以熱生理危害評估經驗模式探討現行高溫作業勞工作息時間標準之適用性

Application of Physiological-based Thermal-Hazard Empirical Assessment Models to Evaluate the Feasibility of Current Thermal-Hazard Prevention Standards

本研究嘗試以現場量測資料，應用熱生理危害評估經驗模式，探討我國高溫作息標準規定與美國政府工業衛生師協會（ACGIH）之建議標準，在兩種不同性質工作場所之適用性。研究對象包括二個染整廠之三個工作區及二個鑄造廠之二個工作區，計合勞工79人。結果發現利用熱危害經驗評估模式所推估之每小時容許工作時間，無論對鑄造廠或染整廠勞工，均與我國現行高溫預防標準規定不一致，唯若與ACGIH之建議標準相互比較，可發現於鑄造廠環境下二者間並無差異，但於染整廠環境則並不一致。另本研究亦嘗試探討ACGIH及ISO-8996中利用查表法以推估代謝率之合理性。結果發現各類查表法所推估之代謝率，相較於採用心跳率推估之代謝率值會呈現高估現象，因此在推估容許工作時間時，將造成低估之情形。有鑑於心跳即時量測技術已實際可行，因此本研究建議未來應可考慮直接以心跳率代替查表法來估算勞工之代謝率。

The feasibility of current standards, including both regulated in Taiwan and recommended by the American Conference for Governmental Industrial Hygienists (ACGIH), are evaluated in this study by applying physiological-based thermal-hazard empirical assessment models (PTEAMs) to field measurement data obtained both from two kinds of workplaces. The field study was conducted at 3 workplaces located at 2 textile dyeing plants and 2 workplaces located at 2 steel casting plants , and a total of 79 workers were selected from above workplaces. Results show that hourly allowable exposure times PTEAMs are inconsistent with those obtained from current Taiwan regulation for both selected environments. However, if compared with allowable exposure times recommended by ACGIH, the consistency can be found for data from steel casting workers, but not for textile dyeing workers. In addition, the feasibility of using table-reference methods to estimate metabolic rates recommended by ACGIH and ISO-8996 are also evaluated in this study. The result shows that metabolic rate obtained by usins both table-reference methods are found to be overestimated as compared to those obtained from heat rates, and thus might lead to the situation of over-protection of workers. Since modern techniques for heart rate real-time monitoring has become possible, it is concluded that the techniques should be adopted to replace table-reference methods for metabolic rate estimations in the future.