Brosseau L M, Ellenbecker M J, Evans J S
Harvard School of Public Health, Department of Environmental Science and Physiology, Boston, MA 02115.
Am Ind Hyg Assoc J. 1990 Aug;51(8):420-6. doi: 10.1080/15298669091369880.
Air purifying dust/mist respirators are presently tested using a silica aerosol under conditions of steady flow. In experiments, the predictive validity of such tests was evaluated by testing respirators using silica and asbestos aerosols under conditions of both steady and cyclic flow. Silica penetration at steady flow was reasonably predictive of silica penetration under cyclic flow. However, asbestos penetration under cyclic flow was not predicted well by penetration of either silica or asbestos at steady flow. Furthermore, the potential for exhalation valve failure under cyclic flow was identified. Current NIOSH protocols for evaluating respirator performance should be reconsidered in light of these findings.
空气净化防尘/防雾呼吸器目前是在稳定气流条件下使用二氧化硅气溶胶进行测试的。在实验中，通过在稳定气流和循环气流条件下使用二氧化硅和石棉气溶胶对呼吸器进行测试，评估了此类测试的预测有效性。稳定气流下的二氧化硅穿透率能合理预测循环气流下的二氧化硅穿透率。然而，循环气流下的石棉穿透率并不能通过稳定气流下二氧化硅或石棉的穿透率很好地预测。此外，还确定了循环气流下呼气阀故障的可能性。鉴于这些发现，应重新考虑美国国家职业安全与健康研究所（NIOSH）目前评估呼吸器性能的方案。
