Def Stan 00-56 Safety Management Requirements for Defence Systems captures the requirements and guidance of the United Kingdom Ministry of Defence regarding the procurement, analysis, development and operation of safety-critical systems.

This safety standard lists objectives relating to:

• an overarching safety management system
• relevant legislation, regulations, standards, policy and contractual requirements, in both products and activities;
• considering safety early in the life cycle;
• competency
• integrating safety into wider activities with clear interfaces
• safety case delivery as necessary
• identifying all credible hazards and accidents
• reducing risks to As Low As Reasonably Practicable (ALARP)
• managing changes that may impact safety; and
• monitoring and incident reporting.

Issue 2 of this standard was to be used with the following closely related standards from the United Kingdom Ministry of Defence but from Issue 3 onwards has superseded these documents.

• Def Stan 00-54 Requirements for Safety Related Electronic Hardware in Defence Equipment
• Def Stan 00-55 Requirements for Safety Related Software in Defence Equipment
• Def Stan 00-58 HAZOP Studies on Systems Containing Programmable Electronics

Def Stan 00-56 is also widely credited as popularising the use of the safety case as a means of showing that a level of acceptable safety has been reached.