Combustible Piping in Type 1A Parking Garages

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Combustible Piping in Type 1A Parking Garages

Postby jimmynew » Mon Jan 07, 2013 10:58 am

This question comes up in almost every new parking garage that is built that has combustible construction over a non-combustible type 1A garage. I get quite a few R-2 over S-2 buildings that use the Special Provisions section (IBC 509.2). The mechanical contractor often wants to use some type of combustible plastic piping, usually PVC or CPVC, in some area of the garage. Section 603.1.2 allows this only "when installed in accordance with the limitations of the IMC and the IPC". These codes offer little help in allowing this installation.

Arguments to allow this vary from "the pipe is always filled with water" to "the pipe is plenum rated, so it's OK." Or, "the garage is sprinklered and all the piping is exposed". I have in the past required these pipe runs to be installed within a 2-hr chase, or covered by an approved product (intumescent coatings, ceramic based insulations, etc.).

Enforcement around the area seems varied to me. I've seen a garage full of PVC that is in our state's second largest city. Mechanical contractors often comment that they get this approval in other cities. I'm wondering how others interpret this requirement and deal with it.
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Re: Combustible Piping in Type 1A Parking Garages

Postby Bob Rood » Thu Jan 10, 2013 2:44 pm

From the Code Commentary for Sec. 603.1.2 (in part)- "Piping is not addressed by construction type requirements and the use of piping must not be controlled by construction type provisions."

Also see Sec. 712.4.1.1.2 for through penetration firestop systems. Penetrations through the floor assembly must have a T rating unless contained within the cavity of of a wall. It is difficult if not impossible to achieve the required T rating with metallic piping. Better to use exposed PVC with a listed intumescent fire stop.
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Re: Combustible Piping in Type 1A Parking Garages

Postby jimmynew » Fri Jan 11, 2013 8:23 am

Thanks Bob, the info in the commentary you provided was helpful. I didn't think to check there and it reinforces what myself and my co-workers in Minneapolis have agreed to allow based on a meeting we had yesterday.

It seems the Uniform Codes, when they were enforced over a decade ago, had a problem with plastic piping, and this reputation has been wrongfully assumed to be carried into the I-codes. Here are some reasons we chose to consistently allow exposed plastic piping in Type 1 and 2 buildings (assuming the firestopping submittals allow it at the penetrations):

1. Is the pipe really combustible? Most of the plastics, except ABS, don't burn by themselves and need sustained flame from another source to stay ignited.

2. Flame spread and smoke development numbers for most of the plastic pipe is within Class C limits.

3. Fire load from automobiles (fuel, plastic, rubber, fiberglass, vinyl, etc) parked in the garage, as well as other items which may be stored there, is a much larger concern than the added fire load from the plastic piping.

4. Nothing in the IPC (or the State Plumbing Code which is our official charging document) prohibits it.

5. The IMC only regulates its use in plenum areas.
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