# High efficiency gas water heater venting through open plenum ceiling



## mccmech (Jul 6, 2011)

Sooo, I have to vent a high efficiency gas water heater, using the concentric termination fitting, vertically through an open plenum ceiling. The debate over using PVC as an exhaust pipe aside, is there an alternative to just fire wrapping the pipes?


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## dhal22 (Jul 30, 2010)

That's a good question. And I don't have an answer but you got me thinking.


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## skoronesa (Oct 27, 2015)

Air space maybe? Like run the pvc centered through large diameter round duct?

What's your concern with fire wrapping them?


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## wyrickmech (Mar 16, 2013)

Fire wrap would be the most effective even if the fire wrap codes have gotten a lot more stringent. If you could keep the intake and exhaust separate you could sleeve the pipe to keep it from being in the plenum.


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## mccmech (Jul 6, 2011)

skoronesa said:


> Air space maybe? Like run the pvc centered through large diameter round duct?
> 
> What's your concern with fire wrapping them?


No concern, just asking in case anyone with more experience dealing with the situation had other, or better idea.


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## dhal22 (Jul 30, 2010)

Sleeving was the only other idea I could come up with beyond wrapping.


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## moonapprentice (Aug 23, 2012)

I like the sleeving idea, makes sense to me. Plumb drum what's your take?


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## ace4548 (Feb 10, 2015)

I'm not sure on your codes or anything. But I have done a couple jobs now with plenum ceilings. I'm on one right now. Because of fire ratings we have to make all connections below the ceiling in cast, and has to be cast all the way up then. You will have to check building codes. We ran PVC in the basement for storm , but risers through floor and up are all cast. All vents even in basement are cast as well. Not sure on that logic.


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## plumbdrum (Nov 30, 2013)

moonapprentice said:


> I like the sleeving idea, makes sense to me. Plumb drum what's your take?


 my take is read whatever code you fall under and conform to it, find another route, or speak to whatever inspector that would fall under and come up with a solution. What might be approved in one code/trade may not be approved in another.


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