Safety Critical Element Management Manual EP 2009-9009 Restricted 6 Performance standard (PS) for Operate phase A statement, which can be expressed in qualitative or quantitative terms, of the functional performance required of a system or item of equipment, and which is used as the basis for managing the risk from the Major Hazards. Deviation An approved noncompliance of the mandatory requirements of a procedure, standard or specification. In this manual, this is applied to assurance and safety critical corrective and preventive work orders which will not be or have not been carried out by the due date. CMMS Throughout this document, CMMS is used to refer to the Computerised Maintenance Management System, which inmost Operating Units is the plant maintenance and other modules of SAP. The principles of this manual equally apply to any CMMS although some terms used may have meanings specific to SAP. Appendix 2 includes requirements specific to the use of SAP as the CMMS.