What could go wrong?

**John Arnold** · 04-08-2013, 04:17 PM

TPR pipe (wrong material) drains into (untrapped, at least in the same room) standpipe, with mystery pipe joining the fun. Mystery pipe is probably the TPR drain, or possibly water heater pan drain, from unit above.

tpr pipe.jpg tpr pipe tee.jpg

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**Lon Henderson** · 04-08-2013, 04:56 PM

Hard to say what could go wrong, but we can say it is wrong........

**Jerry Peck** · 04-08-2013, 07:34 PM

Originally Posted by John Arnold

TPR pipe (wrong material) drains into (untrapped, at least in the same room) standpipe, with mystery pipe joining the fun. Mystery pipe is probably the TPR drain, or possibly water heater pan drain, from unit above.

Wrong material? Is that PVC? The couplings and adapter look like white PVC, the pipe looks like CPVC color - but the two are different sizes and would not fit together like that???

The untrapped pipe you refer to is the upper pipe or the lower pipe it drains into? The upper pipe should not be trapped, but should not have a tee fitting into the side of it either. The T&P discharge pipe (which is what that is) needs to discharge in the same room or space as the water heater is in ... and it is ... and through an air gap ... and it is ... it can then discharge into/onto many things of which I disagree with the code on, but ... what *I* think it should do does not matter, what the code says (allows, does not allow) is what matters.

**John Arnold** · 04-09-2013, 02:33 AM

Originally Posted by Jerry Peck

...The untrapped pipe you refer to is the upper pipe or the lower pipe it drains into?...

The lower pipe, which is the washer stand-pipe, has no trap, unless it is below the floor.

**Jerry Peck** · 04-09-2013, 07:26 PM

Originally Posted by John Arnold

unless it is below the floor.

That would be my guess, but only a guess.

I would not discharge the T&P discharge into a standpipe for the clothes washer, likely not allowed either.

**Ian Page** · 04-14-2013, 11:26 PM

Improper material used for TPR discharge pipe. Improper TPR termination and crappy sweating of supply connections. Looks very DIY to me.

**Lon Henderson** · 04-15-2013, 06:11 AM

Originally Posted by Ian Page

Improper material used for TPR discharge pipe. Improper TPR termination and crappy sweating of supply connections. Looks very DIY to me.

Here, that is not improper material for the pipe. The rest of it is wrong.

**Ian Page** · 04-15-2013, 01:28 PM

Originally Posted by Lon Henderson

Here, that is not improper material for the pipe. The rest of it is wrong.

Looks like Sch. 40 (may be sch.80) PVC pipe, with PVC joints to me - not CPVC (or copper/stainless steel/galv. steel etc.) Are you saying that PVC pipe is permitted in this application with its significantly lower temp. and pressure rating? Even some of the glued joints look questionable.

**Lon Henderson** · 04-16-2013, 12:49 PM

Originally Posted by Ian Page

Looks like Sch. 40 (may be sch.80) PVC pipe, with PVC joints to me - not CPVC (or copper/stainless steel/galv. steel etc.) Are you saying that PVC pipe is permitted in this application with its significantly lower temp. and pressure rating? Even some of the glued joints look questionable.

Yes, on a normal discharge pipe, the pressure shouldn't be an issue with the short piece of pipe having an open end. While the temperature of the water in a release will be extremely hot, it isn't close to compromising the pipe for a five foot run

**Ian Page** · 04-17-2013, 12:06 AM

Originally Posted by Lon Henderson

Yes, on a normal discharge pipe, the pressure shouldn't be an issue with the short piece of pipe having an open end. While the temperature of the water in a release will be extremely hot, it isn't close to compromising the pipe for a five foot run

Lon

Without wishing to belabor the issue but my observation (and your response) is not with regard to the length of the pipe "...isn't close to compromising a five foot run." Not withstanding that "...the pressure shouldn't be an issue", irrigation type PVC (that's what it looks like to me) is not an approved pipe for TPR discharge purposes irrespective of the run length, open end or what it discharges into. My concern is that should the pipe be PVC with typically glued sch40 joints, the pipe (and joints) will likely fail as a consequence of extreme heat and pressure, should the TPR valve open with a sudden blast of energy. Even if the pipe is CPVC the fittings are not and, in all liklehood, the (unknown) glue may not be suitable for extreme heat and pressure either.

**Lon Henderson** · 04-17-2013, 07:11 AM

Originally Posted by Ian Page

Lon

Without wishing to belabor the issue but my observation (and your response) is not with regard to the length of the pipe "...isn't close to compromising a five foot run." Not withstanding that "...the pressure shouldn't be an issue", irrigation type PVC (that's what it looks like to me) is not an approved pipe for TPR discharge purposes irrespective of the run length, open end or what it discharges into. My concern is that should the pipe be PVC with typically glued sch40 joints, the pipe (and joints) will likely fail as a consequence of extreme heat and pressure, should the TPR valve open with a sudden blast of energy. Even if the pipe is CPVC the fittings are not and, in all liklehood, the (unknown) glue may not be suitable for extreme heat and pressure either.

I am unaware of actual testing of various piping material in our scenario, so I don't believe there is much research to support either of our contentions. All I can say, is that PVC is allowed and often used for the discharge pipe around here.