The different parts (design, manufacture, inspection, …) of a harmonised standard, a code or a specification for pressure equipment form a consistent set of documents which should be followed.
Nevertheless, the partial use of a harmonised standard, a code or a specification is not forbidden.
In these conditions, the essential requirements covered by the part(s) of harmonised standards, codes or specifications used shall be identified.
The essential requirements not covered by the part(s) of harmonised standards, codes or specifications shall be subject to an analysis to judge the validity of the adopted solutions.
Then, if several different parts of harmonised standards, codes or specifications are used, it shall be verified that there are no incompatibility or inconsistency between these parts, particularly for the application data (permissible stress, safety coefficient, extent of the inspection, …).