Code/fire safety question – penetrations
PeteBradley
| Posted in Construction Techniques on
I want to run a 1″ steel conduit from the basement to a 2nd floor kneewall space through an interior closet wall. It’s going to be used as a chase for computer network wiring. Since this is basically going to result in a “chimney”, what steps do I need to take for fire safety? My reading of the code suggests that since it’s steel, it’s ok, but not sure.
Thanks,
Pete
Replies
I may be wrong on this but I don't believe the code would require you to seal it. Commercial is the only time I've ever encountered an inspector who wanted things sealed around such.
But from a practical and theoretical viewpoint, you are right. It could suck air and become a torch. (I remember as a volunteer firefighter once we went to a home where the lady had been a cosmetics sales person - Avon? - and when the upstairs window to her storeroom went out, we had a blue torch flame running twenty feet horizontally for over an hour out that window. We were lucky it was on the second floor. That stuff burns hot)
The best way to seal it from what I know is with quality GE 2000 plus silicone. That line of caulk can stand temps in excess of 2000 degrees for limited time.
When the cables have been pulled stuff both ends, and any other opening, with fire stop putty. It does not set and can be removed to allow the cable to be replaced. Once the work is done the openings are repacked. This stuff doesn't stick tightly until heated. When heated it glues itself in place, expands and creates a great deal of insulating char that seals the pipe even if the cables melt away.
http://www.envirograf.com/products/product060.html
There are many manufacturers. I couldn't find the brand I used long ago. This product seems similar to what I am familiar with. The removability is a boon in these types of situations.
Piffin
Dap's acrylic Blockade is recommended for combustable and non-combustable penetrations, probably for it's ability to expand into the voids created by the materials as they're consumed by fire.
It's silicon based Fire stop is recommended for non-combustable penetrations.
http://www.dap.com/retail/retail_list.cfm?catid=1&subcatid=3
Mike
It's O.k. to think out of the box, Just don't walk off of the plank!
Edited 9/4/2002 11:31:15 PM ET by Mike S
Thanks guysExcellence is its own reward!
Draftblock,draftblock,draftblock. Can't say it enough. You need to stop, slow etc air from moving during a fire. Buys precious time.
Not only the inside of the pipe but the outside at the penetrations.
Sorry about the rant but it is important.
J.
wouldn't terminating both ends of the conduit into a box provide enough protection against fire-heated air concerns?
To plug the ends of conduit, whether in a box or not, I've been using rock wool (NOT fiberglass). I know it won't expand to seal like the fire caulk does, but its lots less messy to remove and replace when (frequent) changes are made, packed tightly it provides an air seal and will not combust.
>Not only the inside of the pipe but the outside at the penetrations.
The outside even more so than the pipe itself -- try blowing thru a completely dry, empty garden hose. The head (friction) of the pipe can easily be far more than that of the remaining slop in the hole it goes thru.
-- J.S.
Thanks to all for the great information! Think I'll go with the putty & caulk route, since I don't expect to have to change the wires very often.
I have a related question along these lines. I will need to create an access to the space behind the kneewall to allow maintenance/replacement of a radon pump. Besides fire safety, I also want to keep the noise from the pump out of the living space. One thought I had was to screw down a drywall cover for fire safety with cabinet door or panel to hide the drywall cover. Since I don't expect to need to get in there often, the hassle of unscrewing the drywall should be ok.
Is there such a thing as a ready-made access door for this kind of thing?
Pete