SCE verification

What Does Verification of Safety Critical Elements Look Like ?

Managing risk on a facility requires a clear understanding and verification of:

  1. Our significant hazards and their potential consequences
  2. The controls in place to help us reduce the likelihood of an undesired outcome from occurring
  3. What assurance we have in place to ensure the controls will work on demand

Controls are generally physical, software or procedural. Physical and software (automated) controls tend to be more effective than procedural controls that rely on human action.

For the purpose of this blog, I will refer to Safety Critical Elements (SCE’s) as those controls that have a physical aspect to them and form part of the plant, as per illustration below. They are generally designed with integrity and reliability in mind and are depended on to prevent high consequence process safety incidents or limit their scale. We need assurance that these controls are suitable and effective.


To have confidence in your overall management of SCEs, the following four questions should be answered:

  1. Have all major incident hazards been identified, and have all control measures been identified to eliminate or minimise the risk, so far as is reasonably practicable?
  2. Have performance standards been established for the SCE’s?
  3. Is the design adequate i.e., in line with industry standard and/or code requirements?
  4. Will the SCE remain suitable throughout the lifetime of the facility?


In line with guidance in industry or published by regulators, many Operators I have come across have their SCE verification arrangements well documented and achievable relative the resources available to them. There are however still variations in understanding and interpretation of this guidance in and across industry, and not all Operators have a multitude of resources available to them to achieve these requirements. For those that are still in the process of achieving this, the most appropriate place to start is to develop a plan for verification based on the activities illustrated below:

SCE workflow

If your plan covers all of the above areas, allows for independent, competent, and experienced people to perform the above verification tasks, and is embedded within your Management Systems, you are well placed to manage high consequence process safety risks on your site.

Download our SCE Verification Checklist for more information on how to approach this important topic

Download SCE Checklist