How Strong are your Barriers?

Article by Ashley Hynds CEng FIChemE

What can be learned from inspections of loss of containment audit and assurance systems in the UK offshore oil and gas industry? Ashley Hynds discusses

THE UK’s offshore oil and gas industry has long relied upon the number of hydrocarbon releases per year as a barometer of its safety performance. Over the last ten years, there has been a consistent and welcome downward trend in the rate of minor releases, reflecting the efforts by many to focus attention on key risk areas such as small bore tubing and corrosion under insulation. But is the industry really getting safer?

Over the same period, the rate of major releases has not changed. There have typically been between two and eight occurring annually, with no discernible trend (see Figure 1). Each of these releases has been larger than the initiating event at Piper Alpha.

With only a handful of major releases across the industry, most operators will likely go for years without having one. With major accidents being low frequency events however, it doesn’t necessarily follow that that they are managing their risks well.

Figure 1: Hydrocarbon releases reported to HSE 2008–2018 provisional

Operators can only be seen to be managing their risks well if they can show that their major accident hazard barriers are strong. These barriers will be a mixture of “hardware” and “software” measures, which work together to prevent releases, or lessen their effects. Typical operational barriers are shown in Table 1.

So how can an operator know how strong their barriers are? The solution is a well-structured assurance system, which systematically tests compliance with the key risk control measures, and checks their effectiveness. Making sure that such assurance systems are in place is a key process safety leadership function.

Table 1: Examples of offshore oil & gas hydrocarbon release barriers

Operators’ legal duties

Operators have duties under the Management of Health & Safety at Work Regulations 1999 to “make and give effect to such arrangements as are appropriate…for the effective…monitoring and review of the preventive and protective measures.”

The Offshore Installations (Offshore Safety Directive) (Safety Case etc) Regulations 2015 go further, and also require duty holders to “include in their safety case sufficient particulars to demonstrate that” they have “established adequate arrangements for audit and for the making of reports of the audit.” Copies of audit reports are required to be kept and there are several further prescriptive requirements as to their content, and the recording of recommendations and corrective actions.

Both the Energy Institute1 and the Center for Chemical Process Safety2 have published extensive guidance on assurance systems to support legal compliance.

Article by Ashley Hynds CEng FIChemE

HM Principal Inspector for Process Engineering within HSE’s Energy Division - Offshore.

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