High temperature pipe & flange ratings

[Bribyk]

I need to know what (blind) flange class is equivalent to Sch-20 carbon steel (or Sch-10 SS) at 1300-1500 degF for engine exhaust service. The free references to ASME/ANSI standards online don't seem to go to this high of a temperature and I don't want to buy a standard to find out that it doesn't either. Can someone point me to the relevant standard for these pipe schedules and flanges for high-temp service?

 

[BigInch]

i think you might want to post in the automotive forum.

"Less than 1% of the energy moving a car goes towards the driver."
Amory Lovins - The Oil End Game

http://virtualpipeline.spaces.live.com/

 

[MJCronin]

Brib...

Be careful when you choose a code or standard for your particular situation......

ASME B31.1 and B31.3 apply to power and chemical piping systems of a certain minimum pressure (15 psig), below certain maximum temperatures, in a particular service (eg. power plants and chemical plants) and carrying certain fluids.

I feel that your exhaust system is not governed by these rules...

-MJC

 

[Bribyk]

It isn't covered by any piping codes, just OH&S regs and manufacturer's recommendations (Gas Code requirement). One manufacturer and NFPA 37 recommend it be strong enough to sustain a deflagration event (~150 psig from the references I've found for a methane backfire) & service conditions. One engine manufacturer recommends Sched-20 carbon steel piping as a minimum and another doesn't provide any strength recommendations. I have ends caps on our system and I need to make sure they don't become projectiles (again). I'm considering using blind flanges equivalent to Sched-20 instead of the "rigged" caps but it looks like the required flanges are going to be very heavy and cumbersome (14" & 20") anyway.

 

[jte]

Bribyk-

Yes, ASME B16.5 has ratings for flanges (e.g. most of material groups 2.x so Stainless) which go up to 1500 deg F, though you're looking at at least a CL-300 flange to start with.

So, its safe for you to spend the money buying a copy of the standard.

jt

 

[MJCronin]

Ok.....

Got a better picture now.....

Ummm.... at 1300-1500F, carbon steel materials will not last too long. That may or may not be a problem. Sched 10S stainless may be a better choice

If the normal operating pressure is low, but the system may be subject to a rare upset condition of about 150 psig, I suggest that you use a Sched 10 system and use welded pipe caps. Type 409 stainless has been used extensively in exhaust systems

See this link for FLOWLINE thin walled Fittings (there are many competitors)

http://www.flowlinefittings.com/catfittc.asp

-MJC

 

[Bribyk]

Thanks, jte et al. I hate to buy standards and then find out it doesn't have what I'm looking for.