4"-250# Flange Mated with 4"-150# Feasble Technically or Not?

[Skorp1on]

Hi all,

Just have a real quick question:

I am nowing dealing with flange rating question concerning SRV (Set Presure at 150 psig) which has 4"-250# inlet connection. But the pressure veseel this SRV is to be mated to happens to have 4"-150# which I believe is not intended.

So the quesiton is, can 4"-250# Flange be mated with 4-150# from a technical feasbility standpoint? I think hole pattern of the flanges are similar while the bolt diameter of the 250# is like 1/16" larger in diameter.

Thanks in advance for any opinion or guidance.

 

[Skorp1on]

Nevermind, it seems that it doesn't work afterall due to the difference in Bolt Circle...

 

[rconner]

Yes, with an adaptor spool or even more compact special "Flange Adaptor" (see e.g.

http://www.acipco.com/adip/specials/adaptor.cfm)

 

[Skorp1on]

thanks rconner.

I like the more compact special "Flange Adaptor" solution but I am trying to find one that has CRN (since it will be installed in Alberta Province) and one suitable for pneumatic application. Anyone with information of a supplier that can satisfy the above would be much helpful.

My last resort is to fab up an adaptor spool.

 

[Canadieng]

Try UCANU manufacturing

http://www.ucanu.ca/

I believe it is them that have a letter from ABSA stating that there is no Alberta requirement for CRN's on bleed rings, and they will even provide that letter to you for reference. It may be that ABSA doesn't require a CRN on a flange adapter plate as well - something to look into.

On the other hand, if you/your company require a CRN - try TransAm Piping:

http://www.transampiping.com/

I have gotten CRN'd slip blinds from them before.

Also there is another manufacturer, in Edmonton if I recall correctly, that does indeed have CRN'd bleed rings - maybe they also have CRN'd adapters . I will ask a co-worker tomorrow for the name of that company if I don't remember tonight.

 

[Canadieng]

Yes........

Now I recall - Barber Engineering - try them, I seem to recall they have, at least, CRN'd bleed rings - so maybe flange adapters as well.

http://www.barbereng.com/

 

[rneill]

Skorp1on,

In Alberta, pressure relief devices are required to have CRNs as well. I'm curious whether your SRV has a CRN. 250# is very unusual for pressure equipment and the pressure relief device may not have a CRN.

 

[Skorp1on]

Thanks all.

rneill,
Yes, the PRVs (made by Tyco) have CRNs. But unfortunately, the inlet flanges provided are 250# while i got receiver tanks that have been fabricated and hydro'd with 150# flange. CRN's pretty much has been the story of my life for the past year and 1/2 =)

Canadieng,
A colleague of mine also mentioned Barber Eng. While I visited their website, but haven't been able to locate adaptor flanges. So I will likely have to call them.

 

[rneill]

You would probably know that the Class 250 flanges are gray iron per ASME B16.1 whereas any vessel is going to be carbon steel as opposed to iron so the flanges would have to comply with ASME B16.5 which does not have a Class 250 so they have to use either Class 150 or Class 300 on the vessel.

As an FYI, many end users don't permit iron components in pressure piping.