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Firestop

3K views 7 replies 6 participants last post by  BigJimmy 
#1 ·
I am looking for a solution to firestop areas where the electrical is run through the floor joists. Had a local inspector give me fits about having electrical wires run through the floor joists with no firestoping. Any suggestions?

Also, the cold air returns in my house are enclosed with sheet metal between the 2x16 floor joists. A provision in the NEC code allows electrical wiring to pass through such returns however it leaves me uneasy for a potentially bad situation. The wires currently running thorugh it are all Romex however they are not encased in any conduit. Should I consider encasing them or providing some means of firestoping?

Thanks
 
#3 ·
There are few diffrent type of fireproofing caucking materals and http://estore.websitepros.com/stores/1805348/catalog/wf300_firestop_caulk.jpg

this one will show you a genral idea what the tube will look like IIRC some big box store may stock this otherwise electrical supply centre will useally stock this the last time i brought it it was about 5 buck a tube i think and becarefull they do come in serveal ratings.

some are in 30 min rating some are at 1 hour rating and some are more than that the higher rating it goes it cost somehow little more expensive but it worth every cent.

[ I do not know what your area need for the rating but AFAIK most useally ask for either 30 min or 1 hr rating { check with the Inspector for it } ]

Merci, Marc
 
#4 ·
You DO NOT need firestopping in floor joists. It is only required in holes between floors.

Also, what "potentially bad situations" are you concerned about with the returns? As long as the wires cross the return and are not run along them you are fine.
Also, the codes are not in place because of fear of fire form the wiring. They are there to prevent the wiring from burning in case of fire.
 
#5 ·
The "theory" is that if a wire which runs through a cold air return duct shorts out and sparks a fire, it will provide an avenue for fire/smoke to spread unabatted through the rest of the home. The cold air duct is enclosed between 2 of the floor joists, which the wires run directly through.

Thanks for the replies, I will look into these products.
 
#6 ·
The "theory" is that if a wire which runs through a cold air return duct shorts out and sparks a fire, it will provide an avenue for fire/smoke to spread unabatted through the rest of the home.
And how is this ANY different from any other place in the home? Such as in an attic with tons of cardboard boxes all around.

Like I said, it has NOTHING to do with the wires causing the fire.
 
#7 ·
The general rule under 300.22 does not allow romex in ducts or plenums.

The exception allows runs that pass perpindicular to the duct run in cold air returns.

The purpose is to limit the amount of Rubber or PVC in the Air Handling space, regardless of the cause of the fire.

Fire stopping is required so that a fire does not have a hole to blow through as heat rises in a fire, thus slowing the spread of fire between floors. It is not required in the holes in floor joists, but in the holes that penitrate the sole plate and down to the next level or crawl space. It is also required in the holes that go up into the attic.

I have no insitefull wisdom on fire calking. Purchase fire calk, squirt in holes.
 
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