gas heater in elec room 2

[rmusa]

If a gas unit heater (30 mbh) is installed in elec room, does this need to be explosion proof? The room has transformer, 1200kva panel.

 

[dbill74]

Does what need to be explosion proof?
From what you provided, the only thing I can see with the potential to explode is the gas unit heater.

 

[msquared48]

Probably means the eletrical room structure.

Mike McCann, PE, SE (WA)

 

[rmusa]

Does presence of gas pipe pose any hazard around elec transformer, due to any sparks by short circuit or something? with possibility of a gas leak.

 

[Compositepro]

If you have a gas flame already present, why worry about a spark?

 

[dbill74]

Unless the pilot light goes out and you fill the room to the proper concentration there is very little risk of the gas igniting and exploding.
Also, the transformer itself and panels are designed to minimize and prevent sparking as arcing damages the electrical equipment.

Overall the risk of an explosion from gas in the room igniting from an electric arc is so remote as to be negligible. However, if you are that untrusting and paranoid, don't put the gas heater in the room.

 

[trashcanman]

Since when does an electric room need heat? Where is it, North Slope Al?

 

[GroovyGuy]

Not that it should make any difference, but is the transformer dry-type or liquid-filled (ie mineral oil).
I doubt very much that anything in the room needs to be explosion-proof. After all I have a gas-fired furnace in my basement and nothing is EP.

Per trashcanman's question above "Since when does an electric room need heat? Where is it, North Slope Al?".
Can a heater, if required at all, not be electric? I have never seen a gas-fired heater installed in an electrical room (or transformer vault).
GG

I am forever learning and changing.
W.E. Deming

 

[Gottago]

As far as my experience goes, all you need is good ventilation in that room. Putting a gas fired unit heater simply seems out of question. No law will allow you to take such chances. Any minor gas leak and spark means a total disaster. I would appreciate if you could share a relevant clause of the code / standard that allows it to happen.

 

[dbill74]

I would appreciate if you could share a relevant clause of the code / standard that allows it to happen.

Show us where it is prohibited.
To my knowledge, code does not prohibit; therefore it is allowed.

Consider also, unless the ratio of gas to oxygen in the room is within a specific range, the gas will not ignite and explode. Above or below that range and no boom. The range is different for various gases.

As for the need for heat, you don't need to go to the north slope. The heat generated from transformers and panel boards is not that great, you can touch the surfaces with your hand and not get burned.

 

[ScottyUK]

A distribution transformer is remarkably efficient, typically 98.5% - 99% or so.

If that 1.2MVA transformer is loaded up near its maximum capability then it will be rejecting about 12kW - 18kW into the space, without counting the losses in the cables and switchgear. A heavily loaded oil-filled transformer will give you a painful burn.

 

[GroovyGuy]

Scotty is correct. The usual problem with electrical rooms is getting the heat out of the room, and not injecting more heat. Having said that, having a small heater in the room, for those periods of extreme low ambient temperature and/or during plant down-times, is always a good idea. It doesn't take much heat to keep condensation off of electrical equipment.

I have just wrapped up several projects, where we had to do one (1) air change every 40s to suck the heat out of the room produced by several large drives (with xfmrs). Losses here are several hundred kilo-watts. The ambient temperature, at these locations, ranges from -45C to +35C, which is rather extreme. These rooms were also provided with several electrical unit-heaters for keeping the room from freezing during down-time (in winter months).

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