What Is a Flexible Hose? Applications

A flexible hose is a pressure-containing tubular element that can bend, flex, and absorb movement in a piping system. Flexible hoses are used where rigid pipe connections are impractical due to vibration, thermal movement, misalignment, or the need for portable connections. They consist of an inner tube (or corrugated core), reinforcement layers (braid or spiral), and often an outer protective cover.

In oil and gas applications, flexible hoses connect vibrating equipment (pumps, compressors, engines), provide temporary connections for loading and unloading operations, and absorb movements that exceed the capability of the piping system.

Flexible Hose Types

Type	Construction	Typical Application
Metal braided hose	Corrugated stainless steel core with one or two stainless steel wire braids	High-pressure, high-temperature process connections, vibration isolation
Composite hose	Multiple layers of thermoplastic films and fabric reinforcement	Chemical transfer, tank truck loading, marine hoses
Rubber hose	Elastomeric inner tube with textile or wire reinforcement and rubber cover	Water, air, low-pressure oil, general utility
PTFE-lined hose	PTFE inner tube with stainless steel braid	Corrosive chemicals, high-purity, steam
Marine loading hose	Heavy-duty rubber with multiple fabric and wire plies, flanged ends	Ship-to-shore crude oil and product transfer
Offshore flexible riser	Multi-layer bonded or unbonded polymer and steel construction	Subsea-to-platform fluid transfer

Key Design Parameters

Parameter	Typical Specification
Standards	EN ISO 10380 (metal hoses), EN 13765 (composite hoses), API 17J (offshore risers)
Pressure rating	10-350 barg (metal braided); 10-25 barg (composite); 5-100 barg (rubber)
Temperature range	-200 to +800 degrees C (metal); -40 to +150 degrees C (composite/rubber)
Size range	DN6 to DN600 (application dependent)
End connections	Flanged (ASME B16.5, EN 1092), threaded, quick-connect couplings
Inner tube material	321 or 316L stainless steel (metal), PTFE, UHMWPE, NBR, EPDM
Braid material	304 or 316 stainless steel wire
Bend radius	Minimum 5-10 times hose ID (must never be exceeded in service)
Cycle life	Limited—depends on pressure, movement amplitude, and frequency

Common Mistake

Installing a flexible hose with a bend radius tighter than the manufacturer’s minimum is the most common cause of premature hose failure. A hose bent too tightly at the fitting connection point concentrates stress, cracks the corrugations or inner tube, and leads to leaks or burst failure. Always use proper bend supports or elbow fittings at hose ends to maintain the minimum bend radius.

Flexible Hose vs. Expansion Joint

Feature	Flexible Hose	Expansion Joint
Primary function	Absorb vibration, misalignment, portability	Absorb thermal expansion
Movement type	Multi-directional (bending, lateral, axial)	Primarily axial, lateral, or angular
Pressure capability	Moderate (limited by hose construction)	High (multi-ply metal bellows)
Length	Typically 0.3-3 m	Short, inline element
Installation	Portable or semi-permanent	Permanently installed in piping
Cycle life	Limited—fatigue failure risk from vibration	Defined cycle life per EJMA

Flexible hoses in process piping must be rated for the system design pressure and temperature per the pipe class specification. Regular visual inspection and pressure testing are required, as hose assemblies are potential leak points in the piping system.

Read the full guide to oil and gas equipment