What is it?

Reliability analysis consists of several interrelated disciplines and techniques which collectively fall under the branch of engineering known as RAMS (Reliability, Availability, Maintainability and Safety). RAMS focuses on assessing and optimising the dependability of systems and components to:


  • Minimise equipment and human failures (reliability)
  • Maximise output (availability)
  • Reduce downtime (maintainability)
  • Protect people, assets and the environment from harm (safety)

A fundamental aspect of RAMS is the identification, analysis and management of risk.

Why is it important?

Reliability is an attribute that affects all systems. It is generally agreed that greater reliability is preferable to lesser reliability. However, increased reliability often comes with increased cost. The basis of a successful RAMS programme is to find the appropriate balance. For example, the triple redundancy often required for a nuclear safety system would not be considered appropriate for a chemical process plant. Significant cost savings (OPEX and CAPEX) and output improvements are possible by selecting:


  • Correct combination of robust equipment specification
  • Equipment operating environment
  • Equipment redundancy and diversity
  • Operating procedures
  • Maintenance policy

Workers in Hi-vis jackets and helmets

What do we do?

Workers in Hi-vis jackets and helmets on building site

Our team members are some of the UK’s leading practitioners in the field of Probabilistic Safety and Reliability Analysis. We have experience of applying RAMS techniques to a wide range of industries, including Nuclear Power, Defence, Transport and Oil and Gas. Our team members have been involved with this programme since its inception in the early 1980s and as a result, CRA offers expertise unmatched by any other consultancy in the UK. The success of the team is attributed to our ability not only to listen to our clients’ needs, but to clarify and influence their needs for the benefit of their organisation.

Our Work

Much of our work has taken place as part of the comprehensive, rigorous and periodic Probabilistic Safety Analyses required by the Health and Safety Executive for all of the UK’s nuclear power stations.

nuclear power plant

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