Discomfort in the use of personal protective devices (PPD) has been one of the chief causes of their non-use. A field trial using industrial helmets was carried out to ascertain whether by training and repeated wearing subjects could experience a significant adaptation to discomfort. Ten subjects took part in the trial in a tropical environment by wearing helmets repeatedly (6 h a day) for one month. Subjective evaluations of discomfort were made at the end of the 1st, 3rd, 5th, 14th and 30th day. It was revealed that complaints of discomfort, viz. hotness, heaviness, bad fit, etc., decreased markedly throughout the 30 day period. Though positive responses of adaptation to discomfort seem to reach an optimum towards 30 days, it is difficult to draw any conclusions on the optimum period of adaptation for each discomfort factor. In relation to inherent discomforts that are extremely difficult to overcome without compromising the protection efficiency of a PPD, the principle of adaptation seems to be a very important facet which has to be developed for an effective PPD programme.

Hotness, weight, fitting problems etc., have been found to be the chief causes of the unpopularity of industrial safety helmets in tropical environments in developing countries (DC). Some selected safety helmets manufactured in industrialized countries (IC) were modified to provide extra head ventilation and to reduce weight, in order to make them more acceptable to users in hot environments. The modified helmets were subjected to ergonomics evaluation both objectively and subjectively in the laboratory (in simulated tropical conditions) as well as in the field situation. There was evidence that white helmets had some advantages in comfort, viz. reduction of hotness, compared to the other colours, e.g. red, green etc., when worn in the presence of radiant heat in the laboratory. Ventilation holes provided at the top of the shell seemed to reduce the greenhouse effect within the helmet shell which therefore felt less uncomfortable than a fully covered helmet. Even with a small reduction of weight, such as 45 g in helmets weighing about 350g, the difference in weight was perceived by the wearers. In adapting helmets made in IC for use in tropical climates, head ventilation and low weight perception are important aspects in comfort which need to be considered. In addition to low cost, a harness material suitable for sweat absorption is required. Adjustability and sizing to fit 90% of the user population also needs to be considered in the design and manufacture of safety helmets for people in DC.

Pictorial visualization is expected to facilitate communication between industrial professionals when planning working environments and production systems. This hypothesis was investigated by studying how 24 participants including managers, supervisors, machine operators, and occupational health and safety officials, judged three types of computer animated visualization varying in dimensional view (scale and scope of a production line): shop floor view/survey of shop floor; production unit view/semi-survey of production unit; and workplace view/close-up of workplace, in relation to a set of planning issues. The participants participated in a controlled 2-day planning workshop, redesigning a fictitious manufacturing process by means of computer graphics, and then responded to a questionnaire. It can be concluded that shop floor view as well as production unit view are significant for survey planning issues, while all 3-dimensional views are significant for close-up planning issues. Analogously, all dimensional views are significant for technocentric planning issues, whereas only the workplace view is valuable for anthropocentric planning issues.

It is assumed that pictorial visualization can be used to facilitate communication between industrial professionals when planning working environments and production. This article analyses how managers, supervisors, machine operators, and occupational health and safety officials, accustomed to using both paper drawings and computer animation of both shop floor and workplace view, evaluate these four types of visualization in relation to a set of planning issues. Twenty-four subjects participated in a controlled two-day planning workshop. They designed a new production layout by means of computer graphics, and responded to a questionnaire. From the analysis it may be concluded that the four types of visualization are unique enough to be evaluated differently with regard to some of the planning issues. Hence, great care should be devoted to analysing what features a visualization of a production layout or a working environment aims at illustrating. Furthermore, it can be concluded that each of the four types of visualization seems to be significant for planning activities in ways that can be anticipated. Shop floor view and workplace view is valuable for planning issues related to survey of a plant and specific machines, respectively. Computer animation is in general preferable to a paper drawing concerning dynamic planning issues. Computer animation of workplace viewis valuable for planning issues related to working environment considerations. All of the four types of visualization are less significant for illustrating or describing physical factors of the working environmen

A possible basis for the risk assessment for hand-transmitted vibration may be to determine the amount of energy absorbed in the human hand and arm. In the present study, the mechanical energy absorption in the hand-arm system was measured within the frequency range of 4 to 1000 Hz. The study was carried out on ten healthy subjects during exposure to sinusoidal vibration. The influence of various experimental conditions, such as vibration direction (Xh, Yh, Zh), grip force (25-75 N), vibration level (8-45 mm/srms), and hand-arm posture were studied. The outcome shows that the energy absorption in the human hand and arm depended mainly on the frequency and direction of the vibration stimulus. Higher vibration levels, as well as firmer handgrips, resulted in higher absorption of energy. Varying hand-arm postures had only a small influence on the amount of absorbed energy, while the constitution of the hand and arm affected the energy absorption to a larger extent.

Current research on slips and falls has mainly focused on floors and/or contaminated floors. Although icy and snowy surfaces near melting temperature are more slippery, more important still, slip and falls on icy and snowy surfaces involve not only outdoor workers, but also pedestrians and the general public; and occur in cold regions and in the winter season in many parts of the world. However, in comparison with the size of the problem, research work done so far in this area has been limited. The objective of this paper is to present a systems perspective of slip and fall accidents, with special focus on its occurrence on icy and snowy surfaces. In order to explore the aetiology of slip and fall accidents further, and to provide the basis for prevention, the authors put forward a systems model towards the slips and falls on icy and snowy surfaces based on a review of literature and current knowledge. Various contributing factors are systematically discussed to highlight the multi-factorial nature of the problem, providing the possibility of a multi-faceted approach to reach systematic prevention. Unresolved issues related to slips and falls on ice and snow are also identified, which necessitate further research.

Current research on slipperiness of footwear has mainly focused on floors and lubricated floors. Slips and falls on icy and snowy surfaces involve not only outdoor workers, but also pedestrians and the general public; and occur in cold regions and in winter season in many parts of the world. However, in comparison with the size of the problem, research on slips and falls on icy and snowy surfaces has been scarce. The objective of this paper is to explore the slip resistant properties of footwear (soling materials, roughness and hardness) on ice. The coefficients of kinetic friction of four different soling materials (synthetic rubber, nitrile rubber, natural rubber and polyurethane) were measured on ice (-12°C). The outsole roughness and hardness were also measured. Results showed that the polyurethane soling did not perform better than synthetic rubber, nitrile rubber and natural rubber on pure hard ice (-12°C). Soling roughness was positively correlated with the coefficient of kinetic friction. The most slip resistant soling material (polyurethane) on floors and lubricated floors may not provide sufficient slip resistance on ice.

A number of human-centred methodologies--subjective, objective, and combined--are used for slipperiness measurement. They comprise a variety of approaches from biomechanically-oriented experiments to psychophysical tests and subjective evaluations. The objective of this paper is to review some of the research done in the field, including such topics as awareness and perception of slipperiness, postural and balance control, rating scales for balance, adaptation to slippery conditions, measurement of unexpected movements, kinematics of slipping, and protective movements during falling. The role of human factors in slips and falls will be discussed. Strengths and weaknesses of human-centred approaches in relation to mechanical slip test methodologies are considered. Current friction-based criteria and thresholds for walking without slipping are reviewed for a number of work tasks. These include activities such as walking on a level or an inclined surface, running, stopping and jumping, as well as stair ascent and descent, manual exertion (pushing and pulling, load carrying, lifting) and particular concerns of the elderly and mobility disabled persons. Some future directions for slipperiness measurement and research in the field of slips and falls are outlined. Human-centred approaches for slipperiness measurement do have many applications. First, they are utilized to develop research hypotheses and models to predict workplace risks caused by slipping. Second, they are important alternatives to apparatus-based friction measurements and are used to validate such methodologies. Third, they are used as practical tools for evaluating and monitoring slip resistance properties of footwear, anti-skid devices and floor surfaces.

In the process of introducing ergonomics to Iran and the objective of the Center for Ergonomics of Developing Countries (CEDC), the management of PTW (Prevention, Treatment and Welfare) of Iran Khodro Car Company in Iran (IKCo) has decided to apply ergonomics to improve IKCo's workstations. This was a cooperative project between PTW and the CEDC. The first phase of the project was planned to last for 18 months, during which 32 engineers, occupational health specialists and safety engineers from IKCo have been trained in ergonomics theories and practice at various workshops. The emphasis of the project was on employees' participation and on taking advantage of local skills and resources. A special organization was designed for this project. Proposed ergonomics activities were divided into three categories: 1) ergonomics training, ergonomics application and evaluation, 2) research and activities, and 3) network building. Thanks to phase 1 of the ergonomics intervention project at IKCo, the management is now in a much better position to deal with and make best use of human resources.

Work postures and movements of the upper limb were analysed for 12 'mouse' operators and 12 'non-mouse' computer operators employed in word-processing work. Measurements were carried out during correction of a given text. 'Mouse' operators spent 64% of the working time with the operative wrist deviating more than 15 degrees towards the ulnar side, while 'non-mouse' operators spent 96% of the time with the corresponding wrist in neutral position towards radial deviation. The rotation in the shoulder was at all times in neutral position towards inward rotation for 'non-mouse' operators, while 'mouse' operators worked 81% of the time with the shoulder rotated outward more than 30 degrees. 'Mouse' operators corrected a longer text during the given time. Our observations showed long periods of strenuous working postures for 'mouse' operators compared to 'non-mouse' operators. We believe that further investigations need to be carried out on the effects of word-processing techniques and to develop ergonomic work station designs for the 'mouse' and other non-keyboard input devices.

The study had two primary aims. The first aim was to combine a human resources costing and accounting approach (HRCA) with a quantitative statistical approach in order to get an integrated model. The second aim was to apply this integrated model in a quasi-experimental study in order to investigate whether preventive intervention affected sickness absence costs at the company level. The intervention studied contained occupational organizational measures, competence development, physical and psychosocial working environmental measures and individual and rehabilitation measures on both an individual and a group basis. The study is a quasi-experimental design with a non-randomized control group. Both groups involved cleaning jobs at predominantly female workplaces. The study plan involved carrying out before and after studies on both groups. The study included only those who were at the same workplace during the whole of the study period. In the HRCA model used here, the cost of sickness absence is the net difference between the costs, in the form of the value of the loss of production and the administrative cost, and the benefits in the form of lower labour costs. According to the HRCA model, the intervention used counteracted a rise in sickness absence costs at the company level, giving an average net effect of 266.5 Euros per person (full-time working) during an 8-month period. Using an analogue statistical analysis on the whole of the material, the contribution of the intervention counteracted a rise in sickness absence costs at the company level giving an average net effect of 283.2 Euros. Using a statistical method it was possible to study the regression coefficients in sub-groups and calculate the p-values for these coefficients; in the younger group the intervention gave a calculated net contribution of 605.6 Euros with a p-value of 0.073, while the intervention net contribution in the older group had a very high p-value. Using the statistical model it was also possible to study contributions of other variables and interactions. This study established that the HRCA model and the integrated model produced approximately the same monetary outcomes. The integrated model, however, allowed a deeper understanding of the various possible relationships and quantified the results with confidence intervals.

The aim was to investigate whether a preventive intervention carried out in a predominantly female workplace, that of hospital cleaners (consisting of a group of 97 women), had any effect on patterns of absenteeism. As a background, a model for analysing complex patterns of absenteeism, including sickness absences, was also developed. A further aim was to study the interactions between different forms of absenteeism. Comparison was made with a reference group consisting of employees in the same job category who only received the customary personnel support. For individuals in the intervention group who were <42 years of age, total absence due to sickness decreased. In a multiple regression analysis, the contribution from the intervention to the decrease was significant at the 5% level. This change was particularly obvious in those who had a previous history of high absence due to sickness. No clear relationship was shown between short-term absenteeism and the interventions applied. For those who were > 42 years, short-term absence decreased for those who had been in the same jobs for a long time. The combination of increased age and experience showed a tendency to enhance this decline in short-term absenteeism due to sickness. For those > 42 years, and who at the same time have a previous history of high absenteeism, long-term absenteeism due to sickness seemed to be increasing. Increased experience tended to reduce this increase in long-term sickness absence. This combination of different effects possibly indicated the presence of a process of selection which determined who remained in the job as opposed to those who did not. An important conclusion is that different forms of absenteeism need to be looked at in parallel, and at the same time multivariate statistical analysis needs to be carried out to determine the different interactions between the factors.

Carrying heavy and moderate military loads in backpacks or as body armour compresses the chest, causing a change in lung function that is typical of a restrictive ventilatory impairment. It is not known if a lighter backpack load of only 6 kg, such as is typical of loads carried by students, will have a similar effect on lung function. There have been no studies examining whether backpacks of different strapping styles have an effect on lung function. Several designs of student backpack have recently been introduced to the market. One of the most popular is a single-strap backpack. This study examined Forced Vital Capacity (FVC), Forced Expiratory Volume in one second (FEV1), FEV1.FVC( - 1)% and Peak Expiratory Flow (PEF) in 13 participants (4 males, 9 females) wearing each of two 6 kg backpacks, one with two shoulder straps (a Double Strap Backpack (DSB)) and the other with a single strap (a Single Strap Backpack (SSB)) worn across the shoulder and chest. In comparison with the control of no pack (N), SSB significantly reduced FVC (by 3.94%, p = 0.006) but there were no significant differences in FEV1, FEV1. FVC( - 1)% and PEF. The DSB also significantly reduced FVC (by 1.97%, p = 0.034) but no significant differences were found in FEV1, FEV1. FVC( - 1)% and PEF measures. In comparison with DSB, the SSB was associated with a significantly lower FVC (by 2.05%, p = 0.049) and FEV1 (by 1.88%, p = 0.029) but there were no significant changes in FEV1. FVC( - 1)% and PEF. It is concluded that a backpack load of 6 kg could produce a mild restrictive type of ventilatory impairment in lung function. This effect was greater for a single cross-chest strap than for a more conventional double strap harness.

Ergonomics is at an early stage of development in China; however it is expanding and has grown steadily during the last few years. This paper gives a brief account of some current ergonomics activities in China. A historical perspective of its development is also described, and the progress and problems in ergonomic research and education are discussed. There can be no doubt that in the near future the importance of ergonomics will increase substantially in China, with its population of over one billion and its position as the world's largest developing nation striving to accomplish an unprecedented modernization programme.

A device for three-dimensional registration of human movement was tested. For this, a special garment with 43 attached light-emitting diodes was developed. The garment was specially designed for biomechanical purposes and made of a highly elastic material in the form of an overall. A recording system working with infra-red light was also tested considering both technical aspects and software. Test recordings of predetermined body movements within a defined work area of over 10m2 showed that the device satisfies general practical requirements. The garment worked very well for different movements and for bodies of different shapes and sizes. Technically the system was tested with respect to noise and linearity, operating function, range and manageability. It worked well with some limitations such as reflections. The tested software functions, such as recording speed, processing time, interpolation and user compatibility, proved to fulfil their main needs.

The purpose of this article is to develop knowledge and learning on the best way to automate organizational activities in deep mines that could lead to the creation of harmony between the human, technical and the social system, towards increased productivity. The findings showed that though the introduction of high-level technological tools in the work environment disrupted the social relations developed over time amongst the employees in most situations, the technological tools themselves became substitute social collaborative partners to the employees. It is concluded that, in developing a digitised mining production system, knowledge of the social collaboration between the humans (miners) and the technology they use for their work must be developed. By implication, knowledge of the human’s subject-oriented and object-oriented activities should be considered as an important integral resource for developing a better technological, organisational and human interactive subsystem when designing the intelligent automation and digitisation systems for deep mines.

Environmental conditions such as lighting and dimensions of the workplaces and factors related to Visual Display Units have been measured during day and night shifts for 28 operators at a telephone information centre. The results of the survey show that operators have preferred, in general, much lower luminance and workplace illuminance than previously reported in the literature. The study also revealed large interindividual differences in screen and workplace lighting adjustment.

Since its formal inception more than half a century ago, ergonomics has time and again demonstrated that it has a niche among the held of scientific disciplines aspiring to make the world a better place. How far has it really gone? Can we now lay claim that it is indeed well-known and accepted? Are the benefits it purports to deliver realized in all parts of the world? About two-thirds of human beings live in the Third World. This is where poverty and inequality are relatively more common. This is where much work is still degrading and far from being humane. This is also where ergonomics has yet to make its presence felt in practice. This paper attempts to show that ergonomics can and will become a globally applied science. However, it has to make its contribution to the Third World prevalent and long-lasting. The paper focuses on the current state of ergonomics in the Third World, the so-called Industrially Developing Countries (IDCs).

Technological development has contributed to economic growth and social progress as well as a reduction of many sources of occupational accidents, injuries and stresses. However, advanced technology has also brought new sources of work stress and injuries. Industrially developing countries (IDC) have tended to try to achieve economic growth and development by importing technology designed for IDC. However, because of several complex technical, cultural and socio-economic factors, this policy has not been always successful. Inappropriate technology transfer has led to many work environment and productivity problems. Consideration of ergonomics in the choice and utilization of the transferred technology can help to create a good fit between technology, technology users and the operating environment. Application of ergonomics is, however, not widely spread in most IDC. Ergonomics input will create the appropriate working environment in which people are safe and motivated to participate and can better utilize company resources for increasing system productivity, reliability and availability.

Examined relationships between operators' accommodation changes after 6 hrs of work at a display unit and work-station lighting and screen characteristics. The measurements were carried out in 2 field studies. Operator's visual accommodation before and after work, workplace lighting, and luminance contrasts and screen qualities for 29 display screen operators (mean age 27 yrs) were measured during day and night shifts. Field laser optometry was used for determining the state of visual accommodation. Photometric and radiometric characteristics of the display screens were measured using a spectrometer-photometer. Findings reveal a low significant relationship between lighting conditions on the one side and incidence of accommodation changes on the other. More Ss showed overaccommodation when working at stations with higher luminance contrast. The influence of screen characteristics, such as screen illuminance, luminance, and irradiance, upon visual accommodation were evident during the night shift. (French, German & Japanese abstracts) (21 ref

Established nutritional science methods and a new concept for meal–classification were applied to shiftworker (rotating 3-shift) data. The frequency of meals and snacks of different nutritional quality as a function of work schedule was evaluated, as well as the content of selected nutrients (energy, fat, sucrose, dietary fibres, ascorbic acid) in these meals and snacks. The results do not indicate that rotating 3-shift work affects the nutritional quality of the diet or the frequency of different types of meals and snacks. A qualitative classification of meals and snacks might be a cost–effective strategy for data–evaluation in field studies of shift workers' eating habits when quantitative estimations of the dietary intake are to be complicated

A foot plethysmograph is described and evaluated. It is intended for recording changes in foot volume when the instrument has to be removed from the foot between measurements to make physical activity possible. The mean sensitivity was ±0·5 ml and the mean experimental error 1·6 ml or 0·16% of the mean foot volume (n = 37). The accuracy of the method is thus considerably higher than that of previously reported methods for corresponding applications. In addition, it is inexpensive and can easily be used outside the laboratory.