Barrier Diagrams the Next Stage for Enhancing Offshore Operations Safety
Authors: Pitblado Robin , Tahilramani Ravi 
Published: July 2010

Published data show that the O&G industry has been very successful in reducing occupational accidents, but not as successful in larger scale process safety accidents. The EU has pioneered an approach using barrier diagrams, called bow ties, to identify and communicate barriers effectively, and thereafter to manage these through life. In North America, IADC offers these as the basis for demonstration of safety for MODU facilities which travel between regulatory jurisdictions.

Ongoing safe operations in the UK and Norwegian offshore sectors have shown that comprehensive barrier management improves safety performance.

However, communicating the information from hazard and risk registers and bow ties is essential to make sure that everyone understands the full set of barriers in use, their personal responsibilities, that these barriers are operational, and meet their effectiveness requirements.

This paper provides an example demonstration combining bow tie risk management tools with a Sharepoint interface for communications as applied for a large upstream company. Two versions were created - a simpler Pull interface and more complex Push interface.

Operations Safety Needs

It is clear that Process Safety - particularly preventing major accidents - is not yet a solved problem for the process industry globally. A prior paper (Pitblado, 2008) highlighted that while the industry has been very successful in reducing occupational accidents over the past 15-20 years, trends on process safety have been flat or even getting worse. In fact this very success can mislead site management into thinking that process safety is under control as the more frequent occupational incidents have reduced so much. Kleindorfer et al (2007) note that early hopes for process safety improvement have not occurred. The EPA published reduction in accident frequencies and impacts based on the combined effects of the OSHA PSM standard and the EPA RMP Rule was estimated to be 75% of the baseline accident/impact rates over the first 5 years of implementation. In fact no statistically valid reduction was found.

Following the Texas City accident, the Baker Panel (2007) identified many problems with today's implementation of Process Safety Management (PSM) programs and with Process Safety Culture, not only in BP but the whole industry. The CSB identified similar issues in its assessment (CSB, 2007) as well as important technical integrity issues, beyond the terms of reference of the Baker Panel.

In the USA, two major regulations address process safety, OSHA 1910.119 Process Safety Management and the EPA Risk Management Plan regulations (part of the Clean Air Act amendments). These are broadly similar regulations, but OSHA focuses on onsite personnel and EPA focuses on offsite impacts. These regulations have been relatively static since their development in the late 1980's and early 1990's, and enforcement has been less emphasized until after the CSB recommendations to OSHA. A National Emphasis Program is addressing the enforcement issue now for refineries falling under OSHA regulations (Lay et al, 2009).

In the EU, by contrast, the primary regulations are driven by the EU Seveso Safety Case Directives and these have been more dynamic, being updated several times in response to the ongoing series of events. The Seveso Directive is implemented differently in every EU country, and thus local incidents also drive regulatory changes (e.g. in France after the Toulouse explosion and in Belgium after the Antwerp pipeline explosion).