Keep your pressure relief systems fit for purpose
In today’s chemical manufacturing environment, process changes and stricter compliance requirements can make older safety systems unsuitable.
Pressure Relief Device (PRD) evaluations help to protect people, assets and operations. Evaluations also support compliance and reduce business risk.
What is a PRD Evaluation?
A PRD, such as a relief valve or burst disc, protects equipment and systems from overpressure during abnormal operating conditions. A PRD evaluation reviews installed devices against current standards and industry best practices. It confirms that each device remains suitable for the process it protects.
The evaluation captures changes made since installation, documents the design basis and verifies ongoing performance.
Importantly, the review looks beyond the PRD itself. It examines the full pressure relief system, including equipment, vessels and pipework. This helps identify issues such as pressure losses in inlet or discharge lines and highlights how process changes could affect performance.
“Understanding the design basis of each relief device is crucial, not just for compliance, but for operational resilience."
Paul Dumain
The risk of standing still
Over time, small process changes can have a significant impact on pressure relief systems. A PRD that was suitable when installed may no longer provide adequate protection.
On sites with many devices, these risks can accumulate.
PRD evaluations help to identify and address these hidden vulnerabilities before they lead to incidents.
Compliance
Changes to company standards, audit findings and evolving industry guidance can all create the need for a review.
A well-managed evaluation programme demonstrates compliance and strong process knowledge.
It can also support more favourable discussions with insurance providers.
Safety culture
Many organisations begin PRD evaluations following a safety incident or perhaps a change of ownership or insurer.
However, a proactive programme helps to strengthen safety culture before issues arise.
It reinforces safe behaviours and highlights the importance of continuous risk management.
Change management
Facilities undergo many modifications during their lifecycle. These changes are not always assessed against existing PRDs.
Evaluations ensure design information remains accurate and complete, supporting informed decisions when changes are planned.
Successful evaluation exercises
There are four key steps to a successful PRD evaluation programme:
1. Preparation
- Review Scope and Timeline
- Pressure Relief Philosophy & Methodology
2. Data Gathering
- Existing Documentation Review
- Site Survey
- Data Gap Filling
3. Calculations
- Credible Overpressure Scenarios Review
- Orifice Sizing Calculations
- Piping Pressure Drop Calculations
- Vent Header Sizing
4. Output
- Identify Result of PRD Evaluation
- PRD Documentation Packs for all Devices
“Helping clients to protect their people and operations is what matters most. A proactive review helps to identify gaps and gives teams a clearer basis for action.”
Paul Dumain
Principal Process Safety Engineer
