ISO 4126-6:2014

Overview

ISO 4126-6:2014 - Safety devices for protection against excessive pressure - Part 6: Application, selection and installation of bursting disc safety devices - provides guidance for the correct use of bursting disc safety devices to protect pressure equipment from excessive pressure and/or vacuum. The standard clarifies how to apply, select and install non-reclosing bursting disc assemblies so they perform reliably within a pressure-relief system.

Key topics and technical requirements

This part of ISO 4126 focuses on practical considerations rather than manufacturing specifications (manufacture, inspection and marking are covered in Part 2). Key topics include:

• Terms and definitions: clear definitions for bursting disc, bursting disc assembly, holder, specified bursting pressure, coincident temperature, performance tolerance, relieving pressure and differential back pressure.
• Application: guidance on where and when bursting disc safety devices are appropriate for vessels, piping, gas cylinders and other enclosures.
• Selection: criteria for selecting bursting discs, including selection of specified bursting pressure, performance tolerance and materials compatible with service conditions (pressure, temperature, fluid).
• Installation: recommended location, handling and installation practices to avoid degraded performance (correct holder fit, orientation, venting and protection against back pressure or vacuum).
• Performance and testing: non-mandatory procedures for flow testing (Annex E) and type testing (Annex F) to determine flow resistance and rated flow characteristics; Annex G gives typical performance characteristics.
• Operational considerations: guidance on relieving pressure, coincident vs relieving temperature, vent area, and how differential back pressure affects function.
• Lifecycle and maintenance: Annex B provides guidance on determining replacement periods for discs; Annex A lists purchaser-supplied information needed for correct selection and supply.
• Pressure relief system capacity: Annex C gives guidance on calculating discharge capacity (single-phase fluids).

Applications and who uses it

ISO 4126-6 is aimed at professionals responsible for pressure-relief safety and system integrity, including:

• Process, mechanical and safety engineers designing pressure vessels and piping
• Manufacturers and suppliers of bursting disc safety devices
• Maintenance and inspection personnel who install or replace discs
• Procurement officers specifying purchaser information and performance tolerances
• Regulatory bodies and safety auditors assessing compliance with pressure-relief practices

Typical applications include chemical plants, oil & gas, pharmaceutical, compressed gas systems, and any industry where overpressure or vacuum protection is critical.

Related standards

ISO 4126 is a multipart series. Relevant parts include:

• ISO 4126-1 (safety valves), ISO 4126-2 (bursting disc safety devices - manufacturing/requirements), ISO 4126-3, -4, -5, -7, and others that address sizing, combined devices and common data. Use ISO 4126-6 in conjunction with Part 2 for manufacturing and testing details.

Keywords: ISO 4126-6:2014, bursting disc, bursting disc safety devices, pressure relief, selection, installation, performance tolerance, relieving pressure, flow testing, replacement period.