Heinonen K, Kulmala I, Säämänen A
VTT Manufacturing Technology, Safety Engineering, Tampere, Finland.
Am Ind Hyg Assoc J. 1996 Apr;57(4):356-64. doi: 10.1080/15428119691014891.
The performance of a modified local ventilation unit equipped with local supply and exhaust ventilation was evaluated during the manual handling of flour additive powder. The investigation tested five different configurations to study the effects of the exhaust opening location and local supply air on worker exposure. The measurements were done under controlled conditions in a test room. The breathing zone (BZ) dust concentration was measured by gravimetric sampling and real time monitoring. The different local ventilation configurations were also modeled numerically using computational fluid dynamics. Without local ventilation the average BZ dust concentration was 42 mg/m3. With local exhaust only the exposure was reduced below 1 mg/m3. The addition of local supply air further reduced the exposure to below 0.5 mg/m3. The lowest results were achieved by locating two exhaust openings on either side of the contaminant source combined with local supply air. With this configuration the average BZ exposure was only 0.08 mg/m3, a reduction of 99.8%. Numerical simulations also gave useful information about the airflow fields in stationary conditions. However, the worker's exposure was greatly affected by body movements, and this was not possible to simulate numerically. The results of this investigation can be useful when controlling dust exposure in manual powder handling operations.
在人工处理面粉添加剂粉末的过程中，对配备局部送风与排风的改良型局部通风装置的性能进行了评估。该调查测试了五种不同配置，以研究排风口位置和局部送风对工人接触粉尘情况的影响。测量是在测试室内的受控条件下进行的。通过重量采样和实时监测来测量呼吸带（BZ）粉尘浓度。还使用计算流体动力学对不同的局部通风配置进行了数值模拟。在没有局部通风的情况下，呼吸带平均粉尘浓度为42毫克/立方米。仅采用局部排风时，接触量降低至1毫克/立方米以下。增加局部送风后，接触量进一步降低至0.5毫克/立方米以下。通过在污染物源两侧设置两个排风口并结合局部送风，可获得最低的测量结果。采用这种配置时，呼吸带平均接触量仅为0.08毫克/立方米，降低了99.8%。数值模拟还给出了静止条件下气流场的有用信息。然而，工人的接触情况受身体动作的影响很大，而这无法通过数值模拟实现。该调查结果对于控制人工粉末处理操作中的粉尘接触情况可能会有所帮助。
