Tanaka Masatoshi
Fukushima College, 1-1 Chigoike, Miyashiro, Fukushima City, Fukushima 960-0181, Japan.
Ind Health. 2007 Jan;45(1):85-90. doi: 10.2486/indhealth.45.85.
Threshold limit values (TLVs) are intended to protect workers from the severest effects of thermal stress and to establish the exposures to heat in working conditions. Earlier, acute heat strokes often occurred as a result of working in hot environments in Japan. However, acute heat strokes recently sometimes occurred in outdoor work environments such as industrial constructions and agriculture. Seasonal variations in weather are significant and the climatic conditions vary. The criteria are mainly set for working in mines, factories, and so on. WBGT is a useful evaluation index for hot environments; however, it is not commonly used for work practices. WBGT could be calculated and should be commonly used as a standard during summer. Japan mainly has a very hot and humid climate during summer. With regard to the thermal standard for offices, humidity also creates a problem in the indoor thermal conditions. Therefore, it is better to decide the TLVs of the thermal conditions according to seasons and activity levels. Inadequate thermal stress may cause discomfort and adversely affect the performance, safety, and harm to health. Further, thermal factors in the work environment must be measured and evaluated under light workload conditions like desk work for safety and work efficiency.
阈限值（TLVs）旨在保护工人免受热应激的最严重影响，并确定工作条件下的热暴露情况。早些时候，在日本，急性中暑经常因在炎热环境中工作而发生。然而，急性中暑最近有时发生在工业建筑和农业等户外工作环境中。天气的季节性变化很大，气候条件各不相同。这些标准主要是为在矿山、工厂等场所工作而设定的。湿球黑球温度（WBGT）是评估炎热环境的一个有用指标；然而，它在工作实践中并不常用。WBGT可以计算出来，并且在夏季应该作为一个标准普遍使用。日本夏季主要气候炎热潮湿。关于办公室的热标准，湿度在室内热环境中也会产生问题。因此，最好根据季节和活动水平来确定热条件的阈限值。热应激不足可能会导致不适，并对工作表现、安全和健康造成不利影响。此外，为了安全和工作效率，必须在诸如案头工作等轻工作量条件下测量和评估工作环境中的热因素。
