What constitutes a hazardous location?
• The National Fire Protection Association (NFPA) provides the above explanation, and is recognized as authority on fire protection. The NFPA recognizes that even they with their vast resources cannot identify all locations and instruct in the treatment of that location. The NFPA relies on the “authority having jurisdiction”(definition to follow-#3) to govern what the NFPA has not addressed. For anything to explode or burn certain conditions have to be met. A combustible substance must be present with oxygen and an ignition source. In the case of a sanitary sewer system, a gas may be generated from the decomposition of the sewage, the chemical treatment of that sewage or the gases created from substances (gasoline, paint thinner etc.) that have entered the sewage system. These conditions may be present in lines as well as equipment housings, wet wells etc.
