4" DWV done in ABS in underground garage in a highrise

I just drove into a renovated underground garage in a highrise building.
The drains were 4" DWV all ABS.
There was some cast iron left from before the renovation, in the floor of the lowest level of the garage.

Since when are plastic drains OK in concrete highrise buildings?

Is it possible that they used DWV ABS for the rain gutters/storm drains and that is what you are looking at?

I've seen plastic in concrete buildings before...

You have to use intumescent rings where the pipe will pass through a fire-rated wall though.

Here, if the building is fire rated, you CANNOT use plastic of any kind, anywhere, because the plastic itself can become a fire path, regardless of how the holes in the floors are sealed.

hj said:

Here, if the building is fire rated, you CANNOT use plastic of any kind, anywhere, because the plastic itself can become a fire path, regardless of how the holes in the floors are sealed.

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You must have magical electrical installations that don't compromise the fire rating then...

It's a bit different with a hollow plastic pipe verses a plastic jacketed metal wire bundle.

They DO make metal conduit you know. The electricians do not have to use PCV.

jadnashua said:

It's a bit different with a hollow plastic pipe verses a plastic jacketed metal wire bundle.

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No, it's not. All penetrations in a fire rated design need intumescent caulking, collars or spray applied fire stopping...

This is a good topic. A few years ago the UPC started allowing plastic pipes in any building. What started happening is plumbing contractors started designing high rises with a typical cast iron stack and branches but would use ABS for the vent stack and trap arms/dirty arms. Problem is plumbers, like my self, are not too familiar with occupancy and fire ratings. I'm all too familiar with the rockwool and firestopping of penetrations since that's all I did my first year of apprenticeship but that was when everything was cast iron. Now with ABS coming in it was typical for some contractors to use cast iron pups through the floor but then switch to ABS for all of the stacks and all between floor piping and then go back to cast pups throught the next floor up. Now we have a nice big chimney for a fire to jump from floor to floor. It was a huge mess with some of these big high rises and big contractors. In the end we had to put out an emergency declaration about the use of "Mixed materials" in a rated building. No mixing of cast and plastic is allowed BUT ( always a big but) if you do use mixed material, say in a TI space or on a big remodel, then you need to submit fire rating plans to the city and go through a fire review. Basically if you mix cast and plastic you would need to provide plastic pups through the floor with a crush collar and provide a crush collar on every cast to plastic connection you have in the building. On a small TI would probably be no big deal but that's what was required on some pretty big new high rises down town. I think the money they saved by using ABS was wasted in the crush collars they had to purchase. Just in case you're wondering, the plans didn't show any ABS at the time of review. I guess that's another heads up call for Washington state plumbers.