Hall G S, Rice C H, Lockey J E, Lemasters G K, Gartside P S
University of Cincinnati, Department of Environmental Health, OH 45267-0056, USA.
Ann Occup Hyg. 1997 Oct;41(5):555-60. doi: 10.1016/S0003-4878(97)00011-2.
As part of an ongoing, industry-wide study in the manufacture of refractory ceramic fibres (RCF), time weighted average (TWA) exposures have been collected at five facilities according to a standardised protocol. Work activities were grouped into dust zones (DZs). Persons to be sampled were randomly selected according to a protocol designed to assure that at least one sample was collected annually from each DZ; each work shift is also sampled at least annually. TWA exposures calculated over a sampling period of at least 360 min were included in the data set. DZs were combined into one of three groups (DZGs): fibre production; vacuum processes; other. The data were analysed to identify any differences by DZG between airborne fibre exposures, by the shift worked at each facility, and across all facilities. There were no statistically significant shift-related differences detected between airborne fibre exposures across the five RCF facilities when analysed as a group. Within four of the facilities, no shift-related differences were detected between airborne fibre exposures; however, at one facility, first and third shift exposures were statistically different. No documentation related to job activities was found to account for the observation. The data generally support the use of a single exposure estimate for each DZG in each of these facilities, regardless of shift worked. Researchers reconstructing exposure and not able to determine the shift worked by study subjects may find these results useful, but are cautioned that substantial differences in exposure across shifts may exist in other types of manufacturing.
作为一项正在进行的、全行业耐火陶瓷纤维（RCF）制造研究的一部分，已根据标准化方案在五个工厂收集了时间加权平均（TWA）暴露量。工作活动被分组到粉尘区域（DZ）。根据旨在确保每年从每个DZ至少收集一个样本的方案随机选择要采样的人员；每个工作班次每年也至少采样一次。数据集包括在至少360分钟的采样期内计算的TWA暴露量。DZ被合并为三组（DZG）之一：纤维生产；真空工艺；其他。对数据进行分析，以确定各DZG之间在空气传播纤维暴露方面、各工厂工作班次之间以及所有工厂之间是否存在差异。作为一个整体分析时，在五个RCF工厂的空气传播纤维暴露之间未检测到与班次相关的统计学显著差异。在其中四个工厂内，空气传播纤维暴露之间未检测到与班次相关的差异；然而，在一个工厂，第一班和第三班的暴露量在统计学上存在差异。未发现与工作活动相关的文件能够解释这一观察结果。这些数据总体上支持对这些工厂中每个DZG使用单一暴露估计值，而不考虑工作班次。重建暴露情况且无法确定研究对象工作班次的研究人员可能会发现这些结果有用，但需注意，在其他类型的制造业中，不同班次的暴露量可能存在很大差异。
