AutoPIPE Wiki 07. How does the program calculate ASME B31.1 allowable values in AutoPIPE?

07. How does the program calculate ASME B31.1 allowable values in AutoPIPE?

	Applies To
	Product(s):	AutoPIPE
	Version(s):	2004, XM, V8i, CONNECT;
	Area:	Calculation
	Original Author:	Bentley Technical Support Group
	Date Logged & Current Version	May. 2016 10.01.00.09

Problem:

How does the program calculate ASME B31.1 allowable values in AutoPIPE?

Solution:

Open AutoPIPE, see the following AutoPIPE help section:

Help > Contents> Contents Tab> Reference Information> Code Compliance Calculations> ASME B31.1> select a code year, see the various topics,

Read the entire entry. Somewhere in the write-up will be information about how AutoPIPE calculates the various allowable values for the output report.

Note: there are some settings under Tools> Model Options> Results that may affect the Allowable value, confirm these values and take them into consideration when calculating the allowable(s).

Allowable Stress (ASME B31.1 - 2010)

Hoop Allowable

Equation/Nomenclature	Location in AutoPIPE
σ = W∙SE; SE = Ej∙SH	Code Calculation
W = Weld Joint Strength W factor	Insert/Modify > Pipe Properties
Ej = Weld Efficiency Factor	Tools > Model Options > Results
SH = Hot Allowable Stress	Insert/Modify > Operating Temperature and Pressure

Occasional Allowable

Equation / Nomenclature	Location in AutoPIPE
σ = k∙SH	Code Calculation
k = k-factor	Tools > Combinations > “Code Comb.” tab
SH = Hot allowable stress	Insert/Modify > Operating Temperature and Pressure

Sustained Allowable

Equation / Nomenclature	Location in AutoPIPE
σ = SH	Code Calculation
SH = Hot allowable stress	Insert/Modify > Operating Temperature and Pressure

Thermal Expansion Allowable

Equation / Nomenclature	Location in AutoPIPE
if SA > SE σ = Sa If SE> SA and SH> SL σ = SA + f (SH - SL)	Code Calculation
f = Range reduction factor	Insert/Modify > Pipe Properties
SA = expansion allowable stress.	Tools> Model Options> Results> Sustain Margin (Y/N/E)
if Sustain Margin = Y > SA = f(1.25SC+0.25SH)+f(SH-SL)
if Sustain Margin = N > SA =f(SC+0.25SH)
if Sustain Margin = E> SA= f (SC+0.25SH) unless σ > SA, otherwise SA=f(1.25SC+0.25SH)+f(SH-SL)
f = Range Reduction Factor	Insert/Modify > Pipe Properties
SC = Cold Allowable Stress	Insert/Modify > Pipe Properties
SH = Hot Allowable Stress	Insert/Modify > Operating Temperature and Pressure
SL = Sustained Load	Taken from Sustained Load calculation