Standards of Permissible Exposure Limits at Job Site Article 4
As used herein, the time-weighted average shall be computed as follows:TWA= (C1T1 + C2T2+------+CnTn)/ (T1+ T2+---+Tn)Where:TWA is the time-weighted average for the computed working period of (T1+ T2+---+Tn).Ci is the concentration during any period of time Ti.Ti is the duration in hours of the exposure at the concentration Ci.
中文原文 勞工作業場所容許暴露標準第4條
本標準所稱時量平均濃度，其計算方式如下：第一次某有害物空氣中濃度ｘ工作時間＋第二次某有害物空氣中濃度ｘ工作時間＋..＋第ｎ次某有害物空氣中濃度ｘ工作時間───────────────────＝時量平均濃度總工作時間