| 1. |
|
|
| 2. |
- Abeysekera, John, et al.
(författare)
-
Some design recommendations to improve comfort in helmets : a case study from China
- 1996
-
Ingår i: Journal of Human Ergology. - 0300-8134. ; 25:2, s. 145-154
-
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
|
|
| 3. |
- Kuklane, Kalev, et al.
(författare)
-
Methods for handwear, footwear and headgear evaluation
- 1997
-
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
-
Konferensbidrag (refereegranskat)
|
|
| 4. |
|
|
| 5. |
- Liu, Xiaoxiong, et al.
(författare)
-
Evaluation of Evaporative Heat Transfer Characteristics Of Helmets
- 1997
-
Ingår i: Applied human science : journal of physiological anthropology. - : Japan Society of Physiological Anthropology. - 1341-3473. ; 16:3, s. 107-113
-
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.
|
|
| 6. |
- Liu, Xiaoxiong, et al.
(författare)
-
Evaporative heat transfer characteristics of industrial safety helmets
- 1995
-
Ingår i: Applied Ergonomics. - 0003-6870 .- 1872-9126. ; 26:2, s. 135-140
-
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.
|
|
