The Interoperability Process Reference Manual (IPRM) defines a process by which industry stakeholders may procure, test, and assert interoperability between disparate vendors of smart grid products to identified standards. This is accomplished by defining the relationships between smart grid stakeholders invested in this goal. This standard defines requirements and recommendations for general test policies, test suite specifications, test profiles, interoperability testing and certification authority technical programs, governance, laboratory qualifications, and (process) improvements. Finally, this standard describes an implementation approach.