Difference between Codes & Recommended Practices (RP)

Codes are mandatory. It is mandated by jurisdiction or the project. You can not violate or ignore a code requirement else, you are not complying with the code.

For example, if a pressure vessel is built and stamped as per ASME VIII code, then, it should comply with all the design, material, manufacturing and testing requirements of the code, otherwise, the ASME code would be void and ASME stamp is not valid anymore.

Any statement with the word “SHALL” means mandatory requirement and must be fully complied with. You can not deviate from it nor ask for concession.

Recommended practices are based on good engineering or industry practice. You can deviate from it as long as you have engineering reason to do so for your specific needs. That is why, RPs are synonymous with the word “SHOULD” which means recommended but not mandatory.