Limits of 600# flange

[EngineerRed]

I'm looking towards using the existing pipe flange for my new valve, But my new valve has more outlet pressure than the previous one . According to specification it needs 900# flange whereas my existing piping has only 600# . How can I check if I can use this same existing flange ? Service temperature 60 Celsius , Service Pressure 125 barg , material WCC .

 

[LittleInch]

You look at the pressure/ temperature ratings in ASME B 16.5 for class 600 flange.

Maximum working pressure for a group 1.1 material flange at 60 C is 98.8 bar.

Therefore you cannot use a class 600 flange at a pressure of 125 barg. You need a class 900 flange.

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

 

[racookpe1978]

But just the ONE (new 900 lb rated) pipe flange mating the new 900 lb flange on the outlet of the new valve will NOT serve the rest of the pipe system!
What is the ACTUAL system diameter, operating pressure, temperature and service fluid of the ENTIRE pipeline being served INTO and OUT OF the new valve? Upstream side matters too.

Now, that the new valve has a 900 rated flange may NOT mean the system pressure requires a full, new higher-rated pipe. We cannot tell. Yet.

 

[georgeverghese]

The 900lb flange on the new valve will not fit the flange on the 600lb existing pipe also.
You may have stated the service pressure of the new valve?
But what is the actual process design pressure of this piping segment - do you have a P&I diagram ?

 

[LittleInch]

Nothing about this post makes sense.

A valve doesn't create pressure...

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

 

[EngineerRed]

Okay , I should have mentioned clearly , my bad . The Valve that I'm gonna fit is a PRV . My existing piping has 3/4 600# flange on the upstream and 1" 300# on the downstream . I've given a PRV that has 3/4 male nipple SW end without a slip-on flange , Outlet of the PRV is however 1" 300# . The PRV tag recommends a 3/4" 900# on the inlet . I'm skeptical about welding the PRV 3/4 nipple to a 600# slip-on flange . I cannot however weld a 900# SO flange to the PRV inlet as my existing pipeline connection is 600# flange only . I just want to make sure that it is safe to use the PRV still on the 600# inlet

 

[LittleInch]

Not if the design pressure is 125 bar you can't (at least not if you're following the design codes properly).

You will need to cut off the 3/4" class 600 flange and replace it with a class 900/1500 flange

Class 900 and 1500 below 2" are the same dimensions, but not class 600 to 900.

That's not to mention all the other things listed which have hopefully been checked on what seems to be a change of design pressure for this system?

And in your OP it should say, my valve has a higher inlet pressure if it's a Pressure Relief Valve.

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

 

[Vikko]

I do not know what "WCC" stands for, but in no case; there are no such materials where you can used #600 flange at any temperature for 125bar according to ASME B16.5.

Maybe, the only way is to try to use some different calculation methods than the normal Taylor Forge (ASME VIII Div 1 Apx 2, or EN 13445-3 11), like EN 13445-3 Anx G, or EN 1591-1. Because usually the standard flanges and the calculation according to Taylor Forge results with a bit oversized flange.

 

[SnTMan]

EngineerRed, there is some reason the existing system has a 600# flange. You need to find out what is is.

EDIT: Before you go changing things....

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[LittleInch]

Vikko,

I assumed he or she meant WCB, but 2003 is a no old version... The latest B 16.5 is 2020...

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

 

[r6155]

@ EngineerRed
Do you have the original drawing?
Do you have the nameplate?

I suggest Welding neck flange sch 80.
Welder shall be qualified for the actual position of the nozzle.

Also see ASME VIII iv 1 Appendix M
M-12 REACTION FORCES AND EXTERNALLY
APPLIED LOADS
(a) Reaction Thrust. The discharge of a pressure relief
device imposes reactive flow forces on the device and associated
piping. The design of the installation may require
computation of the bending moments and stresses in the
piping and vessel nozzle. There are momentum effects
and pressure effects at steady state flow as well as transient
dynamic loads caused by opening.

Regards