ISO 23933:2006

Overview - ISO 23933:2006 (Aerospace PTFE hose assemblies)

ISO 23933:2006 is a procurement specification for aramid reinforced lightweight PTFE (polytetrafluoroethylene) hose assemblies used in aerospace. It defines design, material, construction, testing and quality requirements for hose assemblies intended for aircraft hydraulic, oil, fuel and certain pneumatic systems at temperatures from −55 °C to 135 °C (−65 °F to 275 °F) and nominal pressures of 20 684 kPa (3 000 psi) or 21 000 kPa (3 046 psi). The standard classifies assemblies into Type A (20 684 kPa) and Type B (21 000 kPa), with Type B as the default when unspecified.

Key topics and technical requirements

• Scope & classification: Temperature and pressure limits; applicability to hydraulic, oil, fuel and select pneumatic systems.
• Materials: Seamless virgin PTFE inner tube, treated para-aramid braid reinforcement, outer cover/braid protection, corrosion-resistant steel and/or titanium fittings.
• Construction: Requirements for inner tube, reinforcement coverage (UV protection), one-piece or welded insert fittings, and continuous lay line marking.
• Inner tube properties: Density/relative density limits, longitudinal and transverse tensile strength, minimum elongation (≥200 %), tube roll and proof pressure tests, and electrical conductivity criteria by size.
• Dimensional & performance requirements: Hose/fitting dimensions, bore check (sphere passage when bent to minimum radius), assembly length tolerances, and thread standards (ISO 5855-3, ISO 3161).
• Qualification & testing: Manufacturer and product qualification procedures, physical and impulse testing, fire resistance references, and acceptance sampling/inspection requirements.
• Quality assurance and delivery: Inspection responsibilities, inspection classifications, packaging, marking and ordering data.

Applications - who uses ISO 23933:2006

• Aerospace manufacturers and OEMs specifying PTFE hose assemblies for aircraft systems.
• Hose and fitting suppliers seeking qualification to aerospace procurement requirements.
• Maintenance, repair and overhaul (MRO) organizations ensuring component conformity and traceability.
• Design and systems engineers specifying hose assemblies for hydraulic, fuel, oil and pneumatic installations in aircraft.
• Procurement, quality assurance and certification bodies overseeing supplier approval, testing and documentation.

Related standards

Key normative references used by ISO 23933:2006 include:

• ISO 8829-2 (PTFE innertube test methods)
• ISO 7258 (PTFE density test methods)
• ISO 5855-3, ISO 3161 (fitting threads)
• ISO 6772 (impulse testing)
• ISO 2685, SAE AS 150/AS 1055/AS 1241 (fire and fluid compatibility/testing)

ISO 23933:2006 is essential for anyone specifying or supplying aramid reinforced PTFE hose assemblies in aerospace environments - ensuring safe, tested and traceable hose systems that meet stringent temperature, pressure and material performance requirements.