Gas Water Heater in Electrical Room
Gas Water Heater in Electrical Room
(OP)
Hi there, I was asked to check an existing building. The building has a restaurant and a retail area and the intention is to renovate the retail area. I don't have any drawings yet on the existing conditions, the owner is working on that.
There are two gas operated water heaters inside the electrical room. Should this area be considered class 1, division 1? or is this installation in non compliance with the dedicated equipment space? The equipment inside the room is one Dry type transformer H.V. on primary (guess +/- 13kV), the main panelboard and 4 sub panels and of course all the things they don't have a place for store them. Any comments will be appreciated.
Thank you.
There are two gas operated water heaters inside the electrical room. Should this area be considered class 1, division 1? or is this installation in non compliance with the dedicated equipment space? The equipment inside the room is one Dry type transformer H.V. on primary (guess +/- 13kV), the main panelboard and 4 sub panels and of course all the things they don't have a place for store them. Any comments will be appreciated.
Thank you.






RE: Gas Water Heater in Electrical Room
RE: Gas Water Heater in Electrical Room
But don't you think that this location should be considered a Class 1, Division 1 as stated on the NEC section 500.5 (B)(1)(2). There is a chance of a gas leakage at this location. Also there is one exhaust fan right above the transformer (2 to 3ft above). By the way the water heaters are floor mounted.
RE: Gas Water Heater in Electrical Room
RE: Gas Water Heater in Electrical Room
RE: Gas Water Heater in Electrical Room
RE: Gas Water Heater in Electrical Room
1) The gas water heaters need ventilation and combustion air (NFPA 54)
2) You indicate that the TX is 13KV and therefore needs to be in an 3-hr fire rated room (NEC-110.31(A).
3) NEC-500.5(B)(1)(3) indicates that locations where breakdown or faulty operation of equipment may release ignitible concentrations of flammable gases or vapors------are class I Division 1 locations.
As "stevenal" indicates a "failure of equipment" would be if the gas valve would fail in the open position. The question is if the room ventilation and combustion air supply is sufficient to dilute to below ignition point.
RE: Gas Water Heater in Electrical Room
The best advice I can give you is to talk to the AHJ, BEFORE starting any work (or quoting any price). He/she has the FINAL say as to the proper interpretation of the NEC as it applies to this area. That is the best way to avoid any potential problems or conflicts that may arise. Remember that codes vary greatly across the US in both interpretation and in enforcement, so an opinion from someone outside of your area may or may not be accurate. Also keep in mind that this work may involve other codes than just the NEC.
Bigbillnky,C.E.F.....(Chief Electrical Flunky)
RE: Gas Water Heater in Electrical Room
That said, it is lousy design for the electrical equipment and the gas water heaters to be in close proximity, but as far as I can tell it is not a code violation. Frankly, the pressurized water vessels and pipelines, particularly the pressure relief valves, give me more concern than the fact that they are gas water heaters.