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Workspace for disabled people
In Experiment 2, the spatial frequency channels activated by each display were evaluated by measuring the effect of display adaptation on the contrastsensitivity function. The results suggested that high-RAR screens and hard-copy print activated higherfrequency channels than did Iow-RAR screens. In Experiment 3, significantly better visual search performance was obtained for high-RAR screens and for hard-copy print than for low-RAR screens. It was concluded that screen R A R is an important variable to consider in the design of CRTs.
Workplace and equipment design 21.3.26 (116916) Ivergard, T. Handbook of control room design and ergonomics. Taylor & Francis, London, 1989, 220 pp, 125 refs. The author defines the aims of ergonomics as: (1) to prevent ill-health, injury and fatigue; (2) to create comfort and well-being; (3) to promote efficiency and improve reliability; (4) to create interesting and meaningful jobs. The b o o k contains practical guidelines for the ergonomic design of control systems, based u p o n 15 years of research in different industries and hundreds of interviews with control room operators in different environments. It contains a mixture of basic human factors data, practical advice on the design of control rooms and computerised systems, and practical implications distilled from different theories and models of control operations and man-machine systems.
21.3.27 (116155)
Nowak, E. Workspace for disabled people.
Ergonomics, 1989, 32.9, 1 0 7 7 - 1 0 8 8 , 10 refs. The paper aims at determining the workspace for disabled young people. The investigation embraced a group of young people with m o t o r dysfunction of the lower extremities. Seventeen measurements were taken of 32 boys and 45 girls aged 1 5 - 1 8 . There are significant differences in functional dimensions of the arm between the healthy and the disabled populations. The differences clearly indicate that there is a need for different shaping of space in which people of limited m o t o r efficiency must function. A method based on Das and Grady's concept was used in determining workspace. This
method was modified by the author. The method allows determination of workspace by means of several simple anthropometric measurements. Workspace for young people investigated was determined for the sitting position in the transverse and sagittal planes. The results of the investigation constitute data for design and estimation of workplaces for disabled young people with m o t o r dysfunction of the lower extremities. The results can also be used to determine functional space in classrooms, school workshops, educational and rehabilitation centres.
21.3.28 (116452) Gronqvist, R., Roine, J., Jarvinen, E., and Korhonen, E. Art apparatus and a method for determining the slip resistance of shoes and floors by simulation of human foot motions. Ergonomics, 1989, 32.8, 9 7 9 - 9 9 5 , 28 refs. An apparatus to measure the coefficient of kinetic friction (/aK) between the shoe sole and the underfoot surface was constructed, and a method including criteria to evaluate the risk of slipping during walking was developed. The apparatus is a p r o t o t y p e stationary step simulator capable of simulating the movements of a human foot and the forces applied to the underfoot surface during an actual slip, and the drainage capability of the contact surface between the shoe sole and the flooring when different lubricants or contaminants are used. The apparatus consists of a movable artificial foot controlled by a computer with the aid of three hydraulic cylinders. The frictional force (Fu) , the normal force (FN) and theft-ratio (PK = Fu/FN) are measured with a two-wa~, force platform when the foot slides along its surface. Two separate gait patterns, heel-slide (#K 1) and soleslide (/~K2) gait pattern, are used for the evaluations. The method classifies studied shoe, lubricant and underfoot surface combinations into five slip resistance classes according to the measured/a K 1. The slip resistance assessments are specified with some complementary safety criteria - e g, the ratio #K 1/laK2" The reliability of the developed measurement method was assessed in an international comparison test. According to available results discussed in this paper, the method seems to be valid and the slip resistance measurements seem to be repeatable. 21.3.29 (116461) Raafat, H.M.N. Risk assessment and machinery safety. J OccupatAccidents, 1989, 11.1, 3 7 - 5 0 , 10 refs.
The rapid development in the field of machine design coupled with the increasing use of fluid power and programmable electronic systems in operating modern machinery has led to an increasing concern for the safety of all personnel involved in machine operation and maintenance. In many respects, modern machinery tends to pose unique problems and hazards which might differ in nature from those presented by conventional machinery. The introduction of the British Standard Code of Practice BS 5304:1988 for Safety of Machinery will benefit manufacturers from a more uniform application of safeguarding principles. Until the European Community legislation and supporting Standards are available, the Code will be the major document detailing how British machinery safety legislation can be complied with. Although the application of risk assessment to machinery safety was explored briefly in the new British Standard, it has very limited application and rigid requirements for safeguarding are still imposed, mainly as a result of 'experience' or past accident statistics. Designers feel 'justifiably' severely restricted in their innovation by a set of rigid rules presented by the new Standard as well as the EC Directive on Product Liability. This paper considers the role of probabilistic risk assessment as a modern approach to machinery safety through a case history and proposes a guide for the acceptability o f risk.
Environment 21.3.30 (117125) Hjortsherg, U., Rosen, I., Orbaek, P.,
Lundborg, G., and Balogh, I. Finger receptor dysfunction in dental technicians exposed to high-frequency vibration. Scand J Work, Environment & Health, 1989, 1 5 . 5 , 3 3 9 - 3 4 4 , 24 refs. The effects of high-frequency vibration (up to 40 kHz) on digital nerve function were studied in ten dental technicians and ten age-matched referents. Nerve condition velocities, including fractionated antidromic measurements over the carpal tunnel, showed no difference between the groups. In the group of dental technicians the difference between the response latency of the mechanical and electric stimuli in the median nerve distally on the fingers of the right hand was slightly higher than in the reference group, and therefore distal nerve or receptor dysfunction was suggested. Vibration warming and cooling thresholds were significantly increased and thus revealed damage to both myelinated and unmyelinated fibres in the fingers of subjects exposed to highfrequency vibration.
Workplace and equipment design 21.3.26 (116916) Ivergard, T. Handbook of control room design and ergonomics. Taylor & Francis, London, 1989, 220 pp, 125 refs. The author defines the aims of ergonomics as: (1) to prevent ill-health, injury and fatigue; (2) to create comfort and well-being; (3) to promote efficiency and improve reliability; (4) to create interesting and meaningful jobs. The b o o k contains practical guidelines for the ergonomic design of control systems, based u p o n 15 years of research in different industries and hundreds of interviews with control room operators in different environments. It contains a mixture of basic human factors data, practical advice on the design of control rooms and computerised systems, and practical implications distilled from different theories and models of control operations and man-machine systems.
21.3.27 (116155)
Nowak, E. Workspace for disabled people.
Ergonomics, 1989, 32.9, 1 0 7 7 - 1 0 8 8 , 10 refs. The paper aims at determining the workspace for disabled young people. The investigation embraced a group of young people with m o t o r dysfunction of the lower extremities. Seventeen measurements were taken of 32 boys and 45 girls aged 1 5 - 1 8 . There are significant differences in functional dimensions of the arm between the healthy and the disabled populations. The differences clearly indicate that there is a need for different shaping of space in which people of limited m o t o r efficiency must function. A method based on Das and Grady's concept was used in determining workspace. This
method was modified by the author. The method allows determination of workspace by means of several simple anthropometric measurements. Workspace for young people investigated was determined for the sitting position in the transverse and sagittal planes. The results of the investigation constitute data for design and estimation of workplaces for disabled young people with m o t o r dysfunction of the lower extremities. The results can also be used to determine functional space in classrooms, school workshops, educational and rehabilitation centres.
21.3.28 (116452) Gronqvist, R., Roine, J., Jarvinen, E., and Korhonen, E. Art apparatus and a method for determining the slip resistance of shoes and floors by simulation of human foot motions. Ergonomics, 1989, 32.8, 9 7 9 - 9 9 5 , 28 refs. An apparatus to measure the coefficient of kinetic friction (/aK) between the shoe sole and the underfoot surface was constructed, and a method including criteria to evaluate the risk of slipping during walking was developed. The apparatus is a p r o t o t y p e stationary step simulator capable of simulating the movements of a human foot and the forces applied to the underfoot surface during an actual slip, and the drainage capability of the contact surface between the shoe sole and the flooring when different lubricants or contaminants are used. The apparatus consists of a movable artificial foot controlled by a computer with the aid of three hydraulic cylinders. The frictional force (Fu) , the normal force (FN) and theft-ratio (PK = Fu/FN) are measured with a two-wa~, force platform when the foot slides along its surface. Two separate gait patterns, heel-slide (#K 1) and soleslide (/~K2) gait pattern, are used for the evaluations. The method classifies studied shoe, lubricant and underfoot surface combinations into five slip resistance classes according to the measured/a K 1. The slip resistance assessments are specified with some complementary safety criteria - e g, the ratio #K 1/laK2" The reliability of the developed measurement method was assessed in an international comparison test. According to available results discussed in this paper, the method seems to be valid and the slip resistance measurements seem to be repeatable. 21.3.29 (116461) Raafat, H.M.N. Risk assessment and machinery safety. J OccupatAccidents, 1989, 11.1, 3 7 - 5 0 , 10 refs.
The rapid development in the field of machine design coupled with the increasing use of fluid power and programmable electronic systems in operating modern machinery has led to an increasing concern for the safety of all personnel involved in machine operation and maintenance. In many respects, modern machinery tends to pose unique problems and hazards which might differ in nature from those presented by conventional machinery. The introduction of the British Standard Code of Practice BS 5304:1988 for Safety of Machinery will benefit manufacturers from a more uniform application of safeguarding principles. Until the European Community legislation and supporting Standards are available, the Code will be the major document detailing how British machinery safety legislation can be complied with. Although the application of risk assessment to machinery safety was explored briefly in the new British Standard, it has very limited application and rigid requirements for safeguarding are still imposed, mainly as a result of 'experience' or past accident statistics. Designers feel 'justifiably' severely restricted in their innovation by a set of rigid rules presented by the new Standard as well as the EC Directive on Product Liability. This paper considers the role of probabilistic risk assessment as a modern approach to machinery safety through a case history and proposes a guide for the acceptability o f risk.
Environment 21.3.30 (117125) Hjortsherg, U., Rosen, I., Orbaek, P.,
Lundborg, G., and Balogh, I. Finger receptor dysfunction in dental technicians exposed to high-frequency vibration. Scand J Work, Environment & Health, 1989, 1 5 . 5 , 3 3 9 - 3 4 4 , 24 refs. The effects of high-frequency vibration (up to 40 kHz) on digital nerve function were studied in ten dental technicians and ten age-matched referents. Nerve condition velocities, including fractionated antidromic measurements over the carpal tunnel, showed no difference between the groups. In the group of dental technicians the difference between the response latency of the mechanical and electric stimuli in the median nerve distally on the fingers of the right hand was slightly higher than in the reference group, and therefore distal nerve or receptor dysfunction was suggested. Vibration warming and cooling thresholds were significantly increased and thus revealed damage to both myelinated and unmyelinated fibres in the fingers of subjects exposed to highfrequency vibration.