Pang Toh Yen, Subic Aleksandar, Takla Monir
School of Aerospace, Mechanical and Manufacturing Engineering, RMIT University, Bundoora, VIC 3083, Australia.
Appl Ergon. 2014 Mar;45(2):300-7. doi: 10.1016/j.apergo.2013.04.011. Epub 2013 May 9.
The main objective of this study is to establish an approach for measuring the dry and evaporative heat dissipation cricket helmets. A range of cricket helmets has been tested using a sweating manikin within a controlled climatic chamber. The thermal manikin experiments were conducted in two stages, namely the (i) dry test and (ii) wet test. The ambient air temperature for the dry tests was controlled to ~ 23 °C, and the mean skin temperatures averaged ~ 35 °C. The thermal insulation value measured for the manikin with helmet ensemble ranged from 1.0 to 1.2 clo. The results showed that among the five cricket helmets, the Masuri helmet offered slightly more thermal insulation while the Elite helmet offered the least. However, under the dry laboratory conditions and with minimal air movement (air velocity = 0.08 ± 0.01 ms(-1)), small differences exist between the thermal resistance values for the tested helmets. The wet tests were conducted in an isothermal condition, with an ambient and skin mean temperatures averaged ~ 35 °C, the evaporative resistance, Ret, varied between 36 and 60 m(2) Pa W(-1). These large variations in evaporative heat dissipation values are due to the presence of a thick layer of comfort lining in certain helmet designs. This finding suggests that the type and design of padding may influence the rate of evaporative heat dissipation from the head and face; hence the type of material and thickness of the padding is critical for the effectiveness of evaporative heat loss and comfort of the wearer. Issues for further investigations in field trials are discussed.
本研究的主要目的是建立一种测量板球头盔干热和蒸发热散失的方法。在可控气候室内，使用出汗人体模型对一系列板球头盔进行了测试。热人体模型实验分两个阶段进行，即（i）干测试和（ii）湿测试。干测试的环境空气温度控制在约23°C，平均皮肤温度约为35°C。佩戴头盔的人体模型测得的隔热值范围为1.0至1.2克罗。结果表明，在五款板球头盔中，马苏里头盔的隔热效果略好，而精英头盔的隔热效果最差。然而，在干燥的实验室条件下且空气流动极小（风速 = 0.08 ± 0.01米/秒）时，测试头盔的热阻值之间存在微小差异。湿测试在等温条件下进行，环境温度和皮肤平均温度约为35°C，蒸发阻力Ret在36至60平方米·帕/瓦之间变化。蒸发散热值的这些巨大差异是由于某些头盔设计中存在一层厚厚的舒适衬里。这一发现表明，衬垫的类型和设计可能会影响头部和面部的蒸发热散失速率；因此，衬垫的材料类型和厚度对于蒸发热损失的有效性和佩戴者的舒适度至关重要。文中还讨论了在现场试验中有待进一步研究的问题。
