| Applies To | |||
| Product(s): | AutoPIPE, | ||
| Version(s): | All | ||
| Environment: | N/A | ||
| Area: | Code Combinations | ||
| Original Author: | Bentley Technical Support Group | ||
Problem:
What safety factors are used in AutoPIPE for Hoop Stress, Thermal stress, etc...?
Answer:
Each Piping code has a different method of calculating the allowable.
Please see the following AutoPIPE help section:
Help > Contents> Contents Tab> Reference Information> Code Compliance Calculations>select any piping code (ex. B31.3-2012) > select a topic (ex. Hoop)
Somewhere in the write-up there is information about the Allowable calculation:
ex. allowable stress (SE).
Review the "Definition of Terms" for details on this or other acronyms mentioned in the write-up.
In this example, SE can be found under Material Properties:
As seen above the value of SE has multiple definitions that are dependent upon the Piping Code selection (ex. B31.3 - 2012) used in analyzing the model. Therefore the allowable can be adjusted up or down by adjusting the respective factors as needed.
Most of these factors are typically located in one of two places:
1. Pipe Properties dialog
2. Results Model Options dialog
Note: depending on the Piping code selected for analyzing the model, some factors will NOT be editable (grayed out) on these dialogs.
Another factor that may be available for modification is the "Allowable (K) Factor", this can be found on the Combinations dialog screen.
Note: depending on the piping code selected, by unchecking "Auto Update" check-box OFF on the respective combination row, the K - factor may not be editable (grayed out).
Furthermore, for more control over the Allowable calculation, manually calculate an allowable value, uncheck "Auto Update" on the respective combination row, and manually overwrite Allowable Stress "Automatic" value with the hand calculated value.
Definition of Terms
As mentioned earlier, the "Definition of Terms" is located in AutoPIPE's online help under:
Help > Contents> Contents Tab> Reference Information> Code Compliance Calculations> Definition of Terms. The section is split into the following sections:
Pipe Properties
Material Properties
Pipe Loads
Geometric, Loading and Stress Factors
Weld Factors
Range Reduction Factor
Y Factor
Nominal vs Corroded
Each of these sections has information about the acronyms used in the code compliance calculations. Just because an acronym is defined does not mean it will be available in the program. Many settings are hidden from view or are grayed out (not editable) depending on the Piping code selected in the model. Refer to the Code calculation first and then to the definition of terms to understand the acronym.
Example:
under Help > Contents> Contents Tab> Reference Information> Code Compliance Calculations> Definition of Terms> Geometric, Loading and Stress Factors> the following acronyms are listed:
AH = Safety factor for allowable hoop stress
AL = Safety factor for allowable longitudinal stress
The piping code selected is ASME B31.3 - 2012, where are these settings in the program?
Answer: These settings are located under, Results Model Options dialog.
However, as mentioned in the online help: "This field is active for the General piping code option."