scope:

This Defence Standard is designed to offer guidance, on the terminology used within R&M and, using examples, how this terminology might be tailored in order to define SMART requirements for different programmes.

The role of the Standard is to provide the building blocks to assist those concerned with setting requirements to understand how to adapt appropriate definitions, primarily from IEC 60050-191, in order that suitable requirements can be derived. Consequently, the definitions in Def Stan 00-49 Issue 1 are deemed obsolete with the release of this Standard at Issue 2.

In all cases the requirement(s) must be demonstrable, through analyses and trials if appropriate, using the R&M Case methodology. If not it is likely that achievement of the requirement can not be verified/validated and/or the User will lack confidence in the delivered solution.

This Standard contains a number of examples based on specific definitions selected from IEC 60050-191. The definitions and related terms in each example are examined to provide guidance on how the variations in their meaning might affect and be utilised in R&M requirements.

The examples, being generic in origin, are not designed to be used in their current form; they represent only a small sample of the available terminology to be used when specifying R&M requirements. Further information is obtained in the Related Documents listed below and further guidance is available from the Defence, Engineering and Support, Through Life Support - Reliability, based in MOD Abbey Wood, BRISTOL.