Emergency shut-down and blow-down valve integrity management
Article published in the Regulator Issue 3:2015
Design and performance verification of facility emergency shut-down and blow-down systems has been a priority for process safety management since the Piper Alpha tragedy which claimed the lives of 167 people in 1988.
A major accident event, such as a hydrocarbon release leading to fire and explosion, resulting from a loss of containment of hydrocarbons from, for example, risers or topsides process plant requires emergency shut-down and depressurisation (blow-down) systems. These systems act as technical controls to mitigate the consequences of the event. Planned inspections conducted by NOPSEMA over the past three years have shown that many operators have comprehensive systems in place for monitoring performance of their emergency shut-down and blowdown valves and are continuously improving. Some examples of good practice include:
• Performance standard assurance plans that establish links between identified technical controls and associated major accident events.
• Testing, inspection, monitoring and maintenance conducted at a frequency determined by a recognised industry standard.
• Risk-based assessments conducted in accordance with associated performance criteria.
• Procedures, performance standards, results and records associated with maintenance activities are embedded in the maintenance system.
• Ensuring that emergency shut-down valve performance is ascertained on the valve’s ‘as found’ condition prior to performing maintenance.
• Leak test work orders referencing specific leak test criteria, which are referenced to industry-recognised codes and standards for the emergency shut-down system.
• Ensuring supervisors and personnel working with emergency shut-down and blow-down valves have good knowledge of the system, are adequately trained, and, have experience relevant to the operation, maintenance and assurance of the emergency shutdown systems.
• Regular monitoring of the degradation of valve performance over time to facilitate preventative, rather than reactive maintenance.
• Facility-specific independent auditing or performance verification of emergency shut-down and blow-down valves and the associated maintenance management systems.
NOPSEMA inspectors also found, that operators commonly have systems in place to notify and report failures of emergency shut-down and blow-down valves (to meet performance standards) to NOPSEMA as a ‘dangerous occurrence’. O
ver the same period, NOPSEMA has issued 48 recommendations and four improvement notices to operators across 21 facilities. The majority of these recommendations and enforcement actions related to deficiencies in the implementation of functional assurance plans for emergency shut-down and blowdown systems, and for the operators failure to meet relevant performance standards.
As of 1 October 2014, improvement notices have been published on NOPSEMA’s website as part of a concerted effort to provide greater transparency in relation to NOPSEMA’s enforcement processes and, to allow for associated learnings to be shared among industry.
Operators of facilities are reminded to take all reasonably practicable steps to implement and maintain appropriate procedures and equipment for the control of and, response to emergencies at the facility in accordance with Clause 9(2)(e) of Schedule 3 to the OPGGS Act.