Thick wall pipeline stress calculation 2

[fireamin]

Hi
I'm using ASME B31.4 to design a pipeline with following specifications:
Design Pressure: 8360 Psi - Pipe size: 6" - Temp: 120 C - material: API 5L X60
the calculated thickness with ASME b31.4 is 22.23 mm and the d/t ratio will be 7.5.
It's mentioned in B31.4 that the stress formula from internal pressure is not applicable for d/t<20.
Now i'm asking what formula or standard i can refer to for stress calculations? is it ok to calculate thickness with B31.4 and stress calculations from another source?

 

[LittleInch]

Maybe, but this needs to be stated up front in the design basis and agreed with the client.

The only pipeline code I know which actually gives you a different formula for thicker pipe is BS PD 8010-1. section 6.4.2.1

see upload for extract

ISO 13623 uses the mid wall thickness (section 6.4.1.1)

The issue is probably that the thickness you get will be lower, so which do you choose?

At that pressure you might be better off using API 6A as you'll need to use API 6A flanges.

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

 

[fireamin]

thank you for your reply dear littleinch.

The issue is probably that the thickness you get will be lower, so which do you choose?

you mean if i use ISO 13623 the calculated thickness will be lower than what i get from BS 8010? if yes that might be good for me because the thickness i calculated with B31.4 is already high.

At that pressure you might be better off using API 6A as you'll need to use API 6A flanges.

can u please specify in which section of API 6A it talks about pipe design and thickness calculation?

also i was wondering if i could use ASME sec viii div 2 for stress calculations of thick wall pipes. is it possible?

 

[LittleInch]

It doesn't. See

http://www.woodcousa.com/about_wnf.htm

for an explanation.

Basically find a flange to suit which then list max bore and that's your wall thickness based on X 60.

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

 

[BigInch]

Actually you cannot use the thick pipe formula with B31.4 Mixing provisions of different codes is prohibited, unless specifically stated a provision of another code can be applied. Otherwise it will constitute a deviation from the design code, so a signed variation order from your client, or government authority, is needed to continue.