Electrical Room (Addition) Wall Rating

[glzath]

2009 IBC code basis. Factory F-2, IIB, 1-story. Meets 507.2 unlimited area. Pre-engineered building steel structure with insulated metal siding.

We have a 100,000 SF existing building that we are changing the occupancy from S-1 to an F-2. The facility is fully sprinklered and the system will remain. Due to space limitations we are adding on an approx 1000 SF electrical room to the Southeast corner of the building ... basically a common wall, 3 exterior walls and a shed roof. No transformers inside the room, just motor controls and distribution panels. The space will have 2 exits.

First, with the change of occupancy to an F-2, would the electrical room addition need to be sprinklered or otherwise be 2-hour protected? It appears that F-2 does not require a sprinkler system, but due to the existing system which is remaining does this now require any F-2 additions to be sprinklered?

Second, if 2-hour protection would be required at the electric room addition, would the common wall, 3 exterior walls and the roof need to be 2-hour? Or can just the common wall between the electric room addition and the existing F-2 be 2-hour? I know fire walls have special considerations with adjacent walls and roof areas, but this would be a fire barrier.

Thanks in advance.

 

[Paul Sweet]

I think it would be less expensive to extend the sprinkler system than to build a fire wall which would remain standing if the construction on either side collapsed to separate the sprinklered building from the unsprinklered addition. Your insurance costs would probably increase significantly if the facility isn't completely sprinklered. You could probably use a pre-action system if you're worried about water in an electrical room.

 

[globe trekker]

Paul,

FWIW, for the most part the fire service community does not want water mixed with electricity

in a fire event, but rather to have that 2 hr. fire rated construction to surround the electrical

room. Electricity & water typically does not mix well with humans.

glzath,

I would not add any sprinklers to the electrical room, and to confer with the FCO.

.

 

[steveray]

If the building does not "need" the sprinklers, the room does not....and it should not need to be separated either.....

 

[mtlogcabin]

I think exceptions 1 or 2 may be applicable. Ask the AHJ

[F] 903.3.1.1.1 Exempt locations.

Automatic sprinklers shall not be required in the following rooms or areas where such rooms or areas are protected with an approved automatic fire detection system in accordance with Section 907.2 that will respond to visible or invisible particles of combustion. Sprinklers shall not be omitted from any room merely because it is damp, of fire-resistance-rated construction or contains electrical equipment.

1. Any room where the application of water, or flame and water, constitutes a serious life or fire hazard.

2. Any room or space where sprinklers are considered undesirable because of the nature of the contents, when approved by the fire code official.



3. Generator and transformer rooms separated from the remainder of the building by walls and floor/ceiling or roof/ceiling assemblies having a fire-resistance rating of not less than 2 hours.

4. Rooms or areas that are of noncombustible construction with wholly noncombustible contents.

5. Fire service access elevator machine rooms and machinery spaces.

 

[peach]

I agree with globe trekker.. ask for permission to delete the sprinklers, since it's an exemption; then you also don't have to separate it.. not all exempt locations need to exist.. just one.

 

[glzath]

Thanks all!