Overview
ISO 5771:2024 - "Rubber hoses and hose assemblies for transferring anhydrous ammonia - Specification" defines minimum performance requirements for rubber hoses and hose assemblies intended for transferring anhydrous ammonia (liquid or gas) at ambient temperatures from −40 °C to +55 °C and a working pressure of 2.5 MPa (25 bar). The standard addresses hose construction, materials, dimensional limits, physical properties and required tests. It is limited to hose and hose-assembly performance and does not specify end fittings.
Key topics and requirements
- Pressure ratings
- Maximum working pressure: 25 bar (2.5 MPa)
- Proof pressure: 63 bar (6.3 MPa)
- Minimum burst pressure: 125 bar (12.5 MPa)
- Temperature range: −40 °C to +55 °C for service and testing (low-temperature flexibility tested to −40 °C).
- Materials & construction
- Lining minimum thickness: 1.5 mm, free from porosity and defects; resistant to ammonia-induced hardening.
- Reinforcement: material resistant to ammonia permeation; corrosion‑resistant stainless steel cited as suitable.
- Cover: gas‑tight covers to be pin‑pricked (≥40 effective pinholes per metre) to allow gas release without penetrating the lining.
- Hose assemblies: only hoses conforming to ISO 5771 may be used; permanently attached ferrous‑metal fittings are required.
- Dimensions & tolerances
- Specified nominal inside diameters and permitted ID ranges (examples: 12.5 mm up to 76 mm nominal sizes).
- Concentricity limit: ≤ 1.0 mm for IDs up to 76 mm.
- Physical & performance tests
- Tensile and elongation (ISO 37) for lining/cover compounds: minimum tensile 7.0 MPa, minimum elongation 250%.
- Ageing (ISO 188:2023) and ammonia resistance conditioning tests.
- Hydrostatic proof and burst tests (ISO 1402).
- Adhesion tests (ISO 8033), ozone resistance (ISO 7326), low‑temperature bending (ISO 10619‑2).
- Documentation & quality
- Clauses cover marking, packaging, storage, type/routine test frequency (Annex A) and test certificates.
Applications and users
ISO 5771:2024 is relevant to:
- Hose manufacturers designing and certifying hoses for anhydrous ammonia service.
- Equipment specifiers and purchasers in agriculture (fertilizer handling), industrial refrigeration, chemical processing and transport.
- Maintenance and safety engineers responsible for in‑service testing, marking and documentation of ammonia delivery systems.
- Regulators and conformity assessors checking compliance with performance and testing requirements.
Related standards
Keywords: ISO 5771:2024, rubber hoses, hose assemblies, anhydrous ammonia, 25 bar, ammonia resistance, hydrostatic testing, hose manufacturers, industrial refrigeration.