max working pressure as per b31.3

[AliGrailly]

[pre][/pre]hi

i used eq : p=2se(t-c)/d-2×y(t-c) to calc max pressure for A106-B seamless at temp 100F
Od=1.315 , t=0.133"-12.5% s=137.9mpa
Result=26.3mpa or 263bar

but i visited some websites and got following formula with safety factor ( while b31.3 not mentioned safety factor just states basic allowable stress)

sf from 1.5 to 10
sf:1.5 --->>> so p=22.6mpa


See here 1" Od and see column p=226psig???

Equation: P = (2*S*T)/((O.D.-2*T)*SF)

Where: P = Fluid Pressure (psi)


T = Pipe Wall Thickness (in)
O.D. = Pipe Outside Diameter (in)
SF = Safety factor (General Calculations 1.5 – 10, Use 1 For Bursting Pressure)
S = Material Strength (psi)
Ultimate Tensile strength or Yield strength can be used.
Ultimate should be used to determine the bursting pressure.
Yield can be used for estimating pressures at which permanent deformation begins.
1Mpa=144.55psi

 

[1503-44]

S allowable stress

https://www.engineeringtoolbox.com/temperature-allowable-stresses-pipes-d_1338.html

P=

https://www.engineeringtoolbox.com/asme-31.3-piping-pressure-calculations-d_2158.html

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[XL83NL]

It’s a bit fuzzy and I’m not sure what exactly you’re asking, but in general I never trust such data sheets. I don’t care what MAWP they tell you, 99% they’re incorrect as some of their input is different from yours. Only you know your input. You’re the engineer (oh and you’re mixing up units of measure).

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

 

[1503-44]

The sheet data did not say B31.3, so I moved on from that. 36.10 might be the same, but might not, as it didn't tell us what they used for S, etc.

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[AliGrailly]

i used the formula of B31.3 for 1/6 thickness and internal pressure but data sheet is different i do not why used max pressure 226 psi for 1" and thk=0.133
max allowable stress in table A1=20ksi amd table A1-M=138 or 137.9mpa

following used for which code ?
p=2s×e×t / ((D-2×y×t)×sf)
sf between 1.5 to 10

b31.3 did not guide to safety factor only states basic allowable stress --> means allowable stress divided by 3 or tensile devided by 3=maximum allowable stress?

 

[XL83NL]

Read B31.3 para 302 something. The factors against yield and UTS are in there. No need for an (extra). FOS for whatever reason.
Ps: I think it called design margin against ****, where **** is a specific failure mode. For example plastic collapse.

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