In practice the choice is between two constructions: strip-wound (interlocked) metal hose for static routing, mechanical protection and exhaust duty — and corrugated flexible metal hose (EN ISO 10380) for pressure-tight, vacuum-tight, dynamically flexing service. Strip-wound hose is not gas-tight or pressure-tight on its own; corrugated hose with stainless braid handles high pressure, full vacuum and cryogenic media. Misapplying strip-wound hose to dynamic pressure duty is one of the most expensive specification errors in industrial piping.
Here is how the two constructions differ, which specifications to check per size, and where each belongs.
What is the difference between strip-wound and corrugated metal hose?
Strip-wound hose is a profiled metal strip wound helically so adjacent turns interlock mechanically — flexible, robust, but with leak paths at every interlock. Corrugated hose is a gas-tight tube (welded or seamless) formed into annular or helical corrugations that act as a bellows — pressure-tight, vacuum-tight and fatigue-rated.
The mechanical consequence is fundamental. The interlocked strip gives axial strength and crush resistance, and tolerates static misalignment, but repeated small-radius flexing fatigues the strip edges and the geometry cannot contain gas pressure without an internal liner or packing. Corrugated construction spreads bending strain across the whole corrugation profile, which is why it carries defined flexure and impulse ratings under EN ISO 10380 — and why braided corrugated assemblies are the default in process plant.
Within corrugated hose, annular corrugations (discrete rings) are the standard for pressure, vacuum and high-cycle duty; helical (continuous spiral) corrugation favours drainage and flow but resists vacuum poorly and is confined to low-pressure duties such as exhaust.
Construction classes at a glance
| Construction | Pressure containment | Vacuum | Dynamic flexing | Typical duty |
|---|---|---|---|---|
| Strip-wound, interlocked | None to low (liner-dependent) | Not suitable | Poor (strip-edge fatigue) | Exhaust connectors, protection conduit, ventilation |
| Corrugated annular, unbraided | Low (bellows only) | Good | Good | Expansion elements, low-pressure connectors |
| Corrugated annular + 1 braid | Medium-high | Full vacuum | Very good | Process transfer, steam, thermal expansion |
| Corrugated annular + 2 braids | High | Full vacuum | Very good | High-pressure gas/liquid transfer |
| Corrugated helical | Low | Poor | Moderate | Exhaust, drainage-oriented lines |
Braid is what carries the pressure. Indicative ratings for 316L annular corrugated hose (verify against the manufacturer's size table — working pressure always falls as DN rises):
| DN | Single braid WP | Double braid WP |
|---|---|---|
| DN 12 | ≈ 130–180 bar | ≈ 200–280 bar |
| DN 25 | ≈ 80–130 bar | ≈ 130–210 bar |
| DN 50 | ≈ 40–65 bar | ≈ 65–110 bar |
| DN 100 | ≈ 16–25 bar | ≈ 25–40 bar |
Corrugated assemblies to EN ISO 10380 are qualified with a minimum 4:1 burst-to-working-pressure ratio and defined cyclic flexure testing; proof testing is performed at about 1.5 × working pressure. Strip-wound hose has no comparable pressure qualification — treat any pressure figure for it as liner-dependent and static-duty only.
Temperature, vacuum and media envelope
Corrugated 316L hose covers roughly −196 °C (liquid nitrogen; special designs to −270 °C for helium) up to about +550 °C continuous, with short excursions higher — the end fittings and braid, not the tube, usually set the practical limit. Strip-wound hose in stainless steel tolerates hot gas well (exhaust duty), but is not suitable for cryogenic liquids: product trapped in the interlock gaps vaporises on warm-up and generates pressure surges.
Annular corrugated hose is the only flexible metal construction rated for full vacuum. Strip-wound interlocks collapse inward and helical corrugation resists external pressure poorly — check the datasheet vacuum rating before putting any metal hose on a suction or condensing line.
Material selection follows the medium: 316L (molybdenum-bearing) as the baseline for chlorides, seawater and acids versus standard 304; nickel alloys for hot halides and aggressive chemistry. Where the pressure envelope of steel should combine with universal chemical resistance, PTFE-lined corrugated assemblies are the standard answer — the PTFE liner covers the chemistry (FDA 21 CFR 177.1550 for food contact), the steel covers the mechanics. For chloride-exposed environments, remember stress-corrosion cracking: 304 braid on a coastal site is a known failure pattern, so specify 316L throughout.
Which standards govern metal hose?
- EN ISO 10380 — corrugated metal hoses and hose assemblies: materials, pressure ratings, burst factor, cyclic flexure and leak-tightness qualification.
- EN 14585-1 — corrugated metal hose assemblies for pressure applications: assembly and end-fitting requirements for PED-relevant service.
- PED 2014/68/EU — pressure equipment directive; assemblies above the pressure-volume thresholds need conformity assessment and documentation.
- EN 1092-1 / EN 10226 / ASME B1.20.1 — flange and thread interfaces (note: BSPT and NPT tapered threads are not interchangeable).
- EN 10204 3.1 — material certificates for wetted components; the baseline expectation in process, pharmaceutical and oil-and-gas procurement.
For pharmaceutical duty, add USP Class VI on polymer-lined versions and internal surface-finish certification; for ATEX areas, confirm electrical continuity of the assembly (resistance testing per ISO 8031).
Where does each construction belong?
Strip-wound: engine and generator exhaust connectors, flexible protection conduit over cables and thermocouples, ventilation and fume extraction — jobs about geometry and heat, not pressure containment.
Corrugated (braided): pump and compressor connectors absorbing vibration, thermal-expansion compensation on hot headers, steam and condensate lines, cryogenic transfer (LN₂ at −196 °C, LNG at −162 °C), gas panels and any duty combining pressure with movement. In high-cycle applications, request the flexure-cycle data from the EN ISO 10380 qualification rather than assuming fatigue life.
Browse metal hoses and expansion compensators and the wider industrial hose range, or run a search for metal hose to compare braided assemblies by size and pressure class.
Selection checklist
- Classify the duty: static or dynamic. Any repeated flexing → corrugated, with documented cycle data.
- Define pressure at temperature — ratings are quoted at +20 °C and derate as temperature rises; apply the manufacturer's derating curve, per size.
- Check vacuum exposure — condensing steam and pump suction demand annular corrugated construction.
- Match alloy to medium and environment — 316L minimum for chlorides; consider nickel alloys or PTFE-lined hose for aggressive chemistry.
- Specify end fittings and attachment — welded ends are standard for higher pressures and temperatures; flanges to EN 1092-1; verify the fitting rating equals or exceeds the hose rating.
- Allow straight tangents at the ends — keep a straight length behind each fitting and never bend at the ferrule; use elbows where geometry is tight.
- Never torque through the hose — torsion is the fastest killer of both constructions; use two spanners and, where rotation is unavoidable, a swivel joint.
- Demand documentation — EN 10204 3.1 certificates, pressure test certificate, PED conformity where applicable.
Failure modes and inspection
Strip-wound hose fails by interlock separation — gaps opening in the helix under tension or fractured strip edges under bending fatigue; once a convolution opens, replace immediately. Corrugated hose fails by corrosion-fatigue cracking at corrugation crests (pinhole leaks = end of fatigue life), broken braid wires (an early warning that the inner hose is overworked), and chloride stress-corrosion cracking of 304 components. Inspect braided assemblies visually every 3–6 months in vibrating service, and pressure-test before re-insulating any lagged line.
For adjacent decisions in this cluster, see stainless steel hose vs PTFE hose and the industrial hose specifications deep-dive.
Cost and total cost of ownership
Strip-wound hose costs a fraction of an equivalent-bore braided corrugated assembly — and that is exactly the trap. Misapplied to dynamic pressure duty it fails in months, and repeated replacement plus downtime quickly exceeds the corrugated assembly that would have lasted years. Conversely, specifying double-braided 316L for a static exhaust connector is wasted capital. Match construction to duty, then let lifetime — not unit price — decide.
Specify with test certificates, not assumptions
Send us the medium, pressure, temperature, movement pattern and end connections — our engineering team selects the construction and alloy, fabricates the assembly and pressure-tests it with full documentation. Browse compensators and metal hoses, download the technical catalogues, or request a quotation.