Investigations of major accidents in the Oil and Gas sector often reveal multiple failures in layers of protection or barriers. Companies should learn from the findings and aim to continuously develop and tighten their own management controls to provide assurance that critical barriers are working effectively. However, this approach to process safety management pre-supposes that the barriers required to provide significant risk reduction are necessary in the first place. This paper supports a complimentary inherent safety approach to designing processing facilities, an approach that aims to removes hazards or minimises their consequences by better design rather than a reliance on ‘bolt-on’ protective barriers that can and do fail.
Inherent Safety principles are not new and were introduced into the process industry by safety guru Trevor Kletz in the 1970's with his motto, "What you don't have, can't leak". These principles have not gained the same momentum as other process safety risk assessments such as HAZOP studies. Whilst there are good examples of inherently safe process designs within the Oil and Gas sector, it is suggested that opportunities to apply inherent safety principles during the design process are not being systematically identified and exploited.
This paper is written by the author of updated guidance for Inherent Safety in Design (ISD) published in 2014 by the UK Energy Institute. The guidance is targeted at Project Leaders in upstream and downstream Oil and Gas facilities and aims to change the culture that favours designs with ‘bolt-on’ safety features. It highlights the benefits from applying ISD at a very early stage of the design process, looking to reduce the overall major accident potential whilst offering the added benefit of reducing capital and operating costs.
For major projects in the Oil and Gas sector, the EI guidance introduces the requirement for an Inherent Safety workshop at the concept selection stage, before HAZID studies that are subsequently used during the FEED stage. A multi-disciplinary team identifies potential hazardous events based on a Process Block Diagram, and applies Inherent Safety principles to identify possible improvement options, following the hierarchy; Elimination, Substitution, Minimisation, Moderation, Segregation and Simplification.