ASME Section VIII Nonmandatory Appendix

[rdallas]

Are the items in a "nonmandatory" apendix truly nonmandatory, that is do not have to be met. For example, in Appendix M relief device inlet and outlet allowable pressure drop are specified. Are these requirements that have to be met, or only suggestions?

 

[metengr]

What is the reason for your question? The definitions are self explanatory in the Code. An Appendix is used to provide either supplemental information or more specific information that is not otherwise mentioned in the main body of the Code. Nonmandatory Appendices are provided as sources of information regarding good engineering practices. Use them for what they represent.

 

[Sharik]

Actually this is a good question and one which has not ever been answered completely. For example, for PSV's, in UG-135, Installation, there are several references to Appendix M (non-mandatory). It doesn't say to use Appendix M as a guideline or for information, in someplaces it actaully specifies "under the conditions set forth in Appendix M".

So since this non-mandatory appendix is specified in the Code, do the requirements in this appendix now become mandatory?

 

[metengr]

The local Jurisdiction typically mandates the installation requirements of pressure vessels and pressure relief vales. Nonmandatory Appendices provide general information that a user or designer may use in the event a Jurisdiction does not provide any rules OR the Jurisdiction may reference this Nonmandatory Appendix. If this is the case, the Jurisdictional rules prevail and Appendix M must be used.

The Code committees cannot write rules for every application. Therefore, Nonmandatory Appendices are intended to provide general guidance.