LOPA

Layer of Protection Analysis is a technique for a simplified method of risk assessment. It is typically used as a screening tool and operates by reviewing an identified hazardous event and attaching a risk tolerance criteria to that event.

The initiating event frequency is then calculated together with all the layers of protection that are in place to prevent the hazardous event, the result identifies if additional protection is required, such as safety instrument systems.

LOPA is normally used as an order of magnitude analysis but can be developed and refined with the use of additional risk studies such as HEART (Human Reliability Assessment using the Human Error Assessment and Reduction Technique).

P & I Design have developed software to assist in conducting LOPA's and have also been extensively involved with the HSE - BSTG (Buncefield Standards Talk Group) and PSLG (Process Standards Leadership Group) in advancing the techniques and the use of LOPA by developing guidelines for its use.