Frequent Questions

NFPA 4 Criteria

A stationary source has a mixture above the threshold. At standard temperature and pressure, the mixture does not meet the criteria for a National Fire Protection Association flammability rating of 4 (NFPA 4). At elevated temperatures and pressures, however, the mixture meets the NFPA 4 criteria. Is this process covered under the risk management program regulations? 

No. The determination of whether a substance or mixture meets the NFPA 4 hazard rating is made in accordance with the definition of flammability hazard rating 4 in the NFPA 704, Standard System for the Identification of the Fire Hazards of Materials, and boiling point and flash point shall be defined and determined in accordance with NFPA 321, Standard on the Basic Classification of Flammable and Combustible Liquids. Standard (or ambient) temperatures and pressures are referenced in these standards. Although this mixture as described is not subject to part 68, it is subject to Section 112(r)(1), the general duty clause (See questions under General Duty Clause).

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