Hot Spot ISO 4126-10:2023- Sizing of safety valves and bursting discs for gas/liquid two phase flow

What is it?

ISO 4126-10:2023 covering sizing of safety valves and bursting discs for gas/liquid two phase flow has now passed the final approval stage and will shortly be published by ISO.

This new standard in the ISO 4126 safety devices family covers the process of sizing for two phase flows. The sizing methods specified are, out of necessity, more complex than for single phase flow and use an approach that is supplementary to that covered by ISO 4126-7 common data.

Why is it Important?

Well-established recommendations exist for the sizing of safety valves and bursting discs and their inlet and outlet lines for steady-state, single-phase gas/vapour or liquid flow. However, in cases of two-phase vapour/liquid flow, the required relieving area to protect a system from overpressure is generally larger than that required for single-phase flow and all the prevailing conditions need to be carefully considered.

This part of ISO 4126 includes an engineering tool for the sizing of the most typical safety valves and bursting discs in two phase fluid services and as such provides a standardised approach to this complex sizing problem.

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