This Guide is intended for use in the petroleum, petrochemical and chemical industries. It identifies and defines a set of common additional and modified requirements to ISO 15649 and ANSI/ASME B31.3 necessitated by the PED. Additional guidance is provided by a suite of annexes (A to E) which are intended to be read independently, but in the context of the main text. These include an actions checklist, tables identifying key requirements of the PED and the corresponding clauses of the ISO/ANSI-ASME standards, and supplementary information.