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Electric Unit Heaters for Hazardous Areas

Hazardous (Classified) locations can be defined as locations or areas where fire or explosion hazards may exist due to the presence of flammable gases or vapors, flammable liquids, combustible dust, or ignitable fiber or flyings. There is often a need to provide heating either for freeze protection or comfort into areas which are potentially hazardous. Special explosion-proof electric unit heaters designed for use in hazardous locations has become a standard to provide safe and reliable heating for many classified areas. 

We may not always be aware of the potential for fire or explosion in areas which we occupy on regular bases. We can easily identify the potential hazards of gasoline and solvents but flour, corn starch, powdered sugar, wood and coal dusts can be just as hazardous. So when a vocational school in Southern California needed to provide heating to their workshop classrooms they chose Indeeco Series-233 explosion-proof unit heaters.

Design Requirements

The workshop classrooms did not require cooling but needed a stand-alone source of heating for comfort and to maintain room temperatures for curing and drying in various workshops. Since there was a presence of flammable gases and vapors and combustible dusts in the workshops, explosion-proof unit heaters were specified. The heaters needed to be suitable for Class I, Groups C and D (gases and vapors) and Class II, Groups F and G (dusts) to be acceptable for the various areas. The heaters were to be wall mounted and be controlled by an explosion-proof wall mounted thermostat.


Twenty-six (26) 5 KW, 480-volts, 3-phase ULTRA-SAFE EXP unit heaters were provided to meet the heating requirements for the school’s workshops. The heaters were furnished with wall mounting brackets and wall thermostats.

Indeeco Advantages

What won the order for Indeeco? The quotation, submittals and ordering process went extremely easy said Duane Harrison of Dretzka & Associates, Indeeco representative for California; I was able to do the submittals myself. The heaters were part of a mechanical package which included fans and other HVAC equipment. Duane contributes the order to the ease of doing business with Indeeco, an excellent product and the sales engineers that are always ready to help with technical support and competitive pricing.