ISO 19973-4:2014

Overview - ISO 19973-4:2014 (Pressure regulators)

ISO 19973-4:2014 is the ISO standard for assessing the reliability of pneumatic pressure regulators by testing. It defines specific test procedures, required test equipment and failure criteria (threshold levels) for manually adjustable and remote‑piloted pressure regulators - both relieving and non‑relieving - while excluding regulators with a permanent bleed. General test conditions and the statistical calculation method are given in ISO 19973-1; the standard applies the three‑points moving average (3PMA) method to determine the first failure (without repairs, excluding outliers).

Key topics and technical requirements

• Scope: Reliability assessment of pneumatic pressure regulators (manually adjustable and remote‑piloted; relieving and non‑relieving).
• Test circuits and equipment: Defines basic and alternative test circuits (figures), locations for pressure gauges/transducers, use of silencer, shut‑off valves/quick‑couplings and required directional control valves.
• Pretest checks: Forward flow test per ISO 6953-3 to determine forward sonic conductance (Cf) for each test unit.
• Inlet and regulated pressures:
  • Inlet: 800 kPa ± 40 kPa or the manufacturer's maximum rated inlet if lower.
  • Regulated set point: 80% (±5%) of inlet pressure or 80% (±5%) of the manufacturer’s rated maximum regulated pressure (whichever is lower).
  • Set point must be obtained while regulated pressure is increasing; reset after 24 h of continuous cycling to compensate for initial drift and record as initial set pressure.
• Volumes and valve sizing: Test volumes and directional valve sonic conductance must meet sizing requirements referenced to ISO 19973-1 and the measured Cf.
• Failure criteria: Specifies types of failure to record - functional failures, leakage, unacceptable pressure characteristics - and threshold levels for these failures.
• Data analysis and reporting: Test data collection, endurance testing approach, analysis using methods in ISO 19973-1, and standardized test reporting requirements.

Practical applications & who uses it

• Manufacturers and R&D teams - validate regulator reliability during design and pre‑production.
• Quality and test laboratories - perform standardized endurance tests and report comparable reliability data.
• Machine builders and system integrators - select regulators based on quantified life (cycles) to size maintenance intervals and spare‑parts inventories.
• Procurement and warranty analysts - assess supplier reliability claims and support warranty/field‑failure investigations.
  Using ISO 19973-4 helps stakeholders model system reliability, improve design robustness, optimize service intervals and reduce unexpected downtime.

Related standards

• ISO 19973-1 - General procedures and calculation methods for component reliability testing
• ISO 6953-1 / ISO 6953-3 - Characteristics and flow‑rate measurement methods for pressure regulators
• ISO 1219-1, ISO 5598, ISO 80000-1, IEC 60050-191 - symbols, vocabulary and units referenced by ISO 19973-4

Keywords: ISO 19973-4:2014, pneumatic pressure regulators, reliability testing, test procedures, failure criteria, pressure regulator test standard, 3PMA, test equipment.