Layers of Protection Analysis (LOPA) is a key technique to quantify the risks of a process scenario and provide insight into where controls need to be added and if they are justified. After the Buncefield incident in 2005, The UK HSE issued a recommended practice guide as part of the Process Safety Learning Group (PSLG) investigation report. This guidance was the genesis of the advanced form of LOPA which "couches" scenarios as a bowtie and structures the assessment within that framework. There are other formulations of LOPA that are equally as effective however all can be misused, abused or mistreated - this is the nature of risk assessment. The outcome of a poor quality LOPA can lead to:
Bellow are some of the learnings and red flags I have developed over the years from executing LOPAs, reviewing my colleagues LOPAs, auditing and training in the topic. There are 4 broad areas of comment:
We at Safety Solutions feel that because critical decisions are made from this activity, an independent check is needed on the LOPA study quality. We do this internally using the following checklist and embed this into the LOPA report.