: Comprehension of Symbols by Drinking Habit............................53
Table 14: Comprehension of Symbols by Smoking Habit ...........................54
Table 15: Comprehension of Symbols by Job Position...............................54
106
Table 16: Comprehension of Symbols by Safety Activities ........................55
Table 17: Correlation Between Three Symbol Categories...........................59
Table 18: Statistic on Comprehension of Symbols by Drinking Habit .......63
Table 19: Independent Sample t- Test for Comprehension of Symbols by
Drinking Habit ..........................................................................................63
Table 20 Statistic on Comprehension of Symbols by Safety Activities......66
Table 21: Independent Sample t-Test for Comprehension of Symbols by
Safety Activities .......................................................................................66
Table 22: ANOVA for Comprehension of Symbols by Job Positions .........74
Table 23: Tukey’s Test for Comprehension of Symbols by Job Positions.75
107
Abstract
This study ascertained the effectiveness of safety symbols commonly
used in Hong Kong construction industry and the role of personal
characteristics in practitioners’ comprehension of safety symbols. A
total of 30 symbolic mandatory, warning and prohibition signs were
investigated. Questionnaires were distributed to 280 construction
practitioners on four construction sites and Construction Industry
Training Authority in Hong Kong and 194 (69.2%) responded back.
Results showed that the comprehension of ‘Oxidizing’ (28.9%), ‘Irritant’
(19.6%) and ‘Harmful’ (17.0%) were unsatisfactory. The performance of
mandatory signs was the best (87.9%), followed by warning signs
(61.2%), and then prohibition signs (55.3%). Practitioners who are non-
alcohol consumed, site staffs and those who have involved in site safety
activities understand the safety symbols significantly better than others.
These findings are believed to be important for Labour Department and
construction practitioners to evaluate the existing safety symbols used
in construction industry.
Acknowledgements
I would like to express my gratitude to Dr. Tam, C M, Associate Head
and Associate Professor in Department of Building and Construction at
City University of Hong Kong for his invaluable advice and suggestion
on my progression of this project.
Moreover, I am indebted to Mr. Fung, Ivan W H, Instructor II in
Department of Building and Construction, for his inestimable guidance
and encouragement during the research period.
In addition, I would like to express my thanks to Mr. Harry Chu, the
Project Coordinator of Hong Kong Housing Society; Mr. Ngai, H W, Mr.
Chik, Mr. Lo Alan and Mr. Choi, who assisted me to distribute the
questionnaires on construction sites and in Construction Industry
Training Authority.
Finally, I wish to extend my thanks to my girlfriend, Kaman Leung for
her continuing encouragement and support.
CChhaapptteerr OOnnee
IInnttrroodduuccttoorryy CChhaapptteerr
Chapter 1
Introductory Chapter
1.1 AN OVERVIEW OF CONSTRUCTION INDUSTRY IN HONG KONG
T he construction industry in Hong Kong plays an important role in
Hong Kong economic activities. According to the report of
Construction Industry Review Committee (CIRC) published in 2001, due to the
expansion of population and growing economic prosperity, the community
requires more and better infrastructures, which not only have enhanced our
quality of life and living environment, but also have provided suitable formed land
and completely developed facilities to meet the economic growth (CIRC Report,
2001). From the statistic report of Census & Statistic Department of the
Government of Hong Kong Special Administrative Region (HKSAR), the
industry’s percentage contribution to GDP has been decrease from 6.0% in 1998
down to 5.3% in 2000. Although it had a downward trend, the gross value of
construction work performed by main contractor still had $26.6 billion in the third
quarter of 2001 in nominal term (see Table 1). Up to September 2001, the total
number of construction organizations was 964, and there were 76524 workers in
1
this industry (Government of HKSAR, 2001). These figures indicated that the
construction industry in Hong Kong still has a substantial influence in local
economy.
Private sector sites
Public sector sites
Locations other than sites
Total
Value Value Value Value ($ Million) ($ Million) ($ Million) ($ Million)
1997 56,837 42,146 32,518 131,500
1998 61,233 40,742 31,341 133,316 1999 44,380 49,173 32,884 126,437
2000 39,094 50,817 32,161 122,071
2000 Q3 9,869 12,603 7,947 30,419 Q4 10,601 12,448 7,891 30,940
2001 Q1 8,898 11,619 8,132 28,649
Q2 9,572 10,347 7,798 27,717 Q3# 9,560 9,197 7,810 26,567
Table 1: Gross Value of Construction Work Performed by Main Contractors Analysed by Broadtrade Group (in Nominal Terms)
Although the property market in Hong Kong became inactive and some of
construction projects have been suspended after the economic crisis, still most
of construction projects are still performing and some of construction projects in
public sector will be commenced very soon. For example, the Tseung Kwan O
line of Mass Transit Railway Corporation (MTRC), which cost $18 billion, will be
2
able to use in mid- August. The West Rail and Ma On Shan Extension of The
Kowloon- Canton Railway Corporation (KCRC) will be under construction in the
coming years. The Hunghom to Tsim Sha Tsui and Lok Ma Chau spur line will be
commenced in these few years. The Shatin to Central rail link and route 10 have
also been proposed. Apart from transportation systems, the Disney theme park
in Lantau Island’s Penny’s Bay is under construction and scheduled to be
completed in 2005. The Tung Chung cable car project on Lantau Island has also
been proposed and will be completed in 2006. All of these indicated that the
construction industry plays an important role in building up Hong Kong and
improving our quality of life.
1.2 AN OVERVIEW OF CONSTRUCTION SAFETY IN HONG KONG
ec
faB ause of the topography reason of Hong Kong, most of buildings and
cilities are constructed on hillside and on reclaimed land, which very
deep foundation design and heavy equipment should be employed. Also, high
mobility of workforce, low level of worker’s education level, multi-level of
sub-contracting and long working hours, etc. make the overall performance of
construction industry becomes very poor (Ma & Chan, 1999). Therefore, the
construction industry is widely recognized as one of the most hazardous
3
industries in Hong Kong. According to Audit Report of Audit Commission, the
financial provision estimated for industrial safety and health was $265 million in
1998-99. Lot of money has been spent in legislation, education and promotion to
improve the industrial safety records, but the outcome was unsatisfactory.
The high level of accident rate arose the concern of the Government and most of
construction practitioners the importance of improving the safety performance in
the industry and connect the number of accidents caused in the construction
industry to satisfaction level. Consequently, in 1988, the Hong Kong
Occupational Safety and Health council (OSHC) was established in order to
encourage all construction practitioners to play their respective roles towards the
provision and upkeeping of a safe and health working environment. In order to
improve the workers’ awareness and their knowledge on safety and health, the
“Factories and Industrial Undertakings (Amendment) Ordinance (1999)”
recommends all workers in construction and container handling industries
should receive mandatory safety training and obtain a valid certificate (Green
Card). This mandatory safety training ordinance has already come into effect on
1 May 2001. Further to promote the occupational safety in construction industry,
the Occupational Safety and Health Council (OSHC) established an annual
4
Good Housekeeping Campaign in 1999 aimed at reducing the industrial
accidents by promoting the 5S practice on site , enhancing the working condition
and safety standard. Since the overall performance of Hong Kong construction
industry is far away from satisfaction and the number of accidents and fatalities
is much higher than other local industries, therefore, the Construction Industry
Review Committee reviewed the problems occurred in the industry in 2001,
which included the safety problems, and recommended several measures to
improve the poor safety record. The recommended measures mainly covered at
four areas:
a) designing for construction safety and integrated management;
b) safety promotion and training;
c) incentives for sound safety management; and
d) enhanced enforcement.
For the same purpose, the Labour Department joint hands with OSHC, the
Works Bureau, the Housing Authority (HKHA), the Construction Industry Training
Authority (CITA), the Occupational Deafness Compensation Board, the Hong
Kong Construction Association, the Hong Kong General Building Contractors
Association and the Hong Kong Construction Industry Employees General
5
Union to launch a Construction Industry Safety Award Scheme in November
2001. The aim of this scheme again is to improve the awareness of construction
practitioners on safety and health at work and to assist the construction workers
to build up a positive safety culture. A two days exhibition was also held by
Labour Department on 29 January 2002 in promoting that safety award scheme.
All the measures and activities mentioned above seems quite effective which
successfully reduced the number of construction accidents and the casualty
rates in the past few years in Hong Kong. According to statistic on Industrial
Accidents complied by Labour Department, the number of construction
accidents decreased from 19,588 in 1998 to 11,925 in 2000, representing a drop
of 39.1 per cent. Accordingly, in 1998, 248 reportable accidents per 1000
workers were recorded, which were extensively decreased to 149 in 2000
(Government of HKSAR, 2001). This statistic shows that the safety performance
in construction industry during the past four years observably improved.
6
Figure 1: Industrial Accidents in Construction Industry (1991-2000)
1991 1992 1993 1994 1995 1996 1997 1998 1999 2000
No. of Accidents 23115 18815 16573 16422 15268 16469 18559 19588 14078 11925
No. of Fatalities 54 48 80 51 63 51 41 56 47 29
*Employment 63450 62232 56226 59710 65611 74907 81629 79007 70941 79599
Acc. rate/1000 Workers 364.3 302.3 294.8 275 232.7 219.9 227.4 247.9 198.5 149.8
Fatality rate/1000
Workers 0.851 0.771 1.423 0.854 0.96 0.681 0.502 0.709 0.663 0.364
Table 2: Numbers of Industrial Accidents in Construction Industry (1991-2000)
However, the safety performance of construction industry in Hong Kong is still
very poor and unacceptable. Although it was a downward trend of construction
accidents from 1998, the number of accidents and the casualty rate remain in a
high level. Accordingly, in 2000, 11,925 accidents were reported in construction
industry, which were approximately 35 percent of the total number of industrial
accidents recorded in that year (see Table 2). Twenty- nine workers were killed in
construction industry which the fatality rate was the highest among all industries
7
in Hong Kong (Government of HKSAR, 2001). Therefore, the report of
Construction Industry Review Committee (2001) stated that: “Although
significant improvement has been made in the safety performance… our site
accident rate remains unacceptably high” (p.125). In particular, two serious
construction accidents occurred in 2001. Concrete beam and section of floor
collapsed in the Kowloon Motor Bus depot, which was still under construction, in
Lai Chi Kok on 29 May 2001. One worker was killed and nine workers were
injured (South China Morning Post, 2001). The other accident was occurred in
Yau Tong where a six- storey building, which was under demolition, was
collapsed due to the overloading of floor slab by debris on 29 October 2001.
Again, one worker was killed and nine were injured (South China Morning Post,
2001). All of these indicated that there still has room to improve the safety
performance in construction industry. Therefore, enhancing the effectiveness of
existing safety programs is urgently needed in Hong Kong construction industry.
8
1.3 BACKGROUND
P revious studies on construction safety were mainly focused on
safety attitude and behavioral techniques. Lingard and Rowlinson
(1994) investigated the background to commitment at different work groups and
organization levels theoretically and presented a research model on site level.
Tam and Fung (1998) studied the relationship between the safety attitudes,
practices and construction firms’ characteristics with the safety performance on
construction sites in forty- five construction companies. Safety training, use of
direct labour, use of post- accident investigation as a feedback and promoting
safety practices by safety award campaigns and incentive schemes were
indicated as the most effective ways to improve the safety performance and
reduce the site casualty rate. Lingard and Rowlinson (1998) examined the
effectiveness of Behaviour- based methods of safety management (BSM) on the
building construction sites of Hong Kong Housing Authority and concluded that
the BSM was not so effective in Hong Kong construction industry. Tam and Chan
(1999) evaluated the effectiveness of a series of safety measures and
mandatory programs introduced by Hong Kong Government by examining the
figures of accident statistic from 1987 to 1996 in Hong Kong construction
industry. Wong, Chan and Lo (1999) investigated the importance of safety
9
factors affecting the safety performance from the perception of government
officials, clients’ and contractors’ employees. Tam, Fung and Chan (2001)
ascertained the attitude change of practitioners by applying an attitude model
called ‘ reinforcement theory’.
Although a lot of work has been done to date, little information is available in the
past studies on analyzing the effectiveness of safety symbols currently used on
construction sites in Hong Kong. Although the Factories and Industrial
Undertakings (Dangerous Substances) Regulations has governed the format
(form and size) and the use of seven risk symbols, namely, explosive, oxidizing,
flammable, toxic, corrosive, harmful and irritant. This regulation is only applied to
some listed dangerous substances but not suitable for occupational safety
purpose. No any guidelines or standards are introduced by official parties for
occupational safety symbols used in Hong Kong construction industry. Also,
safety has become the most important concerns in the construction industry. A
lot of resources have been spent by Government and organizations in promoting
construction safety and enhancing the existing poor safety record to satisfactory
level. Symbolic signs are extensively used to convey safety message to workers
on sites (see Figure 2). Moreover, the design and format of most safety symbols
10
currently used in Hong Kong construction industry are following the standard in
foreign countries, which their effectiveness may be reduced due to cultural and
environmental differences.
Figure 2: Safety Symbols Commonly Used in Construction Sites
1.4 OBJECTIVE
T he purpose of this dissertation was to ascertain the effectiveness of
symbolic safety signs which were commonly used in Hong Kong
construction industry. The relationship between the understanding of safety
symbols by construction practitioners and their related characteristics were
investigated. The findings of this study would be significant to Occupational
Safety and Health Council, Labour Department, contractors, safety professionals
and all who were concerned about safety on construction sites by offering them
information when they organized the teaching materials, re- designed the
11
symbols, made decision when selecting symbols on sites, etc. Resources and
budget used in safety training and promotion would be allocated better in order
to enhance the poor construction safety performance in Hong Kong efficiently
1.5 METHODOLOGY
he method adopted here was similar to the researches conducted
by Al- Madani (2000) and Al- Madani & Al- Janahi (2002), which
investigated the relationship between the comprehension of traffic signs and the
characteristics of drivers. The questionnaire included thirty multiple-choice
questions with safety symbols which were commonly used in Hong Kong
construction sites and sixteen short questions which related to the respondents
characteristics. The questionnaires were printed both in colour and in Chinese.
Two hundreds and eighty (280) copies were distributed to construction
practitioners on four different construction sites and in Construction Industry
Training Authority (CITA). The data collected was analyzed by a statistic tool
called Statistical Package for Social Sciences version 9.05 (SPSS 9.05) and
Microsoft Excel 2000. Details of the procedures of this study will be discussed in
separate chapters.
T
12
1.6 SCOPE AND LIMITATIONS
his dissertation considers the effectiveness of the symbolic safety
signs which are commonly employed on sites to improve the safety
performance in Hong Kong construction industry. Chapter two reviews the
previous studies related to the construction safety in Hong Kong and about the
safety signs in foreign countries. Chapter three describes the procedures
adopted and the hypotheses of this research. Chapter four describes the data
collected and compares the comprehension scores of each tested symbols.
Chapter five analyses the possible reasons for the different outcomes from
different groups of respondents. The performance of existing safety symbols will
also be evaluated. Chapter six makes recommendations to the Hong Kong
construction industry based on the findings in this study and advices for further
studies will also be suggested. The final chapter concludes the overall
performance of this study.
T
There are several limitations in this dissertation. Firstly, the studies about the
comprehension of safety symbols in construction industry are limited no matter
in Hong Kong or in other countries. Not so much information can be obtained for
reference. Secondly, the sample size of this study is not large enough, but it still
13
can provide useful findings for discussions and further studies. Thirdly, some
workers seem difficult to complete the questionnaire because of low education
level. Therefore, some returned questionnaires were uncompleted.
14
CChhaapptteerr TTwwoo
LLiitteerraattuurree RReevviieeww
Chapter 2
Literature Review 2.1 INTRODUCTION
ince the number of occupational accidents remains at a very high level
for many years, therefore, the Government of Hong Kong Special
Administrative Region (HKSAR) and many individuals want to ascertain methods
to improve the safety performance in construction industry. Previous studies in
Hong Kong mainly focused on the evaluation of current safety strategies and
investigated the safety attitude and behaviour of construction workers. Some
suggestions, such as safety training and promotion, have already been raised
and employed in the industry to alter the negative safety attitude of construction
workers in order to improve the existing unsatisfactory safety performance in
Hong Kong. These measures and the existing safety conditions in Hong Kong
construction industry will be reviewed.
S
Warnings, such as warning labels and symbols, are recognized as effective tools
to influence behaviour and increase the risk perception of the recipients.
However, only limited studies covered this area in Hong Kong. Nearly none has
15
been ascertained in construction industry. Consequently, some studies
concerning the warning designs will also be reviewed in this chapter. The
understanding of warning design will provide valuable information in evaluating
the existing safety management strategies in Hong Kong construction industry.
2.2 A REVIEW OF CONSTRUCTION SITE SAFETY IN HONG KONG
2.2.1 Current Problems
afety record in Hong Kong construction industry was recognized
as very poor and unacceptable. Some studies have already
identified the existing problems and the causes of large number of industrial
accidents on construction sites in Hong Kong. Ma and Chan (1999)
expressed that the poor site safety performance was mainly due to six
factors:
S
Weather conditions
Labour mobility
Low education level of workers
Labour dispersion over the sites
Highly subcontracting &
Tight construction period.
16
Tam and Fung (1998) stated that the accident cost transfer, insufficient
education and safety training for workers, high percentage of subcontracting,
construction methods and unreasonable contract period caused the poor
site safety record in Hong Kong. Lingard and Rowlinson (1994) indicated
that the client attitude towards site safety, the legislation and enforcement,
licensing of plant operators and insurance policies also affected the safety
performance on construction sites. According to the questionnaire survey,
which has been jointly conducted by Occupational Safety and Health
council (OSHC) and Construction Industry Training Authority (CITA), the
occurrence of construction accidents mainly associated with gender,
education level, employment period, working duration per month, overtime
work, provision of protective equipment by employers, attitude and risk-
taking behaviour (OSHC & CITA, 2000).
2.2.2 Workers Attitude and Safety Strategies
The above- mentioned studies expressed that workers’ attitude towards
safety and their behaviour were two factors to induce the poor site safety
record in Hong Kong. Since attitudes have potential to influence behaviours,
17
therefore, if one’s attitude is change, the relevant behaviour will also be
influenced. Consequently, in order to improve the existing poor safety
record, the negative attitudes of workers towards construction safety should
be changed. Glendon and Mckenna (1995) expressed that: “…we need to
change attitudes in order improve health and safety…” (p.71).
Accordingly, a lot of studies have been carried out to investigate the
workers’ safety attitude and safety culture in Hong Kong construction
industry. Tam and Fung (1998) explored the relationship between the site
safety performance and safety attitudes, practices and characteristics of
forty- five construction companies. Tam and Fung concluded that
employment of direct labors, safety awards and incentive schemes, safety
training and post- accident investigation were the most effective measures
to improve the current site safety performance and reduced the site
casualties rate in Hong Kong. Ma and Chan (1999) studied the attitude of
workers toward construction site safety by conducting face-to-face
questionnaire survey. The findings showed that most workers
misunderstand that it was the responsibility for main contractors to comply
with safety regulations only but not the workers. Also, many workers were
18
unwilling to receive safety training and reluctant to use safety equipment.
These results implied that the safety attitudes of workers were very poor
and should be altered. Tam, Fung and Chan (2001) examined the attitude
change of workers before and after the implementation of Supervision Plan
by applying an attitude-changing model called “reinforcement theory”. The
results showed that the attitudes of workers tend to become more positive
after the application of Supervision Plan since very strong messages
implied that they would receive heavy penalties for negligence.
2.3 A REVIEW OF TRAFFIC SIGNS AND ROAD ACCIDENTS
A s mentioned in the last section that human behaviours can be changed
by altering the attitudes of peoples. On the other hand, human
behaviours can also be influenced by warnings. Warnings can prevent someone
to do something which he intended to do, or make him to do something which he
may omit (Edworthy and Adam, 1996). Warning signs are extensively used in
traffic system to provide information to drivers. Consequently, many studies have
investigated the effectiveness of traffic signs and driving attitude in order to
reduce the number of traffic accidents. Some principles and findings can be
modified and adopted in construction industry for further investigations. Carson
19
and Mannering (2001) studied the effectiveness the ice- warning signs in
Washington State and concluded that the current ice- warning signs were
ineffective to reduce the ice related traffic accidents. Standardization of signs
placement, improvement of roadway and roadside design were recommended.
The results implied that other than the signs’ design, there were still many
factors influencing the occurrence of accidents.
There has been the largely untested assumption that signs are easily
understood by peoples with different culture and linguistic background. Hence,
some studies concentrated on the understanding of traffic signs with different
user groups. Al- Mandani (2001) investigated the recognition of twenty- eight
traffic signs with different personal characteristics, such as age, monthly income,
year of education, etc., in five countries by conducting questionnaire survey. The
short answer questions were used to identify the drivers’ characteristics and the
multiple choice questions were designed to evaluate the understanding of traffic
signs. Results showed that the performance of some traffic signs were less
effective on drivers who are female, young, with low income and low education
level. Al- Madani then recommended that training of traffic signs recognition
should concentrate more on drivers in these categories in the future. Similar
20
study has been conducted by Al- Madani and Al- Janahi (2002), who ascertained
the relationship between personal characteristics and the comprehension of
symbolic traffic signs. The findings were believed to be useful for traffic trainers
to allocate more resources and concentrate their efforts on drivers who were
females, with lower education levels and lower incomes. Also, Al- Madani and
Al- Janahi recommended that further studies should focus on understanding of
signs in attitude- behaviour aspect. Apart from these, Al- Madani (2000)
examined the relationship between the comprehension of traffic symbols and
safety related characteristics, for example, driving experience, accident
involvement and seat belt usage. The results indicated that the more the driving
experience and seat belt usage, the higher the comprehension score of the
traffic symbols.
The above- mentioned studies expressed that the understanding of traffic signs
was different from people in different categories. Although these studies were
not conducted in construction industry, the implications were very useful and
important for selection and design of safety symbols in the industry.
21
2.4 A REVIEW OF WARNING LABEL AND ITS EFFECTIVENESS
here are many kinds of warnings in the world, including verbal
warnings, bells, beep sounds, etc. warning label is one of the most
common type of warnings used in Hong Kong construction industry.
T
Warning label is a kind of communication tool to convey message to the readers.
It not only performs some kinds of alert functions, but also contains other
information regarding the hazards informing the readers what can do and cannot
do.
Normally, a warning label contains four components: signal words such as
“Caution”, a hazard statement, a statement informing the readers what will
happen if noncompliance and a statement telling the readers how to avoid the
hazard. The major aspect of the warning label is to draw the observers’ attention
and convey immediate signals of the level of danger or hazard to the receipts. In
order to fulfill this requirement, the design features of warning labels should be
concerned.
22
Colour
Edworthy and Adams (1996) indicated that the colour of warning labels
should attract the attention of the readers and increasing salience. In
addition, different colours represented different levels of risk due to cultural
influence or physiological response. Traditionally, red colour represented
the highest level of hazard, followed by orange, yellow, green, blue and
white.
Signal Words
Apart from colour, warning labels should contain signal word, such as
“Danger”, “Warning” and “Caution”, to identify the level of hazard. Normally,
Danger represented the highest level of hazard, Warning indicated the
intermediate level of hazard and Caution demonstrated the lowest level of
hazard (Chapanis, 1994) (see Figure 3). In addition, “Attention”, “Think”,
“Deadly” and “Notice” were also employed as a signal words to signify the
level of risk.
23
Figure 3: Tested Warning Labels Used in Chapanis Study
Signal Words and Colour
Many studies investigated the influence of signal words together with the
colour in order to ascertain their interactions. Edworthy and Adams (1996)
expressed that: ‘…colour and signal words tend to interact…for example,
the effect of a word associated with a high degree of risk can be weakened
by assigning it a colour associated with low levels of risk’ (p.31). Chapanis
(1994) examined the perception of hazard levels by asking the participants
to match the three signal words (Caution, Warning and Danger) with four
24
background colours (white, yellow, orange and red). The findings showed
that ‘Danger’ with a red background represented the highest degree of level,
but no significant different between ‘Warning’ and ‘Caution’.
Position and Presentation Format
Besides of colour and signal word, the position of warning statement is also
important to affect the effectiveness of the warning label. Consequently,
some studies concentrated on the factors related to the warning design
influencing the warning compliance of the observer. Frantz (1993)
investigated the position and the presentation format of the warning
information and the product instructions (see Figure 4). Four warning labels,
with similar design but with different warning statement locations and
formats, were employed to test the warning compliance of participants. The
first label contained a moderate degree of safety instructions integrated into
the product usage instruction. The second label contained safety
instructions which were completely separated from product usage
instructions. The third label contained safety instructions which were
completely integrated into the product usage instructions presented in prose
format. The final label contained safety instructions which were also
25
completely integrated into the product usage instructions but presented in
point form. The results showed that greater attention was attracted with
label having safety instructions integrated into the usage instructions.
Attentions of participants were led by their goal of using the product to finish
their task. Therefore, participants’ attentions focused more on the usage
directions rather than on precautions part. The findings implied that when
designing and evaluating a warning label, the interaction between the users,
the products and the product information should be concerned in order to
maximize the effectiveness of the label.
Figure 4: Warning Labels Tested in Frantz Study
26
2.5 A REVIEW OF SAFETY SYMBOL AND ITS EFFECTIVENESS
s mentioned in the section 2.4, warning label usually contains four
components: signal words, hazard statement, noncompliance
statement and some instructions. These elements can be substituted by
symbols (Edworthy and Adams, 1996). The increase in the international
communications required us to convey simple messages by simple graphic
symbols since pictorial symbols can transfer signals quickly and effectively
without special learning.
A
Edworthy and Adams (1996) expressed some advantages of using symbols:
Symbols could be understood by readers with different language
backgrounds
For verbal signs and symbols with the same size, symbols could be
recognized from a greater distance
Readers could recognize symbols more quickly and accurately
Symbols could resist interference more than worded signs
A sign contained both symbols and words was more effective than worded
signs
27
Actually, due to high portion of immigrants with different language background
and poor work environment on construction sites, symbols are very suitable to
be used and some have already been employed on sites. However, the
effectiveness of symbols applied on construction sites still have not been
examined at all.
The communication effectiveness of safety symbol is not only related to the
symbols’ design, but also included several factors. In some conditions, a
well-designed symbol still cannot function properly and causes confusions.
Besides, the meanings of some well-understood symbols have been distorted to
cover some conditions which they are not designed for (Edworthy and Adams,
1996).
Therefore, when designing and evaluating warning symbols, not only the design
itself but also the cognitive of readers and their behaviours should be
considered.
Frantz, Miller and Lehto (1991) evaluated the performance of flame and poison
symbols appeared on the adhesive container, which both of them were well
28
recognized and understood. However, their performances were not satisfactory.
The results showed that the specific risk nature and specific precautions
required by the product have not been informed to readers since most of them
did not recognize the flammability of adhesive vapour and concluded that the
adhesive, rather than the vapour, was flammable so that improper precautions
have been carried out. In addition, Frantz, Miller and Lehto concluded that the
interpretation of one symbol could be affected by other symbols or warning
statements on the same label. As such, the interaction between the users, the
product itself and the product information should be considered when designing
and evaluating the warning symbols.
Apart from warning labels and warning symbols, which always appear on the
containers of construction materials on sites, another kind of symbol which also
commonly seen on construction sites are occupational safety symbols, for
example, ‘ Helmet must be worn’ and ‘Eye protection must be worn’. Most of
them not only appear on containers or packages of construction materials, but
are extensively used anywhere on sites.
However, only few studies covered the performance of occupational safety signs
29
to date. Cairney and Sless (1982) studied the effectiveness of nineteen
occupational safety symbols on adult students in different categories by applying
face-to-face recognition test. Cairney and Sless indicated that the
communication effectiveness of symbolic signs should be evaluated on three
sets of factors:
The nature of the message and the target of the message wanted to direct
should be concerned.
The shape and colour code of symbolic signs should be properly built up in
assisting the understanding of symbols by readers, for example, mandatory
actions signs usually used white symbol on blue background, warning signs
usually used black symbols on yellow triangle with black broader.
The efficiency of readers to translate the intended messages from symbols.
In conclude, Cairney and Sless (1982) expressed that to evaluate the
effectiveness of symbolic signs, the encoding and decoding processes of
readers to translate the intended message from symbols in psychological basis
should be ascertained.
30
2.6 CHAPTER SUMMARY
n this chapter, the safety performance in Hong Kong construction
industry, previous studies regarding the warning signs and symbols
have been reviewed. Although most studies were not conducted in construction
industry, the findings implied that warning signs and safety symbols play an
important role in accident occurrence and their effectiveness should be
evaluated, especially when most of them have already been applied and
extensively used on construction sites. The implications demonstrate the needs
and provide valuable information to support the investigations on the
effectiveness of safety symbols used in construction industry.
I
31
CChhaapptteerr TThhrreeee
RReesseeaarrcchh MMeetthhooddoollooggyy
&& HHyyppootthheesseess
Chapter 3
Research Methodology
& Hypotheses 3.1 INTRODUCTION
T wo hundreds and eighty (280) copies of questionnaires consisted of
48 questions were distributed to the construction practitioners on
four different construction sites and in Construction Industry Training Authority
(CITA) in Hong Kong. The questionnaire was divided into two parts. The first part
contained 30 multiple choice questions evaluated the practitioners’
understanding of safety symbols. The second part of questionnaire contained 18
short answer questions including demographics, household information,
accident involvement, work experience in construction industry and questions
relating to safety training to identify the practitioners’ working and safety related
characteristics. The suitability of the questionnaire was approved by safety
professionals. The questionnaires were printed in colour and in Chinese in order
to minimize any deviations and misunderstandings. The comprehension scores
were percentages of safety symbols answered correctly by respondents in part
one of the questionnaire. All the data collected was analyzed by utilizing
32
Statistical Package for Social Sciences version 9.05 (SPSS 9.05).
3.1.1 Symbol Selections and Settings
All the safety symbols adopted in part one of this questionnaire was
selected from the catalogue of the warning signs suppliers in Hong Kong so
that all symbols in this questionnaire were commonly seen by practitioners
on construction sites. The signs were intended to convey three different
categories of message by means of a distinctive shape and colour code.
Nine were mandatory action, which were indicated by a white symbol on a
blue circular background (Questions 1, 5, 10, 11, 12, 13, 15, 21 and 23);
four were prohibition messages, which were indicated by a red annulus and
slash with a black symbol on a white background (Questions 9, 29, 24 and
30); sixteen were warning messages, which were indicated by a black
image on a yellow or white background surrounded by black triangular
boarder, or a black image on a yellow or white diamond (Questions 2, 3, 6, 7,
8, 14, 16, 17, 18,20, 22, 25, 26, 27, 28 and 29). Question four was a traffic
sign which stated the speed limit surrounded by a red circular boarder in
order to control the vehicle speed inside the construction site, which was
grouped to the mandatory action category.
33
3.1.2 Adoption of Multiple Choice Format
There were some disadvantages to adopt multiple choice based question.
Dewar (1994) stated that the results of the comprehension test could be
greatly affected by poor quality distractors. The correct answer could be
ruled out easily if the wrong answers were unreasonable, i.e. less plausible.
However, there were still some advantages. Firstly, multiple choice based
questions provided choices to the respondents in order to minimize the
freedom of respondents to build up their own explanations on the questions.
Also, it could minimize the possible areas of confusion (Hawkins et al.,
1993). Secondly, multiple choice based questions could eliminate the
answering time because no writing was required and choices were provided,
which especially suitable to be applied in studies of construction industry
because of low education level of workers and poor environment on
construction sites. Thirdly, the clear-cut distinction between right and wrong
answers could reduce the correction time, the analysis cost and the
judgmental error in answers (Al- Madani & Al- Janahi, 2002).
34
3.1.3 Demography Survey
Part two of the questionnaire contained eighteen questions which were
used to identify the practitioners’ personal and safety related characteristics,
including (a) gender, (b) education level, (c) nationality, (d) marital status
and (e) monthly income. Moreover, some questions related to the accidental
involvement and safety training received by the respondents.
3.2 STATISTICAL ANALYSES
fter collecting all the data, the statistical analyses were performed by
using SPSS 9.05. The analysis was divided into two parts: the first part
was used to describe the data and the second part was used to draw inferences
about the meaning of data.
A
3.2.1 Data Description
Central Tendency, which included mean, mode and median, were calculated
to describe the data and tried to draw a complete picture of the results.
Tables and charts were also employed to present the data. Also, variance
and standard deviation were also calculated to describe the distribution of
the results.
35
3.2.2 Inferential Statistics
To examine whether the differences of the results were genuine but not
simply chance fluctuations, inferential statistics should be employed. In this
research, Pearson Correlation Coefficient, t- test and analysis of variance
(ANOVA) were utilized to analyse the data.
a) Pearson Correlation Coefficient– Pearson correlation coefficient
ranges from positive one to negative one (+1 to –1). A value of +1 means
the two symbol groups are perfectly related: when the comprehension
scores of one symbol group increase, the scores of other group also
increase, and vice versa. However, if the coefficient is a negative value,
then it means when the comprehension scores of one symbol group
increase, the other group decrease. Zero (0) means the scores of two
groups are unrelated.
b) T- test– t test was employed because it could calculate whether the
difference of the comprehension scores between two groups of
respondents reflected the genuine population difference or occurred by
36
chance only. Mostly, two independent sample t- test at 0.05 significant
level was used in this study to test whether the two population means
are equal or not based on the results observed in two independent
samples since the standard error of the mean difference was estimated
from the variances and sample sizes of two independent groups. For
example, the mean difference of the comprehension scores between
male and female could be analysed by two independent sample t- test.
c) ANOVA– For analyzing multiple independent variables, analysis of
variances, or ANOVA, could be used. ANOVA was an extension of t- test
to the cases which involving more than two means. In this study, One-
way Analysis of Variance at 0.05 significant level was employed to
compare the average comprehension scores for several groups of
respondents. For example, the means of comprehension scores
obtained in part one of the questionnaire by respondents with four
different education level groups could be compared by One-way ANOVA
in this research.
37
d) Tukeys’ test-- Moreover, when performing the One-way ANOVA
analysis, the Tukeys’ test was also be carried out to identify which
categories in the factor variables were significantly different from the
others.
3.3 PILOT STUDY
efore the questionnaires were distributed to construction
practitioners, pilot study has been carried out to test the
performance of the questionnaire and to demonstrate the use of Statistical
Package of Social Sciences (SPSS) for analyzing the data.
B
Twenty- five copies of questionnaires were distributed to respondents with
different age and education levels in construction industry. Some comments
have been received and the questionnaire has been modified to make sure it
worked as intended. The modified items are listed below.
a) A number has been added to the speed limit symbol in question four to
make sure all symbols in the questionnaire were equivalent or closed to
the symbols located on the construction sites.
b) The wordings of the choices in question one and six have been changed
38
to minimize any confuses and misunderstandings.
c) The groupings of the ranges in question thirty- three, thirty- five, thirty -
eight, thirty- nine and forty have been amended to minimize the
answering and analyzing time.
d) The formats of question forty- four and forty- five have been changed so
that more accurate answers could be received.
3.4 RESEARCH HYPOTHESES
s mentioned in Chapter one, the aim of this study is to evaluate the
effectiveness of the safety warning symbols which are commonly
used in Hong Kong construction industry. Questionnaire is employed to
investigate the influence of practitioners’ understanding of safety symbols on
some of their safety related characteristics, including works experience, accident
involvement, education level, monthly income, smoking and drinking habits. To
achieve the above goals, the following hypotheses are tested:
A
H1 Practitioners involved more in industrial accidents understand the
safety symbols better than practitioners who less involved in
construction accidents.
39
H2 There are differences in recognizing safety symbols between
practitioners in different age groups.
H3 Practitioners who have received formal safety training are expected to
know the safety symbols better than those who have not attended any
safety training courses
H4 The comprehension scores of practitioners with no drinking habits are
expected to be higher than those who are alcoholic consumers.
H5 The understandings of safety symbols are different between three
levels of workforce, included workers, site staffs and senior
managements.
H6 The performance in recognizing safety symbols are different between
practitioners who have and have not involved in safety activities
provided by their employers.
H7 The comprehension rate of safety symbols are different between
practitioners with different education levels.
3.5 CHAPTER SUMMARY
This chapter described the method adopted in this research in order to achieve
the objectives set in Chapter One. Questionnaire survey was employed to collect
40
data from construction practitioners with different personal background. The
information collected was analysed by Pearson Correlation Coefficient, t- test
and ANOVA to find out the differences between practitioners in recognizing
safety symbols and the effectiveness of tested symbolic signs. Seven
hypotheses have also been set in this chapter and tested in this study.
41
CChhaapptteerr FFoouurr
RReeppoorrtt FFiinnddiinnggss
Chapter 4
Report Findings 4.1 INTRODUCTION
otally, two hundreds and eighty (280) copies of questionnaires were
distributed to construction practitioners on four different construction
sites and Construction Industry Training Authority (CITA) in Hong Kong. Two
hundreds and six (206) practitioners responded back. However, twelve (12)
copies of questionnaires were uncompleted so that only one hundred and ninety
four (194) valid questionnaires were received. The response rate of 69.2% was
achieved. Both the number of responses and the response rates were thought to
be sufficient.
T
In this chapter, data collected will be described statistically by counting
frequencies and calculating central tendency, such as means and medians. The
different between the comprehension rate of symbols and the comprehension
performance of different sample groups, for examples, marital status and
education levels, will also be interpreted.
42
The tested safety symbols in this survey are shown as follow:
Q1.
Eye protection must be worn
Q2.
Toxic
5
Q3.
Oxidizing
Q4.
Speed Limit
Q5.
Safety helmet must be worn
Q6.
Caution, A Pit
Q7.
Slippery Surface
Q8.
Do not put your head or body into the cage-lift rack
Q9.
Upright gas cylinders
Q10.
Dust mask must be worn
Q11.
Face shield must be worn
Q12.
Ear protection must be worn
43
Q13.
Use adjustable guard
Q14.
Radiation Hazard
Q15.
Gloves must be worn
Q16.
Corrosive
Q17.
Flammable
Q18.
Chain All Cylinders
Q19.
Do not use ladder
Q20.
Caution, lifting in progress overhead
Q21.
Foot protection must be worn
Q22.
Caution, Trip Hazard
Q23.
Safety belt must be worn
Q24.
No Naked Flames
44
Q25.
Explosive
Q26.
Mind Your Head
Q27.
Site entrance, Beware of vehicles
Q28.
Irritant
Q29.
Harmful
Q30.
Illegal workers are strictly prohibited
Figure 5: Tested Safety Symbols in Questionnaire
Category Mandatory Symbols Warning Symbols Prohibition Symbols
Correctness 89.94 % 61.24 % 55.28 %
Table 3: Comprehension Percentage for Symbols in Three Categories
Symbol Upright Cylinders No Ladder No Flame Illegal Workers
Correct % 69.1 58.8 86.1 7.2
Incorrect % 30.9 41.2 13.9 92.8
Table 4: Comprehension Percentage for Prohibition Symbols
45
Symbol Spectacles Speed Limit Helmet Mask Face Shield Ear Plug Guard Gloves Boots Safety Belt
Correct % 87.1 85.1 91.2 89.2 80.4 96.4 87.1 82.0 90.2 90.7
Incorrect % 12.9 14.9 8.8 10.8 19.6 3.6 12.9 18.0 9.8 9.3
Table 5: Comprehension Percentage for Mandatory Symbols
Symbol Toxic Oxidizing Pit Slippery Cage Lift Radiation Corrosive Flammable
Correct % 85.6 28.9 78.4 86.6 64.4 51.5 73.7 63.4
Incorrect % 14.4 71.7 21.6 13.4 35.6 48.5 26.3 36.6
Table 6: Comprehension Percentage for Warning Symbols
Symbol Chain Cylinder Lifting Area Trip Explosive Mind Head Site Entrance Irritant Harmful
Correct % 47.9 80.9 77.8 62.9 79.9 61.3 19.6 17.0
Incorrect % 52.1 19.1 22.2 37.1 20.1 38.7 80.4 83.0
Table 7: Comprehension Percentage for Warning Symbols
46
4.2 OVERALL PERFORMANCE OF SYMBOL COMPREHENSION
he comprehension scores of each symbols are presented in Table 4, 5,
6 & 7. Detailed results for each symbol were showed in Appendix II.
Results showed that practitioners recognition of mandatory, warning and
prohibition symbols were around 87%, 61% and 55% respectively, which
indicated that the comprehension performance of respondents in mandatory
symbols were much better than warning symbols, followed by prohibition
symbols.
T
4.2.1 Mandatory Symbol
Mandatory category (Question 1, 4, 5, 10, 11, 12, 13, 15, 21& 23) was best
recognized in this test. High proportions were correctly identified. Nine of
them had 90% recognition rate. The ‘Ear protection must be worn’ symbol
(Q12) was highly recognized by practitioners, which had 96.4% correctness,
followed by ‘Helmet must be worn’ (Q5), ‘Safety must be worn’ (Q23) and
‘Foot protection must be worn’ symbol (Q21). The comprehension rates
were 91.2%, 90.7% and 90.2% respectively.
The ‘Glove must be worn’ symbol (Q15) was not so readily identified as
47
other symbols in this group. Most respondents confused the meaning and
selected the ‘Glove Storage’ option. Similar confusion has been found in
Question 11, the ‘Face shield must be worn’ symbol. Some respondents
misunderstood the meaning and chose ‘Be cautions of breakage glasses’
option. However, both symbols still had 80% recognition rate.
4.2.2 Warning Symbol
As a group, more difficulties were experienced with warning signs
(Questions 2, 3, 6, 7, 8, 14, 16, 17, 18, 20, 22, 25, 26, 27, 28 and 29). Of
these, ‘Toxic’ (Q12), ‘Slippery Surface’ (Q7), ‘Caution, lifting in progress
overhead’ (Q20) and ‘Mind your head’ (Q26) signs were best recognized
and had more than 80% recognition.
The ‘Radiation Hazard’ (Q14) found some difficulties to be correctly
identified, despite its widespread international use. The most frequently
identification was ‘Be careful of rotating fan’, which the same result has
been found in Cairney and Sless (1982) study. Similar difficulty was found in
‘Chain all cylinders’ symbol (Q18), which only 47.9% respondents were able
to identify it. Most respondents identified it as symbol of ‘Gas cylinders
48
collecting area’ and ‘Gas cylinder segregated’. The designs of both symbols
made respondents to confuse and generated inappropriate responses.
Three symbols that gave rise to the poor performance were ‘Oxidizing’ (Q3),
‘Irritant’ (Q28) and ‘Harmful’ (Q29), which the recognitions were only 28.9%,
19.6% and 17.0% respectively. At worse, three of them were recommended
by Labour Department and used in warning labels governed by Factories
and Industrial Undertakings (Dangerous Substances) Regulations. For
‘Oxidizing’ Symbol (Q3), since the design was very close to ‘Flammable’
symbol (Q17), which was also recommended by Labour Department,
respondents often confused both of them and provided a wrong answer.
Less than one-forth of respondents were able to recognize the ‘Irritant’ and
‘Harmful’ symbols as both symbols had no definite, concrete referents so
that nearly all practitioners did not understand what the symbols referred to.
Although Regulations governed those symbols should be used with signal
words and hazard statements, the problems cannot be solved because
some construction workers, who are immigrants or illiteracy, do not
understand traditional Chinese and English. Symbol is unique way for them
49
to identify the hazard. The extremely low comprehension scores indicated
that all three symbols did not function properly well and proved difficult to be
recognized for practitioners with different cultural and linguistic
backgrounds.
4.2.3 Prohibition Symbol
In prohibition category (Questions 9, 19, 24 and 30), ‘No naked flame’ (Q24)
was best recognized by respondents, followed by ‘Upright gas cylinders’
symbol (Q9). Only 58% respondents correctly identified the ‘Do not use
ladder’ (Q19) and most frequent identification on this symbol was ‘No
climbing’. This symbol can be modified to reduce the confusion between the
users.
4.3 DESCRIPTIVE STATISTICS FOR DIFFERENT RESPONDENT GROUP
T he mean scores of different groups were calculated and shown in
Appendix II . Generally, the mean differences within each personal
group were very closed. On average, the mean scores of most groups were
between 20 to 21, however, significant differences have also been observed in
some categories.
50
4.3.1 Age and Marital Status
Correct Answer
22.25 23.00 4.3320.70 22.00 4.3820.50 21.00 3.0320.00 20.00 3.0820.81 21.00 3.90
Age of Respondents16-2425-3435-44>45Total
Mean MedianStd.
Deviation
Table 8: Comprehension of Symbols by Age
Table 8 shows that the observed comprehension scores generally decrease
with age. Practitioners in younger age group (16-24) comprehend
significantly better than those in the older groups.
90.9375 67.3828 58.593787.0370 60.9568 56.172886.9643 60.0446 54.910789.2000 57.0000 49.000087.9381 61.2436 55.2835
Age of Respondents16-2425-3435-44>45Total
Correct %for
MandatorySymbols
Correct %for
WarningSymbols
Correct %for
ProhibitionSymbols
Table 9: Comprehension of Symbols in Three Categories by Age
The recognition of safety symbols in three different categories generally
also decrease with age (see Table 9 ). Nevertheless, the performances of
respondents in older age group (>45) were similar to younger in recognizing
mandatory symbols. This performance was better than other age groups
and contradicted the downward trend.
51
Correct Answer
20.53 20.50 3.5221.13 22.00 4.3020.81 21.00 3.90
Marriage StatusMarriedSingleTotal
Mean MedianStd.
Deviation
Table 10: Comprehension of Symbols by Marital Status
The mean scores of respondents with different marital status are presented
in Table 10. The result showed that practitioners in single performed a little
better than married. Since most of respondents in younger age group were
single, while the majority in older age group were married. Therefore, age
was the main factor affecting the comprehension scores, but not the marital
status.
4.3.2 Education Level
Correct Answer
20.29 21.00 4.1521.33 22.00 3.4822.07 22.00 2.8122.56 22.00 3.3220.81 21.00 3.90
Education Level<Form 5Form 7 to Higher DiplomaDegreemaster or >Total
Mean MedianStd.
Deviation
Table 11: Comprehension of Symbols by Education Level
The average comprehension scores, as illustrated in Table 11, increased
with practitioners’ education level. Respondents with higher understood the
safety symbols better than those with lower education background.
52
4.3.3 Monthly Income
T meable 12: Comprehension of Symbols by Monthly Inco
Table 1 ith monthly
.3.4 Smoking and Drinking Habit
T
2 shows that the comprehension of symbols increased w
income. However, respondents with higher incomes usually had higher
education level. Therefore, educational levels become the main contributor
to the comprehension but not the monthly salary.
4
able 13: Comprehension of Symbols by Drinking Habit
Correct Answer
20.52 21.00 4.4920.86 22.00 3.8121.00 20.00 2.9821.50 21.00 3.1220.81 21.00 3.90
Salary<$10,000$10,000 - $20,000$20,001 - $30,000>$30,000Total
Mean MedianStd.
Deviation
Correct Answer
19.43 21.00 4.7521.06 21.50 3.6920.81 21.00 3.90
Drinking HabitYesNoTotal
Mean MedianStd.
Deviation
53
Correct Answer
20.64 21.00 3.9720.92 21.00 3.8820.81 21.00 3.90
Smoking HabitYesNoTotal
Mean MedianStd.
Deviation
Table 14: Comprehension of Symbols by Smoking Habit
Respondents without drinking habit had better performance in recognizing
safety symbols than those who used to consume alcohol (see Table 13).
However, no significant different had been found between smokers and
non- smokers in signs comprehension (see Table 14).
4.3.5 Job Position
Correct Answer
19.59 20.00 4.4922.20 22.00 2.7621.19 21.00 3.3320.81 21.00 3.90
PositionWorkersStaffManagementTotal
Mean MedianStd.
Deviation
Table 15: Comprehension of Symbols by Job Position
Table 15 indicates that site staff achieved better comprehension scores,
followed by senior managements and then construction workers. Detailed
analysis and interpretation will be discussed in next chapter.
54
4.3.6 Involvement in Safety Related Activities
Correct Answer
21.62 22.00 3.4419.60 20.50 4.2520.81 21.00 3.90
Involvement inSafety ActivitiesYesNoTotal
Mean MedianStd.
Deviation
Table 16: Comprehension of Symbols by Safety Activities
As mentioned in Chapter One, some construction companies in Hong Kong
have provided safety activities to their employees, for example, morning
exercise, morning assembly and safety briefing, etc. Table 16 shows that
practitioners who have involved in these activities obtained higher scores
than those who have not. Detailed analysis will be discussed in next
chapter.
4.4 CHAPTER SUMMARY
I n this chapter, the comprehension rate of mandatory, warning and
prohibition symbols have been described. The average scores of different
respondent groups in recognizing safety symbols were also presented. The
results show that mandatory signs were best recognized, followed by warning
signs, and then prohibition symbols. According to the comprehension rate,
‘Oxidizing’, ‘Irritant’ and ‘Harmful’ signs were most difficult to be recognized and
understood. Moreover, respondents who were young, single, site staff, no
55
drinking habit, involved safety activities, and those who had higher education
level and monthly income, have achieved better performance in symbol
comprehension than the others.
However, no conclusion has been drawn to date since descriptive statistics can
only reflect the result in the sample, the 194 respondents, but not able to reflect
the genuine difference in the entire population, the all construction practitioners
in Hong Kong. Instead of descriptive statistic, inferential statistics should be
carried out to investigate which distinctions are real but not simply by chance or
fluctuations in symbol comprehensions. This will be discussed more details in
next chapter.
56
CChhaapptteerr FFiivvee
DDaattaa AAnnaallyyssiiss
&& DDiissccuussssiioonn
Chapter 5
Data Analysis
& Discussion 5.1 INTRODUCTION
s mentioned before, the mean differences of different respondent groups
found in Chapter 4 only reflect the comprehension performance in the
194 respondents but cannot draw any conclusions on the whole population of
practitioners in Hong Kong construction industry. It is because the recognition
differences between different respondent groups can be genuine, or may just
appear in these 194 respondents. Since it is impossible to obtain data from all
construction practitioners, therefore, the population values can be estimated
from samples based on statistic calculations so that conclusion can be drawn.
A
In this chapter, parametric tests, such as t-test and analysis of variance (ANOVA),
are employed to determine whether the differences found in last chapter reflect a
real population differences or just only occurred by chance. Moreover, Pearson
correlation coefficient is calculated to test the relationship between mandatory,
warning and prohibition symbols. All details are shown in Appendix III. Factors
57
with significant differences will be discussed below.
5.2 CORRELATION BETWEEN SYMBOLS IN THREE CATEGORIES
n this section, Pearson correlation coefficient is employed to study the
relationship between the comprehension scores of mandatory, warning
and prohibition symbols. Pearson correlation coefficient ranges from positive
one to negative one (+1 to –1). A value of +1 means the two symbol groups are
perfectly related: when the comprehension scores of one symbol group increase,
the scores of other group also increase, and vice versa. However, if the
coefficient is a negative value, then it means when the comprehension scores of
one symbol group increase, the other group will decrease. Zero (0) means the
scores of two groups are unrelated.
I
Apart from coefficient, a P- valve will also be calculated. If the P- value is smaller
than 0.01 at 0.01 alpha level (P<0.01), it means the correlation between two
symbol groups is significantly different from zero, which indicates that the
relationship, no matter positive or negative, fast on both small sample size and
large sample size. The smaller the P- value, the more significant of the
relationship.
58
5.2.1 Pearson Correlation Coefficient
1.000 .440** .397**. .000 .000
194 194 194.440** 1.000 .311**.000 . .000194 194 194.397** .311** 1.000.000 .000 .194 194 194
Pearson CorrelationSig. (2-tailed)NPearson CorrelationSig. (2-tailed)NPearson CorrelationSig. (2-tailed)N
Mandatory Symbols
Warning Symbols
Prohibition Symbols
MandatorySymbols
WarningSymbols
ProhibitionSymbols
Correlation is significant at the 0.01 level (2-tailed).**.
Table 17: Correlation Between Three Symbol Categories
The relationship between mandatory and warning symbols are presented in
the second column of Table 17. The Pearson correlation coefficient (as
shown in yellow) was 0.440 and the P- value (as shown in blue) was zero
(P<0.01). The figures indicate that mandatory and warning symbols were
positively correlated and this relationship was significant on both small and
large sample size.
As shown in the same table, significant relationships have also been found
in mandatory- prohibition symbols and warning- prohibition symbols. Both
correlations were positive and significant at 0.01 alpha levels.
59
5.2.2 Discussion on Relationships between Three Symbol Categories
Results indicated that the strength of relationships between mandatory-
warning symbols (0.440) was stronger than mandatory- prohibition symbols
(0.397), followed by warning- prohibition symbols (0.311). Since all of them
are positively correlated, therefore, when designing safety training programs
or promoting the uses of safety symbols, the weight of these symbol types
should be balanced. Say, if practitioners comparatively not so
understanding the meanings of mandatory signs, their understandings on
warning signs and prohibition signs may be poor also. Hence, when
teaching or promoting the meanings and the uses of safety symbols, three
kinds of symbols should be covered averagely in the trainings or
promotions.
5.3 COMPARE THE COMPREHENSION SCORES BETWEEN TITIONERS WITH DIFFERENT CHARACTERISTICS BY T- TEST
IPRAC
n this section, the comprehension scores of practitioners with and without
drinking habit; and the scores of practitioners with and without involved in
safety activities provided by their employers will be compared separately. In
order to carry out this comparison, Independent- sample t- test is employed,
which is used to compare the mean of two groups of different subjects
60
(practitioners who consume alcohol and not consume alcohol) on one variable
(the comprehension score).
Before performing this test, null hypothesis (Ho) should be stated. Null
hypothesis is a statement which is antitheses of the research hypothesis. Usually,
it is an expression of no difference or no relationship between the variables.
After stating the null hypothesis, the t- value will be calculated. If the t- value is
small than 0.05 (t< 0.05), the null hypothesis can be rejected and concluded that
there are significant different in the scores between two groups of practitioners.
However, there are two t- values in the table for each calculation. One for equal
variances assumed and one for equal variances not assumed. To determine
which t- value is valid will base on the probability value calculated in Levene’s
test. If the Levene’s test has a probability value small than 0.05 (P< 0.05), the t-
value for equal variance not assumed will be used. Otherwise, t- value for equal
variances assumed should be used.
61
5.3.1 Comprehension of Symbols by Drinking Habit
H0: Alcoholic consumed practitioners do as well as non- alcoholic consumed
practitioners in recognizing safety symbols
The results of t- test are presented on next page. Since the P- value in
Levene’s test was 0.131 (P>0.05), therefore, t- value for equal variances
should be used (see Table 19). As the 2- tail significant t- value was 0.035,
which was smaller than 0.05 in 95% confidence intervals, thus, the null
hypothesis should be rejected and concluded that there are significant
differences between alcoholic consumed practitioners and non- alcoholic
consumed practitioners in recognizing the safety symbols.
5.3.2 Discussion on Comprehension of Symbols by Drinking Habit
The above result indicates that there are significant differences between
construction practitioners with and without drinking habit in recognizing
safety symbols. Refer to the Mean column in Table 18, practitioners without
drinking habit had higher comprehension rate than those who were used to
consume alcohol.
62
30 64.7773 15.8218 2.8886164 70.2033 12.3003 .9605
Drinking HabitYesNo
Correct % for All SymbolsN Mean
Std.Deviation
Std. ErrorMean
Table 18: Statistic on Comprehension of Symbols by Drinking Habit
2.305 .131 -2.119 192 .035 -5.4260 2.5604 -10.4761 -.3759
-1.782 35.689 .083 -5.4260 3.0441 -11.6016 .7497
Equal variancesassumedEqual variances notassumed
F Sig.
Levene's Test forEquality of Variances
t dfSig.
(2-tailed)Mean
DifferenceStd. ErrorDifference Lower Upper
95% ConfidenceInterval of the
Difference
t-test for Equality of Means
Table 19: Independent Sample t- Test for Comprehension of Symbols by Drinking Habit
63
Possible reasons can be raised to interpret the differences. First of all,
previous studies indicated that confusion and memory lapses were two
examples of alcohol problems found in alcoholic consumers. Alcohol may
influence the respondents much easier to confuse the safety symbols with
similar designs or meanings which they have seen on construction sites.
Also, they are more difficult to memorize the symbols which they have seen
before so that they cannot recall the symbols successfully during the test.
As a result, poor recognition rate was achieved.
The second reason is that alcohol makes the practitioners easier to confuse
no the symbols they have seen on sites, but the symbols they have seen on
the questionnaire, especially when some symbols with similar meanings
appeared at the same time together with multiple choice options influencing
them.
The third reason is that the majority of alcoholic consumed practitioners are
construction workers. Section 5.4.1 will demonstrate that job positions may
influence the comprehension rate of safety symbols. The symbols
recognition of construction workers, compare with site staffs and senior
64
managements, are the weakest in this study. Accordingly, job positions may
be the prime contributor to influence the practitioners’ comprehension
performance, but not the drinking habit.
The influences of alcohol on colour recognizing, symbol focusing and
concentrating may be the possible reasons for the differences and left for
further investigation.
5.3.3 Comprehension of Symbols by Safety Activities
As mentioned in Chapter One, many construction companies have provided
safety related activities, such as morning assembly and exercises, to their
employees in order to increase their risk perceptions and improve the poor
site safety records. In this section, the symbol comprehension scores
between practitioners with and without involved in these safety activities will
be compared.
Ho: There are no differences between practitioners have and have not
involved in safety related activities in safety symbols comprehension
65
116 72.0691 11.4520 1.063378 65.3415 14.1764 1.6052
Involvement inSafety ActivitiesYesNo
N MeanStd.
DeviationStd. Error
Mean
Table 20 Statistic on Comprehension of Symbols by Safety Activities
2.616 .107 3.642 192 .000 6.7276 1.8473 3.0841 10.3711
3.494 141.198 .001 6.7276 1.9254 2.9213 10.5339
Equal variancesassumedEqual variancesnot assumed
F Sig.
Levene's Test forEquality of Variances
t dfSig.
(2-tailed)Mean
DifferenceStd. ErrorDifference Lower Upper
95% ConfidenceInterval of the
Difference
t-test for Equality of Means
Table 21: Independent Sample t-Test for Comprehension of Symbols by Safety Activities
66
The P-value of Levene’s Test is presented in the third column of Table 21.
Since the P- value was 0.107 (P>0,05), the t- value for equal variances
assumed was used. The sixth column of the table shows that the 2- tail
significant value was zero (0), which was small than 0.05 (t<0.05), therefore,
the comprehension differences between two groups of practitioners were
highly significant. Consequently, the null hypothesis was rejected. The
recognition percentage of practitioners who have involved in safety related
activities are comparatively higher than those who have not involved (see
Table 20).
5.3.4 Discussion on Comprehension of Symbols by Safety Activities
The above analysis demonstrates that involvement in safety activities may
influence the practitioners’ performance in safety symbols recognition.
Possible reasons will be discussed below.
5.3.4.1 Risk Perception
In psychological aspect, Elaboration Likelihood Model can be used to
interpret the results. This model indicated that persuasive
communications can cause attitude change in two ways: The first one
is called Central Route to Persuasion, which peoples are motivated to
67
pay their attention to the arguments. The second one is called
Peripheral Route to Persuasion, which peoples do not pay their
attentions to the argument but interest in surface characteristics instead,
such as the credibility of the speaker or the length of the speech.
Attitude changed by Central Route to Persuasion is long- lasting and
more resistant to change, while the attitude changed by Peripheral
Route to Persuasion is temporary and susceptible to further change.
Personal Relevant (Personal Awareness) to the argument is one
factor to motivate peoples to take the Central Route to Persuasion
(Aronson, Wilson and Akert, 1998). This can explain why there are no
significant differences between practitioners have and have not
received any formal trainings; or between greencard and non-
greencard holders in recognizing safety symbols (results are shown in
Appendix III). Instead, significant difference in symbol recognition has
been found between practitioners have and have not involved in safety
related activities.
Since most safety training courses are conducted off- site, i.e. inside
68
classrooms or training centers, by unfamiliar tutors. From the
practitioners’ points of view, the personal relevance is low because they
are quite safe when attending the courses inside a classroom and the
tutor is not attractive enough to draw their attentions so that long-
lasting attitude changes toward safety cannot be developed.
However, morning exercises and assemblies are always conducted on-
site, where it is a workplace for workers and a place that they may face
accidents. Moreover, most exercises and assemblies are lead by
contract managers or site agents, who are the top managements on
sites. Furthermore, the safety matters arise by the speakers in the
assemblies or after the morning exercises should be related to that
sites where the workers work. As a result, the place, the speaker and
the topic of the argument are all relevant to the practitioners so that
long- lasting attitude changes towards site safety can be developed
among practitioners.
Since more positive safety attitudes have been created, those
practitioners are expected to become more sensitive to risk- related
69
matters. Hence, these safety activities are anticipated to increase the
risk perceptions of the practitioners and make them to pay more
attention on safety related matters, including the use of personal safety
equipment and safety symbols around. As such, the understandings of
safety symbols are better so that the comprehension rates are much
higher than the others.
5.3.4.2 Safety Management of the Companies
Companies that provide safety activities to employees assumed to
have better safety management strategies. More safety knowledge and
messages are expected to be received by workers. Therefore, more
symbols or promotions may be used on sites to increase the risk
perceptions of the employees. Hence, symbol recognition of those
practitioners are better than those who do not involved in any safety
activities.
5.3.4.3 Learning and Cognition
An effective symbol should be learnt easily and understood by peoples
with different cultural and linguistic background (Cairney and Stress,
1982). To investigate learning and cognition of peoples, memory is one
70
important factor should be considered.
Cairney and Sless (1982) expressed that psychological processes
should be investigated in order to understand why some symbols were
more effective than others. The process for readers to encode the
referents into symbolic form, and the decoding process of the readers
to attribute the meaning from the symbols should be considered. In
psychological aspect, an important process occurs in working memory,
called Elaborative Rehearsal, can be used to interpret the recognition
differences (see Figure 6). Elaborative rehearsal is a process which
helps to transfer information to long- lasting memory. This process
relates the information received to other concepts, which have already
in long- term memory, and develops new associations among those
concepts (Leahey and Hams, 1993). For example, suppose in morning
assembly on site, the site agent always remind his workers to wear
safety belt before performing any overhead works. One day, when a
worker see the ‘Safety belt must be worn’ symbol, he may relate that
symbol to the site agent persuade him to use the safety belt in morning
assembly and then encode the symbol to his long- term memory.
71
Figure 6: Overview of Information Processing System in Human Beings
The above example demonstrates that safety activities may assist the
practitioners to memorize the safety symbols so that respondents who
have involved in safety activities can recall the symbols better and thus
have better performance in symbol comprehension.
5.4 COMPARE THE COMPREHENSION SCORES BETWEEN PRACTITIONERS WITH DIFFERENT CHARACTERISTICS BY ANOVA
ince t- test can only compare the mean scores of two groups of
respondents. If the comprehension scores of practitioners in four age
or in three workforce levels want to be compared, then another
parametric test, called analysis of variance (ANOVA), will be employed. ANOVA
is essentially an extension of t- test to compare the mean scores of three or more
groups of respondents on particular variable.
Sgroups,
72
Similar to t- test, a F- value is calculated to test the null hypothesis (H0) of the
study. If the F probability is smaller than 0.05 in 95% confident level (P<0.05),
the null hypothesis will be rejected and concluded that there are significant
differences among the group means. Otherwise, null hypothesis will be
accepted.
5.4.1 Comprehension of Symbols by Job Positions
In order to find out the relationship between the symbol recognition and job
positions, the positions of practitioners are classified into three levels and
defined as follows:
Senior Managements
Contract Manager, Project Manager, Project Coordinator of Employer, Site
Agent and Safety Manager
Site Staff
Structural Engineer, Building Services Engineer, Clerks of Works, Safety
Supervisor and Safety Officer
Workers
Foreman, Assistant Foreman and Construction Workers
73
The comprehension differences of safety symbols are tested by One- way
ANOVA and the results are presented on next page.
Ho: There are no differences between three workforce levels in recognizing
the safety symbols
Correct % for All Symbols
2910.797 2 1455.399 9.342 .00029756.810 191 155.79532667.608 193
Between GroupsWithin GroupsTotal
Sum ofSquares df
MeanSquare F Sig.
Table 22: ANOVA for Comprehension of Symbols by Job Positions
The last column in Table 22 shows that a significant different has been
found between three levels of workforce in recognizing safety symbols
(P<0.05) so that the null hypothesis was rejected. However, Table 22 has
not shown where the differences come from: between worker and site staff,
between site staff and management, or between worker and management.
As such, Post Hoc Test should be carried out to determine which level is
significantly different from other levels in recognizing safety symbols. In this
study, Tukey’s test was employed and the result was shown in Table 23
below.
74
The first row of the table demonstrates that significant different in
recognizing safety symbols has been found between worker and site staff
only, but not involved senior managements.
Dependent Variable: Correct % for All SymbolsTukey HSD
-8.7128* 2.0464 .000 -13.5088 -3.9167-5.3478 2.3452 .059 -10.8443 .14888.7128* 2.0464 .000 3.9167 13.50883.3650 2.4711 .361 -2.4265 9.15655.3478 2.3452 .059 -.1488 10.8443
-3.3650 2.4711 .361 -9.1565 2.4265
(J) PositionStaffManagementWorkersManagementWorkersStaff
(I) PositionWorkers
Staff
Management
MeanDifference
(I-J) Std. Error Sig.LowerBound
UpperBound
95% ConfidenceInterval
The mean difference is significant at the .05 level.*.
Table 23: Tukey’s Test for Comprehension of Symbols by Job Positions
5.4.2 Discussion on Comprehension of Symbols Between Site Staff & Workers
The possible causes will be discussed to interpret the differences between
site staffs and workers in recognizing safety symbols
5.4.2.1 Direct and Indirect Labour
In Hong Kong construction industry, site staffs, such as clerks of works
75
and safety officers, are usually employed by clients or main contractors.
Their attitudes towards safety are more positive because they
understand the companies’ or sites’ safety strategies more and want to
improve the safety records in order to satisfy the companies’ goal.
Especially nowadays most construction companies have internal safety
audits and safety competitions between different sites which can
enhance the risk perceptions and awareness of site staffs. Therefore,
site staffs may more concentrate and sensitive on safety related
matters on site, including safety symbols, so that their performances in
recognizing safety symbols are better.
On the other hand, most construction workers are labours of sub-
contractors, who may work on one site for a very short period and then
work on the other sites. This high mobility induces the workers have an
idea that they are not responsible for site safety and comply with safety
regulations (Ma and Chan, 1999). Thus their risk perceptions are
much lower than site staffs and do not concern on the site safety
measures, including safety symbols, so that their comprehension rates
are poor than site staffs.
76
5.4.2.2 Cultural and Linguistic Background
Some workers in Hong Kong construction industry are not locals but
are immigrants from China. Most of them do not know traditional
Chinese and English so that they are more difficult to understand the
meaning of signal words and hazard statements in warning labels or
symbols. Moreover, the symbols used in Hong Kong may not as same
as used in China. Differences in pictures, colours, shapes and formats
make the immigrants confuse and misunderstand the meanings. Both
reasons identified that different in cultural and linguistic background
may influence the comprehension of safety symbols.
5.4.2.3 Locations of Safety Symbols
Practically, safety symbols usually appear at the site entrance and
outside the temporary site office on construction sites. Warning signs
and symbols are seldom adhered on the concrete wall surfaces or
workplaces of workers, especially at upper floors of building structures
because these symbols and signs will impede the work operations,
such as plastering, tiling and painting. Therefore, site staffs, who
usually work inside the site office, are able to see the symbols
77
frequently while workers are not. The higher exposure rate for site
staffs leads them to recognize the symbols better than construction
workers.
5.5 CHAPTER SUMMARY
n this chapter, Independent sample t- test and One-Way ANOVA were
employed to analyse the different between the comprehension scores in
different respondent groups. The results demonstrated that practitioners who
were non- alcoholic consumed, site staffs and involved in safety activities
performed better in recognizing safety symbols. Possible reasons for each
different has also been discussed. Moreover, Pearson Correlation Coefficient
has also been calculated and showed that the recognition of mandatory, warning
and prohibition symbols were inter-related.
I
78
CChhaapptteerr SSiixx
RReeccoommmmeennddaattiioonn
Chapter 6
Recommendation 6.1 INTRODUCTION
he function of safety symbols is to convey warning messages to the
readers. Symbolic signs assumed to be easily understood and learnt
by peoples with different cultural and linguistic background. However, results
showed in last two chapters indicated that some tested symbols are not so
effective and improper functioned. Hence, some suggestions will be proposed to
construction practitioners and Labour Department to enhance the effectiveness
of the safety symbols. Moreover, some advices will be recommended for further
studies in order to evaluate the existing warning systems and thus improve the
overall safety performance in Hong Kong construction industry.
T
6.2 RECOMMENDATIONS FOR CONSTRUCTION PRACTITIONERS AND LABOUR DEPARTMENT
ccording to the results showed in this study, the performance of some
safety symbols are very poor and unsatisfactory. Efforts and resources
should be reallocated to enhance the effectiveness and enlarge the influences of
symbolic signs in safety issues.
A
79
6.2.1 Design of the Symbols
In Chapter 4, some symbols have been found to be ineffective. Among the
thirty test symbols, performance of ‘Oxidizing’, ‘Irritant’ and ‘Harmful’
symbols are the worst. Unfortunately, all three symbols are recommended
by Labour Department to be used on warning labels in dangerous
substances. Evaluations and re-designs of these three symbols are
recommended to enhance their effectiveness.
6.2.2 Trainings and Educations
When designing or evaluating the safety training materials for construction
practitioners, the weight of three symbol categories: mandatory, warning
and prohibition, should be concerned because all of them are positively
inter-related. Also, results showed that no differences have been found
between greencard and non-greencard holders; and practitioners have and
have not received formal construction trainings. Therefore, teaching
materials of these trainings are recommended to be evaluated to include
more information on the meanings of the safety symbols.
80
Moreover, construction workers are recommended to be set as the main
target group in teaching and promoting the uses of safety symbols since the
comprehension scores are the lowest among the three workforce levels.
Teaching materials and contents should be designed suitable for workers
with different cultural and linguistic backgrounds.
6.2.3 Drinking Habit
Although no evident to support alcohol readily influence the comprehension
ability of symbols among construction practitioners to date, further
investigations should be made on this issue. The findings in this study
implied that alcohol may reduce the risk perceptions on practitioners. Large
numbers of documents expressed that alcohol induces the occurrence of
traffic accidents and implicated in up to 50% of fatal crashes and falls,
drownings, and burns are the second, third and fourth leading causes of
unintentional death in the United State. It is recommended that alcohol
should be forbidden on construction sites and more studies should be
carried out in this matter.
81
6.2.4 Locations of Safety Symbols
One possible reason for interpreting the comprehension different between
workers and site staffs is the location of safety symbols. Safety officers are
recommended to evaluate the existing locations of safety symbols on their
sites. Symbols should be located in the prominent places all over the
workplaces. Besides, previous studies expressed that the meanings of
safety symbols are affected by their locations. Symbols used in improper
places may confuse the readers and cannot convey the hazard signals to
the recipient.
6.2.5 Standardization
It is recommended that the safety symbols used in Hong Kong should be
standardized. Nowadays. The symbols used on different sites may be
different, depends on the designs of the suppliers. Workers saw one safety
symbol on one construction site might be different from the other site, but
still conveyed the same meaning. Worker may confuse easily and difficult to
understand what is the hazard implied. Also, the shape and the colour
should also be standardized as both the shape and colour of symbols can
convey warning message to the reader. In Hong Kong, some warning
82
symbols have yellow background with black triangular boarder, some have
yellow background with diamond shape, and some have white background
with diamond shape. The flexibility of the design may cause confusion to the
readers and lead to low recognition of the safety symbol. Therefore,
handbooks or code of practice are recommended to govern the design, the
use, the colour and the shape of the safety symbols.
6.3 RECOMMENDATIONS FOR FURTHER STUDIES
p to now, only limited studies covered the effectiveness of safety
symbols, this topic is quite fresh to be conducted in Hong Kong
construction industry. Some feasible recommendations will be suggested below
for further investigations, they included:
U
6.3.1 Shape and Colour
This study only focused on the overall effectiveness of the safety symbols.
However, the effectiveness of particular components in the symbols have
not been tested. Some studies have already shown that inverted triangular
warning symbols can attract more attention and more effectiveness than the
origin one. Some studies concluded that red colour is always rated as the
83
one conveying the highest level of hazard or risk, but our warning symbols
still using yellow instead of red. So many combinations can be arisen and
required to test.
6.3.2 Signal Words and Placement
This study has only focused on the symbol itself but not evaluate the signal
words and hazard statement. Mostly, a signal word appears under the
symbols both in English and Chinese. The effectiveness of the signal words
and the combined effects of the signal words with symbols are
recommended to be investigated. The size, the shape and the colour of the
symbol and the signal word may influence each other and different strength
of hazard signal will be created. Moreover, previous studies demonstrated
that mnemonics could improve the encoding efficiency. This included peg
word, first letter, key word and figure alphabet. It is recommended that the
uses of these mnemonics strategies in safety symbols can be tested.
6.3.3 Compliance Test
The functions of safety symbols are to convey hazard signals to the readers
and then try to alter the reader’s behaviour. Effectiveness of a safety symbol
84
not only means the ease of understanding and learning of the symbol, but
also the reader will comply to the symbol’s signal and follow its instruction.
Compliance test is always be used to test the effectiveness of the warning
labels. The same technique can be employed to evaluate the effectiveness
of the safety symbols.
6.4 CHAPTER SUMMARY
ased on the results and discussions in previous chapters, some
advices have been recommended to Labour Department and
construction practitioners, including redesign of poor symbol, evaluate existing
safety training and promotion programs, evaluate the locations of safety symbols
currently used on construction sites and standardize the design and use of
safety symbols. Some suggestions have also been recommended for further
studies, including symbols’ color and shape investigations, the effect of different
signal words and placement, and the compliance of humans after seeing the
symbols.
B
85
CChhaapptteerr SSeevveenn
CCoonncclluussiioonn
Chapter 7
Conclusion
he purpose of this study was to ascertain the effectiveness of safety
symbols commonly used in Hong Kong construction industry and
investigate the comprehension performance of different groups of construction
practitioners. The findings were expected to be useful for construction
practitioners and relevant parties for better allocation of resources and budgets
in safety training and promotion. Generally, all the objectives set in this study
were achieved.
T
The effectiveness of thirty safety symbols, which were commonly seen on
construction sites, was examined by conducting questionnaire survey to
construction practitioners on four construction sites and Construction Industry
Training Authority.
The results showed that the effectiveness of ‘Oxidizing’, ‘Irritant’ and ‘Harmful’
symbols were the worst. The performance of symbols in mandatory group was
86
the best, followed by warning symbols, and then the prohibition symbols. A
positive correlation has also been found between three symbol categories.
The recognition performances of construction practitioners in different personal
groups were compared. Alcohol, site safety activities and job positions were the
main contributors for the comprehension different of safety symbols. Non-
alcoholic consumers, practitioners involved in safety activities and site staffs
recognized safety symbols better than the others. In order to better understand
the reasons for the effectiveness of some safety symbols and ineffectiveness of
others, memory and information processing in psychological aspect should be
investigated in order to understand the encoding and decoding processes of the
practitioners.
Based on the findings and discussions in this study, Labour Department was
recommended to re- design the ineffective symbols and re- organize the
resources in safety trainings and promotions. Also, standardization of safety
symbols into a more effective and systematic communication tool was
recommended. Construction practitioners, such as developers and main
contractors, were also recommended to evaluate the existing safety symbols
87
currently used on construction sites.
In conclusion, the safety performance in Hong Kong construction industry is still
very poor and unacceptable although lots of money and resources have already
been spent to enhance. This study hopes can bring a new idea to safety
professionals and investigate further to construct a safe working environment in
Hong Kong construction industry.
88
RReeffeerreenncceess
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