#600 Flange onto a Sch 40 Pipeline 1

[Leinster]

Is there any problem with installing a 4" ANSI B16.5 #600 flange onto a 4" API 5L ASTM A106 Sch 40 pipeline?

The working pressure of the system is 70 bar and as per the specs for Sch 40 and #600 this should be adequate. Please advise as I have never seen a #600 flange installed onto a Sch 40 pipe but cannot see there be any problems.

Just wanted some expert advice to make me feel a little more comfortable.

 

[zdas04]

You are the engineer. You need to do the wall thickness calcs and define a minimum wall thickness (plus a corrosion allowance) for your required operating pressure. 70 bar is typically a reasonable range for Sched 40 Grade B or X-42 pipe. It is too high for ANSI 300 flanges, so you go to ANSI 600. Doesn't look like much of a problem to me.

David

 

[BigInch]

It will be perfectly fine IF,

1.) the materials are weld compatible, meaning that the flange material should probably not have a grade higher than Y-52, or 52,000 yield strength, and

2.) the wall thicknesses of pipe and flange at the welding neck point do not vary by more than 3/16".

 

[TBP]

Looking at it from the other end, I've seen 150# weld neck flanges, with a sch 160 neck.

 

[BigInch]

Maybe a long span between supports?????
Hope it was taper bored for the weld.

I once saw a 30" flange on a 31" pipe (very high hydrotest pressure )

 

[dcasto]

material compatibility and wall thickness must be taken into account.

I must ask, why did you buy pipe rated for 2000 psi only to operate it at 1000 psia?

Just wondering

 

[TBP]

Big Inch - I don't even know what the service was. I "2-holed" it, squared it up to the sch 160 pipe, and the welder did the rest.

I'll always remember it though. "Wow - THIS is different..."

 

[rmw]

Talking about different - I once did a lot of engineering in a plant with a lot of low pressure steam where the Maintenance Sup't had a lot of oil field experience and he regularly put 900# and 1500# flanges on 15 psig and 100 psig steam piping. It is what he knew and no amount of explaining would convince him to use less. Talk about strange looking, 900# flanges on a 15 psig deaerator......


rmw

 

[BigInch]

Field fab at its best!

 

[Duwe6]

meaning that during Field Fab, there has to be some engineering direction. Otherwise, you get the horrible examples again. Give them the material, pipe schedule, flange rating and face, whether buttweld or socket weld on small-bore, and whether Slip-On flanges are OK.

The easy "out" for Leinster's situation is to have the fab welder use a Slip-On flange. Otherwise, you have to choose between ordering a 600# Weld-Neck counterbored to Sch40, or forcing the fitter & welder to grind for 4 to 8 hours to achieve the required 3:1 ID taper. Neither are cheap options.

BTW, 600# steam belongs inside Sch80 pipe. The generous Corrosion Allowance is needed, unless the operatior ALWAYS perform a proper Wet-Layup to prevent corrosion [never happen]

 

[BigInch]

EAsy perhaps, but a lot of companies prohibit slipons for that application, meaning anything over 2" and over ANSI#150, and with good reason I might add.