NM (Romex) in A-3 Occupancy

[Glennman CBO]

2008 NEC, 2006 IBC. Occupant capacity is 211. Type V-B, single story A-3 (church) building. The building is 4000 sq ft, and is all built of wood. There are no rated walls, no close proximity to property lines, etc.

Is installing Romex NM wiring throughout approved?, or is it required to be matalic sheathed?

Thanks all...

 

[raider1]

Re: NM (Romex) in A-3 Occupancy

NM cable would be permitted to be installed throughout except for above suspended lay in tile ceilings.

334.10(3) permits NM cable in buildings of Type III, IV, or V construction where the cable is concealed within walls floors or ceilings with a finish material that has a finish rating of at least 15 minutes.

334.12(A)(2) prohibits NM cable from being installed exposed in a dropped or suspended ceiling.

518.4(B) permits NM cable to be installed in assembly occupancies where the building is not required to be of fire rated construction.

Chris

 

[Glennman CBO]

Re: NM (Romex) in A-3 Occupancy

Thank you raider 1. Thats all I need. I only have a 2005 NEC, and I didn't know if anything had changed in the '08.

 

[raider1]

Re: NM (Romex) in A-3 Occupancy

Thank you raider 1. Thats all I need. I only have a 2005 NEC, and I didn't know if anything had changed in the '08.

Nope nothing changed for those sections in the 2008 NEC.

Chris

 

[peach]

Re: NM (Romex) in A-3 Occupancy

what if it's a rated suspended ceiling?

 

[pwood]

Re: NM (Romex) in A-3 Occupancy

what if it's a rated suspended ceiling?

I suppose you could approve as alternate method etc..., but i would try to avoid that slippery slope.

 

[skipharper]

Re: NM (Romex) in A-3 Occupancy

Rated ceiling does not matter. Still no romex :lol:

 

[peach]

Re: NM (Romex) in A-3 Occupancy

you can have not rated "construction" but still have required rated elements..

like corridors..

you can't attach anything to a grid ceiling anyway.. it needs to be independently supported, right?

 

[McClary's Electrical]

Re: NM (Romex) in A-3 Occupancy

As raider pointed out, NM cannot be used over top of a drop ceiling in other than a dwelling unit. But two other things to remember when using NM in other than dwelling units, if the place of assembly is over 100 people, NM cannot be used. Also, NM would have to be concealed in a wall, floor or ceiling that has at least a 15 minute fire rating. So, if there's a 10' wall,but the sheetrock only goes up 8 feet, then has a lowered ceiling, the wall would not be allowed to have NM in it. PER nfpa 220 which is actually an excerpt from NFPA 5000 will not rate a wall at 15 minutes with open bays at the top.

 

[raider1]

Re: NM (Romex) in A-3 Occupancy

As raider pointed out, NM cannot be used over top of a drop ceiling in other than a dwelling unit. But two other things to remember when using NM in other than dwelling units, if the place of assembly is over 100 people, NM cannot be used. Also, NM would have to be concealed in a wall, floor or ceiling that has at least a 15 minute fire rating. So, if there's a 10' wall,but the sheetrock only goes up 8 feet, then has a lowered ceiling, the wall would not be allowed to have NM in it. PER nfpa 220 which is actually an excerpt from NFPA 5000 will not rate a wall at 15 minutes with open bays at the top.

If the assembly occupancy is not required to be built using fire rated construction then you can use NM cable.

Check out 518.4(B).

Chris

 

[McClary's Electrical]

Re: NM (Romex) in A-3 Occupancy

Chris, while I understand what you're saying, I can think of a few things that contradict that. NFPA 5000 (for example) does not require an interior, non load bearing, partition wall to carry any fire rating. However, if it has NM in it,it would still be required to meet the 15 minute fire rating. An open bay wall will not meet this rating. Therefor, cannot have NM ran in it.

 

[raider1]

Re: NM (Romex) in A-3 Occupancy

Chris, while I understand what you're saying, I can think of a few things that contradict that. NFPA 5000 (for example) does not require an interior, non load bearing, partition wall to carry any fire rating. However, if it has NM in it,it would still be required to meet the 15 minute fire rating. An open bay wall will not meet this rating. Therefor, cannot have NM ran in it.

remember that any wall that is sheetrocked with 1/2" sheetrock would conceal the NM cable within a wall that had a 15 minute finishe rating even though the wall is not a fire rated wall.

When 518.4(B) talks about non-rated construction it is talking about the fact that the wall does not require a fire rating but it may have a fire rating by default due to the wall being sheetrocked.

I agree that the NM cable must be completely enclosed within a wall floor or ceiling that has a finish rating of at least 15 minutes.

Chris

 

[Paul Sweet]

Re: NM (Romex) in A-3 Occupancy

The finish material is required for physical, not fire, protection of the cable. For instance, painted 1/4" plywood could comply with Chapter 8 finish requirements, but its fire rating is negligible.