TPR Drain pipe

[mwood1]

What do you think about this copper drain pipe. I remember reading something about it not supposed to routed upward?

[James F. McKee]

You are right....that is wrong !!!

[Richard A. Moran, 2nd]

Morgan, check around the NACHI site. There is a TPR on-line course.

Dick

[Jeffrey R. Pope]

Absolutely, 100% wrong. The discharge pipe, that is. . .

[rmaday]

Originally Posted by mwood1

What do you think about this copper drain pipe. I remember reading something about it not supposed to routed upward?

Correct, must drain by gravity into atmosphere (air gap) in the same room as WH, no more than 6" from floor.

[mwood1]

Thanks guys.

[Ben J. Gromicko]

From http://www.nachi.org/plumbingcoursereleased2008.htm

Discharge Pipe on TPR Valve:
The following are thirteen requirements for a discharge pipe serving a TPR valve: 1) The pipe should not be directly connected to the drainage system; 2) The pipe should discharge through an air gap located in the same room as the water heater; 3) The pipe should be constructed of materials tested, rated, and approved for such use; 4) The pipe should not be smaller than the diameter of the outlet of the valve served and should discharge full size to the air gap; 5) The pipe should not have valves or tee fittings installed; 6) The pipe should not have a threaded end; 7) The pipe should serve a single relief device and should not connect to piping serving any other relief device or equipment; 8) The pipe should discharge to the floor, to an indirect waste receptor or to the outdoors. Where discharging to the outdoors in areas subject to freezing, discharge piping should be first piped to an indirect waster receptor through an air hap located in a conditioned space; 9) The pipe should not terminate more than 6 inches (152 mm) above the floor or waste receptor; 10) The pipe should discharge in a manner that does not cause personal injury or structural damage; 11) The pipe should be installed so as to flow by gravity; 12) The pipe should discharge to a termination point that is readily observable by the building occupants; and 13) The pipe should not be trapped.

The termination of a relief valve discharge pipe should always be visible and conspicuous. An air gap is necessary to prevent backflow and contamination of the potable water system. The discharge pipe must not be reduced in size, and must not be less than the size of the relief valve outlet. A reduction in size will act as a restriction and would impede the flow rate of the discharge. Relief valves must not be exposed to freezing temperatures. The slow drip of a leaking valve in freezing temperatures would cause ice to form and restrict the discharge and disable the valve.

[iniquette]

kind of curious as to who installed that, I wonder if they really thought it was correct.

[Jeffrey R. Pope]

The pipe should not terminate more than 6 inches (152 mm) above the floor or waste receptor;

In CA, it must be more than six inches. CPC requires termination between 6" and 24" from the floor or receptor.

Also, it is not allowed to drain into the water heater overflow pan.

Just food for thought Ben. Also, when you start work on the water heater course, let me know. I'll help with info on the Watts 210 valve and it's requirements. I hear these are a rarity in the East and Mid-West.

[Ben J. Gromicko]

Yep. A relief-valve pipe terminating into a water leak catch pan is not permitted, because the pan is not an indirect waste receptor. Most pans have only a ¾ inch-diameter (19 mm) drain outlet, which is not capable of gravity draining the pressurized discharge of the relief valve at full flow. (Section 5.17 InterNACHI Plumbing Course)
Thanks.

"In CA, it must be more than six inches. CPC requires termination between 6" and 24" from the floor or receptor." That's terrible. I've seen TPR valves blow at full flow. The discharge is all over the place at 6 inches from the floor. I can't imagine the damage that can be caused at two feet from the floor.

[rmaday]

Originally Posted by bgromicko

Yep. A relief-valve pipe terminating into a water leak catch pan is not permitted, because the pan is not an indirect waste receptor.

How is that different from simply terminating 6" from the floor?

[Ben J. Gromicko]

If the TPR discharge pipe terminates 6" from the floor (which is good) and into a water leak catch pan that is on the floor (which is not good) - I would "flag it" so to speak.

[William J. Decker]

Originally Posted by bgromicko

From http://www.nachi.org/plumbingcoursereleased2008.htm

Discharge Pipe on TPR Valve:
The following are thirteen requirements for a discharge pipe serving a TPR valve: 1) The pipe should not be directly connected to the drainage system; 2) The pipe should discharge through an air gap located in the same room as the water heater; 3) The pipe should be constructed of materials tested, rated, and approved for such use; 4) The pipe should not be smaller than the diameter of the outlet of the valve served and should discharge full size to the air gap; 5) The pipe should not have valves or tee fittings installed; 6) The pipe should not have a threaded end; 7) The pipe should serve a single relief device and should not connect to piping serving any other relief device or equipment; The pipe should discharge to the floor, to an indirect waste receptor or to the outdoors. Where discharging to the outdoors in areas subject to freezing, discharge piping should be first piped to an indirect waster receptor through an air hap located in a conditioned space; 9) The pipe should not terminate more than 6 inches (152 mm) above the floor or waste receptor; 10) The pipe should discharge in a manner that does not cause personal injury or structural damage; 11) The pipe should be installed so as to flow by gravity; 12) The pipe should discharge to a termination point that is readily observable by the building occupants; and 13) The pipe should not be trapped.

The termination of a relief valve discharge pipe should always be visible and conspicuous. An air gap is necessary to prevent backflow and contamination of the potable water system. The discharge pipe must not be reduced in size, and must not be less than the size of the relief valve outlet. A reduction in size will act as a restriction and would impede the flow rate of the discharge. Relief valves must not be exposed to freezing temperatures. The slow drip of a leaking valve in freezing temperatures would cause ice to form and restrict the discharge and disable the valve.

Darn know it alls

[Ben J. Gromicko]

Oh my Goodness! Hardly. I'm the worse source for quick information. I spent weeks of reading and studying and editing my plumbing course. I'm really good at finding something to say and copy-pasting it in the message board. lol

For my next nachi.tv video, which may be about notching defects in conventional lumber, I will probably spend 80 hours reading about it. I'm slow man, slow, like walking through a 2-feet deep pool of honey in winter. slow.

[Bruce A. King]

Ben, the bro must be paying some pretty good coin to get you out there.

Maybe I can work for ole Nicky when I retire too : )