I have a question regarding the need to provide electrical classification for a building using Class 1A flammable liquids.

For this building, 4 gallons could be out in use (located anywhere in the building). The MAQ is 10 gallons. I have discussed this with NFPA 30 committee, the manufacturer, and the AHJ (who is a knowledgeable FPE). They have all determined that even if the MAQ is not exceeded, electrical classification is required if a flammable/explosive mixture could be present.

The NFPA 30 staff directed me to a provision in NFPA 497, Section 5.5, that if the materials will not reach 25% of the lower flammable limit (LFL), this could be utilized to justify not providing classified electrical fixtures.

Does anyone know how to do this calculation, or know of firms that can be hired to do this?

I am an FPE and do not know how to perform it, and I have spoken with other FPE’s who also are not aware. The gentleman I spoke with at NFPA 30 agreed it would be by an industrial hygienist or a chemical engineer and not an FPE.

But does anyone know any that can be hired for a one-off calculation, or have a place where I could learn how to perform it myself (NFPA reference, SFPE article, course, etc.?).

Thank you!

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