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Physiological responses of fire fighters to workload and thermal stress
arm motion is often difficult to perceive. The present paper presents a model of human reaction time and emergency behaviour. The total reaction time is the sum of three elements: perception, decision making and motor response. Each of these three elements is modelled using concepts such as perceptual discriminability and signal detection theory. Finally, the results of an experiment are presented where the human reaction time is modelled as a function of robot arm speed. 19.4.7 (108185)
Rasmussen, J. Approaches to the control of the effects of human error on chemical plant safety. In: Proc Int Symp preventing major chemical accidents, Washington, DC, USA, 3 - 5 Feb, 1987. Amer Inst Chem Eng, New York, 1987, pp 6 . 1 - 6 . 2 2 . Major chemical accidents generally have multiple causes traceable to mistakes made during design, maintenance and operation. Several safety control approaches are possible, depending upon human error type and task/work conditions. This paper discusses the nature of human error and the role of predictive analysis and analysis of event reports in safety control during design and operation. Mistakes of operators, maintenance staff and management are considered. 19.4.8 (108230)
Skoldstrom, B. Physiological responses of fire fighters to workload and thermal stress. Ergonomics, 1987, 30(11), 1589-1597. The physical work performance of eight fit fighters wearing fire brigade uniforms and wearing breathing apparatus was assessed. They were tested in a climatic chamber set at temperatures of 15°C and 45 ° C, respectively. The test was performed with and without fire fighting equipment. The subjects walked on a treadmill at a speed of 3"5 km/h, which produced a workload equivalent to 20% of the subjects' maximal oxygen uptake without equipment, and 30% with equipment. The test lasted for 60 min. Heart rate, oxygen uptake, skin and deep body temperatures were measured during the test. The subjects estimated perceived physical exertion and perceived temperature. Wearing fire fighting equipment increased the oxygen uptake by 0"4 1/min. Heart rate at the end of the experiments reached near-maximum levels when the temperature was 45°C with equipment, and deep body temperature increased to an average of 38" 7°C. The subjects' ratings of perceived exertion
338
Applied Ergonomics
were highly correlated to heart rate. The loading induced by heat and protective equipment reduced the ability to perform strenuous work. The combination of thick clothing and heavy breathing apparatus was found to have a significant limiting effect on the endurance of fire fighters. 19.4.9 (108233)
Schuldt, K., Ekholm, J., HarmsRingdahl, K., Nemeth, G., and Arborelius, U.P. Effects of arm support or suspension on neck and shoulder muscle activity during sedentary work. Scand J Rehab Med, 1987, 19(2), 7 7 - 8 4 . The aim of this study was to evaluate the effects on the levels of neck and shoulder muscular activity of ergonomic aids used to support or suspend the arm in different sitting postures, both with and without movement of the arm-hand. Ten skilled women workers performed a standardised simulated work cycle similar to assembling printed circuit boards, in different sitting postures with and without ergonomic aids. The elbow was supported by a loosely mounted, padded plate. For suspension, a new device - the K-block - was used giving an adjustable constant suspending force. Full-wave rectified, low-pass filtered, time-averaged and normalised EMG was used. Surface electrodes were applied over six neck and shoulder muscles. The results show that a reduction in the level of activity in neck and shoulder muscles can be obtained with either aid. The reduction, whether caused by suspension or support of the arm, was related to the sitting posture. Elbow support might be more efficient than arm suspension in a sitting posture with the whole spine flexed, while arm suspension might be more efficient when the trunk is inclined slightly backward. Elbow support and, particularly, arm suspension may thus be recommended as technical aids in sedentary assembly work for patients with easily elicited cervical spine and/ or shoulder pain. It is also suggested that arm suspension may be used to improve ergonomics conditions at workplaces.
on industrialised countries (ICs) fol the supply of most industrial goods, l'his dependence is increased by development aid programmes of ICs to IDCs. An attempt has been made to ascertain the degree of design incompatibility experienced by users of these imported goods due to differences in the body size of people in producer and user countries. A comparative study of variations in body size has been made from data available in literature and anthropometric surveys conducted by the author. The results reveal differences in almost every part of the human body, particularly between populations of ICs and IDCs. Simple examples have been illustrated, which provide some evidence of the problems experienced by the users of goods in IDCs. The need for reliable anthropometric data ill respect of IDCs is stressed. Urgent measures are required to introduce changes in equipment, particularly for the benefit of users in IDCs. 19.4.11 (108240)
Mebarki, B. An anthropometric study of Algerian women with special reference to domestic work. Univ Birmingham, Dept of Eng Prod, Birmingham, 1987, 89 pp. The anthropometry of 666 Algerian women in standing, sitting, kneeling, squatting and crawling positions was studied. The sample (age range 1 6 - 6 5 years) was randomly drawn from different socio-economic, educational, geographic and ethnic groups throughout the country. Thirty measurements were taken on each subject, chosen for their importance in equipment and furniture design and domestic workplace layout. Results are presented and discussed in the light of influencing factors, and compared with those of other female populations of the world. 19.4.12 (108245)
Stoffert, G., and Timme, U. Are women better suited for bending work? (Sind Frauen fffr Buckarbeiten Besser Geeignet?). (In German.)
Zeitschrift )''fir A rbeitswissenschajL 1987, 41(3), 174
184.
Are physically uncomfortable jobs in plant cultivation traditionally assigned to women, or are women A comparative study of body size better suited physically for this variability between people in bending work than men? To address industrialised countries and industrially this question, the bodily proportions of developing countries, its impact on the German, Yugoslavian, Italian and use of imported goods. In: Ergonomics in developing countries: An international Turkish men and women were studied symposium. International Labour Office, using the dimensions given in DIN 33 402 and the values published by Geneva, 1987, pp 6 5 - 9 1 . Jurgens, and the absolute and proporThe industrially developing countries tional deviations of female and male (IDCs) today, to a great extent, depend grip axes above the ground (support 19.4.10 (108235)
Abeysekera, J.D.A.
December 1988
Rasmussen, J. Approaches to the control of the effects of human error on chemical plant safety. In: Proc Int Symp preventing major chemical accidents, Washington, DC, USA, 3 - 5 Feb, 1987. Amer Inst Chem Eng, New York, 1987, pp 6 . 1 - 6 . 2 2 . Major chemical accidents generally have multiple causes traceable to mistakes made during design, maintenance and operation. Several safety control approaches are possible, depending upon human error type and task/work conditions. This paper discusses the nature of human error and the role of predictive analysis and analysis of event reports in safety control during design and operation. Mistakes of operators, maintenance staff and management are considered. 19.4.8 (108230)
Skoldstrom, B. Physiological responses of fire fighters to workload and thermal stress. Ergonomics, 1987, 30(11), 1589-1597. The physical work performance of eight fit fighters wearing fire brigade uniforms and wearing breathing apparatus was assessed. They were tested in a climatic chamber set at temperatures of 15°C and 45 ° C, respectively. The test was performed with and without fire fighting equipment. The subjects walked on a treadmill at a speed of 3"5 km/h, which produced a workload equivalent to 20% of the subjects' maximal oxygen uptake without equipment, and 30% with equipment. The test lasted for 60 min. Heart rate, oxygen uptake, skin and deep body temperatures were measured during the test. The subjects estimated perceived physical exertion and perceived temperature. Wearing fire fighting equipment increased the oxygen uptake by 0"4 1/min. Heart rate at the end of the experiments reached near-maximum levels when the temperature was 45°C with equipment, and deep body temperature increased to an average of 38" 7°C. The subjects' ratings of perceived exertion
338
Applied Ergonomics
were highly correlated to heart rate. The loading induced by heat and protective equipment reduced the ability to perform strenuous work. The combination of thick clothing and heavy breathing apparatus was found to have a significant limiting effect on the endurance of fire fighters. 19.4.9 (108233)
Schuldt, K., Ekholm, J., HarmsRingdahl, K., Nemeth, G., and Arborelius, U.P. Effects of arm support or suspension on neck and shoulder muscle activity during sedentary work. Scand J Rehab Med, 1987, 19(2), 7 7 - 8 4 . The aim of this study was to evaluate the effects on the levels of neck and shoulder muscular activity of ergonomic aids used to support or suspend the arm in different sitting postures, both with and without movement of the arm-hand. Ten skilled women workers performed a standardised simulated work cycle similar to assembling printed circuit boards, in different sitting postures with and without ergonomic aids. The elbow was supported by a loosely mounted, padded plate. For suspension, a new device - the K-block - was used giving an adjustable constant suspending force. Full-wave rectified, low-pass filtered, time-averaged and normalised EMG was used. Surface electrodes were applied over six neck and shoulder muscles. The results show that a reduction in the level of activity in neck and shoulder muscles can be obtained with either aid. The reduction, whether caused by suspension or support of the arm, was related to the sitting posture. Elbow support might be more efficient than arm suspension in a sitting posture with the whole spine flexed, while arm suspension might be more efficient when the trunk is inclined slightly backward. Elbow support and, particularly, arm suspension may thus be recommended as technical aids in sedentary assembly work for patients with easily elicited cervical spine and/ or shoulder pain. It is also suggested that arm suspension may be used to improve ergonomics conditions at workplaces.
on industrialised countries (ICs) fol the supply of most industrial goods, l'his dependence is increased by development aid programmes of ICs to IDCs. An attempt has been made to ascertain the degree of design incompatibility experienced by users of these imported goods due to differences in the body size of people in producer and user countries. A comparative study of variations in body size has been made from data available in literature and anthropometric surveys conducted by the author. The results reveal differences in almost every part of the human body, particularly between populations of ICs and IDCs. Simple examples have been illustrated, which provide some evidence of the problems experienced by the users of goods in IDCs. The need for reliable anthropometric data ill respect of IDCs is stressed. Urgent measures are required to introduce changes in equipment, particularly for the benefit of users in IDCs. 19.4.11 (108240)
Mebarki, B. An anthropometric study of Algerian women with special reference to domestic work. Univ Birmingham, Dept of Eng Prod, Birmingham, 1987, 89 pp. The anthropometry of 666 Algerian women in standing, sitting, kneeling, squatting and crawling positions was studied. The sample (age range 1 6 - 6 5 years) was randomly drawn from different socio-economic, educational, geographic and ethnic groups throughout the country. Thirty measurements were taken on each subject, chosen for their importance in equipment and furniture design and domestic workplace layout. Results are presented and discussed in the light of influencing factors, and compared with those of other female populations of the world. 19.4.12 (108245)
Stoffert, G., and Timme, U. Are women better suited for bending work? (Sind Frauen fffr Buckarbeiten Besser Geeignet?). (In German.)
Zeitschrift )''fir A rbeitswissenschajL 1987, 41(3), 174
184.
Are physically uncomfortable jobs in plant cultivation traditionally assigned to women, or are women A comparative study of body size better suited physically for this variability between people in bending work than men? To address industrialised countries and industrially this question, the bodily proportions of developing countries, its impact on the German, Yugoslavian, Italian and use of imported goods. In: Ergonomics in developing countries: An international Turkish men and women were studied symposium. International Labour Office, using the dimensions given in DIN 33 402 and the values published by Geneva, 1987, pp 6 5 - 9 1 . Jurgens, and the absolute and proporThe industrially developing countries tional deviations of female and male (IDCs) today, to a great extent, depend grip axes above the ground (support 19.4.10 (108235)
Abeysekera, J.D.A.
December 1988