A Risk Assessment Matrix (RAM) is a simple tool used to assess risk in the context of a process plant, whereby “risk” is defined as the product of:
- The likelihood of a hazard occurring, and
- The impact of that hazard, if it occurs, on plant, personnel and the environment
Often, process owners have a Risk Assessment Matrix in place for their plant. It applies to a wide range of safety matters, including Permit to Work systems, process safety, personal safety and the assessment of risk and reward for safety-related investment. The same Risk Assessment Matrix can also be used for Functional Safety. By defining ranges of likelihood (or frequency) and ranges of impact (or severity of the consequences), a Risk Matrix can be applied to define the minimum required SIL level for each safety function. A basic example follows below:
Sample risk assessment matrix
Note that an assessment of risk using a Risk Assessment Matrix is best performed by the process owner, rather than by a provider of Safety Instrumented Systems, as local and site-specific constraints and hazards must be taken into account. We can support the above analysis with our insights and experience of industry-typical approaches.