(6e) Using Bow Ties to Improve Process Safety

Major accident safety is still an issue for the process industry. Most risk assessment tools are directed towards design phase decisions and offer less support for the operations phase. The bow tie risk tool is an important exception to this and its focus is fostering ongoing process safety during the operations phase. The CCPS has just published a book (Bow Ties in Risk Management) defining the methodology for the bow tie method and this paper summarizes its key points.

The bow tie method tracks all important threats and consequences of major accident events as identified in PHA sessions. These are combined in a diagram that provides a compact but effective means for communication of major accident events with minimal jargon and no numbers. These can be presented to staff, management or contractors and help to ensure that they are aware of the full range of major accident events and the barriers deployed to prevent or mitigate these. This encourages a focus on barrier status and helps to ensure that barriers are always functional or are backed-up with suitable alternative temporary measures.

CCPS recommends that the bow tie method should be deployed more widely in the process industry and its use will enhance process safety.