200psi water heater relief valve

[joecampbell]

so the international code (504.4) says you cant be more than 150 psi. got any good exceptions, ie can i call this water heater not a water heater and instead a pressure vessel.

the tank is rated to 200psi but due to the imc getting a 200psi relief valve seems likely to be impossible.

is using a apollo 500 series valve not a good idea.

 

[LittleInch]

Errr can you expand a little here and give us a fuller picture.

Which "international code"?
What sort of vessel / heater are you talking about ( size, volume, temperature)?
imc??
details of this appollo 500 series valve?
Some / any context.

150 psi seems quite high for this thing not be called a pressure vessel in most jurisdictions I know of - where is this thing being built / used?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[joecampbell]

200 psi rate asme class VIII tank with indirect heat exchanger tube bundle in the tank.

want a PRV set at 200psi. problem most P&T prv's go to 150 due to IPC 504.5. as such this prv application is somewhat uncommon. all the same i see no issue with calling the vessel a pressure vessel and putting on a correctly sized prv.

504.5, would like to just its not applicable as it will be an ASME tank

https://codes.iccsafe.org/public/document/code/550/9793923

http://www.apollovalves.com/_products/500/SS_500_1120.pdf

 

[LittleInch]

Joe,

I think you have kind of answered your own question.

The key here seems to be when is a vessel full of hot water at pressure a "water heater" under IPC codes and when is it a Pressure Vessel under a pressure vessel code such as ASME VIII.

Normally that designation is a matter of legislation and regulation as to pressures, volumes, temperatures and possible exemption for certain things designed under other codes, like the IPC. This all varies from location to location.

If IPC stops at 150 psig then you're in unfired PV territory and you can then size your relief valve to whatever is the governing flow and pressure. IMHO. A determination by your local AHJ should be sought.


Remember - More details = better answers
Also: If you get a response it's polite to respond to it.