Slip on flanges for normal fluid services

[Xk333]

Is it a good practice to use slip on flanges for normal fluid services for flange rating 150# instead of weld neck flanges to save cost?

Would you recommend slip on flanges for steam service of 10 bar and 30 bar pressure?

 

[Xk333]

ASME B31.3 also states that slip on flanges can be used where severe erosion, crevice corrosion is expected and for toxic, flammable services as well if double welded.

 

[r6155]

ASME B31.3 2022
K308.2.2 Other Flange Types. Slip-on, socket welding,
and expanded joint flanges, and flanges for flared laps, are
not permitted.

Regards

 

[Xk333]

r6155,

I'm on working with Category D and Normal service fluids. K308.2.2 is for High pressure Fluids if I'm not wrong

 

[r6155]

@ Xk333
What edition of ASME B31.3 are you using?
Regards

 

[Xk333]

r6155,

ASME B31.3 2022 page 35

 

[myname_earl]

I keep seeing the 30% strength of a WNF reference to B31.3 - can someone give the full reference from B31.3? Fitters are trying to argue that "we have slip ons all over the place without any issues" doesn't necessarily mean its best practice.

"Experience: that most brutal of teachers. But you learn, my God do you learn.” - C.S. Lewis

 

[XL83NL]

Fitters are trying to argue that "we have slip ons all over the place without any issues" doesn't necessarily mean its best practice.

Are your fitters also the operators who know from day-by-day experience how both systems perform? If not, their argument has little ground.

I think the 30% number could easily be a ballpark figure thought of by someone, some time ago, perhaps in some publication. It could be accurate, it could be not. No matter what, it will always depend on service conditions.

Huub
- You never get what you expect, you only get what you inspect.