Demonstration of NIOSH (National Institute for Occupational Safety and Health) Push-Pull Ventilation Criteria

摘要

A demonstration study to evaluate NIOSH criteria for push/pull ventilation of open surface tanks was conducted. Demonstration chrome plating tanks, 4 or 6 feet wide, equipped with push/pull ventilation systems were utilized to validate earlier NIOSH findings that optimum control of emissions from laboratory tanks in a cross draft of 75 feet per minute (fpm) could be achieved with a push flow of 45 cubic feet per minute per foot of nozzle length (cfm/ft) and a pull flow of 75 cfm per square foot (ft2) of tank area from 4 foot wide tanks or with a push of 35 cfm/ft and a pull of 50 cfm/ft2 from 6 foot tanks. Ventilation measurements and industrial hygiene sampling for total chromium (7440473) and hexavalent chromium (18540299) (Cr(VI)) were conducted.