The effect of local exhaust ventilation controls on dust exposures during concrete cutting and grinding activities
The effect of local exhaust ventilation controls on dust exposures during concrete cutting and grinding activities
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DOI：
10.1080/15428110208984734
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发表时间：
2002-07-01
期刊：
影响因子：
--
通讯作者：
Seixas, NS
中科院分区：
文献类型：
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作者：
Croteau, GA;Guffey, SE;Seixas, NS
本研究评估了商用局部排气通风 (LEV) 系统在混凝土切割和打磨活动期间控制可吸入粉尘和结晶二氧化硅暴露的有效性。工作活动由工会资助的学徒进行，包括折点打磨、表面打磨、摊铺机块和砖块切割（砖石锯）以及混凝土块切割（手持锯）。在受控现场条件下实施的随机区组设计中，对每种工具测试了三种通气率（0、30 和 75 cfm）。每种通气处理以随机顺序重复 3 次，每个研究对象总共进行 9 次 15 分钟的工作。除手持锯外，LEV 的使用可显着 (p < 0.05) 减少可吸入粉尘暴露，75 cfm 处理的平均暴露水平低于 30 cfm 处理的平均暴露水平；然而，这两种处理之间的差异仅在摊铺机块切割方面显着（p < 0.01）。尽管暴露量显着减少（低通气率时减少 70-90%，高通气率时减少 80-95%），但个人可呼吸石英暴露量仍然非常高：低通气率时为 1.4-2.8 x PEL（允许暴露限值），高通气率时为 0.9-1.7 X PEL。由于大多数工作任务的间歇性，在实际现场条件下发现的暴露水平可能会较低。尽管控制不完全，LEV还是有优点的，因为它可以降低工人患病的风险，允许工人使用较低水平的呼吸防护装置，在短期工作期间保护工人，减少与附近工人的接触，并减少与清理相关的粉尘暴露。
This study assessed the effectiveness of commercially available local exhaust ventilation (LEV) systems for controlling respirable dust and crystalline silica exposures during concrete cutting and grinding activities, Work activities were performed by union-sponsored apprentices and included tuck-point grinding, surface grinding, paver block and brick cutting (masonry saw), and concrete block cutting (hand-held saw). In a randomized block design, implemented under controlled field conditions, three ventilation rates (0, 30, and 75 cfm) were tested for each tool, Each ventilation treatment was replicated three times in random order for a total of nine 15-min work sessions per study subject. With the exception of the hand-held saw, the use of LEV resulted in a significant (p < 0.05) reduction in respirable dust exposure, Mean exposure levels for the 75 cfm treatments were less than that of the 30 cfm treatments; however, differences between these two treatments were only significant for paver block cutting (p < 0.01). Although exposure reduction was significant (70-90% at the low ventilation rate and 80-95% reduction at the high ventilation rate), personal respirable quartz exposures remained very high: 1,4-2.8 x PEL (permissible exposure limit) at the low ventilation rate and 0,9-1.7 X PEL at the high ventilation rate. Exposure levels found under actual field conditions would likely be lower due to the intermittent nature of most job tasks. Despite incomplete control, LEV has merit, as it would reduce the risk of workers developing disease, allow workers to use a lower level of respiratory protection, protect workers during short duration work episodes, reduce exposure to nearby workers, and reduce clean-up associated dust exposures.