Holland E J, Laing R M, Lemmon T L, Niven B E
Clothing and Textiles Centre and Centre for Application of Statistics and Mathematics, University of Otago, PO Box 56, Dunedin, New Zealand.
Ergonomics. 2002 Aug 15;45(10):699-716. doi: 10.1080/00140130210159959.
The purpose of this investigation was to evaluate the ventilatory characteristics of vented and non-vented helmets for use in forestry harvesting operations. A ventilation index developed by Birnbaum and Crockford (1978) was used to determine the ventilation capacity of twelve helmets varying in design and presence, location, and dimension of vents. Helmets with top vents had higher ventilation indices than non-vented, side and side/top-vented helmets. Ten physically fit men participated in a maximal oxygen consumption test and four trials wearing a non-vented, round-side-vented, round-top-vented or rectangulartop-vented helmet. Trials simulated typical summer environmental conditions (28 degrees C, 80% rh) and physiological work loads (40% VO(2)max) experienced during forest harvesting in New Zealand. The temperature and humidity under the helmet was typically lowest when the helmet with the largest vented area (288 mm(2)) in the crown was worn, although physiological responses (temperatures at the tympanum, ear and scalp; humidity at the centre of the helmet) of the participants to wearing the helmets differed significantly during some rest periods only. Top-vented helmets (in this experiment measured 288 mm(2)) should be worn to minimize temperature and humidity of the head during forest harvesting operations.
本研究的目的是评估用于林业采伐作业的通风头盔和非通风头盔的通风特性。采用Birnbaum和Crockford（1978年）开发的通风指数来测定12种头盔的通风能力，这些头盔在通风口的设计、有无、位置及尺寸方面各不相同。顶部有通风口的头盔比无通风口、侧面有通风口以及侧面/顶部有通风口的头盔具有更高的通风指数。10名身体健康的男性参与了最大耗氧量测试，并进行了四项试验，分别佩戴无通风口、圆形侧面通风口、圆形顶部通风口或矩形顶部通风口的头盔。试验模拟了新西兰森林采伐期间典型的夏季环境条件（28摄氏度，相对湿度80%）和生理工作负荷（最大摄氧量的40%）。当佩戴顶部通风面积最大（288平方毫米）的头盔时，头盔下方的温度和湿度通常最低，不过仅在某些休息期间，参与者佩戴头盔后的生理反应（鼓膜、耳朵和头皮处的温度；头盔中心处的湿度）存在显著差异。在森林采伐作业期间，应佩戴顶部有通风口的头盔（本实验中测量的通风面积为288平方毫米），以尽量降低头部的温度和湿度。
