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Means of improving tractor drivers' working posture
Ergonomics in Action - F r o m Theory to Practice, Proceedings of the Joint IEA/NES Conference, Oslo, 2 0 - 2 2 Aug 1980, 4 pp.
between firemen and full-time female operators may be due to a variation in the adaptive functions of the two sexes.
The usefulness of the relationship between ergonomics and occupational and social medicine is evident especially in highly automated systemsas, eg, traffic control systems. The stress and strain to which air traffic controllers are exposed is well known. The consequences of it are poor job satisfaction, low level of subjective well-being, turn-over. On the basis of investigations made in this field symptoms of (a) fatigue and pain localised in back muscles and of back stiffness, due to the physical static load stemming from the permanent sitting posture, (b) a certain degree of weakening of the CNS due to the continual emotional stress and mental strain stemming both from objective andsubjective matters, were revealed. With respect to existing work conditions in ATC systems, it is difficult for ergonomists to accomplish such changes to reduce some noxious agents to a minimum level. The classical procedures such as selection, training and integration of human and technical factors do not seem at this stage of technical development to be fully efficient. A more convenient approach is to be found in compensating for the negative influences of physical and mental load and in supporting the resistance of controllers to stress and mental and physical load. Experiences in this area are discussed suggesting that future improvement is possible through preventive rehabilitation care and training in suitable behavioural patterns.
13.1.12 (80639) Viner, D.B.L. Accidents and workload factors in agricultural flying operations. In: 'Human Factors and the Quality of Life', Proceedings of the 16th Annual Conference of the Ergonomics Society of Australia and New Zealand, University of Queensland, Brisbane, Australia, 2 9 - 3 0 Nov, 1979, Edited by G. Devereux, pp 6 9 - 8 4 .
13.1.11 (80633)
Kalimo, R. et al Psychological and biochemical strain in firemen's work. Scandinavian Journal o f Work, Environment and Health, Sep 1980, 6.3, 1 7 9 - 1 8 7 . Mental load and strain in the work of firemen and fire alarm centre operators were studied in a group of 260 firemen and six female full-time operators from three fire brigades. The firemen proved to be satisfied with their work, and signs of chronic psychological problems were uncommon. Situational work load and related strain may, however, be extreme during active operations. A large proportion (42%) of the firemen suffered from strain after the 24 h long daily work period. Those who had recently worked as paramedics in the ambulance service or in the alarm centre were under more strain than ordinary fire fighters. Biochemical stress indicators revealed a high activation of firemen at the alarm centre. The difference found
The commercial pressures on aerial agricultural operations include a very peaky and variable demand profile, one consequence of which is pressure on the pilot to work long hours and long weeks. Recognition of the potentially adverse effects of fatigue under these circumstances has resulted in flying hour limitations by regulation. A study has been made of agricultural pilot workload factors in conjunction with pilot heart rate records in an attempt to reach a better understanding of the pilot's response to his task. Heart rate measurements are reported which demonstrate both task influence and possible fatigue effects. A preliminary analysis indicates the importance of workload related effects in a high proportion of serious accidents to agricultural aircraft.
Physiology, anthropometry and biomechanics 13.1.13 (80680) Morrissey, S.J., et al Anthropometry and strength characteristics of low coal miners with respect to sex and age. In: Human Factors: Science for Working and Living, Proceedings of the 24th Annual Meeting of the Human Factors Society, Los Angeles, Oct 1980, Edited by G.E. Corrick et al, pp 4 3 4 - 4 3 7 . A battery of general anthropometric measures and selected isometric strength measures have been made on a sample of male and female low coal miners in the United States (low coal refers to coal mines in which the coal seam and, thus, tunnel heights are less than 48 in (1220 mm). In comparison to selected military and civilian anthropometric surveys, both the male and female low coal miners showed significantly greater standing leg strengths than the reference population. These differences can be attributed to the occupational and postural demands present in low coal mining.
13.1.14 (80693)
Ridd, J.E., and Davis, P.R. An investigation of materials handling problems at a Norwegian industrial company. In: Ergonomics in Action F r o m Theory to Practice, Proceedings of the Joint IEA/NES Conference, Oslo, 2 0 - 2 2 Aug 1980, 5 pp. Work-environment organisations have been established within Standard Telephon og Kabelfabrick A/S to monitor new and existing work situations. One particular result of this work was the identification of a department with a particularly high incidence of musculo-skeletal problems. Six hundred of the company's 3500 staff work in the cable manufacturing plant and an analysis of the available records for this group showed both that the occurrence of musculoskeletal disease ranked alongside that of infections and bronchial complaints, and also that the average work absence resulting from musculo-skeletal problems was, by far, the longest of all the diagnoses. Further, cable drum handling was implicated in 30% of these accidents and injuries. In light of this evidence the Materials Handling Research Unit was asked b y the work environment organisation to carry out a study of the materials handling problems within the cable manufacturing plant and in particular to investigate cable drum handling. The aim of the study was to identify any stressful procedures and to recommend ways of alleviating that stress and so reduce the number of days lost from musculoskeletal problems. 13.1.15 (80705) Lovested, G.E. Reducing warehousing material handling strains. In: Human Factors: Science for Working and Living, Proceedings of the 24th Annual Meeting of the Human Factors Society, Los Angeles, Oct 1980, Edited by G.E. Corrick et al, pp 6 3 5 654. A study was undertaken to determine the effect introducing redesigned wood pallet boxes in a warehousing operation would have on back strains. The new pallet boxes had been redesigned to provide warehouse pickers a better posture to lift parts out of pallet boxes when they were less than half full. A year after the introduction, the lifting strain incidence rate involving pallet boxes decreased by 67"7%. 13.1.16 (80707) Sjoflot, L. Means of improving tractor drivers' working posture. In: Ergonomics in Action - From Theory to Practice, Proceedings of the Joint IEA/NES Conference, Oslo, 2 0 - 2 2 Aug 1980, 14 pp.
Applied Ergonomics
March 1982
67
Most tractor implements are behind or to the side of the tractor, thus requiring the driver to look backwards or sideways for a large proportion of the working time. This awkward posture causes injuries and pain in the back and neck, besides being generally uncomfortable and reducing working performance. Certain areas around the tractor and implements cannot be seen at all from the driver's place. This will reduce the driver's ability to control his work and might also seriously influence safety. The use of big mirrors, improved steering devices for implements and swivelling and tilting seats have been developed according to ergonomics principles and have been studied in both field and laboratory studies, including the use of a driving simulator. The results of the studies show considerable improvement in working posture, working performance and in the driver's subjective assessment of different working operations with tractors. Some of the ideas and technical improvements have quickly been adopted and made use of by machine manufacturers, while others have required more follow-up work. Cooperation with the manufacturing industry seems very important, but most important is the communication of information to the users of the machines. Feedback from a large number of Norwegian farmers shows that the scientific results are also valid for practical situations and that the costs of ergonomics improvements are felt to be very reasonable in relation to the benefits.
Visual displays
by the fact that they are usually not familiar with such devices. Therefore, incorporation of human factors/ ergonomics variables into the design of distress signals can be an important element in their survival. This report presents a systematic method to evaluate and confirm the effectiveness of human factors/ergonomics variables in the design of distress signals. The effects of several identified variables were tested individually in the lab and synergistically in a (simulated) on-water emergency. It was found that emergency signals that were designed according to human factors/ergonomics recommendations generally required less time to operate than devices that did not follow such guidelines. 13.1.19 (80742)
Rasmussen, P.G., Chesterfield, B.P., and Lowrey, D.L. Legibility of smoke-obscured emergency exit signs. In: Human Factors: Science for Working and Living, Proceedings of the 24th Annual Meeting of the Human Factors Society, Los Angeles, Oct 1980, Edited by G.E. Corrick et al, pp 4 7 6 479. Internally self-illuminated emergency exit signs were investigated to determine the effects of size and background luminance levels on overcoming the visual degradation resulting from the presence of smoke in the visual environment. The results indicate that increased size and background luminance levels can be effective, though inefficient, methods for improving legibility in the presence of dense smoke.
understandability and several dangerous confusions in meaning were identified for symbols proposed for international standardisation. 13.1.21 (80791)
Reynolds, L. The presentation of bibliographic information on Prestel. British Library, Research and Development Department, Report No 5536, Mar 1980, 25 pp. Because of the limited character set and relatively small number of character positions available on each Prestel frame, the scope for typographic and spatial coding of information is very limited. There is the possibility of using colour coding, since seven colour are available at no extra cost, but it must be remembered that these colours differ in legibility and also in their apparent 'importance' when viewed on the screen. Bearing in mind these characteristics of Pres tel displays, and also certain basic principles in the presentation of bibliographic information which have been established in other media, a number of alternative designs are presented for book lists on topical subjects. Designs for author, title, data and classified listings are included. The major recommendations are that the layout should be kept as simple as possible, and the number of colours used should be restricted to two in most cases. Indentation can be used to facilitate the scanning of alphabetically listed entry headings, while colour can be used to emphasise certain elements within the entry if necessary. Emphasis is placed on designing the information according to the way in which it will be used.
13.1.17 (80737)
13.1.20 (80752)
Loewenthal, A., and Riley, M.W.
Lerner, N.D., and Collins, B.L.
The effectiveness of warning labels. In: Human Factors: Science for Working and Living, Proceedings of the 24th Annual Meeting of the Human Factors Society, Los Angeles, Oct 1980, Edited by G.E. Corrick et al, pp 3 8 9 391.
Evaluation of symbols for fire safety. In: Human Factors: Science for Working and Living, Proceedings of the 24th Annual Meeting of the Human Factors Society, Los Angeles, Oct 1980, Edited by G.E. Corrick et al, pp 4 8 4 - 4 8 7 .
Comprehensibility of illustration an analytical model. Information Design Journal, 1980, 1.3,204--213.
Six subjects viewed 16 different warning and nonwarning labels on four different colours. Results indicate that colour alone was not a significant factor in label indication. Also, the messages on the label and the subjects have a significant effect on label identification.
Twenty-five symbols for firealerting, of which 22 were proposed by the International Organisation for Standardisation, were evaluated for 91 US subjects. The purpose of the experiment was two-fold: (1) to determine the understandability of each symbol; and (2) to assess the effects of variations in both presentation and response methods upon the measurement of understandability. There was no significant effect of the mode of stimulus presentation: slides, placards, or booklets. The two response methods - providing a definition or selecting among choice alternatives (and providing confidence ratings for anwers) - led to generally similar conclusions. Some serious problems in
Auditory displays
13.1.18 (80738)
Marras, W.S., amd Kroemer, K.H.E. A method to evaluate h u m a n factors/ ergonomics design variables of distress signals. Human Factors, Aug 1980, 22.4,389-399. The selection and use of distress signals is crucial for a yachtsman in any emergency. This situation is intensified
68
Applied Ergonomics
March 1982
13.1.22 (81027)
Goldsmith, E.
It is suggested that the means to analyse illustration would be of great benefit to students, illustrators, publishers and others, and a model is presented identifying 12 elements which the author believes contribute to the comprehensibility of pictures, particularly those intended to be in support of text.
13.1.23 (80804)
Clegg, J.M. Human factors in featured telephone systems. In: Proceedings of the Ninth International Symposium on Human Factors in Telecommunications, Red Bank, New Jersey, USA, 29 Sept - 3 Oct 1980, pp 171-177.
between firemen and full-time female operators may be due to a variation in the adaptive functions of the two sexes.
The usefulness of the relationship between ergonomics and occupational and social medicine is evident especially in highly automated systemsas, eg, traffic control systems. The stress and strain to which air traffic controllers are exposed is well known. The consequences of it are poor job satisfaction, low level of subjective well-being, turn-over. On the basis of investigations made in this field symptoms of (a) fatigue and pain localised in back muscles and of back stiffness, due to the physical static load stemming from the permanent sitting posture, (b) a certain degree of weakening of the CNS due to the continual emotional stress and mental strain stemming both from objective andsubjective matters, were revealed. With respect to existing work conditions in ATC systems, it is difficult for ergonomists to accomplish such changes to reduce some noxious agents to a minimum level. The classical procedures such as selection, training and integration of human and technical factors do not seem at this stage of technical development to be fully efficient. A more convenient approach is to be found in compensating for the negative influences of physical and mental load and in supporting the resistance of controllers to stress and mental and physical load. Experiences in this area are discussed suggesting that future improvement is possible through preventive rehabilitation care and training in suitable behavioural patterns.
13.1.12 (80639) Viner, D.B.L. Accidents and workload factors in agricultural flying operations. In: 'Human Factors and the Quality of Life', Proceedings of the 16th Annual Conference of the Ergonomics Society of Australia and New Zealand, University of Queensland, Brisbane, Australia, 2 9 - 3 0 Nov, 1979, Edited by G. Devereux, pp 6 9 - 8 4 .
13.1.11 (80633)
Kalimo, R. et al Psychological and biochemical strain in firemen's work. Scandinavian Journal o f Work, Environment and Health, Sep 1980, 6.3, 1 7 9 - 1 8 7 . Mental load and strain in the work of firemen and fire alarm centre operators were studied in a group of 260 firemen and six female full-time operators from three fire brigades. The firemen proved to be satisfied with their work, and signs of chronic psychological problems were uncommon. Situational work load and related strain may, however, be extreme during active operations. A large proportion (42%) of the firemen suffered from strain after the 24 h long daily work period. Those who had recently worked as paramedics in the ambulance service or in the alarm centre were under more strain than ordinary fire fighters. Biochemical stress indicators revealed a high activation of firemen at the alarm centre. The difference found
The commercial pressures on aerial agricultural operations include a very peaky and variable demand profile, one consequence of which is pressure on the pilot to work long hours and long weeks. Recognition of the potentially adverse effects of fatigue under these circumstances has resulted in flying hour limitations by regulation. A study has been made of agricultural pilot workload factors in conjunction with pilot heart rate records in an attempt to reach a better understanding of the pilot's response to his task. Heart rate measurements are reported which demonstrate both task influence and possible fatigue effects. A preliminary analysis indicates the importance of workload related effects in a high proportion of serious accidents to agricultural aircraft.
Physiology, anthropometry and biomechanics 13.1.13 (80680) Morrissey, S.J., et al Anthropometry and strength characteristics of low coal miners with respect to sex and age. In: Human Factors: Science for Working and Living, Proceedings of the 24th Annual Meeting of the Human Factors Society, Los Angeles, Oct 1980, Edited by G.E. Corrick et al, pp 4 3 4 - 4 3 7 . A battery of general anthropometric measures and selected isometric strength measures have been made on a sample of male and female low coal miners in the United States (low coal refers to coal mines in which the coal seam and, thus, tunnel heights are less than 48 in (1220 mm). In comparison to selected military and civilian anthropometric surveys, both the male and female low coal miners showed significantly greater standing leg strengths than the reference population. These differences can be attributed to the occupational and postural demands present in low coal mining.
13.1.14 (80693)
Ridd, J.E., and Davis, P.R. An investigation of materials handling problems at a Norwegian industrial company. In: Ergonomics in Action F r o m Theory to Practice, Proceedings of the Joint IEA/NES Conference, Oslo, 2 0 - 2 2 Aug 1980, 5 pp. Work-environment organisations have been established within Standard Telephon og Kabelfabrick A/S to monitor new and existing work situations. One particular result of this work was the identification of a department with a particularly high incidence of musculo-skeletal problems. Six hundred of the company's 3500 staff work in the cable manufacturing plant and an analysis of the available records for this group showed both that the occurrence of musculoskeletal disease ranked alongside that of infections and bronchial complaints, and also that the average work absence resulting from musculo-skeletal problems was, by far, the longest of all the diagnoses. Further, cable drum handling was implicated in 30% of these accidents and injuries. In light of this evidence the Materials Handling Research Unit was asked b y the work environment organisation to carry out a study of the materials handling problems within the cable manufacturing plant and in particular to investigate cable drum handling. The aim of the study was to identify any stressful procedures and to recommend ways of alleviating that stress and so reduce the number of days lost from musculoskeletal problems. 13.1.15 (80705) Lovested, G.E. Reducing warehousing material handling strains. In: Human Factors: Science for Working and Living, Proceedings of the 24th Annual Meeting of the Human Factors Society, Los Angeles, Oct 1980, Edited by G.E. Corrick et al, pp 6 3 5 654. A study was undertaken to determine the effect introducing redesigned wood pallet boxes in a warehousing operation would have on back strains. The new pallet boxes had been redesigned to provide warehouse pickers a better posture to lift parts out of pallet boxes when they were less than half full. A year after the introduction, the lifting strain incidence rate involving pallet boxes decreased by 67"7%. 13.1.16 (80707) Sjoflot, L. Means of improving tractor drivers' working posture. In: Ergonomics in Action - From Theory to Practice, Proceedings of the Joint IEA/NES Conference, Oslo, 2 0 - 2 2 Aug 1980, 14 pp.
Applied Ergonomics
March 1982
67
Most tractor implements are behind or to the side of the tractor, thus requiring the driver to look backwards or sideways for a large proportion of the working time. This awkward posture causes injuries and pain in the back and neck, besides being generally uncomfortable and reducing working performance. Certain areas around the tractor and implements cannot be seen at all from the driver's place. This will reduce the driver's ability to control his work and might also seriously influence safety. The use of big mirrors, improved steering devices for implements and swivelling and tilting seats have been developed according to ergonomics principles and have been studied in both field and laboratory studies, including the use of a driving simulator. The results of the studies show considerable improvement in working posture, working performance and in the driver's subjective assessment of different working operations with tractors. Some of the ideas and technical improvements have quickly been adopted and made use of by machine manufacturers, while others have required more follow-up work. Cooperation with the manufacturing industry seems very important, but most important is the communication of information to the users of the machines. Feedback from a large number of Norwegian farmers shows that the scientific results are also valid for practical situations and that the costs of ergonomics improvements are felt to be very reasonable in relation to the benefits.
Visual displays
by the fact that they are usually not familiar with such devices. Therefore, incorporation of human factors/ ergonomics variables into the design of distress signals can be an important element in their survival. This report presents a systematic method to evaluate and confirm the effectiveness of human factors/ergonomics variables in the design of distress signals. The effects of several identified variables were tested individually in the lab and synergistically in a (simulated) on-water emergency. It was found that emergency signals that were designed according to human factors/ergonomics recommendations generally required less time to operate than devices that did not follow such guidelines. 13.1.19 (80742)
Rasmussen, P.G., Chesterfield, B.P., and Lowrey, D.L. Legibility of smoke-obscured emergency exit signs. In: Human Factors: Science for Working and Living, Proceedings of the 24th Annual Meeting of the Human Factors Society, Los Angeles, Oct 1980, Edited by G.E. Corrick et al, pp 4 7 6 479. Internally self-illuminated emergency exit signs were investigated to determine the effects of size and background luminance levels on overcoming the visual degradation resulting from the presence of smoke in the visual environment. The results indicate that increased size and background luminance levels can be effective, though inefficient, methods for improving legibility in the presence of dense smoke.
understandability and several dangerous confusions in meaning were identified for symbols proposed for international standardisation. 13.1.21 (80791)
Reynolds, L. The presentation of bibliographic information on Prestel. British Library, Research and Development Department, Report No 5536, Mar 1980, 25 pp. Because of the limited character set and relatively small number of character positions available on each Prestel frame, the scope for typographic and spatial coding of information is very limited. There is the possibility of using colour coding, since seven colour are available at no extra cost, but it must be remembered that these colours differ in legibility and also in their apparent 'importance' when viewed on the screen. Bearing in mind these characteristics of Pres tel displays, and also certain basic principles in the presentation of bibliographic information which have been established in other media, a number of alternative designs are presented for book lists on topical subjects. Designs for author, title, data and classified listings are included. The major recommendations are that the layout should be kept as simple as possible, and the number of colours used should be restricted to two in most cases. Indentation can be used to facilitate the scanning of alphabetically listed entry headings, while colour can be used to emphasise certain elements within the entry if necessary. Emphasis is placed on designing the information according to the way in which it will be used.
13.1.17 (80737)
13.1.20 (80752)
Loewenthal, A., and Riley, M.W.
Lerner, N.D., and Collins, B.L.
The effectiveness of warning labels. In: Human Factors: Science for Working and Living, Proceedings of the 24th Annual Meeting of the Human Factors Society, Los Angeles, Oct 1980, Edited by G.E. Corrick et al, pp 3 8 9 391.
Evaluation of symbols for fire safety. In: Human Factors: Science for Working and Living, Proceedings of the 24th Annual Meeting of the Human Factors Society, Los Angeles, Oct 1980, Edited by G.E. Corrick et al, pp 4 8 4 - 4 8 7 .
Comprehensibility of illustration an analytical model. Information Design Journal, 1980, 1.3,204--213.
Six subjects viewed 16 different warning and nonwarning labels on four different colours. Results indicate that colour alone was not a significant factor in label indication. Also, the messages on the label and the subjects have a significant effect on label identification.
Twenty-five symbols for firealerting, of which 22 were proposed by the International Organisation for Standardisation, were evaluated for 91 US subjects. The purpose of the experiment was two-fold: (1) to determine the understandability of each symbol; and (2) to assess the effects of variations in both presentation and response methods upon the measurement of understandability. There was no significant effect of the mode of stimulus presentation: slides, placards, or booklets. The two response methods - providing a definition or selecting among choice alternatives (and providing confidence ratings for anwers) - led to generally similar conclusions. Some serious problems in
Auditory displays
13.1.18 (80738)
Marras, W.S., amd Kroemer, K.H.E. A method to evaluate h u m a n factors/ ergonomics design variables of distress signals. Human Factors, Aug 1980, 22.4,389-399. The selection and use of distress signals is crucial for a yachtsman in any emergency. This situation is intensified
68
Applied Ergonomics
March 1982
13.1.22 (81027)
Goldsmith, E.
It is suggested that the means to analyse illustration would be of great benefit to students, illustrators, publishers and others, and a model is presented identifying 12 elements which the author believes contribute to the comprehensibility of pictures, particularly those intended to be in support of text.
13.1.23 (80804)
Clegg, J.M. Human factors in featured telephone systems. In: Proceedings of the Ninth International Symposium on Human Factors in Telecommunications, Red Bank, New Jersey, USA, 29 Sept - 3 Oct 1980, pp 171-177.