Intrinsically Safe or Explosion Proof

As far as I know from the test cells I've seen that deal with fuel, and the law that regulates the work with flamable liquids and vapors (in my country), it's a matter of vapor concentration. If you can assure by positive ventilation that the concentration of flamable or explosive vapors in the room is kept below determined levels, there's no need for special equipment. But I dont know your specific situation in terms of quantity of products, type of recipients, leakage potential, etc.

Without knowing it exactly, and without knowing your place regulations, I'd assume that if you have no ceiling, it's opened to ambient, with positive ventilation, you do not have an explosion proof room. We have some around the facility I work in, and they all must be an enclosed space, with minimum openings to the rest of the building, ventilation system that assures ventilation from the building inside the room, and all pumps, instrumentation, wiring, room electrical installation and lamps, etc, is insulated.

In opened spaces, we just ventilate it (really well!!!!!).

That's the way things must be around here in my place. I am not sure about yours.

JMT,

Sorry if this sounds insulting, but if you are asking these questions, you are not qualified to assess the requirements for this location. You need to get an assessment by someone that is versed in the NFPA (fire) and NEC (electrical) codes.

I am not an expert, but here goes:

Intrinsic safety is a specific term to describe a circuit which will not, under any circumstances, have enough electrical energy to be able to produce a spark which would ignite the vapor. It is a bit complicated, but this means low voltage and low current. This would not apply to anything in the room that you have described.

From your description, I would think the room would be classified as a hazardous location, most likely it would be Class 1 Division II area (explosive vapors not present all the time, but present during upset conditions) . This would mean that all equipment in the room should be rated for this service, especially the wires going to the heating mantel, and the heating mantel itself (which also should be rated not to exceed the ignition temperature of IP, even under runaway conditions). The exhaust fan should be rated for this service as well.

Get an expert in this field!

It sounds like your company accepts a possible explosion (no roof) rather than spending minimal dollars to make sure the area is safe.

Tad

Your heating mantel should be wired to EP standards. If vapor gets into the enclosure for the heating elements it could potentially follow the conduit all the way back to the electrical panel that distributes the 4000 watts to each element, and the flammable vapor could slowly accumulate inside the cabinet. The next time the heater is used the arc produced when electrical contactors engage could ignite the accumulated vapors resulting in an explosion. Seals in explosion proof conduit would garuntee that this could not happen.

Anything electrical in this room close to where explosive or flammable vapors could be present should still be wired to IS and/or EP electrical installation standards to ensure that an explosion could not propogate out into other parts of your facility through the electrical conduits.