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INTERNATIONAL JOURNAL OF OCCUPATIONAL SAFETY AND ERGONOMICS
Volume 12 Number 1, 2006
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CONTENTS:
Articles:
  PROTECTION OF HUMAN IN THE WORKING ENVIRONMENT
- Ripples in a Pond: An Open System Model of the Evolution of Safety Culture
F.J. Joel Morley & Don Harris, 3-15 
- Work Ability in Ageing Workers Suffering From Chronic Diseases
Anna Jędryka-Góral, Joanna Bugajska, Elżbieta Łastowiecka, Andrzej Najmiec, Maria Rell-Bakalarska, Irena Bownik, Janina M. Michalak & Marek Kochmański, 17-30
- Workers’ Perceptions of Workplace Safety: An African Perspective
Seth Ayim Gyekye, 31-42
- Thermal Performance Assessment of Heat Resistant Fabrics Based on a New Thermal Wave Model of Skin Heat Transfer
Fanglong Zhu, Weiyuan Zhang & Guowen Song, 43-51
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PROTECTION OF HUMAN AT THE WORKSTATION
NOTES
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Ripples in a Pond: An Open System Model of the Evolution of Safety Culture
F.J. Joel Morley & Don Harris
The development of an effective safety culture is essential to promote safe operations. Previous studies have either identified the characteristics of effective safety culture analytically, inferring them from signs and symbols derived from working practices, or have restricted the study of the development of safety culture to workers within an organisation. This paper describes a large-scale survey-based study in which the factors influencing the evolution of safety culture are identified empirically and, drawing upon open systems theory, are also extended beyond the bounds of the organisation. Three major determinants of safety culture are identified: afety concerns, influences and actions. Sub-components within each of these categories are also identified and the relationship between them is hypothesised.
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Work Ability in Ageing Workers Suffering From Chronic Diseases
Anna Jędryka-Góral, Joanna Bugajska, Elżbieta Łastowiecka, Andrzej Najmiec, Maria Rell-Bakalarska, Irena Bownik, Janina M. Michalak & Marek Kochmański
The aim of this study was to investigate the work ability in ageing workers suffering from osteoarthritis (OA), coronary heart disease (CHD) or hypertension (H). One hundred and sixty-six OA and 355 CHD/H outpatients were evaluated. The Work Ability Index (WAI) served for work ability assessment. Patients’ results were compared with the results of a control group of 225 healthy young workers. Statistical analysis was performed with ANOVA tests. WAI in female and male CHD/H patients was higher than in OA patients (p < .01), better work ability was related to better education (p < .01), white-collar work (p < .01) and better recreation (p < .01); subjective work ability was determined mostly by the objective health status. The promotion of work ability among workers suffering from advanced age-related diseases should be closely related to the promotion of health. It is indicative to improve occupational education and skills, already at an early stage of a disease.
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Workers’ Perceptions of Workplace Safety:An African Perspective
Seth Ayim Gyekye
This study investigated workers’ perceptions of workplace safety in an African work environment, specifically in Ghanaian work places. Workers’ safety perceptions were examined with Hayes et al.’s. (1998) Work Safety Scale. Comparative analyses were done between high- and low-accident groups, and t tests were employed to test for differences of statistical significance. Relative to their colleagues in the low-accident category, workers in the high-accident category exhibited negative perceptions on safety. They had negative perceptions regarding work safety, safety programmes, supervisors, and co-workers’ contributions. Besides, they expressed less job satisfaction and were less committed to safety management policies. Perceptions regarding management’s attitude towards safety between the 2 groups were not of statistical significance. The analyses provided an explanation for the cause of a substantial portion of the high rate of industrial accidents in Ghana’s work environment. Implications for safety management are discussed.
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Thermal Performance Assessment of Heat Resistant Fabrics Based on a New Thermal Wave Model of Skin Heat Transfer
Fanglong Zhu, Weiyuan Zhang & Guowen Song
A thermal wave skin model incorporating surface heat flux from a skin simulant sensor is developed to characterize the thermal performance of heat resistant fabrics covering the skin simulant sensor. Comparisons of time to 2nd-degree skin burn and temperature elevation of skin beneath a layer of fabric between the Pennes’ equation and the newly developed thermal wave skin model are performed in this research. Results of tolerance time from the Stoll criterion method are also compared with those from 2 skin models in a thermal protective performance calorimeter. It is concluded that the thermal properties of heat resistant fabrics can be characterized more precisely than previously.
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Reliability of a Questionnaire and an Ergonomic Checklist for Assessing Working Conditions and Health at Call Centres
Kerstin Norman, Håkan Alm, Ewa Wigaeus Tornqvist & Allan Toomingas
Background. The purpose was to study the test-retest reliability and internal consistency of questions in a questionnaire concerning working conditions and health and the inter-rater reliability of observations and measurements according to an ergonomic checklist. Method. Fifty-seven operators participated in a retest questionnaire and 58 operators participated in an inter-observer test. Results. The questions had fair to good or higher reliability in 142 of the total of 312. Twenty-seven of the total of 44 variables in the ergonomic checklist were classified as having fair to good or higher reliability. Conclusions. About half of the questions had fair to good or higher reliability and can be recommended for further analyses. The majority of variables in the ergonomic checklist were classified as having fair to good or higher reliability. Low reliability does not necessarily indicate that the reliability of the test, per se, is low but may signify that the conditions measured
vary over time or that the answers are aggregated in one part of the scale.
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Workers’ Active Involvement in the Improvement of Occupational Safety and Health in a Textile Enterprise—A Case Study
Małgorzata Milczarek & Katarzyna Szczecińska
Part of the Polish-Swedish OSHMAN project was carried out in a textile company. It aimed at implementing and improving effective health and safety management with workers’ active involvement at all levels of the enterprise. The two main problems to be solved during the project were decreasing occupational risk and improving workers’ poor knowledge on occupational risk. Training courses, workshops and practical activities were undertaken. As expected, there were changes in work organisation and improvement in the way workstations were looked after, which led to a decrease in occupational risk. Workers were highly committed during the project. Nevertheless it seems that more training should be directed at middle management.
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Safety and Human Factors Considerations in Control Rooms of Oil and Gas Pipeline Systems: Conceptual Issues and Practical Observations
Najmedin Meshkati
All oil and gas pipeline systems are run by human operators (called controllers) who use computer-based workstations in control rooms to “control” pipelines. Several human factor elements could contribute to the lack of controller success in preventing or mitigating pipeline accidents/incidents. These elements exist in both the work environment and also in the computer system design/operation (such as data presentation and alarm configuration). Some work environment examples include shift hours, shift length, circadian rhythms, shift change-over processes, fatigue countermeasures, ergonomics factors, workplace distractions, and physical interaction with control system computers. The major objective of this paper is to demonstrate the critical effects of human and organizational factors and also to highlight the role of their interactions with automation (and automated devices) in the safe operation of complex, large-scale pipeline systems. A case study to demonstrate the critical role of human organizational factors in the control room of an oil and gas pipeline system is also presented.
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RD50 Value as the Criterion for Setting Maximum Admissible Levels of Occupational Exposure to Irritants in Poland
Małgorzata Kupczewska-Dobecka, Renata Soćko & Sławomir Czerczak
The aim of this work is to analyse Maximum Admissible Concentration (MAC) values proposed for irritants by the Group of Experts for Chemical Agents in Poland, based on the RD50 value. In 1994–2004, MAC values for irritants based on the RD50 value were set for 17 chemicals. For the purpose of the analysis, 1/10 RD50, 1/100 RD50 and the MAC/RD50 ratio were calculated. The determined MAC values are within the 0.01–0.09 RD50 range. The RD50 value is a good rough criterion to set MAC values for irritants and it makes it possible to estimate quickly admissible exposure levels. It has become clear that, in some cases, simple setting the MAC value for an irritant at the level of 0.03 RD50 may be insufficient to determine precisely the possible hazard to workers’ health. Other available toxicological data, such as NOAEL (No-Observed-Adverse-Effect Level) and LOAEL (Lowest-Observed-Adverse-Effect Level), should always be considered as well.
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The BG Measurement System for Hazardous Substances (BGMG) and the Exposure Database of Hazardous Substances (MEGA)
Stefan Gabriel
German employers’ liability insurance associations or Berufsgenossenschaften (BGs)—institutions for statutory accident insurance—maintain a measurement system for hazardous substances, the so-called BGMG. The aim of the BGMG is to determine and document valid results of measurements of exposure primarily for prevention purposes. The data are collected systematically, in parallel to the sampling in a company. Parameters which are supposed to have a visible effect on exposure levels are documented. The MEGA database (documentation of measurement data relating to workplace exposure to hazardous substances) holds 1,629 million measurement values, which have been compiled in since 1972. The database offers a host of selection possibilities for assessments depending on the evaluation strategy.
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Safety Studies on Hydraulic Proportional Valves With Electrical Position Feedback
Dietmar Reinert, Tetsuya Kimura & Karl-Josef Gorgs
The authors analysed a proportional valve with electrical position feedback for its failure behaviour. Several failures were introduced into the feedback loop, especially into the 2 solenoids and the inductive position transducer. The behaviour of the valve for square and ramp reference signals was recorded and systematically analysed. It was shown that failures could be detected by monitoring the residual signal from the equipment under control or the residual signal from the sensor. It was possible to achieve the safe position within twice the normal response time of the valve by switching off the current of both solenoids. The application of these results for a new generation of safe proportional valves is discussed. The use of the results of these investigations obviates the need for redundancy of the electrical position monitoring arrangement in a safe proportional valve.
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