How CoreDux® helped close a gap no standard could cover
Some engineering challenges start with a question. Others begin with a gap. In this case, it was both.
The request was clear: flexible metal hoses that could safely handle 10,000 PSI (which has led to a 850bar design pressure according ASME and PED compliancy) – far beyond industry norms for stainless steel hoses. The solution had to be flexible, leak tight, pressure-proved, and reliably repeatable, while functioning in a delicate, high-purity environment with little room for compromise.
But such a hose didn’t exist. There was no standard. No blueprint. No off-the-shelf option globally. And the international codes that usually guide high-pressure equipment offered no reference.
This is the story of how a customer’s need pushed us to develop not only the hose itself, but also the supporting data, test regime, and inspection approach to prove its performance – contributions that may now influence the wider standards landscape.
The challenge no one asked to solve
Our partner – a manufacturer of advanced lithography systems – faced a specific challenge: ultra-pure gases needed to be transported at extremely high pressures inside compact modules, where rigid plumbing was impractical. Flexibility was essential for installation, vibration isolation, and servicing.
In high-pressure industries such as oil & gas or chemicals, rigid piping is the rule. Flexible stainless steel hoses at this high pressure level were long seen as unfeasible. At the time, our highest-pressure hose DN6 was rated to 290 bar (MAWP). The new requirement: 850 bar (MAWP). Nearly triple that. And not for one-off use, but for reliable, long-term operation.
Why flexible hoses matter
When systems are compact, pressure is extreme, and uptime is critical, rigid piping limits design and maintenance. Flexible hoses can make integration simpler, reduce fatigue from vibration, and enable servicing without dismantling (or disconnecting) entire assemblies.
This is relevant far beyond one application. Whether in semiconductors, hydrogen infrastructure, or other advanced industries, the combination of high pressure, purity, and limited space makes flexible solutions essential to progress.
When code doesn’t cut it
The technical challenge was matched by a regulatory one.
ASME B31.3 governs much of the world’s pressure piping, but it has no design rules for flexible metal hoses. Europe does: EN 14585, co-authored by our R&D lead Eric Wintrebert, which sets out material, design, and qualification methodology.
But citing a European standard was not enough for integration into ASME-based systems. Proof was required – demonstrated in both engineering and regulatory terms. That’s where the real work began.
No theory without proof: over 10,000 pressure cycles later
Design alone wasn’t enough. The hose had to prove itself in practice.
Prototypes were built and subjected to at least 10,000 pressure cycles, simulating years of fluctuating load (which was clearly set out in the test protocol). Each cycle stretched the hose under high internal pressure, then released it – replicating fatigue in service.
The performance showed that the hose could not only meet but exceed lifetime requirements. Additional burst pressure tests pushed it beyond its design conditions to confirm safety margins and establish failure thresholds, as required for robust design. In figures, this means effective burst pressures reached up to 4,300 bar ( > 62,000 PSI ) with a dispersion of 3% max.
Built to withstand, built to flex
The hose itself was constructed using:
- A corrugated stainless steel core, allowing for controlled flexibility and pressure resistance. Stainless steel also brings excellent corrosion resistance and avoids permeation (full leak tightness).
- Multiple layers of wire braid, containing the expansion forces and preventing rupture.
- Welded end connections and collars, where stress concentrations are highest – and where failure is least tolerable.
Each design decision was grounded in the methodology laid out by EN 14585. But every detail was verified through hands-on testing, not assumptions.
The hidden weak point: weld inspection and the CT approach
Pressure performance is vital, but weld integrity is equally critical.
ASME requires inspection of pressure welds, typically by X-ray. Yet with dense braiding and complex fittings, X-ray was ineffective. Together with notified bodies, we explored alternatives. Industrial computed tomography (CT)—already established in aerospace and medical fields—proved effective, offering 3D imaging that revealed defects conventional methods missed.
From this, new acceptance criteria for welds were defined, paving the way for CT not just as a diagnostic tool, but as a viable certification method for pressure-critical components.
From the lab to the standard
In July 2025, these findings were presented at the ASME Pressure Vessels & Piping (PVP) Conference in Montreal. The objective: to share a pathway for evaluating flexible hoses and welds that existing codes do not yet cover.
The proposals under discussion include a code case recognizing EN 14585 as a design basis in ASME systems, and another for CT-based weld inspection. If adopted, these could become part of the 2028 ASME B31.3 revision.
Looking ahead
The hose is qualified. The welds are validated. The data is robust. The next step depends on whether international committees adopt these contributions.
What matters most is that an urgent customer requirement led to innovations that may benefit an entire field. By addressing that need, we not only delivered a solution, but also helped point the way toward safer, more reliable standards for the future.
When existing standards or solutions don’t quite fit your needs, it can feel like progress stops. That’s exactly where we step in. At CoreDux, we work side by side with our customers to bridge those gaps, turning demanding requirements into proven solutions that last. Are you facing a challenge that current codes don’t cover? Or perhaps a system constraint that seems impossible to overcome?
We’d be glad to explore it with you. Get in touch with us, share your toughest problem, we’re more than happy to find the path forward together.
