This standard describes the basic requirements for qualifying Class 1E equipment and interfaces that are to be used in nuclear power generating stations. The principles, methods and procedures described are intended to be used for qualifying equipment, maintaining and extending qualification, and updating qualification, as required, if the equipment is modified. Meeting the qualification requirements demonstrates and documents the ability of equipment to perform safety function(s) under applicable service conditions including design basis events, thereby minimizing the risk of common-cause equipment failure. This standard does not provide environmental stress levels and performance requirements. Revision Standard - Superseded. The basic requirements for qualifying Class 1E equipment and interfaces that are to be used in nuclear power generating stations are described in this standard. The principles, methods, and procedures described are intended to be used for qualifying equipment, maintaining and extending qualification, and updating qualification, as required, if the equipment is modified. The qualification requirements in this standard, when met, demonstrate and document the ability of equipment to perform safety function(s) under applicable service conditions including design basis events, reducing the risk of common-cause equipment failure.