Muir I H, Bishop P A, Kozusko J
Department of Human Performance Studies, University of Alabama, Tuscaloosa 35487, USA.
Ergonomics. 2001 Sep 15;44(11):953-61. doi: 10.1080/00140130110068915.
Protective clothing (PC) results in a micro-environment between itself and the body. Workers are then exposed to a heat stress greater than the ambient environment alone, which is a reflection of micro-environment, metabolic rate and time. Adjustments to the ambient environment to account for the micro-environment have been formulated as a means to predict heat strain for safety and productivity purposes. Measurement of the actual micro-environment was made for a mean of 63.1 +/- 7.9 min using a remote sensor at the shoulder, hip and thigh levels on 15 subjects during a continuous work protocol (300 kcal/h) in impermeable PC at an ambient temperature of 30.1 degrees C wet bulb globe temperature (WBGT) (32 degrees C dry, 29 degrees C wet, 33 degrees C globe). Micro-environment temperature increased over the duration of the work period. There was no statistically significant difference (p>0.05) between the measurements made at the three different body sites for temperature or humidity. The mean micro-environmental WBGT at the end of work was 34.6 degrees C WBGT. Micro-environment WBGT increased rapidly in the first 20 min of work then slowed, rising only 0.5 degrees C WBGT from 40 to 60 min. These results suggest that at this particular high ambient temperature (30.1 degrees C WBGT) an adjustment factor of 5 degrees C WBGT would give a more accurate indication of thermal stress for up to 1 h of continuous moderate work within PC. For shorter work durations, an even smaller adjustment would be appropriate.
防护服会在其自身与身体之间形成一个微环境。这样一来，工人所面临的热应激就会大于仅处于周围环境时的热应激，这反映了微环境、代谢率和时间的情况。为了安全和生产效率的目的，已制定了针对微环境的周围环境调整措施，作为预测热应激的一种方法。在环境温度为30.1摄氏度湿球黑球温度（WBGT）（干球温度32摄氏度、湿球温度29摄氏度、黑球温度33摄氏度）的条件下，15名受试者穿着不透气的防护服，按照连续工作方案（300千卡/小时）工作时，使用肩部、臀部和大腿部位的远程传感器对实际微环境进行了平均63.1±7.9分钟的测量。在工作期间，微环境温度有所升高。在三个不同身体部位进行的温度或湿度测量之间，没有统计学上的显著差异（p>0.05）。工作结束时微环境的平均WBGT为34.6摄氏度。微环境的WBGT在工作的前20分钟迅速上升，然后放缓，从40分钟到60分钟仅上升了0.5摄氏度WBGT。这些结果表明，在这个特定的高环境温度（30.1摄氏度WBGT）下，5摄氏度WBGT的调整因子对于在防护服内持续进行长达1小时的中等强度工作时的热应激情况能给出更准确的指示。对于更短的工作时长，甚至更小的调整幅度会更合适。
