Piping design of hot water systems

[AndrewBF]

I'm the engineer on multiple water loops in my company's test lab. I've recently started getting requests for testing of hotter water than I have in the past, up to 250F and beyond. Does this mean that my test facility piping needs to fall in line with ASME B31.1? I'm confused by the scope of B31.1 because 100.1.2 indicates the code covers high-temperature water at pressures exceeding 160 psig and/or temperatures exceeding 250F. However, 100.1.3 indicates that hot water heating systems designed for 30 psig or less are out of scope, which seems to imply that above 30 psig is in scope. This contradicts what was stated in 100.1.2. So what code do I need to abide by if I'm greater than 30 psig, but less than 160 psig and 250F?

 

[1503-44]

Depends on the use of the system, not specifically any temperature or pressure.
31.1 is power as in boilers for electrical or mechanical power gen.
31.3 usually involves chemical processing of one sort or another.
B31.5 is Heat Transfer and Refridgeration.

Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[AndrewBF]

It's for hot water heating using a heat pump. So serving the same function as a boiler, but not technically a boiler. And regardless 100.1.2 and 100.1.3 still seem to contradict each other.

 

[RVAmeche]

As 1503 mentioned, B31.1 is normally for boiler piping associated with power generation.

Assuming you aren't feeding hot water into a generator, normal B31.3 is probably your best bet.

 

[AndrewBF]

The attached image is a snip from the code that seems to point me towards 31.1 since as a heat pump I think I fit better into the category of district heating than any of the processes listed in 31.3.

 

[RVAmeche]

The answer comes down to the client they drive that decision. It's not "all hot water heaters are B31.1" which I can tell you is not the case.

 

[1503-44]

Not 31.5? Heat pump is kind of short on "process", but it would be fine for the pipe.

Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[RVAmeche]

At least ASME's blurb about B31.5 seems to say it's not applicable to water piping.

B31.3 blurb, in case you're thinking B31.3 is only oil (it's not):

 

[1503-44]

Actually no of course not. And I never cracked the cover on 5, but I think I've heard of late that supposedly a better fluid for heat pumps is butane, although water is the subject here.

Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[LittleInch]

Try googling hot water design code / standard in your are and see what it brings up.

B31.1 is a bit of a mighty beast to unleash on what is still essentially a hot water system.

I know this is UK / Europe but I found this

https://www.hotwater.org.uk/uploads/5B053A7597A5F.pdf

Look at the codes section

Is there an industry association for your specific item?

As superheated water you definitely need to start doing things properly and looking at safety and risk, but B31.1 really is designed for large power plants and steam boilers

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

 

[1503-44]

I'd go with B31.3
Its the owner's responsibility to chose the most appropriate code.

Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[PEDARRIN2]

What about B31.9 Building Service Piping? Heat pump providing hot water would likely fall into that. Although none of the heat pumps I am aware of can produce water at 250 F.