It is a mandatory company requirement for all offshore and onshore assets to secure the documentation and demonstration of process safety in design (PSID). The common way to conduct the PSID is to apply it within the "Design phase" and after the "Execute phase" to remove or minimize hazards and identify areas of process design that warrant specific focus. In this paper, we will show a case of implementing the PSID verification on an onshore gas production plant during operation phase which is different from the main approach and way of verification during earlier stages of project execution.
Verification is intended to confirm that the detailed documentation and calculations supporting the requirements of the Process Engineering Process Safety Design Standard have been correctly performed.
In broad terms the objective of the verification in the "Operation phase" was;
To confirm that the extent of documentation available meets the minimum requirements of the company standards.
To confirm that adequate layers of protection are being provided throughout the process to reduce risks to ALARP (As Low As Reasonably Practicable).
To confirm that all Blowdown systems and relief valve calculations have been correctly conducted and appropriate relief cases and basis have been used.
To confirm that HAZOP/HAZID has been conducted in a reasonable manner and the actions have been closed out.
To confirm that layers of protection analysis "LOPA" for all site safety instrumented functions (SIFs) as part of Safety Integrated Levels (SIL) assessment have been assessed and verified.
To confirm that specification breaks have been properly located and HP/LP interfaces correctly designed.
To confirm that the philosophies are complete, adequate and implemented.
To confirm that process safety is being assured for the project and to identify and record any failings or flaws in approach, detailed calculations or design that require rectification.
The design contractor produced a Process Safety Dossier which contained sections as following:
Relief and Blowdown Design
The outcome of the verification on the existing gas production plant was a list of findings categorized – from 1 to 4 – according to their priority from safety point of view. We ensured closure of the actions starting from code 1 and code 2 in a tight time frame to avoid any risk to be released.