Interior Wiring method in Assembly Occupancy - Fire Rated Exterior only -- 518.4

[Dark Sparky]

There is a church project that a friend of a friend of mine is working on and the electrical contractor is saying that he needs to use fire rated wire by code, citing 518.4(A), which deals with wiring. The construction type of the building is 3B, which only requires the exterior wall to be 2-hour rated.

Are the "fire rated" wiring methods required for interior work in a building that is type 3B?

I'm also digesting this portion of the NEC now - but need your expertise...

Thanks for all input!

 

[Dark Sparky]

Location: MD

Location: MD

Note - project is in Maryland. Thus 2014 NEC applies.

The 2014 handbook has some good notes (pages 706-707) - but I need some aid digesting this, relevant to the original posted question.

Thanks again.

 

[Dark Sparky]

Follow-up

Follow-up

Well...hearing no responses, here was my response to my friend:

"The 2014 handbook has a great explanation in this section. Exhibit 518.2 there shows a very similar situation to the one that your friend has posed.

My initial take is that yes, the interior work needs to comply with section 518.4(A). The handbook notes state that these wiring methods apply to “any wall, floor, or ceiling within an assembly occupancy, as classified in 518.2.” Wiring methods for areas that are not within assembly occupancies are covered in section (B). Section (C) gives some additional relief, for areas including “places of religious worship” “provided these wiring methods are installed behind a surface that has a 15-minute finish rating."

I'd appreciate anyone's more in depth experience clarifying or expanding on this. Thanks again.

 

[gadfly56]

Well...hearing no responses, here was my response to my friend:

"The 2014 handbook has a great explanation in this section. Exhibit 518.2 there shows a very similar situation to the one that your friend has posed.

My initial take is that yes, the interior work needs to comply with section 518.4(A). The handbook notes state that these wiring methods apply to “any wall, floor, or ceiling within an assembly occupancy, as classified in 518.2.” Wiring methods for areas that are not within assembly occupancies are covered in section (B). Section (C) gives some additional relief, for areas including “places of religious worship” “provided these wiring methods are installed behind a surface that has a 15-minute finish rating."

I'd appreciate anyone's more in depth experience clarifying or expanding on this. Thanks again.

That "15 minute finish rating" is basically 1/2" gyp-board that's properly taped.

 

[cowboyjwc]

I highly doubt that a church is a 3B Occupancy. Most churches are an A occupancy.

 

[gadfly56]

I highly doubt that a church is a 3B Occupancy. Most churches are an A occupancy.

3B is the construction type, which is not the same as, say, a "B" occupancy.

 

[mwm1752]

He could be talking about IIIB as the 2hr exterior wall is the only rated assembly for IIIB -- but remember 518 article covers all buildings or portions of buildings or structures designed or intended for the gathering together of 100 or more persons for such purposes as deliberation, worship, entertainment, eating, drinking, amusement, awaiting transportation, or similar purposes.

there may be some building area's not considered an assembly -- & 15 min finish rating is generally 1/2" drywall

 

[Dark Sparky]

Merci

Merci

Thanks, everyone, for the help. I greatly appreciate your time to assist. This forum is a great resource.

 

[cowboyjwc]

He could be talking about IIIB as the 2hr exterior wall is the only rated assembly for IIIB -- but remember 518 article covers all buildings or portions of buildings or structures designed or intended for the gathering together of 100 or more persons for such purposes as deliberation, worship, entertainment, eating, drinking, amusement, awaiting transportation, or similar purposes.

there may be some building area's not considered an assembly -- & 15 min finish rating is generally 1/2" drywall

That is true, but depending on the layout, which we haven't seen, the exterior may not be the only rated walls. I can't tell you how many engineers miss rated walls at plan check.

 

[mwm1752]

That is true, but depending on the layout, which we haven't seen, the exterior may not be the only rated walls. I can't tell you how many engineers miss rated walls at plan check.

The most common in B's is an occupancy separation -