【摘 要】
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Testing was completed on an earlier roof bolter CAC that used slots to provide a perimeter airflow.NIOSHtested it due to its unique design that differed from ca
【机 构】
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Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, 6
论文部分内容阅读
Testing was completed on an earlier roof bolter CAC that used slots to provide a perimeter airflow.NIOSHtested it due to its unique design that differed from canopies that provided uniform airflow.Based upon NIOSH recommendations from the earlier testing,a 3rd generation roof bolter CAC has been developed by J.H.Fletcher & Co.Thechanges to this CAC involve design modifications to the plenum outlets,using a single row of outlets on the perime ter and a different material for the plenum.This laboratory testing was a continuation of the original perimeter slotted CAC design.Using gravimetric and instantaneous sampling of respirable dust concentrations undeeath and outside of the CAC,the laboratory testing was completed using three different blower fans that delivered differing airflows.The maximum plenum airflow velocities ranged from 2.34 to 3.64 m/s (460-716 fpm).Results showed plenum respirable dust concentrations ranging from 34.6％ to 49.3％ lower than respirable dust concentrations outside the plenum protection zone,thus showing an improvement in protection for the roof bolter operators.
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