| Applies To | |||
| Product(s): | AutoPIPE | ||
| Version(s): | ALL | ||
| Environment: | N/A | ||
| Area: | Calculations | ||
| Original Author: | Bentley Technical Support Group | ||
| Date Logged & Current Version | Aug. 2015 09.06.02.06 | ||
Problem:
How to calculate the allowable expansion stress for ASME B31.4 Ed. 2012 in AutoPIPE?
Answer:
From AutoPIPE help:
Find the code equation used by the program:
a. Please see the following AutoPIPE help section:
Help > Contents> Contents Tab> Reference Information> Code Compliance Calculations
b. Select the proper code and code year. (ex. ASME B31.4 (2012)
c. Select the type of Stress to be calculated. (ex. Thermal expansion stress)
d. Determine if calculation is based on Unrestrained or Restrained calculations:
To determine this open the input grids, select the Piping Restraint tab, locate the model node point of interest, and note the Stress Equation used, see example below:
e. In this section will be information about the allowable (ex. SA)
f. Select "Definitions of Terms" to see details on this value.
g. Select Material properties
h. Search for SA
i. See SA = for specific code and year
OR
Look up the allowable in the code.
For B31.4 (2009 and higher) AutoPIPE does calculate the unrestrained expansion allowable as per clause 403.3.2:
SA=f[1.25(Sc+Sh)- SL]
Where:
SA = Allowable expansion stress
f = Fatigue factor (defined as "Range reduction factor" on Result Model Options dialog)
Sc = 2/3 * Sy (Sy is the minimum yield defined on Pipe Properties dialog)
Sh = 2/3 * Syt (Syt is the yield value at each temperature case, updated on pressure and temperature dialog)
SL = Sustained stress for unrestrained lines
See Also
ASME B31.4 Piping Code Calculation Issues