ISO 5119:2023

Overview

ISO 5119:2023 - "Low temperature sealing capability of elastomeric seals - Test methods" defines a standardized procedure to determine the minimum seal temperature for static elastomeric O‑ring seals exposed to pressurized gas at low temperatures. The standard describes test apparatus design, controlled cooling and pressure application, leakage detection, test sequence and reporting. It is a method standard (does not set pass/fail criteria) - performance requirements must be agreed between supplier and customer.

Key topics and requirements

• Test scope: Static O‑ring seals in elastomeric materials tested with pressurized nitrogen gas; alternate sizes or media may be used but deviations must be reported.
• Test apparatus: Typical assembly with a solid test plug, outer shroud and cap; housing surface roughness and material guidance (e.g., AISI 316L recommended).
• Temperature control: Controlled cooling at 60 °C/h ±10 °C/h; temperature measured by sensor positioned (2 ± 0.5) mm from seal ID or OD.
• Test pressures: Predefined pressures 5 MPa, 10 MPa, 15 MPa (options permitted by agreement).
• Leakage detection: Zero leakage defined as less than 20 cm³/h (equivalent to no discernible bubbles); detection via mass flow meter (range < 20 cm³/h) or leakage tube (ID 6 ± 0.5 mm) into a water bath.
• Test sequence: Pre‑test checks and pressurization to 1.5 MPa; staged cooling and pressure application in 5 °C steps and final 1 °C increments to precisely determine minimum seal temperature.
• Sampling & reporting: Minimum 5 test runs per material using new seals each run; reported minimum is the average of 3 middle values (highest and lowest discarded). Required reporting items include standard reference, seal material, test pressure and minimum seal temperature.
• Fixtures & precautions: Use of dummy static O‑ring in the fixture; alternative sealing if fixture O‑ring would fail below its own minimum temperature.

Applications and users

ISO 5119 is applicable where reliable low‑temperature static sealing is critical, such as:

• Seal manufacturers and material suppliers (product characterization)
• Test laboratories and quality control teams (validation and QA)
• System designers and OEMs in fluid power, cryogenics, aerospace, and industrial gas systems
• Procurement and supplier/customer agreements (defining acceptance criteria)

Benefits include consistent, reproducible measurement of low‑temperature sealing performance and a clear basis for commercial and design decisions.

Related standards

• ISO 3601‑1/2/3 (O‑ring dimensions, housings, quality)
• ISO 5598 (fluid power vocabulary)
• ISO 10423 (zero leakage definition reference)
• Material/functional tests mentioned for estimating expected minimum temperature: ISO 812, ISO 815‑2, ISO 1432, ISO 2921

Keywords: ISO 5119, low temperature sealing, elastomeric seals, O‑ring test methods, minimum seal temperature, leakage detection, static sealing.