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ISO

ISO 4126 (series)

Safety devices for protection against excessive pressure

Issuing body
ISO
Latest edition
Various, 2013–2018
Region
Global
Equipment items
2

Scope

Multi-part standard on safety valves, bursting discs, pilot-operated relief, and combinations.

Key requirements (6)

  • Safety devices for protection against excessive pressure (international counterpart of API 520/526).
  • Parts: 1 (safety valves), 2 (rupture discs), 3 (CSPRS), 4 (pilot-operated), 5 (CSPRS), 6 (rupture disc selection), 7 (general data).
  • Set pressure: ≤ PS (PED design pressure).
  • Pop tolerance: ±3% set (typical) for spring valves.
  • Certified discharge coefficient by manufacturer testing.
  • Used as harmonized PED standard in Europe.

Related standards (1)

Applied to 2 equipment items