ISO 4126-2:2018

Overview

ISO 4126-2:2018 - Safety devices for protection against excessive pressure: Part 2: Bursting disc safety devices specifies requirements for bursting disc safety devices used to protect pressure equipment from overpressure and vacuum. The standard covers the complete lifecycle of bursting disc devices including design, manufacture, inspection, testing, certification, marking, packaging and storage. It applies to non‑reclosing, differential‑pressure actuated devices and the assemblies that contain them.

Key topics and technical requirements

ISO 4126-2:2018 addresses the full technical scope needed for safe, reliable bursting disc performance:

• Materials: selection, specifications and corrosion protection for metallic and non‑metallic discs.
• Types of bursting discs: conventional (forward/ domed), reverse domed, flat, slotted/lined and graphite designs.
• Bursting disc holders and ancillary components: design requirements, pressure‑containing capability, connections, back‑pressure supports, stiffening rings, temperature shields, gaskets/seals.
• Assembly and installation: procedures for replaceable and non‑replaceable disc assemblies.
• Specified bursting pressure: definitions for specified, minimum and maximum bursting pressures and coincident temperature considerations.
• Inspection and test procedures: manufacturer inspection, pressure testing, burst testing (including temperature effects), leak testing, and non‑destructive examination.
• Certification and marking: product designation, mandatory marking on discs, holders and assemblies, and documentation requirements.
• Packaging and storage: protective packaging, labelling and shelf‑storage instructions to preserve integrity.

These topics ensure traceability, repeatability of burst performance, and conformance with safety expectations.

Applications and who uses this standard

ISO 4126-2 is essential for organizations involved with pressure‑relief safety and compliance:

• Manufacturers and suppliers of bursting discs and holders - for product design, QA and factory testing.
• Pressure equipment designers and OEMs - to select compliant relief devices and define specified bursting pressures.
• Inspection bodies and certification agencies - for type testing, certification and marking verification.
• End users and plant engineers in oil & gas, chemical, pharmaceutical, power generation, compressed gas cylinders and process industries - to ensure safe overpressure protection.
• Procurement and maintenance teams - to specify, store and replace compliant devices.

Using ISO 4126-2 helps reduce overpressure risk, supports regulatory compliance and improves interoperability between manufacturers and users.

Related standards

• ISO 4126 series (other parts) for complementary requirements across safety devices for excessive pressure.
• Work carried out under ISO/TC 185 (Safety devices for protection against excessive pressure).