0.8 Design Factor

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The new Appendix B in AS2885.1-2018 appears to provide information that almost discourages the use of a 0.8 Design Factor. Is this the intent?

Not at all. However, selection of a 0.8 design factor requires a significant engineering effort, and may result in hidden extra project costs. The guidance is to ensure that the decision to design and build a pipeline with a 0.8 design factor is taken seriously, and to advise that for shorter or smaller pipelines the costs saved in wall thickness may not outweigh the costs for the extra engineering effort. (James Czornohalan)

The following infographic may be helpful: Things to consider when using 0.8DF


If pipe material (e.g. cut-out) is available for testing, can an existing pipeline designed with 0.72 be reviewed for applying 0.8 for upgrading a pipeline MAOP? (from APGA Webinar on Design Factor, 3 Mar 2021)

Section 9 of AS 2885.1-2018 has comprehensive requirements for upgrade of MAOP. Having a sample pipe to test could be helpful but is only a small part of the conditions to be fulfilled before MAOP can be upgraded. In particular, Clause 9.1(b) says that the increased MAOP cannot be higher than would be allowed under the requirements for hydrostatic testing, which basically means that the pipeline must have been, or is capable of being, hydrotested to 100% SMYS (test pressure factor of 1.25 and MAOP of 80% SMYS). (Peter Tuft)