Overview
ISO 7313:2020 - "Aircraft - High temperature convoluted hose assemblies in polytetrafluoroethylene (PTFE)" specifies requirements for PTFE-lined, convoluted hose assemblies with a corrosion‑resistant metallic braid for use in aircraft fluid systems. The standard covers hose performance and qualification for service temperatures from ‑55 °C to +200 °C and nominal pressures (depending on bore size) up to 6.8 MPa. It distinguishes two types of hose assemblies: Type 1 (non‑conductive inner tube) and Type 2 (conductive inner tube). Special national approval may be required if hoses are used in pressurized gas storage systems.
Key topics and technical requirements
- Materials and construction
- Convoluted PTFE inner tube combined with corrosion‑resistant metallic braid.
- Requirements for metals and non‑metallic materials to ensure uniform quality and resistance to corrosion.
- Design and dimensions
- Specifications for inner tube, reinforcement layers, interlayers and fittings; dimensional tolerances and part numbering for interchangeable parts.
- Performance and testing
- Qualification and acceptance tests, including:
- Proof pressure and burst pressure (room and high temperature)
- Leakage, elongation/contraction
- Flexibility and vacuum behavior
- Pressure impulse (fatigue) testing
- Oil and fuel resistance tests
- Conductivity test (Type 2 only)
- Salt corrosion exposure
- Quality assurance and inspection
- Classification of tests (individual, sampling, periodic control)
- Inspection methods, preparation of specimens and specified test conditions
- Identification and workmanship
- Marking and assembly identification, cleaning and protection of openings
Practical applications
ISO 7313:2020 is intended for specification and procurement of high‑temperature PTFE convoluted hoses in aircraft fluid systems, including hydraulic, fuel and other fluid transfer applications where PTFE's chemical and temperature resistance are required. The conductive Type 2 variant addresses situations where electrical continuity/charge dissipation is necessary.
Who uses this standard
- Aerospace OEMs and systems integrators specifying hose assemblies
- Hose and fitting manufacturers seeking qualification and market compliance
- Maintenance, repair and overhaul (MRO) organizations and inspectors
- Procurement and quality engineers responsible for supplier acceptance and testing
- Test laboratories performing aerospace hose qualification and acceptance testing
Related standards
- ISO 756‑1 (referenced in ISO 7313:2020 for test substances)
- Other aerospace fluid system and material test standards (consult national ISO member bodies for applicable cross‑references)
Keywords: ISO 7313:2020, PTFE hose assemblies, high temperature convoluted hose, aircraft fluid systems, metallic braid, Type 1 non‑conductive, Type 2 conductive, aerospace hoses, hose qualification tests.
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