What to check on a LPG/LNG Cargo Hose.
Liquefied gas cargoes are handled either refrigerated (LNG near minus 162 degrees C, LPG typically minus 40 to minus 50 degrees C for fully refrigerated cargo) or under pressure at ambient temperature. A hose built for these duties must stay flexible and leak-tight at cryogenic temperature without the rubber hardening and cracking the way a standard oil cargo hose would, and it must resist the specific chemistry of the cargo - LPG attacks many elastomers that are fine for crude or products. Construction is typically a composite hose with multiple…
What distinguishes an LPG/LNG hose from general cargo hose
Liquefied gas cargoes are handled either refrigerated (LNG near minus 162 degrees C, LPG typically minus 40 to minus 50 degrees C for fully refrigerated cargo) or under pressure at ambient temperature. A hose built for these duties must stay flexible and leak-tight at cryogenic temperature without the rubber hardening and cracking the way a standard oil cargo hose would, and it must resist the specific chemistry of the cargo - LPG attacks many elastomers that are fine for crude or products. Construction is typically a composite hose with multiple polymer and reinforcement layers, or a corrugated stainless steel cryogenic hose for the coldest LNG duties, rather than a conventional rubber-and-wire-braid hose.
Main components
Inner liner
The layer in direct contact with cargo, selected for chemical compatibility with LPG or LNG and for flexibility at the design temperature; a liner suited to crude oil is not automatically suited to LPG.
Reinforcement layers
Helical wire or composite braid layers carrying the pressure load and giving the hose its burst strength, sandwiched between liner and cover.
Outer cover
Protects against abrasion, UV and mechanical damage during handling on deck; often has a static-dissipating requirement given the ignition risk of the cargo.
End couplings
Flanged or dry-break couplings matched to the manifold; on many LPG/LNG transfers a quick-connect/disconnect coupling with a self-sealing dry-break function is standard to limit spillage on disconnection.
Selection and sizing
- Design temperature matched to the actual cargo and transfer mode - refrigerated versus pressurised service calls for different hose construction, not the same hose rated down to a lower number on paper.
- Working pressure and burst pressure with the required safety margin for the transfer system's maximum pump pressure.
- Bore size matched to the required transfer rate without exceeding safe fluid velocity for a cargo with static ignition risk.
- Bend radius and length suited to the actual ship-to-shore or ship-to-ship geometry, since forcing a hose below its minimum bend radius shortens its service life sharply.
Regulations and class
The IGC Code governs the design and equipment of ships carrying liquefied gases in bulk, including requirements bearing on cargo transfer systems. Cargo hoses are subject to periodic pressure testing and visual inspection at intervals defined by the operator's and class's requirements, and each hose is normally marked with its test date, working pressure and service life limit - a hose used past its stamped service life is rejected regardless of how it looks.
Typical faults
| Fault | Cause | Consequence |
|---|---|---|
| Liner embrittlement or cracking | Repeated cryogenic cycling beyond the hose's rated cycle life, or wrong liner material for the cargo | Internal leak path forms, invisible until pressure testing or failure |
| External cover damage | Abrasion from dragging across deck or a rough manifold edge, kinking below minimum bend radius | Reinforcement exposed, hose loses pressure rating |
| Coupling leak on connection | Worn or damaged seal in the dry-break coupling, misalignment during connection | Cargo release at the manifold during transfer |
| Failed pressure test | Undetected internal deterioration from age or cargo exposure | Hose withdrawn from service before it is used in an actual transfer |
What to look for in a supplier
- Certification matching the specific cargo and temperature range in service, not a generic gas hose certificate.
- Current pressure test certificate and clearly marked service life or cycle life limit.
- Coupling type matched exactly to the manifold in use, including dry-break compatibility where fitted.
- Traceability of manufacture batch, since a hose failure investigation depends on that record.
Track each hose's cycle count and calendar age against its stamped service life, not just its last pressure test date - cryogenic hose fatigues with thermal cycling even when it has never failed a test.