Hazardous Locations

[WA_Sparky]

Hello all,

I'm having a little bit of trouble determining the classification and zone of a proposed building. The client is wanting to have an accessory building built adjacent to an existing building. This building will be 10x10x10 CMU. The contents stored in this building will be fuel, propane, oxygen, and acetylene. The idea is that it will double as a small workshop later on. The building will be fully enclosed. I don't know if they intend on putting a single gas can in this space or 5.

Would you all agree that this would be considered Zone 1?
"In which ignitable concentrations of flammable gases or vapors are likely to exist under normal operating conditions; or.)

If we were to ensure there was sufficient ventilation, this enclosed space would be considered Zone 2, correct?

There must be a gas detection system in place if we wish to have any electrical in the space (receptacles, lights, welders). Gas detection needs to be tied into automatic electrical disconnect for structure, ideally located outside. Alarm will sound if concentrations reach 20% of lowest gas ignitable limit. Electrical will auto disconnect at 40%.

If there is sufficient ventilation and an alarm do light fixtures need to be explosion proof?

Thanks,

 

[Sea Nile]

My biggest fear about becoming an electrician is no being able to stop myself from asking a client, "Are you stupid or something?"

 

[WA_Sparky]

My biggest fear about becoming an electrician is no being able to stop myself from asking a client, "Are you stupid or something?"

Yeah having a welder near contained fuel in a confined space just seems like it is a bad event waiting to happen. Im wondering if there typically is like a Hand Off Auto Device used in this type of space as well.

 

[retirede]

I think you mean division 1/2, not zone.

D1 is an area where the gas is present under normal operating conditions. D2, the hazard only occurs under a fault condition.

It’s not normally the EC’s job to determine this.

Another issue is that acetylene is group A. Not a lot of equipment available for group A.

I’m sure @rbalex ; can give more specific guidance.

 

[jap]

I'm not sure this would qualify the area for any class or division to begin with.

A lot of welding shops and even high schools use oxygen acetylene rigs in their shops, and, maybe even a barbeque grill in the corner for the weekend cookout.

Most all of us have gas cans in our garages unless you're fortunate enough to have someone mow your lawn for you, maybe even a welder.

I've got all of the above in mine.

JAP>

 

[WA_Sparky]

Final conclusion per conversation with building official.
Space is considered Class 1.
Ventilation will be needed.
Gas alarm will be needed.
Fuel must be stored in 30gal tanks or less.
No welders, period.

I think you mean division 1/2, not zone.

D1 is an area where the gas is present under normal operating conditions. D2, the hazard only occurs under a fault condition.

It’s not normally the EC’s job to determine this.

Another issue is that acetylene is group A. Not a lot of equipment available for group A.

I’m sure @rbalex ; can give more specific guidance.

This did not come up in our conversation when I mentioned the types of gas/fuel intended to be stored. I'll make sure to bring this up incase we're asked to consider adding a wood stove or acetylene torch

 

[jap]

In that case it pretty well gets shot down as a double for a workshop at all.

It's been classified as a class 1 location for storage of hazardous material.

JAP>