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ASP practice question: Housekeeping
Question of the Day for Monday, 2 November 2026
ASP · Fire Prevention and Protection
A plant that grinds filled resin parts has a 30,000 ft2 production room. An inspector finds a dust whose lab bulk density is 75 lb/ft3 at least 1/32 inch deep over one continuous area of floor, beams and equipment tops totaling 1,200 ft2, with no other deposits. Using the layer depth criteria cited in OSHA's 2015 dust accumulation memorandum, which conclusion is correct?
Explanation
The memorandum cites NFPA 654 criteria under which a dust explosion or flash fire hazard exists when accumulations over the layer depth cover more than 5 percent of the footprint or when any single accumulation exceeds 1,000 ft2. Five percent of 30,000 ft2 is 1,500 ft2, so the 1,200 ft2 deposit passes that test but fails the 1,000 ft2 single-deposit test. Stopping at the 5 percent test is the tempting error, and elevated surfaces such as beams do count toward coverage. Source: OSHA memorandum, Evaluating Hazardous Levels of Accumulation Depth for Combustible Dusts (April 21, 2015), cited in CPL 03-00-008.Practise more questions like this
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