PVC coated conduits

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rey-man

rey-man

Senior Member
Location
New york
We have a bank of PVC coated conduits going through a fire rated floor slab.

An opening has been provided for the penetration and now the contractor want to pour concrete to fill the spaces in between the conduits in liue of firestop system.

is this install allowed?

will the PVC coating affect the fire rating of the penetration?

thanks.
 
Smart $

Smart $

Esteemed Member
Location
Ohio
rey-man said:
We have a bank of PVC coated conduits going through a fire rated floor slab.

An opening has been provided for the penetration and now the contractor want to pour concrete to fill the spaces in between the conduits in liue of firestop system.

is this install allowed?

will the PVC coating affect the fire rating of the penetration?

thanks.
Click to expand...
Does the fire-rated floor slab consist [mainly] of concrete?

Let me think...
.
.
Concrete slab floor has hole in it...
.
.
Fill hole in concrete with concrete...
.
.
No more hole. :slaphead:
 
P

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
rey-man said:
We have a bank of PVC coated conduits going through a fire rated floor slab.

An opening has been provided for the penetration and now the contractor want to pour concrete to fill the spaces in between the conduits in liue of firestop system.

is this install allowed?

will the PVC coating affect the fire rating of the penetration?

thanks.
Click to expand...

Unless you are somehow responsible for sealing the penetration, it is probably best not getting involved.
 
weressl

weressl

Esteemed Member
Location
Texas by the Gulf, geat crab, great shrimp
rey-man said:
We have a bank of PVC coated conduits going through a fire rated floor slab.

An opening has been provided for the penetration and now the contractor want to pour concrete to fill the spaces in between the conduits in liue of firestop system.

is this install allowed?
Click to expand...

Yes.



rey-man said:
will the PVC coating affect the fire rating of the penetration?
Click to expand...

No.
 
weressl

weressl

Esteemed Member
Location
Texas by the Gulf, geat crab, great shrimp
rey-man said:
We are concerned about the coating of the conduits, if it will melt in the case of fire.

It may create an voids around the conduits for fire and smoke to go through.
Click to expand...

The magnitude is proportionate to the embedded length of the conduit. It is most likely negligible, I mean how thick is that coating? As the PVC burns it forms a charred residue that blocks the void and starves it from oxygen to facilitate burning.
 
renosteinke

renosteinke

Senior Member
Location
NE Arkansas
If it's a concrete floor, it is perfectly appropriate to fill the hole with concrete- just like it's perfectly fine to patch drywall with drywall methode and brick with masonry materials. The fancy 'rated' products are only sold for convenience; they're "rated" according to their ability to replace the original material.

As for the PVC coating on the pipe ... I don't see how that can make the least bit of difference in any fire test.
 
renosteinke

renosteinke

Senior Member
Location
NE Arkansas
It's an 'engineering' call, but consider these details:

1) small holes, like the 1/8" allowed around boxes, have been shown to not have a measuarble effect in fire tests; and,

2) Sandwiched between the pipe and the patch, the PVC coating probably won't 'burn,' so much as 'char'. I suspect that the heat transfereed through the pipe itself will cook the wires inside, and transfer heat through the wall, far quicker than anything that PVC can contribute.

IIRC, even plain PVC conduit is acceptable passing through fire walls. That thin coating can't be any worse.

Indeed, since the purposeof a fire wall is to keep things on the protected side from getting hot enough to ignite .... I'd almost rather see PVC conduit than, say, a copper air line passing through the wall.
 
Smart $

Smart $

Esteemed Member
Location
Ohio
weressl said:
Good point, but I think that the original challenge appears to be: prove that a PVC coated conduit can be used where fire-stop is required.

"will the PVC coating affect the fire rating of the penetration?"
Click to expand...
"Firestop" is required in openings around electrical penetrations. The PVC-coating is part of the penetration, not part of the opening.

300.21 Spread of Fire or Products of Combustion. Electrical
installations in hollow spaces, vertical shafts, and
ventilation or air-handling ducts shall be made so that the
possible spread of fire or products of combustion will not
be substantially increased. Openings around electrical penetrations
into or through fire-resistant-rated walls, partitions,
floors, or ceilings shall be firestopped using approved
methods to maintain the fire resistance rating.
.
Informational Note: Directories of electrical construction
materials published by qualified testing laboratories contain
many listing installation restrictions necessary to maintain
the fire-resistive rating of assemblies where penetrations or
openings are made. Building codes also contain restrictions
on membrane penetrations on opposite sides of a fireresistance-
rated wall assembly. An example is the 600-mm
(24-in.) minimum horizontal separation that usually applies
between boxes installed on opposite sides of the wall. Assistance
in complying with 300.21 can be found in building
codes, fire resistance directories, and product listings.
​
Click to expand...
My response is based solely on NEC requirements. I cannot speak to the affect such may have on a partition's fire rating, as it goes well outside NEC scope...
 
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