John Abeysekera

Quality function deployment (QFD) — A means for developing usable products

In order to develop usable products, human needs and requirements have to be taken into consideration. By employing the QFD (Quality Function Deployment) method the human needs are systematically matched with the product characteristics, which can help to improve the product quality. In this paper the use of QFD in the area of ergonomics is discussed and a case study is presented. The QFD method was used in the case study to translate the needs of safety shoe users in the cold climate into product characteristics. The QFD analysis of the safety shoes revealed that the characteristics of the steel toecap were receiving the highest overall weighting, which means that improving the design of the steel toecap would lead to higher customer satisfaction.

A systems perspective of slip and fall accidents on icy and snowy surfaces

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.

Understanding small graphical symbols: a cross-cultural study

Graphical symbols such as icons or pictograms as interfaces in modern technological devices have become quite common. Although generally designed in western countries, their use can be found worldwide from audio-visual appliances to computers and computer-related devices. A basic ergonomic principle is to involve the potential users in the design and evaluation stages especially when the user groups are quite diverse. This study was part of an international project on evaluating telecommunication symbols. One of the major objectives was to test different graphical symbols (of the videophone), designed, and tested in Western Europe using subject groups from Asia, Europe, and the United States. This paper would discuss the major portions of the tests involving US and Swedish subjects. Performance indices used were hits, certainties, confusions, and semantic differential ratings. They were useful in analysing how the symbols were recognised, confused, and perceived by different subject groups. They also helped detect differences between groups which otherwise seemed to have similar test results. The results showed differences in patterns of ratings, which may be culturally linked and could help determine aspects of symbol design and usage that may be more helpful in designing instructions, learning aids, etc. Awareness of such subject bias and their implications are important on how one interprets the test results.Relevance to industryThe study outcome can be very helpful for industries in designing and evaluating candidate graphical symbols across various types of consumer products for worldwide use.

Ergonomics evaluation of modified industrial helmets for use in tropical environments

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 ...

Slip resistant properties of footwear on ice

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.

Body size variability between people in developed and developing countries and its impact on the use of imported goods

The Industrially Developing Countries (IDC) today, to a great extent, depend on Industrialized Countries (IC) for the supply of most industrial goods. 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 sizes of people in producer and user countries. A comparative study of variations in body sizes is made from data available in literature and from anthropometric surveys. The results reveal differences in almost every part of the human body. The need for reliable anthropometric data in respect of IDC is stressed. Urgent measures are required to introduce changes in equipment, particularly for the benefit of users in IDC.

Subjective evaluation of three helmets in cold laboratory and warm field conditions

Abstract Helmets are widely used in industries as a primary protection means for workers. Helmets can provide efficient protection against occupational hazards to the head, they also cause thermal discomfort to the wearers at work. To develop a reliable heat transfer testing method for helmets any objective testing method must be validated with subjective testing of the same helmets. Subjective evaluation of helmet heat transfer properties was conducted in both cold and hot conditions using three commonly used and commercially available helmets. Twenty-five subjects participated in a laboratory investigation in a simulated cold environment (+3°C and 30% RH); forty-three steel-making workers participated in a field survey in the hot environment (31°C and 32% RH). Subjects were either asked to conduct certain tasks (in the laboratory investigation) or performed their regular production duties (in the filed survey) while wearing a helmet; they were then asked to answer questions in a questionnaire at the end of the surveys. The results of the subjective assessment which were compared with the objective measurements taken on a sweating manikin head using the same helmets, were found consistent. Relevance to industry Thermal discomfort in protective helmets prevents the acceptance and function of head protection devices in industries. Evaluation of heat transfer properties of helmets can provide design basis and suggestions to helmet manufacturers to produce thermally comfortable and well acceptable head protections.

The assessment of the integration of slip resistance, thermal insulation and wearability of footwear on icy surfaces

Prevention of slip hazard in frozen environments is not paid much attention. Current winter and safety footwear does not provide sufficient slip resistance and appropriate wearability for use on icy surfaces. The objectives of this study were to assess the integration of slip resistance, thermal insulation, and wearability of footwear used on icy surfaces, and the anti-slip effect of materials spread on ice using outdoor walking trials. Twenty-five subjects wore four types of footwear walking on five different icy surfaces. A five-point rating scale was used recording wearers perceptions of slipperiness, thermal comfort and wearability. The results showed that pure ice was perceived as very slippery. Spreading sand (180 g/m2) greatly decreased the slipperiness. Slip resistance, thermal insulation and wearability of footwear tested were not properly integrated, and were ranked differently. The tested winter and safety footwear did not provide sufficient slip resistance and good wearability. In addition to thermal insulation, prevention of slip and fall hazard by improving anti-slip property and wearability must also be priorities for development of footwear for use in cold climate.

The identification of factors in the systematic evaluation of slip prevention on icy surfaces

Abstract Slips and falls on icy roads often result in fractures or sprains and is a major problem in Nordic countries. Walking trials by 25 subjects wearing four types of winter shoes on five different icy walking surfaces provided subjective and objective measures of tendency to slip and number of slips, respectively. Since friction is a major determinant of a slip, the influence of material spread on icy surfaces, the surface temperatures and the shoe soling characteristics versus the Coefficient of Friction (COF) of the shoes were measured. Sand and gravel on icy roads had positive effects on improving COF. The study revealed that the aetiology of slips and falls is multi-faceted and attempts to solve the problem must adopt a systems approach. Perception of risk, aging, training, experience and postural balance are other factors to be considered in preventing slips and falls. Future research should concentrate on the degree of impact of each factor to the aetiology of slips and falls, which can help to decide priority action in preventing slips and falls. Relevance to industry The personal protective devices used by outdoor workers during winter season have to provide two types of protection, namely, protection from an occupational hazard and protection from the cold climate. Safety shoes used on snow or ice covered surfaces add a third type of protection, namely, an anti-slip quality of the shoe. The 3rd protection can be achieved from among other things, by improving the friction of the shoe soles.

Ergonomics assessment of selected dust respirators: Their use in the tropics.

The suitability and effectiveness of four different types of British made respirators were studied with respect to comfort, convenience and fit on wearers in Sri Lanka (a developing country). Objective and subjective assessments were made to evaluate the degree of discomfort and interferences to the use of senses. The study revealed that factors such as breathing resistance, work-rate and activity period affected the physiological responses. The weight of the respirator and the skin temperature had no direct relationship with the cardiovascular stress. Positive-pressure respirators that gave lower face temperatures than negative-pressure masks gave this type of respirator an additional advantage in hot environments. Respirators that restricted jaw movement affected the speech intelligibility of the wearer. Orinasal masks restricted vision more than the other types. The problem of fit was found negligible though head and face dimensions significantly differed between the British and the Sri Lankans. Subjective assessment correlated well with objective tests.