Polyisocyanurate Insulation

[bphgravity]

Many of the homes here in Florida use a Polyisocyanurate Insulation on the outer block walls and then faced with ?" furring strips for dry wall. This insulation board is typically 5/8" and has an aluminum facer on both sides.

The typical wiring is NM down the walls and secured with stand-offs to 4" sqaure boxes. The NM is kept 1?" from the furring strips but will be right up against the dry wall.

Any concerns in regard to this or is the possible hazard no more than it is with NM run along metal studding?

[ February 16, 2006, 03:38 PM: Message edited by: bphgravity ]

 

[DaveTap]

Re: Polyisocyanurate Insulation

I have yet to see insulation foil cut through a piece of NM as easily as metal studs but then again metal studs don't usually catch fire. Speaking of foil and metal studs should they be grounded since they are likely to become energized? I'd still be more worried about the drywaller who's studfinder senses the wire as the middle of a stud.
Sometimes I'm almost glad NM isn't allowed here.

[ February 16, 2006, 07:07 PM: Message edited by: DaveTap ]

 

[tom baker]

Re: Polyisocyanurate Insulation

"Speaking of foil and metal studs should they be grounded since they are likely to become energized"
Not required by Art 250, only Structural Metal forming an interconnected building frame.
However you can bond if you want.

 

[infinity]

Re: Polyisocyanurate Insulation

The typical wiring is NM down the walls and secured with stand-offs to 4" sqaure boxes. The NM is kept 1?" from the furring strips but will be right up against the dry wall

This would comply with the 1 1/4" requirement from the edge of the framing member or furring strips. The cable are permitted to be right up against the drywall.

 

[electricmanscott]

Re: Polyisocyanurate Insulation

Originally posted by DaveTap:
I'd still be more worried about the drywaller who's studfinder senses the wire as the middle of a stud.
Sometimes I'm almost glad NM isn't allowed here.

I'd be worried about a drywaller that needs a stud finder.

As for the second sentence.. :roll:

 

[George Stolz]

Re: Polyisocyanurate Insulation

Wow. That's right up there with "That darned code book is so tricky, I'm glad they quit teachin' us how to read!"

 

[DaveTap]

Re: Polyisocyanurate Insulation

Hey I did say sometimes and "ALMOST".... LOL

Currently I'm visiting Florida and while hanging shelves and pictures I've already seen full 4'x8'sheets of drywall held up by under 10 screws. Some of the electrical things I've observed I'll be posting threads on later.

[ February 16, 2006, 08:39 PM: Message edited by: DaveTap ]

 

[DaveTap]

Re: Polyisocyanurate Insulation

Originally posted by tom baker:
"Speaking of foil and metal studs should they be grounded since they are likely to become energized"
Not required by Art 250, only Structural Metal forming an interconnected building frame.
However you can bond if you want.

Okay but aren't metal studs by definition "Structural Metal forming an interconnected building frame"?

 

[iwire]

Re: Polyisocyanurate Insulation

Originally posted by DaveTap:
Okay but aren't metal studs by definition "Structural Metal forming an interconnected building frame"?

Metal studs are rarely structural and I have never seen metal studs provide the frame of a building.

IMO that section is talking about the steel the iron workers erect.

 

[electricmanscott]

Re: Polyisocyanurate Insulation

Dave, the other question I would ask is why would these metal studs be "likely to become energized"?

This is a term I don't think should be in the NEC.

Also I agree with Bob. These are not structural and do not form a building frame.

 

[Paul B]

Re: Polyisocyanurate Insulation

Guys there is a building practice where the steel studs are the building frame, I wish I could remember the name of it. We had one constructed in our area a few years back. None of the inspectors knew how the handle it. The practice involves pre fabed foam filled panels with steel stud frames. I didn't do the job so I don't know the out come from any of the trades.

Paul