Quote Originally Posted by WMBELEDES View Post
If I were to use the definition of a C1D1 or D2 500.5(1&2) it might fall under D1 due to rare occurrence where an operator could inject a bubble of gas into the extruder that is released. If I read 500.5(2)(2), "Concentrations are prevented by positive mechanical ventilation". The plant has wall fans with ceiling louvers that replace quite a large volume of air, might this drop the Zone from D1 to D2? How might this be decided? Is there a more detailed article for testing to determine a zone? If so, is this a self test or a test of a certified mature?


If your plant layout representing the equipment markings found on nameplate's coincide with NEC 505.9(C)(2). Below is the Title of the information included.

"Guidelines for the safe use of flammable blowing agents in the production of extruded polystyrene boards (XPS)"

Tag this link: