The significance of ISO 4126-9:2019 lies in its ability to ensure the safety of pressure equipment and personnel. By specifying the requirements for safety valves, the standard helps to prevent accidents and ensure that pressure equipment is designed and manufactured to operate safely.

: Requires a realistic evaluation of potential overpressure scenarios to ensure the selected device capacity is sufficient.

The standard provides methodologies for calculating the relieving capacity required when a system contains a mixture of vapor and liquid. Unlike single-phase gas (which uses ideal gas laws) or liquid (which uses Bernoulli’s principle), two-phase flow requires the or similar validated methods.

The standard provides specific guidance on installing bursting discs in series with safety valves. This configuration is often used to:

ISO 4126-9 applies to the installation of various safety devices, including: (Part 1). Pilot-operated safety valves (Part 4).

Iso 4126-9 Pdf