How can I calculate pipe wall thickness under external pressure? 1

[Moong]

Hi everyone

I have question about pipe wall thickness under external pressure condition.

I know it can be calculated in accordance with ASME BPVC SEC VIII - UG 28.

In this code, I must determine factor "A" and "B", and it can be determined in ASME SECTION II -1.

But, sometimes I cannot determined factors because Do/t or L/Do do not exist in the table G (in the ASME SECTION II- Subpart 3)

In this situation, what is the best way to determine the factor A & B?

Plz, help me.

Best regards, Moong.

 

[LittleInch]

If this is for a pipe or pipeline you cold try DNV OS F101 for subsea pipelines which looks at collapse pressures.

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

 

[Moong]

Thank you for reply @LittleInch

 

[jte]

Moong-

Or... You could read VIII Div. 1 UG-28, and then review charts in Section II Part D. Specifically, UG-28(c)(1)(step 2) and UG-28(c)(2)(step 1 or step 2).

 

[pdp123]

Hello Moong....

Could you give more specific details so that other members can provide help.

Regards
PME

Hard Work with Smartness is the key to success

 

[blacksmith37]

Collapse is a routine calculation for casing and tubing ; Look in API standards ( I don't remember the exact document ).

 

[SNORGY]

Back in 2011, I did a calculation comparison of estimated collapse pressures for 4" SCH 40 pipe using (1) Timoshenko's Formula; (2) Haagsma's Equation; (3) ASME's approach. What I found was that, as is done by L.C. Peng in his book, if you apply a safety factor of 3.0 to Timoshenko's Formula and Haagsma's Equation, the three approaches yield nearly identical results. I didn't apply it across a range of diameters and thicknesses, but the equations lend themselves nicely to EXCEL (or, presumably, MathCad), and they might be a good place to start.

There is a good paper, OMAE'99, PL-99-5033, BENDING MOMENT CAPACITY OF PIPES by Soren Hauch and Yong Bai, that outlines the calculations.

 

[jte]

Good info, Snorgy!