Overview
SIST ISO 16589-4:2014 defines performance test procedures for rotary shaft lip-type seals that incorporate thermoplastic sealing elements (for example, PTFE-based compounds). As Part 4 of the ISO 16589 series, this document focuses on materials quality control, dynamic testing at normal and low temperatures, and supplementary test requirements used for seal qualification under low-pressure conditions.
Key topics and technical requirements
- Scope and purpose: Specifies general performance tests to verify thermoplastic-sealed rotary lip seals for service use and quality control.
- Pre-test procedures: Inspect seals against drawings/specifications, record material batch numbers, and measure key dimensions (lip diameter, lip thickness on the shaft, case mean diameter, shaft/housing materials, hardness and surface finish).
- Dynamic normal-temperature test:
- Test apparatus requirements (shaft speed control ±5 %, eccentricity and housing alignment within ±0.03 mm, test fluid temperature control ±5 °C).
- Test fluid and setup details (minimum quantity of test fluid as stated in the standard; fluid level specified relative to shaft diameter).
- Test cycle: six seals, ten cycles of 24 h each (14 h at normal operating temperature/speed, 6 h at maximum envisaged temperature/speed, and 4 h cooldown). Alternate cycles may reverse rotation.
- Post-test measurements: seal thickness profile and protection lip diameter where applicable.
- Acceptance criteria: example leakage limits provided (typically total leakage from all six seals ≤ 12 cm³ and leakage from any single seal ≤ 3 cm³), to be agreed between purchaser and supplier.
- Dynamic low-temperature test:
- Applicable when minimum operating temperature is −10 °C or lower.
- Procedure: two seals soaked 16 h at specified minimum temperature with the seal submerged, rotated 10 revolutions by hand in the cold box, then allowed to stand 6 h at room temperature before post-test inspection.
- Material testing: Requirements for thermoplastic elements and elastomeric components (annexes include sample material test reports).
- Documentation: Annexes A–D provide typical test and material report formats for consistent recording.
Practical applications and users
Who uses SIST ISO 16589-4:2014:
- Seal manufacturers for product qualification and quality control
- Independent test laboratories performing dynamic and low-temperature sealing tests
- OEMs and design engineers specifying seals for low-pressure rotating equipment
- Procurement and certification bodies agreeing acceptance criteria with suppliers
Practical value:
- Ensures reproducible performance testing for thermoplastic lip seals
- Helps validate material batches, installation effects, and low-temperature performance
- Provides standard test reports and acceptance benchmarks to reduce dispute risk
Related standards
- ISO 16589 (Parts 1–5) - dimensions, vocabulary, storage/handling, performance tests, visual imperfections
- ISO 6194 - seals with elastomeric sealing elements (complementary guidance)
SIST ISO 16589-4:2014 is essential when specifying, testing, or certifying rotary shaft lip-type seals with thermoplastic elements (PTFE), ensuring reliable, repeatable performance assessment.