ISO 19973-3:2015

Overview

ISO 19973-3:2015 - "Pneumatic fluid power - Assessment of component reliability by testing - Part 3: Cylinders with piston rod" specifies test procedures, equipment and reporting methods to assess the reliability of pneumatic piston-rod cylinders (single-acting and double-acting). The standard defines endurance-test conditions, failure criteria and data‑analysis practices used to determine component lifetime expressed in cycles or kilometres (the term “time” in the standard refers to cycles or km). It complements the general procedures in ISO 19973-1 and is intended for cylinders conforming to ISO 6430, ISO 6432, ISO 15552, and ISO 21287 (or equivalent products used in the same operating range).

Key topics and technical requirements

• Test scope and objective: determine first-failure lifetime using the three-point moving average (3PMA) method, without repairs and excluding outliers.
• Test equipment & circuit: typical test circuit includes a pressure source, cylinders under test, solenoid directional valves and an adjustable flow control (speed controller). Figure examples and safety considerations are provided.
• Mounting and orientation: cylinders are rigidly fixed in the horizontal position, secured at both ends to reduce vibration.
• Side loads and classes:
  • Single-acting cylinders: no side loads applied during testing.
  • Double-acting cylinders: defined side-load masses, mounting points and eccentricities are specified (see Tables 1 and 2). Annex A gives calculation methods for deviating stroke lengths.
• Stroke lengths: test stroke lengths are prescribed by cylinder class and bore (Table 2).
• Initial and acceptance checks: test units must pass final examination and acceptance per ISO 10099; initial leakage limits are defined.
• Failure criteria: functional failure, leakage thresholds, minimum working pressure (double-acting), and exceeding maximum test stroke time are formalized (see Clause 8).
• Data analysis & reporting: guidance on timing of checks, measurements (leakage, stroke time), statistical analysis and required test report format; Annex B contains a test data sheet example.

Practical applications and users

ISO 19973-3 is used by:

• Manufacturers and design engineers to validate piston‑rod cylinder durability and to support design improvements.
• Test laboratories and quality/verification teams conducting endurance and reliability tests.
• OEMs, machine builders and maintenance planners who need reliable lifetime data to set service intervals, spare-parts stocking and warranty policies.
• Procurement and compliance specialists requiring standardized, comparable reliability metrics for supplier evaluation.

Practical benefits: consistent reliability metrics (cycles/km), reproducible test procedures, standardized failure definitions and improved confidence in component selection for pneumatic systems.

Related standards

• ISO 19973-1 (General procedures)
• ISO 10099 (Final examination and acceptance criteria)
• ISO 6430, ISO 6432, ISO 15552, ISO 21287 (cylinder dimensional/constructive standards)
• ISO 1219-1, ISO 5598 (vocabulary and symbols)