I sent an e-mail to the head of the city plumbing dept. regarding this install being improper. I got a response today saying that the city does indeed allow this and it is widely accepted in installations below grade (this is in a basement). Although I disagree, they are the AHJ, at least in the city limits.
How would you guys write up something like this? Would you say the installation is improper, but the AHJ says it is OK? Or would you just say the installation meets their approval? I’ve just never had to deal with a city official saying something is right when the code says it isn’t.
I have saved a copy of the e-mail in my files in case it is needed in the future.
I just want some other opinions on this, and any stories out there regarding other’s battles with AHJ’s.
Try this. I’ve used similar verbage for other situations like this. . .
The drainline for the water heater TPR valve drains uphill. Although this application may have been approved by this jurisdiction, you should be aware that this set-up is not recognized by California Building Officials as an approved method for discharging of the water heater TPR valve. This set-up could also prevent the TPR valve from proper operation, which would be a significant safety hazard, and we recommend that it be modified to conform to Nationally recognized standards.
Tweak this how you wish, but the information should be clear;
It’s installation is contrary to California Building Standards
It’s certainly possible that the pipe could become obstructed to the point where the relief valve couldn’t discharge. But more to the point, the valve itself can easily become corroded to the point that it may fail to operate.
You also lose any advanced warning of a potential problem. With an uphill drain, you will not notice if the valve is leaking. A leaking valve could indicate that the heater is over-heating.
The piping should not be installed in a manner where discharge could go unnoticed.
If the discharge pipe for a TPRV is pitched uphill… It becomes problematic if the TPRV develops a leak… Water accumulates in the ‘downhill’ side of the pipe (essentially a water trap)… If the TPRV were to open due to excessive pressure in the water heater, the escaping pressurized water would slam into the ‘trapped’ water with exploding consequences… It’s the equivalent of driving into a concrete wall… Glenn
In addition to the above information, a TPRV drain line that slopes up hill will fill with water, which will act to restrict the flow of steam through it. Those valves and drain lines need to move a lot of heat through them in a short period of time in order to do their job. The trapped water reduces the rate at which they can relieve the pressure.