The short verdict: choose corrugated stainless steel hose (EN ISO 10380) when temperature, permeation-tightness or mechanical robustness governs, steam headers, hot gases, thermal-oil and cryogenic transfer, vibration compensation on machinery. Choose PTFE hose when chemistry or purity governs, the fluoropolymer bore covers −70 °C to +260 °C, resists practically all process chemicals, and carries food and pharma approvals. The two families overlap far less than catalogues suggest: above PTFE's 260 °C ceiling only metal remains; against hydrochloric acid or hot chlorides only PTFE survives. And one property is routinely missed: virgin PTFE is an electrical insulator, flammable-media duty requires antistatic (carbon-loaded) versions per EN 16643.
Choose stainless steel hose when:
- temperature exceeds PTFE's +260 °C limit, steam, exhaust, hot gas, thermal oil (metal hose serves to several hundred °C with pressure derating per alloy and size),
- zero permeation is mandatory, gases, vacuum, volatile media: a metal wall is absolutely tight,
- the hose absorbs vibration or thermal movement between rigid pipework and machinery,
- cryogenic duty (LNG, liquid nitrogen) at the lowest temperatures.
Choose PTFE hose when:
- the medium attacks stainless steel: HCl at any concentration, hot chlorides, wet chlorine, mixed acids,
- product purity or cleanability decides, pharma, food flavourings, cosmetics, semiconductor chemistry,
- the bore must be non-stick with batch-to-batch changeovers,
- moderate temperature (−70 °C to +260 °C) with high chemical variability.
What Are the Two Constructions?
A corrugated stainless steel hose is a thin-walled 316L (or 321) corrugated tube whose flexibility comes from the corrugation geometry, overbraided with one or two stainless wire braids that carry the pressure load. Assemblies are welded to their end fittings and governed by EN ISO 10380, which defines pressure ratings, proof testing (typically 1.5 × working pressure) and flexing classes. Interlocked (stripwound) metal hose is a related product for exhaust and protection duties, but it is not gas-tight.
A PTFE hose puts a polytetrafluoroethylene tube, smooth-bore for laminar flow and cleanability, or convoluted for flexibility, inside a stainless steel braid that carries the pressure. The chemical resistance lives entirely in the fluoropolymer liner; the braid is structural. Hydraulic-style PTFE hose is standardised as SAE 100R14 under SAE J517; European requirements for PTFE hose assemblies, including the antistatic variants, are covered by EN 16643. Pressure capability is set by the braid: small-bore double-braided types reach into the hundreds of bar, with ratings falling as DN rises, as with every hose family, read the per-size table, never the headline.
Decision Table: Stainless Steel vs PTFE Hose
| Parameter | Corrugated SS hose | PTFE hose |
|---|---|---|
| Temperature range | Cryogenic (to ~−196 °C and below, alloy-dependent) up to several hundred °C with derating | −70 °C to +260 °C |
| Chemical resistance | Good, but attacked by HCl, hot chlorides (pitting/SCC), reducing acids | Near-universal; excepted: molten alkali metals, elemental fluorine |
| Permeation | Zero, metallic barrier | Slight permeation possible through thin walls (relevant for gases/volatiles) |
| Pressure | Moderate; braid-dependent, falls with DN | Braid-dependent; small-bore multi-braid types very high; falls with DN |
| Design factor | 4:1 (braided, per ISO 10380 practice) | Commonly 3:1 for PTFE hose, verify datasheet |
| Bore character | Corrugated (turbulence, hold-up) unless lined | Smooth bore available — Ra far below any metal liner; non-stick |
| Electrical behaviour | Conductive by nature | Insulating, antistatic carbon-loaded liner needed for flammable media (EN 16643) |
| Fatigue behaviour | Corrugation/braid fatigue under vibration, design to flexing class | Flex fatigue in convoluted types; cold flow under clamps |
| Hygienic duty | Possible (electropolished, lined versions) | Standard route — FDA 21 CFR 177.1550, USP Class VI, EC 1935/2004 declarations |
Where Does Each One Win on Chemistry?
Stainless steel's weak points are specific and well known: chloride media (brines, seawater, hypochlorite) cause pitting and, above roughly 60 °C, stress-corrosion cracking; hydrochloric acid attacks 304 and 316L at any concentration; hot concentrated caustic and reducing acids are also problematic. 316L (with molybdenum) outperforms 304, but neither is an HCl solution.
PTFE is the reference material for chemical inertness: across −70 °C to +260 °C it resists practically every industrial acid, base, solvent and oxidiser, with only exotic exceptions (molten alkali metals, elemental fluorine at pressure/temperature). That is why PTFE hose is the default for multi-product chemical duty, aggressive CIP chemistry and anywhere a resistance chart would otherwise need a footnote per cargo. The trade-offs: PTFE's abrasion resistance is poor, thin walls permit slight permeation of some gases and volatiles, and the liner cold-flows under sustained clamp pressure, all managed by correct assembly design rather than material choice.
The ATEX Question Everyone Misses
Virgin PTFE is one of the best electrical insulators in industry. A standard PTFE hose transferring solvents, fuels or powders can accumulate static charge on its bore with no path to earth, an ignition source in ATEX zones. The remedy is the antistatic version: a carbon-black-loaded PTFE liner (bore resistance verified per ISO 8031, requirements per EN 16643) earthed through the braid and fittings, specified explicitly at order. Metal hose does not have this problem, the wall itself conducts, which quietly decides some solvent and fuel applications in favour of stainless, or mandates the antistatic PTFE variant. If your installation is zoned, put the zone classification on the enquiry.
Failure Modes: What to Inspect For
- SS hose: braid-wire fatigue at the fitting transition (broken wires are a late indicator), crevice/chloride corrosion under the braid, corrugation cracking from vibration beyond the flexing class or from installation in torsion. Never install a metal hose twisted, torsion is its fastest killer.
- PTFE hose: cold-flow bore restriction under over-tightened clamps, flex-fatigue cracking in convoluted liners bent below minimum radius, permeation staining on the braid (replace immediately), damaged flare at the fitting from poor assembly.
- Both: assemble torsion-free with a backup spanner, respect minimum bend radius, proof-test after assembly, and put assemblies on a documented replacement schedule appropriate to the duty rather than running to failure.
Typical Applications, Side by Side
Stainless steel hose earns its keep where physics is extreme: steam and condensate connections on distribution networks, hot-gas and exhaust links in power and marine plant, thermal-oil circuits, cryogenic transfer of liquefied gases, and, its quietest but largest role, vibration compensation between pumps, compressors and rigid pipework, where the corrugated wall absorbs movement that would fatigue-crack a welded joint. It is also the default flexible element where absolute gas-tightness is specified: hydrogen, helium, vacuum systems and volatile solvents that would slowly permeate any polymer wall.
PTFE hose owns the chemistry- and purity-driven applications: multi-product chemical dosing and transfer, CIP-intensive food and beverage lines, pharmaceutical API and WFI-adjacent transfer with smooth-bore liners, paint and solvent circulation (antistatic versions), semiconductor process chemicals, and high-temperature hydraulic or compressor connections inside the −70…+260 °C window where rubber hose compounds age out. Its non-stick bore also solves problems that are commercial rather than chemical, flavour carry-over between batches, pigment residues, media that cure or crystallise in the hose.
The hybrid case is real: a convoluted PTFE liner inside a stainless overbraid, or a PTFE-lined metal hose, combines fluoropolymer chemistry with metallic mechanics. When both temperature and aggressive media push the limits simultaneously, ask for these constructions explicitly rather than stretching either standard family.
Cost Logic
Small-bore PTFE braid assemblies and corrugated metal assemblies of the same DN are often in the same price band; the differentiators are elsewhere. Metal hose costs escalate with alloy (321, Monel, Hastelloy) and with certified cryogenic or high-temperature builds; PTFE costs escalate with antistatic liners, pharma documentation (USP Class VI, traceability) and multi-braid high-pressure builds. As always in process plant, the dominating term is a mis-specified hose failing in service, pick the family by the physics and chemistry above, then optimise price within it.
Selection Checklist
- Temperature honestly bounded, above +260 °C only metal; below −70 °C favour metal; between, both are candidates.
- Medium vs material, chlorides/HCl exclude stainless; abrasive or high-permeation duty challenges PTFE.
- Pressure at the actual DN, braid-dependent for both; read the size table; note PTFE's typical 3:1 vs braided metal's 4:1 design factor.
- ATEX/static, flammable media + PTFE = antistatic version per EN 16643, resistance verified per ISO 8031.
- Purity/hygiene, smooth-bore PTFE with FDA 21 CFR 177.1550 / USP Class VI / EC 1935/2004 declarations for the specific version.
- Movement duty, vibration and thermal expansion favour metal hose sized to its flexing class; never in torsion.
- Documentation, proof-test certificate, material traceability (EN 10204 3.1) and conductivity result where applicable.
For adjacent decisions, see the companion comparison chemical hose vs food-grade hose.
Browse stainless steel and PTFE hose assemblies, search directly for PTFE hose, or check dimension and pressure tables in the catalogues. For borderline cases, hot chlorides, zoned areas, pharma documentation — send the application data: our engineering team selects liner, braid and fittings and delivers pressure-tested, certified assemblies.