Process Safety: A Must for Compliance with the Pressure Equipment Directive (PED) Assemblies

What are PED Assemblies?

An assembly under the PED is a combination of pressure equipment and/or safety accessories brought together by a manufacturer into a complete functioning unit. Examples include pressure cookers, hot water installations, steam boiler systems, or pressurized fluid systems handling all kinds of chemicals. The PED imposes specific requirements on these assemblies because the risk of failure depends not only on individual components but also on how these components are combined and operate within the whole.

Design Phase: Process Safety as the Foundation

Process safety must be embedded from the very beginning during the design phase. Identifying hazards and conducting comprehensive risk assessments (e.g. HAZOP) are mandatory to meet the PED’s essential safety requirements. Without a robust process safety approach, it is impossible to design assemblies that reliably withstand operational pressures and prevent catastrophic failures. Safety features such as pressure relief devices, instrumented safeguarding (according the SIL methodology (IEC61511)), material selection, and safety margins must be carefully engineered based on process safety principles.

Manufacturing Phase: Ensuring Safety Through Quality Control

Process safety continues as a critical requirement in manufacturing. Implementing rigorous quality management systems and traceability is essential to guarantee that assemblies are built to exacting standards mandated by the PED. Any lapse in quality control jeopardizes the integrity of the equipment and risks non-compliance with safety regulations. Therefore, process safety-driven inspections, testing, and documentation are indispensable.

Conformity Assessment: Verifying Process Safety Compliance

The conformity assessment phase is a non-negotiable checkpoint where process safety must be demonstrably proven. Conformity assessment bodies (Notified Bodies) rigorously evaluate assemblies to verify that all PED safety criteria—rooted in process safety principles—are met. Passing this stage confirms that the assembly is safe for use and compliant with legal requirements, making process safety evidence mandatory for certification.

Installation and Commissioning: Critical Safety Steps

Although the PED focuses primarily on design and manufacturing, process safety cannot be overlooked during installation and commissioning. Correct assembly integration and functional testing of safety devices are mandatory to prevent hazards caused by improper setup. Process safety procedures during these phases ensure that assemblies perform safely from the moment they enter service. This has to be detailed in the instruction manuals.

Operation and Maintenance: Sustaining Safety Over Time

Sustained process safety is essential throughout the operational life of PED assemblies. Regular inspections, preventive maintenance, and testing are required to detect and mitigate risks such as corrosion or fatigue. Operating and maintenance personnel must be instructed, via the instruction manual, in process safety practices to maintain safe conditions and prevent incidents.

In Summary

Process safety is an indispensable pillar of the Pressure Equipment Directive. Compliance with the PED is fundamentally dependent on applying process safety principles rigorously at every stage—from design through to operation. Organizations that treat process safety as mandatory not only meet regulatory obligations but also protect lives, assets, and the environment while ensuring reliable industrial processes.