| 1. |
- Abeysekera, John D.A., et al.
(författare)
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A Scandinavian perspective on human factors testing of personal protective devices
- 1997
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Ingår i: Performance of protective clothing. - West Conshohocken, Pa : ASTM International. - 0803124023 ; , s. 283-292
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Konferensbidrag (refereegranskat)abstract
- Testing for protection performance and human factors in personal protective devices (PPD) can be undertaken using a standardised methodology. The standardised methodology for performance testing is used for the certification of PPD. However, it is unfortunate that methods of testing for human factors and wearability of PPD are scarce, and even the methods that do exist are not always refined or standardised. In both hot and cold environments, thermal comfort is an important user need of PPD. To test the thermal characteristics of PPD, methods providing objective data are available, yet they are not always standardised. An exception exists for insulation testing of clothing, for which standardised methods have been developed. The fit of PPD is also a priority need among wearers. Clothing fit is often tested subjectively. The objective methods developed to test the fit of PPD and clothing again require refinement and standardisation. Wearability of PPD urgently requires the development and standardisation of both objective and subjective testing methods. This paper provides insights into some testing methods on human factors of PPD that have been particularly useful over the years.
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| 2. |
- Abeysekera, John, et al.
(författare)
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Some design recommendations to improve comfort in helmets : a case study from China
- 1996
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Ingår i: Journal of Human Ergology. - 0300-8134. ; 25:2, s. 145-154
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Tidskriftsartikel (refereegranskat)abstract
- Unless the basic user needs are satisfied in safety helmets, it is difficult to get workers to wear them habitually and for long periods. Hotness, weight and fitting problems are major wearability issues that require improvements. The enormous need for an optimally designed helmet in China prompted a case study on comfort aspects in helmets. The subjective impressions of the wearers of test helmets provided useful information for design changes to improve comfort. The heat transfer measurements through helmets indicated the need for ventilation openings to be provided on the shell of plastic helmets. Due to the advantage of low weight and good ventilation, it is recommended that cane helmets be further developed to improve protection, wearability and durability, and subsequently be produced in large scale
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| 3. |
- Kuklane, Kalev, et al.
(författare)
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Methods for handwear, footwear and headgear evaluation
- 1997
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Ingår i: Proceedings of a European seminar on thermal manikin testing at the National Institute for Working Life, Wednesday, February 12, 1997. - : Arbetslivsinstitutet. ; , s. 23-29
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Konferensbidrag (refereegranskat)
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| 4. |
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| 5. |
- Liu, Xiaoxiong, et al.
(författare)
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Evaluation of Evaporative Heat Transfer Characteristics Of Helmets
- 1997
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Ingår i: Applied human science : journal of physiological anthropology. - : Japan Society of Physiological Anthropology. - 1341-3473. ; 16:3, s. 107-113
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Tidskriftsartikel (refereegranskat)abstract
- The prime purpose of a safety helmet is to protect against occupational hazards. However, thermal comfort is one important ergonomics requirement for a helmet to be accepted by its wearer. To design and manufacture a thermally comfortable helmet, a method for testing and evaluating the thermal properties is essential. Research has long focused on the evaluation of dry heat transfer (conduction, convection and radiation). Evaporative heat transfer was not much addressed. In order to analyze the wet heat transfer (evaporation) component, a sweating thermal head manikin has been used. In this study the method has been further improved by constructing a new sweating head manikin. The surface of the head manikin is divided into five zones which can provide more detailed information about the environmental effects on the heat transfer from the head when a helmet is worn. Water supply (simulated sweating) is also improved by use of an electronic pumping system which provides a steady and adjustable flow rate of water to the head manikin. Experiments were conducted within a climatic chamber with this improved method under different test conditions: the ambient temperature and the head manikin surface temperature are set at the same level: 34 +/- 0.5 degrees C; two levels of head surface wettedness: 0.44 and 1.0; two levels of ambient humidity: 30% and 60%; and two levels of wind speed: 0.4 m/s and 1.0 m/s. Seven different helmets were used in the experiments. The results showed that the improved method revealed more detailed information about the evaporative heat transfer; it is easier to use and control; less error is involved with the measurement.
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| 6. |
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| 7. |
- Liu, Xiaoxiong
(författare)
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Evaluation of thermal comfort of head gear : a method to measure heat transfer characteristics
- 1997
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This study was carried out within the research project "Thermal properties of protective helmets - improvement, validation and standardization of a measurement method" which was a continuation of a research project being carried out since 1992 at the Division of Industrial Ergonomics, Department of Human Work Sciences, Luleå University of Technology, Sweden, with co-operation of the Department of Ergonomics, National Institute for Working, Life (NIWL), Solna, Sweden. A method was developed for measuring the evaporative heat transfer properties of helmets, based on the results of a thorough literature survey. This method has been further improved by building a new sweating head manikin and improving the water (simulated sweat) supply system. Seven different helmets were used in extensive laboratory experiments under various controlled environmental conditions to verify the improvements in the method, and to standardize the measurement procedures. This method was then adapted to measure dry heat transfer properties of helmets. Laboratory tests were conducted with the sweating manikin head under dry conditions (without simulating sweating on the manikin head). The same helmets used in evaporative thermal transfer tests were used in the dry heat loss measurements. Field investigations with human subjects in both hot and cold environments were also carried out to validate the laboratory tests with the method. The results from the laboratory tests showed that the improved method can reveal more detailed information about the evaporative heat transfer from head gear, it is easy to use and control. The field investigation indicated that the subjective results were consistent with the laboratory measurements results in terms of heat transfer. Efforts were made to incorporate the dry heat transfer measurement into the evaporative heat transfer measurement to form a standardized total thermal transfer testing method for head gear thermal evaluations. Further laboratory measurements are proposed to apply this total heat transfer measurement technique to practical tests.
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| 8. |
- Liu, Xiaoxiong, et al.
(författare)
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Evaporative heat transfer characteristics of industrial safety helmets
- 1995
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Ingår i: Applied Ergonomics. - 0003-6870 .- 1872-9126. ; 26:2, s. 135-140
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Tidskriftsartikel (refereegranskat)abstract
- Thermal discomfort is one of the major complaints from the wearers of industrial safety helmets. While studies have been reported on dry heat transfer (conduction, convection and radiation) in safety helmets, the investigation of wet heat dissipating (evaporation) properties has not been found in the literature. To evaluate experimentally the evaporative heat transfer characteristics of industrial safety helmets, a method was developed to simulate sweating of a human head on a thermal head manikin, and to use this manikin to assess the wet heat transfer of five industrial safety helmets. A thermal head manikin was covered with a form-fitting cotton stocking to simulate 'skin'. The skin was wetted with distilled water to simulate 'sweating'. A form-fitting perforated polyethylene film was used to cover the wetted stocking to control the skin wettedness at two levels, 0.64 and 1.0. Experiments were conducted in a climatic chamber, under the following conditions: the ambient temperature = head manikin surface temperature = 34 +/- 0.5-degrees-C; ambient relative humidity 30% and 60%. Also, the effects of wind and a simulated solar heat load were investigated. The five helmets showed statistically significant difference in evaporative heat transfer under the experimental conditions. Skin wettedness, ambient humidity, wind and solar heat showed significant effects on evaporative heat transfer. These effects were different for the different helmets.
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| 9. |
- Liu, Xiaoxiong, et al.
(författare)
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Subjective evaluation of three helmets in cold laboratory and warm field conditions
- 1999
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Ingår i: International Journal of Industrial Ergonomics. - 0169-8141 .- 1872-8219. ; 23:3, s. 223-230
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Tidskriftsartikel (refereegranskat)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 degrees C and 30% RH); forty-three steel-making workers participated in a held survey in the hot environment (31 degrees 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.
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