One family dwelling unit?

[wwhitney]

Would a 100 unit apartment structure be 100 buildings since all of the units are separated by firewalls?

Not if the units are vertically stacked, as it says "fire walls", not "fire walls, ceilings, and floors".

Agreed that the NEC's lack of a definition of fire wall makes the definition of "building" ambiguous. But I think the townhouses described in post #12 are clearly separate buildings, NEC-wise.

Cheers, Wayne

 

[rc/retired]

Would a 100 unit apartment structure be 100 buildings since all of the units are separated by firewalls?

No, haha! The building code has 4 ratings of a firewall. 1 to 4 hours.
So, the term firewall is generic as well.

Ron

 

[wwhitney]

The building code has 4 ratings of a firewall. 1 to 4 hours.
So, the term firewall is generic as well.

While you are correct that walls with different fire resistance ratings are required by the IBC in different situations, the IBC has only one definition of "fire wall":

FIRE WALL. "A fire-resistance-rated wall having protected openings, which restricts the spread of fire and extends continuously from the foundation to or through the roof, with sufficient structural stability under fire conditions to allow collapse of construction on either side without collapse of the wall."

It's tempting to say that as the NEC does not define "fire wall," the IBC is the first place we should look for a definition. Except that colloquially "fire wall" is often used to mean any wall with a fire-resistance rating, so it's not at all clear to me that the IBC definition should take priority over a dictionary.

Cheers, Wayne

 

[rc/retired]

I do agree. We tried to shy away from certain terms. It made things easier for the inspectors and plan reviewers.

Ron

 

[infinity]

Areed that the NEC's lack of a definition of fire wall makes the definition of "building" ambiguous. But I think the townhouses described in post #12 are clearly separate buildings, NEC-wise.

Cheers, Wayne

After some further thought I agree that the NEC thinks that a joined townhouse is two buildings.

 

[david]

When boca and the other two organizations united and became the international code council they had for at least one year a international electric code basically amending the nec. In that code smoke ditectors had to be on a lighting branch circuit.

The international code council and NFPA came to an agreement that the international code council would by referance standard use the NEC and not write there own electric code. The international electric code was done away with

The IRC may read slightly different than the nec but it is supposed to be the same requirements as the NEC.

You can cross referance every section of the IRC electrical provisions with the n NEC. You can use for example conduit in a single family dwelling even though the IRC does not include that in the IRC. You can wire to the NEC or the IIRC which ever you chose

A residential building inspector is not certified as a residential electrical inspector until he passes a test based on the NEC.

 

[david]

You're correct there may be some variation in the definition because the NEC definition of a building is garbage since they do not define what a firewall is. Would a 100 unit apartment structure be 100 buildings since all of the units are separated by firewalls?

No two things town houses have to have grade level access.

And for it to be separate buildings you would have to be able to remove one while the others remain.

Each of the townhouses has to have a two hour separation between the adjoining dwelling

 

[qcroanoke]

I do agree. We tried to shy away from certain terms. It made things easier for the inspectors and plan reviewers.

Ron

Yeah. Like Emergency

 

[david]

SFD vs dwelling unit does not make a ton of difference except for hot tubs (spas) and load calculations,
the slight difference can be a huge gotcha, for example I can't use an optional calc with a set of plans that contain a 'dwelling unit' and a 'guest suite' in one 'building'.
If that guest suite is a 'vacation rental' or short term rental licensed & permitted by the town as such then you have the general public using the spa I'd say you could require 680.41 then.

It may not be that practical today considering load calculations VA Values electric stoves and dryers most commonly 230 volt.

Single family dwellings are the only dwellings required to have a 3 wire supply, and rated a min of 100 amp distrupution equipment.

You could by code supply all other dwellings with 110 volts. I doubt that done very often today.

Been in some old single family dwellings that only have 110 volt services, that not allowed today

 

[tortuga]

It may not be that practical today considering load calculations VA Values electric stoves and dryers most commonly 230 volt.

Single family dwellings are the only dwellings required to have a 3 wire supply, and rated a min of 100 amp distrupution equipment.

You could by code supply all other dwellings with 110 volts. I doubt that done very often today.

Been in some old single family dwellings that only have 110 volt services, that not allowed today

Yeah good points, that 3-wire thing in 230.79(C) is silly it does not specify what the 3 wires need to do? Could I have a 60/120V service or how about 120V corner grounded delta ?