EN ISO 4126-2:2019 PDF

Overview

EN ISO 4126-2:2019 (Safety devices for protection against excessive pressure - Part 2: Bursting disc safety devices) defines requirements for bursting disc safety devices used to protect equipment from overpressure. Published by CEN and aligned with ISO 4126-2:2018, the standard covers the full lifecycle: design, manufacture, inspection, testing, certification, marking, and packaging. It also supports conformity with the EU Pressure Equipment Directive (2014/68/EU / PED).

Key topics and requirements

The standard addresses technical and quality requirements critical for reliable overpressure protection:

• Types of bursting discs: conventional domed (forward-acting), reverse-domed (reverse-acting), flat discs and other designs.
• Materials and corrosion protection: selection, specifications and corrosion mitigation to ensure long-term serviceability.
• Bursting disc holders and connections: design, pressure-containing capability, types of holders and flange/pipe connections.
• Back-pressure supports and opening/non-opening designs to control the behaviour under back-pressure conditions.
• Ancillary components: temperature shields, stiffening rings, gaskets/seals and their role in assembly and performance.
• Assembly and replaceability: requirements for replaceable and non-replaceable bursting disc assemblies.
• Specified bursting pressure: procedures for defining and documenting burst pressure requirements.
• Inspection and test procedures: manufacturer inspection, pressure testing, burst testing (including coincident temperature considerations such as the 15 °C to 30 °C reference range), leak testing and non-destructive examination.
• Certification, product designation and marking: information required for traceability, user instructions, and compliance declarations.
• Packaging and storage: protective packing, labelling and documentation for shipping and storage (Annex A).

Applications

EN ISO 4126-2 is applicable wherever bursting discs are used as primary or secondary overpressure protection:

• Chemical and petrochemical plants
• Oil & gas facilities and pipelines
• Power generation and steam systems
• Pressure vessels, reactors and storage tanks
• Process industries requiring fast, reliable pressure relief

Using bursting disc safety devices helps prevent catastrophic equipment failure, reduce environmental release, and meet regulatory safety obligations.

Who should use this standard

• Manufacturers and designers of bursting discs and holders
• Pressure equipment engineers and system integrators
• Inspection bodies, testing laboratories and certification authorities
• Plant safety engineers and maintenance teams
• Regulatory compliance officers demonstrating conformity with PED

Related standards

• Other parts of the ISO 4126 series (overpressure protection devices)
• EU Directive 2014/68/EU (Pressure Equipment Directive) - Annex ZA in EN ISO 4126-2:2019 explains the relationship and presumption of conformity when applied.

Keywords: bursting disc safety devices, overpressure protection, EN ISO 4126-2, burst testing, PED compliance, pressure relief, bursting disc holders.