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Common questions
Installers, specifiers and homeowners ask the same questions about Ridgeline: the material, the certifications, the install, the cost. We've answered the substantive ones here, with sources.
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New to Ridgeline? Ten quick answers first. The full technical detail, with sources, lives in the sections below.
Ridgeline is a flexible corrugated stainless steel piping system for hot and cold water, central heating, heat pumps and underfloor heating. It bends by hand around obstacles, so long continuous runs can reduce intermediate fittings and concealed joints where the route allows. Browse the product range.
The tube is 1.4404 (316L) marine-grade stainless steel, the same family of stainless used for marine fittings and surgical instruments. Plumbing tube adds a polyethylene sleeve on the outside of the steel to protect it from chlorides in screed, plaster and cement; the sleeve never touches the water. More on materials and water quality.
Yes. Ridgeline is WRAS Approved and KIWA Reg 4 certified for UK drinking water, within the exact assembly's approval scope. The tube's water-contact surface is 316L stainless steel; fittings and seals are separate components. More on hygiene and water safety.
Yes. Ridgeline tube with the P1 fitting system holds WRAS approval and KIWA UK Reg 4 (KUKreg4 ATS 3) certification across the full size range, and the RidgeLock system holds the same approvals on R-15, R-22 and R-28. Full certification breakdown.
Yes, it installs with standard plumber's kit: a metal wheel pipe cutter, a utility knife and two spanners. No press tools, no soldering, no crimpers, and RidgeLock works with standard EN 1254 compression fitting bodies, with the RidgeLock sealing ring replacing the copper olive. More on installation.
Yes. R-32 HP is a dedicated heat-pump size, and the 316L tube handles real outdoor weather then continues indoors as one system with no transition joints. More on heat pumps and underfloor.
Significantly faster, and the more direction changes on the route, the bigger the saving: bends replace elbows, long coils replace cut-and-fit chains, and there is no soldering or hot works. Every job is different, so we do not publish a multiplier. The reasons it is faster.
No. The corrugated geometry spreads bending stress across multiple corrugations instead of concentrating it at a single point, so the tube stays kink-resistant even at very tight bends, and the bend radius equals the tube's outer diameter. More on bending and support.
Plumbing tube runs R-15, R-22, R-28, R-32-HP, R-35, R-42 and R-54, with Pro-FAST and Eco-MAX for underfloor and Flexis for appliance connections. Coils ship from 25 m up to 500 m. Sizing guidance is in flow and pressure.
Ridgeline is sold through UK plumbers' merchants. Use the stockist finder to locate your nearest branch, or request a sample and the team will point you to the best route for your job.
Materials & water quality
The basics on the material we chose, the corrosion data behind it, and what makes Ridgeline different from copper and PEX in your drinking water.
Ridgeline tube is manufactured from 1.4404 (316L) marine-grade austenitic stainless steel, conforming to BS/EN 10088. We chose 316L deliberately, and we use it across the whole range. Plumbing, Underfloor, and Flexis.
There are two reasons it sits a step above the more common 304 grade in a water context. First, 316L contains 2–3% molybdenum, which gives it materially better resistance to chloride pitting and crevice corrosion. UK domestic water is generally low-chloride, but a pipe lives in a building for fifty-plus years, and contact with screed, plaster, cement, and the occasional damp wall environment all introduce chlorides over time. The molybdenum addition is a long-game decision.
Second, the "L" designation means low carbon (≤0.03%). Lower carbon means much better resistance to intergranular corrosion at and around any heat-affected zone introduced during manufacturing. It is the grade specified for hygienic-process pipework in pharma, food, and brewing for the same reason.
In practice, 316L is the same family of stainless that is specified for marine fittings, surgical instruments, and the inside of premium water bottles. If it holds up in seawater and inside the human body, the inside of a UK plumbing system is a benign environment by comparison.
In short. Ridgeline corrodes dramatically less than copper does, in the same water, under the same test conditions. That is not our claim; it is the conclusion of an independent study run by Lancaster University's School of Engineering.
Lancaster ran three independent analytical methods on samples of Ridgeline tube (CSST) and copper tube exposed to identical accelerated corrosion conditions: XPS (X-ray Photoelectron Spectroscopy), ICP-OES (mineral leaching into water), and optical microscopy at high magnification. The three methods triangulate. Surface chemistry, what is actually leaving the pipe into the water, and what the surface looks like before and after.
Across all three methods, Ridgeline showed essentially no measurable corrosion. Surface chromium content was preserved, indicating the protective passive layer was intact and able to self-repair. Iron and chromium readings in the test water remained at trace levels consistent with background, not consistent with material loss from the pipe wall. Microscopy showed the tube surface unchanged before and after testing.
Copper, in the same conditions, showed the opposite. XPS recorded a 3% drop in surface copper after testing. ICP-OES showed copper concentration in the water rising from 0.13 ppm at 16 hours to 1.5 ppm by day 8. Copper was actively being removed from the pipe and entering the water. Microscopy showed substantial surface damage.
Lancaster's verdict, in their own words: "With no evidence of corrosion in all three analysis methods, it is clear that corrosion has not occurred for CSST… As copper showed corrosion in all analysis methods, it is also correct to state that CSST will last longer than copper when in domestic hot water systems."
That is a written, third-party engineering finding that Ridgeline tube outlasts copper tube in UK domestic water service.
Evidence: independent testing at Lancaster University (2022).
The Lancaster study was undertaken at Lancaster University's School of Engineering by Dr Armin Yousefi Kanani and Prof Pedro Rivera, with engineering interns Marcus Holmes and Kawtar Houbad, supported by the Greater Innovation for Smarter Materials Optimisation (GISMO) programme under the European Regional Development Fund. The final report is dated 30 December 2022.
The study compared Ridgeline corrugated stainless steel tubing against copper tubing under accelerated corrosion conditions designed to simulate UK domestic hot water service. Three different analytical methods were used:
XPS (X-ray Photoelectron Spectroscopy) measured the surface chemistry of both materials before and after exposure. Stainless steel showed a virtually unchanged spectrum, with chromium and oxygen levels indicating the passive oxide layer was intact and self-repairing. Copper showed a 3% drop in copper content at the surface and significant accumulation of trace contaminants, indicating substantial surface degradation.
ICP-OES (Inductively Coupled Plasma Optical Emission Spectroscopy) measured trace elements that had migrated from the pipe wall into the water. For Ridgeline, chromium and iron levels in the water remained essentially flat across the test, indicating the pipe was not shedding material. For copper, copper concentration in the water climbed from 0.13 ppm at 16 hours to 1.5 ppm at 8 days. The pipe was actively losing material into the water.
Optical microscopy at high magnification compared the inner surface of each tube before and after testing. The Ridgeline surface was visually unchanged. The copper surface showed clear, significant damage.
The combined conclusion was unambiguous: under conditions modelling UK domestic water service, Ridgeline did not corrode and copper did. The report states it is "reasonable to say that CSST will outlive copper significantly."
Evidence: independent testing at Lancaster University (2022).
The honest engineering answer is: under the conditions of UK domestic water service, no, and there are three reasons we can say that with confidence.
First, 316L stainless steel is intrinsically corrosion-resistant. It forms a thin, self-repairing chromium-oxide passive layer on its surface. If that layer is mechanically scratched or chemically disturbed, it re-forms within seconds in the presence of oxygen, which is always present in a domestic water system. This is why stainless steel cookware, surgical instruments, and chemical-processing pipework all use the same family of alloys.
Second, the corrosion environment in a UK domestic water system is mild. Cold/hot water cycling between roughly 10°C and 60°C, low chloride levels, no continuous mechanical vibration, and no chemical contamination. The Lancaster work modelled deliberately accelerated conditions and found no measurable corrosion. Real-world service conditions will be gentler still.
Third, the documented failure modes for corrugated stainless steel. Stress corrosion cracking, torsional failure, vibration-fatigue cracking, repeated-bending fatigue. All require conditions that simply don't occur in fixed domestic plumbing. Stress corrosion cracking, for example, requires chlorides combined with temperatures above roughly 200°C. UK hot water peaks at 60–65°C. The mechanism cannot initiate.
We back this with a 25-year warranty, but we design and build for a 100+ year service life, which is consistent with both the published behaviour of 316L in potable water and Lancaster's third-party findings.
Evidence: independent testing at Lancaster University (2022).
This is a fair question. Chlorides are the one environment where austenitic stainless steel can be vulnerable, and building materials can carry residual chloride content.
That is precisely why every Ridgeline tube has a high-grade polyethylene outer sleeve as a second protective layer. The sleeve is not there to resist water. Water never touches it. It is there to prevent the stainless steel from making direct contact with chloride-bearing building materials during installation and over the life of the building.
Ridgeline tube can be buried directly in screed, run through plaster lines, or routed through cement without additional sleeving. The PE cover is the protection. If the cover is nicked or damaged in a chloride-contact area during installation, the standard repair is a wrap of self-amalgamating silicone tape (available from Ridgeline) which restores the barrier.
The corrosion-protection logic is the same as the Flexigas (gas) product, which has been certified to BSI Kitemark for nearly two decades using the same construction principle: stainless steel core, PE sleeve outer barrier.
The PE outer sleeve is a barrier between the stainless steel and the building materials around it. Its job is purely external. It protects the tube from chlorides in screed, plaster, cement, and damp wall cavities, and it makes the tube easier to pull through tight spaces. Installers describe it as "feeling more like cable than pipe."
It does not contact the drinking water. Water only ever flows inside the 316L stainless steel tube. The PE sleeve sits on the outside of the steel, not the inside. So when we say Ridgeline has no plastic in contact with drinking water, that is a literal description of the construction, not a marketing line.
This is one of the genuine differentiators against PEX, which is plastic on every internal surface that touches potable water.
No measurable leaching, on the evidence we have.
Ridgeline holds two of the strictest UK and European certifications for materials in contact with drinking water: WRAS Approved (Water Regulations Advisory Scheme. The UK benchmark for materials safe for potable water) and KIWA Certified to KUKreg4 ATS 3 (the equivalent Dutch/European drinking-water materials approval). Both schemes test for migration of metals and organic contaminants into water, and both certifications were granted on the basis of actual migration testing. Not just declared composition.
Lancaster University's ICP-OES work backs this independently. ICP-OES detects trace elements in water down to parts per billion. Across the test, chromium levels in water exposed to Ridgeline tube remained essentially flat. Consistent with the protective passive layer being intact and the steel not losing material. Iron readings rose slightly, but Lancaster attributed this to the steel screws holding the test rig together rather than the tube itself.
For comparison, copper in the same test rig showed rising copper concentration in the water over time, climbing from 0.13 ppm at 16 hours to 1.5 ppm at 8 days. Measurable, ongoing leaching.
So: Ridgeline is certified for direct potable water use under the two strictest UK schemes, and an independent university study using parts-per-billion-sensitive analytical methods found no detectable leaching.
Evidence: independent testing at Lancaster University (2022).
The water-contact surface of Ridgeline tube is 316L stainless steel. Its outer sleeve sits outside the steel and does not contact water inside the tube. This is a clear construction difference from a polymer tube.
That tube-level fact is not a guarantee that water delivered by a complete installation contains no microplastics. Incoming water, fittings, seals and other connected equipment must be considered separately. Ridgeline Flexis also use a stainless flexible element, with separate end-connection seals.
Choose the approved assembly and check its actual wetted components. Material construction alone does not establish a measured health benefit or biological performance advantage. Sources: P1 datasheet, Rev 2, July 2026; current certificates and schedules; Flexis construction and model approvals.
This is a sensible question and a fair concern from anyone who has used cheap stainless cookware. The short answer is: not in our experience and not in the certifying bodies'.
Both WRAS and KIWA Reg 4 test for organoleptic effects (taste, odour and appearance changes) when granting drinking-water material approval. Ridgeline is approved under both. A material that imparted detectable metallic taste would not pass.
Mechanistically, taste from stainless steel comes from metal ions migrating into the water. The Lancaster ICP-OES work measured exactly that, at parts-per-billion sensitivity, and found no meaningful migration of chromium or iron from the tube into water. If the metal isn't moving into the water, the water has no taste vector.
A useful comparison: the same 316L stainless steel grade is what insulated drinking bottles, kitchenware, and brewery and dairy pipework are made from. None of those applications are associated with metallic taste in the finished product.
Where metallic taste can genuinely occur is from cheaper 304 stainless or from low-grade fittings reacting with hot water. Ridgeline avoids both, 316L tube throughout, dezincification-resistant brass on the fitting bodies.
Evidence: independent testing at Lancaster University (2022).
In normal UK domestic water service, no, and it is worth being precise about why.
Galvanic corrosion needs three things at once: two dissimilar metals in direct electrical contact, an electrolyte connecting them, and dissolved oxygen. UK potable water can supply the electrolyte and oxygen, so the question becomes whether stainless steel and copper are dissimilar enough to drive a meaningful current.
In practice, the galvanic potential between 316L stainless steel and copper is small. They sit relatively close on the galvanic series, and the protective oxide layer on the stainless steel further suppresses any current flow. This is why mixed copper-and-stainless-steel installations are common in commercial heating systems, hot-water plant rooms, and food processing, without specialist isolation.
The Lancaster work tested copper in the same rig as Ridgeline, with brass fittings on the CSST. The ICP-OES results showed copper rising in the water (from the copper tube section), but no chromium or iron rise from the stainless tube. The stainless wasn't being driven to corrode by the dissimilar-metal contact.
Where galvanic risk does become relevant is in continuously stagnant, high-conductivity water (high-chloride boiler systems, seawater, stagnant tank water). For domestic UK potable water with regular flow and oxygen, it is not a practical concern, and Ridgeline integrates with copper systems at fittings without isolation.
Evidence: independent testing at Lancaster University (2022).
We commissioned an independent study specifically to answer this, because the corrugated profile looks like it should give limescale somewhere to grip. The reality is no. Ridgeline accumulates limescale at the same rate as copper and PEX, no worse.
The study was run by TWI (The Welding Institute) in 2024 under UK Innovate Edge Project 35768, led by Tamoor Masood. It tested three pipe materials side-by-side in real Cambridgeshire tap water. Corrugated stainless steel (Ridgeline), copper, and LDPE.
Phase 1 was a flat-coupon test: each material at 65°C for 48 hours. Results: stainless steel 0.5g of scale build-up, copper 0.4g, LDPE 0.5g. Adhesion testing showed limescale stuck firmly to all three substrates equally. No material had a meaningful "non-stick" advantage.
Phase 2 was a longer-term test rig: all three pipe types running in parallel at 60°C and 2 bar for one month continuous. The results matched Phase 1. Comparable scale build-up across all three materials.
The conclusion was clear: the corrugated profile does not increase scale accumulation. Ridgeline performs no worse than copper or plastic in hard-water areas.
For installations in the hardest water regions, conventional softening or scale-prevention practice applies the same way it would for any other pipe material.
The 100+ year design life is grounded in published material data for 316L stainless steel in potable water service, not a marketing target.
Three lines of evidence support it.
First, the material itself. 316L stainless steel has been in industrial and infrastructure service since the mid-20th century. Reference data from the Nickel Institute and the International Molybdenum Association (IMOA) (the bodies that publish authoritative corrosion data on these alloys) show 316L in cold and warm potable water environments operating with no measurable corrosion over multi-decade service intervals, with extrapolated service lives well over 100 years under normal conditions.
Second, independent third-party testing of our specific product. The Lancaster University study (December 2022) found no measurable corrosion of Ridgeline tube under accelerated test conditions, across three independent analytical methods. They concluded "there is no reason that the CSST will corrode in UK domestic water systems."
Third, the engineering case from operating conditions. Domestic potable water at 10–60°C, low chloride, no vibration, mild pressure, intermittent oxygen. Sits orders of magnitude below the operating envelope (350–650°C, high pressure, continuous vibration, aggressive chemicals) where industrial 316L bellows still routinely deliver 15–20 year service lives. The same material in a far gentler environment can be expected to last far longer.
We back this with a 25-year warranty as the contractual commitment. Design life is the engineering expectation; warranty is the legal floor.
Evidence: independent testing at Lancaster University (2022).
Ridgeline tube is manufactured with high recycled content as an embedded design choice. Stainless steel is one of the most recycled materials globally, and the arc-furnace route used to make our feedstock is itself a recycling-led process.
We deliberately do not put a single locked-in percentage on it, because recycled-content figures fluctuate batch-to-batch depending on the mix of scrap and primary feedstock the mill is running, and we would rather understate-and-deliver than publish a number we cannot guarantee on any given coil.
What we can say with confidence:
The honest framing is: Ridgeline carries a high recycled-content position from the start of its life and a fully recyclable position at the end of it.
Yes, and unlike most recyclability claims this one is structural rather than aspirational.
Ridgeline tube is 316L stainless steel. A material that retains essentially all of its value through the recycling loop. Stainless steel scrap is collected at the bin level by every UK metals recycler, melted in arc furnaces, and re-formed into new stainless steel. There is no downcycling penalty: the recycled output is the same grade as the input. This is why scrap stainless commands a real price at the kerb.
The polyethylene outer sleeve is a small fraction of the total mass and is also recyclable through PE-stream waste, though for end-of-life the steel is the meaningful bulk.
Compare that with PEX: cross-linked polyethylene is, by chemistry, thermoset. Once cross-linked, it cannot be re-melted and re-formed into new PEX. Mainstream PEX recycling either does not exist or downcycles the material into low-value mixed-plastic outputs. The vast majority of PEX installed today will be landfilled when the building it serves comes down.
This is a structural, not marketing, advantage. We invite anyone who wants to verify it to weigh a length of Ridgeline tube and call any UK metals recycler.
Flow & pressure
Sizing guidance, pressure-drop tables, velocity limits, and what the corrugated bore actually does to system performance.
Corrugation affects tube resistance, so use Ridgeline's own pressure-loss data at the required flow. A nominal diameter or similar bore does not establish the same hydraulic performance as copper, PEX or multilayer pipe.
The practical advantage is flexible routing: permitted bends can replace intermediate fittings. Compare tube friction plus the actual bends, connections, valves and other components on the same route. Copper and polymer systems can also use formed bends where their instructions permit. Fewer fittings do not by themselves prove lower total pressure loss.
Source: P1 datasheet, Rev 2, July 2026, page 4; same-route comparison guide.
Use the same design principles, with product-specific data. Establish the required flow, available pressure or pump head, complete route, fluid and temperatures. Calculate losses for the selected tube and every relevant component; check velocity, terminal pressure and the equipment instructions.
The plumbing range is R-15, R-22, R-28, R-32-HP, R-35, R-42 and R-54. R-32 HP is designed for heat-pump primary routes; it is a candidate to assess, not an automatic answer for every duty. A longer or more restrictive route can require a larger size.
Use the exact size's published data. Do not substitute a copper-equivalence label or another Ridgeline column. See ASHP sizing guide and published reference data and P1 datasheet, Rev 2, July 2026.
The current P1 datasheet, Rev 2, July 2026 includes R-32-HP and R-42, alongside the rest of the seven-size range. Page 4 gives flow in L/min, velocity in m/s and tube pressure loss in Pa per metre. Use populated cells for the exact size; a blank cell is not zero loss.
For example, the published row at 20 L/min gives R-32-HP 373 Pa/m and R-35 128 Pa/m. R-35 therefore cannot serve as a conservative pressure-loss proxy for R-32 HP: substituting it would understate the tube loss in that row.
Multiply the relevant Pa/m value by the measured tube length, then include the remaining circuit losses at the same flow. Confirm the data's applicability to the actual fluid and temperature; the reference table does not state those conditions. The ASHP sizing guide and published reference data retains the source revision, units and selected published rows.
Yes. Tube resistance is part of the circuit the pump must serve. The circulator has to deliver the required flow against the complete pressure loss of flow, return, fittings, valves and other components. Check available head at that flow, rather than the pump's maximum head at zero flow.
For heat pumps, also check minimum, maximum and defrost flow, DHW reheat requirements, fluid concentration and the exact installation arrangement. Avoid deducting equipment losses twice if the manufacturer's available-head figure already excludes them. Boiler and underfloor circuits need their own design checks.
Sources: ASHP sizing guide and published reference data; underfloor selection and design evidence.
The rating belongs to the tube and selected connection system.
| Connection system | Kiwa-certified maximum working pressure | Certified temperature scope |
|---|---|---|
| P1, full plumbing range R-15 to R-54 | 15 bar | Up to 99°C operating; 85°C continuous |
| RidgeLock, R-15 / R-22 / R-28 and listed adapters | 10 bar | 85°C maximum operating |
P1 certificate 2604733 and RidgeLock certificate 2501716 revision (2) cover different assemblies. Check their current schedules before specifying. Flexis connectors have separate model-specific approvals and ratings.
P1's manufacturer-stated high-temperature capability for non-potable service is a separate, pressure-derated specification. It does not extend potable-water certification. Sources: current certificates and their schedules; P1 datasheet, Rev 2, July 2026.
For the certified potable-water scope, P1 is rated up to 99°C operating, with 85°C continuous, and RidgeLock to 85°C maximum operating. Use the complete assembly's current certificate and installation requirements.
The P1 datasheet separately describes non-potable mechanical capability at 150–180°C with pressure derating. Its short-term 200°C condition requires the specified specialist gaskets and no more than 9 bar. Do not apply that condition to ordinary potable installations or to every fitting/seal combination.
Sources: current certificates and their schedules; P1 datasheet, Rev 2, July 2026, page 2. For unusual operating conditions, obtain a project-specific configuration from the technical team.
Specify against the published working-pressure rating, not an inferred burst pressure. A simple smooth-cylinder stress calculation does not establish the burst strength or fatigue life of a corrugated tube and fitting assembly.
Use the selected product's installation and pressure-test instructions. Ridgeline Underfloor has separate test requirements from the plumbing system. For a project requiring burst-test evidence, ask the technical team for data covering the exact assembly.
Sources: P1 datasheet, Rev 2, July 2026; current installation and underfloor documents.
Check both the supply's available pressure under the design flow and the assembly's maximum working pressure. A high pressure rating does not show that a long or restrictive route will deliver enough flow at the outlet.
Allow for elevation, components and the required terminal pressure in the water-system design. Assess pressure surges and any pressure-reducing device separately. For example, a 50% rise above 8 bar is 12 bar, which exceeds RidgeLock's 10 bar rating; it must not be described as within that rating.
Sources: current certificates and their schedules; P1 datasheet, Rev 2, July 2026. Send the measured supply duty and proposed route to the technical team for selection support.
There is no single flow rate suitable for every size and application. Check the selected tube's velocity at the design flow against the project's design criteria for noise, hydraulic performance and operation.
The P1 datasheet, Rev 2, July 2026, page 4, lists velocity beside pressure loss. Use the correct size column and the relevant design guidance. Do not treat a velocity target as evidence of biological protection or a substitute for water-safety management.
A formed bend can avoid a discrete elbow fitting, but no fitting does not mean zero hydraulic loss. Account for the actual bend geometry and applicable manufacturer/design data. Do not assume a straight-tube pressure-loss table includes every possible installed bend.
Compare each system's permitted formed bends and actual fitting schedule. Record concealed joints separately: a fully concealed two-ended fitting has two joints, and a fully concealed tee has three. A fitting-count reduction does not establish a measured reduction in leaks or pump energy.
Source: same-route comparison guide.
Compare complete systems at the same flow and route, using each product's actual bore, tube-loss data and selected connections. Include inserts or reduced-bore fittings where the alternative requires them, and credit permitted bends in every system.
Ridgeline's continuous flexible stainless tube can reduce intermediate fittings and concealed joints. The size and hydraulic outcome still follow the calculation. There is no universal one-for-one nominal-size substitution.
Sources: P1 datasheet, Rev 2, July 2026; whole-home material selection; same-route comparison guide.
Begin with the exact heat pump's required flows and available external pump head. Include design heating, DHW reheat and defrost requirements where applicable. Use the actual water/glycol mixture, temperature, combined flow-and-return length and component schedule.
R-32 HP with P1 fittings is the dedicated heat-pump candidate. Check its published resistance against the complete duty and step up where the calculation requires it. Heat output alone is not a pipe-size lookup.
Sources: ASHP sizing guide and published reference data; screening calculator and methodology. Final selection follows the project design and equipment instructions.
Legionella & hygiene
Product approvals, evidence scope and the role of water-system design and management.
Ridgeline can be specified for potable-water applications within the selected assembly's approval and installation scope. Healthcare and other higher-risk buildings also require a competent project-specific water-safety design and management plan.
The 316L tube and long continuous runs offer a practical material and routing option. Product certification does not certify a building as Legionella-safe. Check the exact tube, fittings, seals and operating conditions alongside temperature control, turnover, access and commissioning requirements.
Sources: current certificates and their schedules; HSE hot and cold water guidance.
Ridgeline's position is that its corrugated 316L stainless element does not increase microbial-growth risk in intended water use. The corrugated shape alone is not evidence that a pipe promotes biofilm.
Keep the evidence types distinct: flow simulations assess fluid behaviour; scale tests assess deposits; biological tests assess organisms. None should be substituted for another. We do not describe the tube as biologically self-cleaning or claim that it prevents or removes biofilm.
Use the approved assembly within a properly designed and managed water system, including control of stagnation. Sources: technical evidence and support; current certificates and their schedules; HSE hot and cold water guidance.
Corrugation changes local flow and tube resistance. The behaviour depends on geometry, flow rate and the operating cycle; an observation under flowing conditions does not describe a long unused pipe.
Hydraulic or passive-scalar modelling is not a biological test and does not establish Legionella control. Use the tube's pressure-loss data for sizing and the building's water-safety plan for hygiene management.
Sources: P1 datasheet, Rev 2, July 2026; technical evidence index; HSE hot and cold water guidance.
The clear construction difference is the water-contact surface of the tube: Ridgeline uses 316L stainless steel, while PEX is a polymer. Fittings and seals are separate components and must be assessed as part of the complete assembly.
A general material comparison, a scale study or a potable-water approval does not establish a percentage reduction in biofilm or disease risk in a building. A biological comparison needs a matched test protocol and results for the actual products and conditions.
Sources: current certificates and their schedules; technical evidence index; HSE hot and cold water guidance.
Yes, within the relevant product and model schedules. P1 and RidgeLock have separate certification scopes; Flexis has its own model-specific approval table. Do not transfer an approval or rating from one assembly to another.
The plumbing tube's PE sleeve is external and does not contact drinking water. The complete system also includes fitting and seal materials. Check all of them in the approved assembly.
Sources: current certificates and their schedules; Flexis model approvals; Water Regs UK evidence of compliance. WRAS and Kiwa are evidence routes; holding both is not itself a universal legal requirement.
The selected Ridgeline assembly can form part of a compliant water-system design. Compliance also depends on the building's risk assessment, operating controls, monitoring and maintenance.
HSE describes hot-water storage at least at 60°C, distribution reaching 50°C at outlets within one minute (55°C in healthcare), and cold-water control below 20°C. Apply the detailed guidance, including scald protection and the actual system arrangement, through the competent designer or responsible person.
Sources: HSE hot and cold water guidance; current certificates and their schedules. Product certification is not approval of the building's water-safety scheme.
The PE sleeve is outside the stainless plumbing tube and does not contact the water flowing inside it. It protects the tube from surrounding building materials. It should not be treated as an internal wetted surface in a tube-material comparison.
Assess the actual wetted components of the complete assembly, including seals, against their approval schedules. Source: P1 datasheet, Rev 2, July 2026; current certificates and their schedules.
Plan pipework and its use to limit stagnation, whatever the material. Long continuous tubing can reduce intermediate connections, but it does not remove the need to manage low-use outlets, redundant branches and periods when a building is unoccupied.
Apply the building's risk assessment and flushing/monitoring plan. Do not extrapolate a result obtained during flow to indefinite stagnation. Source: HSE hot and cold water guidance.
Check the exact assembly's certified pressure/temperature limits, every component in the circuit and the planned procedure. P1's potable-water scope is up to 99°C operating and 85°C continuous; RidgeLock's is 85°C maximum operating. Non-potable high-temperature capability is a different specification.
A thermal-disinfection procedure also presents scalding and operational risks. It must follow the building's competent water-safety assessment and current guidance, not a pipe-material claim alone.
Sources: current certificates and their schedules; HSE technical guidance, Part 2.
Confirm the proposed chemical, concentration, temperature, contact time and rinse procedure for the complete assembly with the technical team and chemical supplier. Compatibility at normal potable-water residual levels does not automatically establish suitability for a concentrated disinfection treatment.
Include the tube, fitting metals, seals and other connected equipment. Use the project's competent water-safety procedure. Sources: P1 datasheet, Rev 2, July 2026; technical support; HSE hot and cold water guidance.
Assess each source for the question it actually tests. A corrosion study addresses corrosion under its stated conditions; a scale study addresses scale; a flow simulation addresses modelled fluid behaviour. Those findings should not be presented as a biological trial or proof of disease prevention.
For specification, start with the current potable-water certificates and obtain the original report and scope for any additional research claim material to the project. The technical evidence index explains the available evidence and contact route. Water-safety management follows HSE hot and cold water guidance.
Installation & repair
Plumber-friendly answers on cutting, bending, supporting, joining, and dealing with damage. No specialist training required.
Standard plumber's kit. No specialist tools.
That's it. No press tools, no soldering, no crimpers, no torch. If you've got a bag for a copper compression job, you can install Ridgeline.
Ridgeline is designed to reduce cut-and-fit work through long continuous runs and hand-formed bends within the installation limits. The time saved depends on the actual route, tube size, connection method, access and installer experience.
Compare the same route fairly. PEX, multilayer pipe and copper can also use bends within their system limits. Do not assume an elbow at every change of direction. Count the fittings each approved design actually needs, then include cutting, preparation, joint assembly, support and testing.
Use the right assembly. RidgeLock connections use a tube cutter, knife and spanners with the specified tube and compression-fitting assembly. P1 has its own preparation and tightening instructions. Coil lengths and bend limits depend on the selected product. Mechanical connections avoid soldering and flame at the joint; site working procedures still apply.
Make the saving specific to the job. Use the concealed-joint worksheet to compare the actual fitting schedules. Fewer intermediate fittings can remove assembly steps and concealed joints, but a joint count alone is not a measured installation-time result.
Sources: current installation instructions; product and connection choices.
Bend radius equals the outer diameter of the tube. That means for R-15 the bend radius is 15 mm; for R-22 it's 22 mm; for R-54 it's 61 mm.
In practice this is very tight. You can achieve adjacent (back-to-back) bends where the run demands it, with full kink resistance maintained even at extremely tight bends. No bending tools or formers required. Just bend it by hand.
Yes, and this is the core of the "Eliminate Elbows" story. The corrugated design allows 90-degree bends (or tighter) by hand, and the bend stays in place. No elbow fitting required.
Every elbow you don't fit means:
For long routes through interior spaces and around obstacles, you can chain multiple bends in a single continuous run with no fittings at all behind the wall.
No. Ridgeline is engineered to be kink-resistant even at extremely tight bends. The corrugated geometry compresses on the inside edge of a bend and expands on the outside edge, so the tube redistributes the bending stress along multiple corrugations rather than concentrating it at a single point (which is how PEX kinks).
This is what the brochure calls "Impossible to Kink, Engineered for Confidence". Installers can work fast in tight spaces without worrying about creating a hidden restriction. No kinks means no delays, no waste, no callbacks.
Support spacing depends on tube size and whether the run is indoor or outdoor:
| Size | Indoor (data sheet) | Outdoor ASHP (lagged) |
|---|---|---|
| R-15 | 1.2 m | . (not used outdoor) |
| R-22 | 1.2 m | . |
| R-28 | 1.2 m | . |
| R-32 HP | 1.8 m | 1.5 m horizontal / 1.8 m vertical |
| R-35 | 1.8 m | . |
| R-42 | 1.8 m | . |
| R-54 | 1.8 m | . |
Indoor spacing applies horizontally and vertically. Standard pipe clips work. You're clipping over the polyethylene outer cover.
For outdoor R-32 HP runs (ASHP feed/return) with 25 mm closed-cell EPDM lagging, drop to 1.5 m horizontal / 1.8 m vertical. The de-rate accounts for the additional weight of the lagging, fluid, glycol, wind catchment on the lagged ~78 mm OD, and ice loading in winter. Always support within 300 mm of any fitting and at every change of direction; on very exposed elevations (coastal, high corner, no shielding) drop to 1.0–1.2 m horizontal or use a continuous external trunking system.
For direct ground burial, follow the current Ridgeline installation guidance and obtain a project-specific specification for protection, insulation, connections and the intended fluid. Do not treat the external PE sleeve or a general potable-water approval as permission for every below-ground installation.
Burial in screed is a different installation condition. Protect the sleeve, follow the relevant instructions and arrange testing before concealment. The current P1 datasheet distinguishes these uses and directs ground-burial projects to the installation guidance.
Sources: P1 datasheet, Rev 2, July 2026, page 2; installation documents; same-route comparison guide.
Yes. Ridgeline is designed for all of these locations.
The big win for concealed installations is no fittings behind the wall. Most leaks happen at joints; Ridgeline lets you put the joints at the visible end of each run.
Standard Water Regulations guidance on concealed installations applies. Minimise concealed fittings where possible through good system design.
The corrugated design provides superior resistance to single freeze events compared to rigid tube. The corrugations have room to accommodate expanding ice, where rigid copper would split.
That said, freeze protection should always be the primary approach. Insulate, lag, or route to avoid freeze risk. In freeze-risk zones, run long continuous lengths without fittings (the fittings are the weak point in any freeze event, on any system).
Important: repeated freeze/thaw cycles may cause permanent deformation. Single freeze event = good chance of survival. Repeated cycles = replace.
If a section of corrugated tube is damaged (puncture, crush, kink beyond service), repair is straightforward:
The Union acts as the in-line splice. No specialist parts, no whole-run replacement.
This works in any location where fittings are permitted by Water Regulations. (Standard guidance on concealed-fitting design still applies.)
In any location where the tube may contact chloride-containing building materials (screed, plaster, cement) any hole in the PE cover must be repaired.
Use self-amalgamating silicone tape (available from Ridgeline). Wrap the damaged area with overlap so the tape bonds to itself and seals out the chloride exposure.
Outside chloride zones (e.g. running through an open void), a hole in the cover is cosmetic rather than structural, but it's still good practice to tape it.
Standard plumbing insulation works fine. There's no proprietary insulation. Use whatever your job spec calls for.
Two practical points:
For ASHP outdoor flow/return, a factory pre-insulated version of Ridgeline is coming soon (entering production) in R-28, R-32-HP and R-35, with a factory-bonded closed-cell nitrile foam insulation layer (0.034 W/(m·K), Class 1 surface spread of flame to BS 476 Part 7, service temperature to 125 °C) under a UV-stable polyethylene outer shell. See the Pre-Insulated Ridgeline + P1 data sheet and register interest with the technical team. Until launch, lag standard Ridgeline on site as above.
In practice, effectively zero, and that is a genuine design simplification.
316L stainless steel has a similar linear expansion coefficient to copper (around 16 × 10⁻⁶ /K, vs 16.4 for copper). On a straight rigid 10 m run at a 50°C temperature swing, the raw linear-expansion arithmetic gives about 8.5 mm of growth. Same as copper, an order of magnitude less than PEX. But Ridgeline isn't a rigid tube. The corrugated geometry absorbs that movement through distributed micro-deflections along the length, every corrugation taking a tiny fraction of the dimensional change. The result is that thermal expansion is effectively absorbed inside the run. It doesn't transfer as force to the fittings, and the system behaves as though the tube isn't moving at all.
The numbers comparison engineers care about, 10 m run at ΔT 50°C:
| Material | Linear expansion | Design implication |
|---|---|---|
| PEX | ~70 mm | Requires expansion loops, flexible supports, slack at every fitting |
| Copper | ~8.5 mm | Requires expansion loops on long runs |
| Ridgeline | ~8.5 mm linear, effectively zero in practice | Corrugations absorb movement through distributed micro-deflections. No expansion loops, no special supports needed |
This is the same engineering principle behind every metal expansion bellows in industrial pipework. Corrugated stainless absorbs axial movement by design. It's also why 316 stainless became the material of choice for residential water mains in seismic zones like Tokyo: the corrugated geometry handles dimensional movement that would crack rigid jointed pipework. Thermal cycling on a domestic plumbing run is millimetre-scale; the corrugation absorption operates well inside that envelope.
Installer guidance. Simple:
For typical residential and light-commercial work (boiler primaries, ASHP feed and return, hot and cold distribution, underfloor) no expansion loops, no offset rules, no anchor calculations. For commercial-scale runs above 50 m of continuous straight pipework with full thermal cycling (district heating, solar thermal primary loops), follow standard piping-flexibility analysis as you would for any metal pipe.
The point to recalibrate for PEX-trained engineers: PEX moves an order of magnitude more than Ridgeline. Anchor and loop spacing rules from PEX systems do not apply.
Ridgeline ships in lengths from 25 m up to 500 m. Shorter lengths come in convenient boxed coils (typically ~60 cm × 60 cm front face); longer lengths come on wooden spools.
UK stock lengths across all sizes: 25 m, 50 m, 100 m. Longer lengths (250 m, 350 m, 500 m) available as master-spool sizes for project work.
Spool/arbor hole is 100 mm (universal across all sizes) so any de-spooler with a 100 mm spindle will fit.
A weight-per-metre comparison (15 mm size, indicative):
The reduced weight per metre is a real win on site. Less lifting, faster handling, and less attractive to copper thieves.
Always check spool weight against your site handling before ordering. A 500 m R-54 spool is heavy.
Use a standard metal wheel pipe cutter. Centre the cutting wheel in the valley between two corrugations (not on the corrugation peak) and rotate.
Two Ridgeline-branded options:
Any decent quality wheel cutter that fits the tube diameter will work. The aim is a clean circular cut with no burrs. That's what gives a reliable seal at the fitting. Don't use a hacksaw (you'll get a ragged edge that won't seat properly against the brass).
Two routes, depending on which fitting system you're using:
With RidgeLock (R-15, R-22, R-28): Use any standard EN 1254 compression fitting available from any UK merchant. On the Ridgeline side, replace the copper olive with a RidgeLock sealing ring. On the copper side, use the standard olive. You now have a WRAS + KIWA Reg 4 approved transition. This is the cleanest route. It works with stock you already have and stock the merchant already has.
With P1 (any size R-15 to R-54): Use a P1 Copper Union (P1-CC range) or P1 Copper Elbow (P1-ECC range). The Ridgeline side terminates onto the corrugated tube; the copper side accepts standard 15/22/28/35/42/54 mm copper.
Either way, the internal diameters are compatible. You can switch between copper and Ridgeline mid-run without flow restrictions.
Connect via a male/female BSP thread combination. In practice:
There's no direct PEX-to-Ridgeline transition fitting. The BSP thread is the universal handshake.
There's no published hard limit on run length. Ridgeline ships in lengths up to 500 m, and you can install a single continuous length on a project as long as it suits the route.
Practical considerations:
The whole point of the long lengths is to eliminate fittings behind the wall. The longer the continuous run, the fewer joints, the fewer leak points.
Big spools are useful but they're not light. A 500 m R-35 spool, for example, is in the order of 90 kg+. That's a two-man lift, definitely not something to wrestle up a ladder.
Practical guidance:
Two scenarios for water installations:
Note: silicone tape is a mandatory part of every Flexigas (gas) install. For Ridgeline (water), it's situational. Used for damage repair and chloride-zone protection rather than as part of the standard fitting procedure.
No proprietary Ridgeline qualification is required. You install Ridgeline using the same skills, tools, and competency standards as any other domestic or commercial water plumbing system.
That said:
For installers new to flexible stainless steel, the learning curve is short. The connection process is closer to a copper compression fitting than to anything novel.
Standards & sustainability
For specifiers and M&E consultants: every relevant standard, every certification, the embodied-carbon position, and the manufacturer warranty.
Ridgeline tube, in combination with both the P1 fitting system and the RidgeLock fitting system, is approved to:
Both approvals apply to Ridgeline Plumbing tube and Ridgeline Flexis. The P1 system carries cover across the full size range (R-15 to R-54). RidgeLock carries cover on R-15, R-22 and R-28.
Ridgeline is a separate product line from Flexigas (gas CSST), which holds BSI Kitemark KM 598726 to BS EN 15266:2007. Flexigas certification does not apply to water installations and Ridgeline certification does not apply to gas. The two systems must not be cross-specified.
WRAS Approved Product status confirms that the product meets the mechanical and water-quality requirements of the Water Supply (Water Fittings) Regulations 1999 and Scottish Water Byelaws 2014, which are the legal framework underpinning every UK drinking-water installation.
For specifiers, WRAS Approval means:
In short: a WRAS Approved system is the default route to demonstrating compliance with the water fittings regulations on a UK project.
KIWA UK Reg 4 (KUKreg4) is an alternative recognised compliance route to the same Water Supply (Water Fittings) Regulations 1999. The "ATS 3" designation refers to the Approved Test Specification under which the product was assessed.
KIWA Reg 4 carries equivalent weight to WRAS Approved status for the purposes of demonstrating regulatory compliance. Many UK water companies and large specifiers explicitly accept either route. Ridgeline holding both means the system can be specified onto any project regardless of which scheme the consultant or contractor prefers to reference.
Yes. BS EN 806 (Parts 1–5) is the current European and UK framework for the design, installation, testing and maintenance of water installations inside buildings conveying water for human consumption. It superseded the former BS 6700.
Ridgeline tube + fittings hold the WRAS and KIWA Reg 4 approvals required to be specified under BS EN 806. The system's certified working parameters (P1: 15 bar, up to 99°C for potable water with 85°C continuous; RidgeLock: 10 bar / 85°C) cover the full envelope of typical hot and cold domestic and light-commercial water services within the EN 806 framework. P1 additionally has a mechanical capability to 150–180°C for non-potable applications such as solar thermal, which sit outside the EN 806 / potable-water scope by design. BS 8558 (the UK-specific complementary guidance to EN 806) and CIBSE Guide G should be referenced alongside for design.
Where main protective bonding is required by BS 7671 (the IET Wiring Regulations), typically where Ridgeline forms part of, or connects to, the metallic incoming water main, Ridgeline supports it directly via the RL Bond™ (EB-01) earthing terminal. RL Bond is a patent-pending 1-step earthing terminal compatible with all P1 Mechanical Fittings, providing the equipotential bonding pathway required under BS 7671 / Water Regs.
Context: BS 7671 requires main protective bonding to extraneous-conductive-parts where they are liable to introduce a potential into a building, including metallic incoming water service pipes. Whether bonding is required at any specific point depends on the installation circumstances, the earth-fault loop impedance, and whether the metallic pipework is treated as extraneous-conductive-part. The electrical installer makes that determination per the Wiring Regs.
Same physical product as FG Bond on the Flexigas (gas) side, rebranded for the water context. The gas version (FG Bond) is BSI-certified for use on Flexigas to BS 6891. The water version (RL Bond) is the same earthing terminal used on Ridgeline + P1 installations.
In short: yes, Ridgeline can be earth-bonded to BS 7671 / Water Regs, and RL Bond is the integrated terminal for it.
Part G (Sanitation, hot water safety, water efficiency). Ridgeline's certified working envelope (15 bar, up to 99°C for potable water with P1 fittings) accommodates all G3 unvented hot-water requirements with significant margin. Cold water and backflow protection are covered through compliant fittings selection.
Part L (Conservation of fuel and power). Ridgeline is compatible with all standard pipe insulation systems. The polyethylene outer cover provides a smooth surface for chosen insulation. The corrugation profile means insulation product selection should be made with the corrugation in mind. Manufacturer guidance is available on request.
Part B (Fire safety). Ridgeline's load-bearing element is metallic 316L stainless steel and does not contribute to fire spread through the tube wall itself. The polyethylene sleeve is a separate consideration: penetration sealing through compartment walls and floors should be specified with the project fire consultant, treating the PE cover as part of the assembly.
Part P (Electrical safety). Part P applies to electrical installations, not to the water pipework. The relevant standard for any required equipotential bonding is BS 7671 (see Q5).
Yes. Ridgeline meets the regulatory baseline UK insurers expect for domestic and commercial water installations:
The market context matters for specifier and developer conversations:
Evidence: ABI, ASBP and UK insurer data.
Ridgeline tube has a 100+ year design life based on the documented behaviour of 316L stainless steel in potable water (Nickel Institute, World Stainless Association). A 25-year manufacturer warranty applies to the product when installed in accordance with the published installation instructions and using approved fittings.
The design life is the engineering durability of the material in service. The warranty is a separate contractual undertaking and is shorter than design life by convention. Specifiers comparing systems should compare design life to design life and warranty to warranty rather than mixing the two.
Full warranty terms (claim process, coverage limits, exclusions) are available on request.
NBS specification listings for Ridgeline are in development. Specifiers wanting a Ridgeline section drafted into a project NBS spec in the meantime should contact us directly. The technical content is ready and can be supplied in NBS-style clauses on request.
Revit families and BIM objects for Ridgeline are in development. In the interim, dimensioned tube data and full P1 / RidgeLock fitting schedules are published in the Ridgeline + P1 Data Sheet and Ridgeline + RidgeLock Data Sheet. Sufficient for manual modelling or generic-family parameter overrides on a current project. Contact us directly for fitting-by-fitting dimensional data.
Per the Ridgeline Plumbing Long Brochure (carbon page):
The driver is twofold. First, the manufacture of stainless steel via modern electric-arc furnace processing yields lower CO2e per tonne than refined copper (3.50–5.00 mt CO2e/tonne) and is comparable to PEX (2.10–3.00 mt CO2e/tonne). Ridgeline sits at 2.20–2.50 mt CO2e/tonne. Second, and more importantly, Ridgeline uses significantly less material per metre of tube thanks to thin-wall construction.
The CO2e advantage is structural to thin-wall corrugated stainless steel and is not dependent on a specific recycled-content figure to deliver. Ridgeline's greenhouse-gas footprint is currently being audited by Ernst & Young. Published figures will be the EY-verified numbers once that work concludes.
The Ridgeline Plumbing Long Brochure publishes the following indicative weight and CO2e ranges per tonne, by tube size, alongside copper and PEX comparators:
| Size | Product | mt CO2e per tonne manufactured | Weight per metre of tube |
|---|---|---|---|
| 15mm | Ridgeline | 2.20–2.50 | 75 g |
| 15mm | PEX | 2.10–3.00 | 90 g |
| 15mm | Copper | 3.50–5.00 | 266 g |
| 22mm | Ridgeline | 2.20–2.50 | 140 g |
| 22mm | PEX | 2.10–3.00 | 160 g |
| 22mm | Copper | 3.50–5.00 | 505 g |
| 28mm | Ridgeline | 2.20–2.50 | 190 g |
| 28mm | PEX | 2.10–3.00 | 260 g |
| 28mm | Copper | 3.50–5.00 | 900 g |
CO2e per kg of copper is sourced from published Copper Development Association data (copper.org). CO2e per kg of PEX is averaged across published PEX manufacturer EPDs; figures vary by manufacturer. Weights are estimates and will vary by manufacturer.
For projects requiring whole-life carbon assessment input, Ernst & Young is currently auditing Ridgeline's GHG emissions and the audited dataset will supersede these brochure figures.
Ridgeline tube is manufactured from high recycled content marine-grade 316L stainless steel. We deliberately don't publish a specific percentage at this stage. Recycled content fluctuates batch-to-batch with the mill's scrap-to-primary mix, and we'd rather understate-and-deliver than publish a figure we can't guarantee on every coil. The Ernst & Young GHG audit currently in progress will set the verifiable position.
For specifiers preparing a BREEAM Mat 03 / responsible sourcing return: the auditable position today is "high recycled content," continually increasing. The verified percentage will be supplied once the EY audit closes.
This is consistent with the recycled-stainless ecosystem. Secondary scrap is the dominant input to the global stainless industry, and the EAF (electric-arc furnace) route is the standard low-carbon production method.
Yes: Ridgeline tube is 100% recyclable at end of life.
316L stainless steel is one of the most recycled materials in industrial use. Stainless feedstock retains its full mechanical properties through repeated recycling cycles, which is not the case for crosslinked polyethylene (PEX) or multi-layer composite plastics, which are functionally non-recyclable in the UK domestic waste stream.
For a project pursuing circular-economy or BREEAM Wst credits, Ridgeline can be specified and recovered through the standard scrap-stainless route at end of building life.
Ridgeline corrugated stainless steel tube is UK designed. It is produced to our specification by an established stainless steel tubing manufacturer with the production capacity, technical pedigree and quality systems required for the corrugated 316L tube specification.
Tube is shipped to the UK in container quantities (over 70,000 m per container, given the lightweight thin-wall construction) and stocked at Ridgeline's UK distribution centre in Somerford Booths, Cheshire. Fittings supply, customer support, certification, training, design service and warranty all sit within the UK Ridgeline business.
The combination of patent-pending connection IP and the underlying corrugated 316L tube format means specifiers selecting Ridgeline are selecting a defensible, IP-backed system, not a generic commodity. Trademarks Ridgeline, RidgeLock and P1 are registered to the Ridgeline business.
No. Mixing Ridgeline tube with another manufacturer's fittings, or vice versa, is forbidden and will void both the Ridgeline warranty and the WRAS / KIWA Reg 4 certification cover.
The reason is technical, not commercial. The P1 self-flaring seal and the RidgeLock sealing-ring geometry are matched to the specific corrugation pitch, profile, wall thickness and tolerance of Ridgeline tube. A nominally compatible-looking competitor fitting will not seal predictably against Ridgeline tube, and Ridgeline fittings cannot be assumed to seal against competitor tube.
For connections to other piping systems (copper, PEX, MLCP):
This rule applies to Ridgeline exactly as it applies to Flexigas (where mixing CSST manufacturers also voids the Kitemark). It is a property of correctly engineered piping systems, not a commercial restriction.
Heat pumps & underfloor
Why R-32 HP exists, what it does for ASHP circulators, how Pro-FAST and Eco-MAX compare, and the underfloor design fundamentals.
R-32 HP is Ridgeline's dedicated heat-pump tube size, used with P1 fittings for primary water flow and return. The published dimensions are 32 mm outside diameter with cover and 27 mm inside diameter.
Its own pressure-loss column is in the current P1 datasheet. Compare that data with the required flow, complete route and available pump head. A larger size may be required; R-32 HP is not a universal copper-equivalent selection.
Sources: P1 datasheet, Rev 2, July 2026, pages 2 and 4; ASHP sizing guide and published reference data.
Ridgeline combines a stainless tube water path with hand-formed routing and long continuous runs. That can reduce intermediate fittings on an awkward route and help place connections where they remain accessible.
Compare it with the actual alternative system. PEX and multilayer systems can also be flexible and supplied in coils. Give every option credit for its permitted bends, then compare tube/fitting losses, insulation, supports, access and installed work on the same duty.
Sources: P1 datasheet, Rev 2, July 2026; same-route comparison guide.
Yes. Ridgeline tube is rated for indoor and outdoor use, and the P1 / RidgeLock fitting systems carry the same approval. The 316L stainless steel core does not corrode under UK weather conditions, and the PE outer sleeve adds a chloride barrier. Ridgeline can also be buried without additional protection or sleeving (relevant for ground-source heat-pump approaches and where outdoor ASHP runs go below ground).
For ASHP flow and return specifically, the tube is suitable outdoors but the insulation requirement is separate. See the next question. Outdoor Ridgeline still needs to be insulated to meet MIS 3005 and Building Regulations Part L; that is a heat-loss / freeze-protection requirement, not a tube limitation.
Single-event freeze: the corrugated geometry is more tolerant of accidental freeze than rigid tube, because the corrugations can accommodate a small amount of ice expansion. Repeated freeze-thaw cycling can still cause permanent deformation, so freeze protection (insulation, glycol on primary circuits) remains the primary approach.
Yes. Every external ASHP flow/return run needs insulation along its entire length. This is a regulatory requirement under MIS 3005 (the heat-pump installation standard, 2025) and Building Regulations Part L, and it's there for two reasons: heat-loss control between the heat pump and the building, and freeze protection in cold weather.
The recommended specification for Ridgeline outdoor ASHP runs:
A factory pre-insulated version of Ridgeline is coming soon (entering production) in R-28, R-32-HP and R-35, supplied in coils of up to 100 m (plus 15 m and 25 m boxes), with a factory-bonded closed-cell nitrile foam insulation layer (0.034 W/(m·K), Class 1 surface spread of flame to BS 476 Part 7, service temperature to 125 °C) under a UV-stable polyethylene outer shell. That will remove the on-site lagging step entirely; until launch the installer applies tube and insulation separately as described above.
The PE cover on Ridgeline is smooth and accepts any of the standard pipe-insulation systems without modification.
It affects hydraulic resistance, so include the tube's own data in the pump-duty calculation. Eliminating fittings can help a route, but the complete calculation determines whether it meets the required flow.
For primary flow and return, preserve heat with correctly specified insulation. A more conductive tube is not by itself evidence of a higher heat-pump COP. Underfloor output is a separate floor-system calculation involving pipe size, spacing, build-up, covering, flow and temperatures.
Sources: ASHP sizing guide and published reference data; underfloor selection and design evidence.
Check the exact heat-pump model, fluid, operating conditions and assembly. R-32 HP uses P1 fittings. The P1 potable-water certificate records 15 bar maximum working pressure, up to 99°C operating and 85°C continuous; the datasheet's non-potable high-temperature capability is separately pressure-derated.
RidgeLock has a separate 10 bar / 85°C certified scope on R-15, R-22 and R-28 with listed adapters. Do not apply it to an R-32 HP assembly. Confirm glycol/inhibitor compatibility and equipment requirements for the project.
Sources: current certificates and their schedules; P1 datasheet, Rev 2, July 2026.
Distinguish a heat pump's connecting water pipework from the buried ground collector. Ridgeline plumbing tube is not presented as a generic substitute for a designed ground array.
For any buried connecting route, specify hydraulic duty, insulation, water/ground protection, penetrations, support and access in accordance with the installation guidance. The current P1 datasheet says to follow Ridgeline guidance for direct ground burial; the PE sleeve alone is not a complete buried heat-network design.
Sources: P1 datasheet, Rev 2, July 2026, page 2; same-route comparison guide.
It can, particularly where a continuous hand-formed route avoids intermediate fittings and hot works. The actual saving depends on the route, access, permitted bends, connections, insulation and installation method for each option.
Use a counted fitting and labour schedule. Include supports, preparation, termination, insulation, testing and commissioning for every alternative. State measured or estimated timings explicitly. We do not publish a universal installation-time multiplier.
Compare concealed joints as a separate count; fewer fittings do not quantify leak probability. Source: same-route comparison guide.
Design the unit's defrost-condensate drainage separately from the water pipework. The pipework needs suitable insulation and weather/UV protection, with a vapour-control specification where condensation is possible.
Follow the heat-pump manufacturer's freeze-protection strategy, including any specified glycol, valves, controls and power-failure provisions. Insulation slows heat loss but does not guarantee that stationary water cannot freeze.
The P1 datasheet describes resistance to a single freeze event, but makes freeze prevention the primary approach and warns that repeated cycles may permanently deform the tube. Do not rely on that tolerance as the protection strategy.
Sources: P1 datasheet, Rev 2, July 2026, page 3; same-route comparison guide.
Select against the exact equipment manual and warranty conditions, including required flows, available head, pressure, temperature, fluid, connections and any specified isolation or vibration-control arrangements. A suitable stainless material or matching thread does not establish blanket approval by every heat-pump manufacturer.
P1 fittings provide the relevant connection options for R-32 HP. Confirm the actual interface and full circuit duty before selection. Underfloor manifold adapters are a separate product/connection check.
Sources: P1 datasheet, Rev 2, July 2026; ASHP sizing guide and published reference data; project technical support.
The tube material, geometry and hydraulic/thermal properties differ. Ridgeline Underfloor uses corrugated stainless steel; PEX uses polymer tubing. Select and compare the complete floor system, not conductivity alone.
Hold room duty, floor build-up, coverings and design conditions constant. Check output, surface-temperature limits, flow, circuit loss, spacing and manifold connections for each candidate. Any temperature or energy saving must come from that matched design or a stated test, not a universal percentage.
Source: underfloor selection and design evidence; underfloor datasheet.
Decision is driven by installation method and circuit length, not by Kh. All three sizes deliver a similar Kh value at the same pipe centres because they all share the corrugated 316L profile. The differences are pressure drop and fit.
| Size | OD | ID | Pressure drop | Best for |
|---|---|---|---|---|
| Pro-FAST 15 | 15.0 mm | 10.0 mm | Similar to 12 mm PEX | Compatible with all PEX overlay boards (15/16 mm). Drops into any PEX-method install |
| Pro-FAST 17 | 17.2 mm | 12.2 mm | Similar to 15 mm PEX | The default for most underfloor jobs. Comparable hydraulics to standard PEX |
| Eco-MAX | 22.4 mm | 16.6 mm | Minimal | Heat-pump installs, long circuits, large rooms. Supports 150-200 m circuits and very close pipe centres |
In practice:
You can also mix sizes on the same manifold (Eco-MAX on the index circuit (longest run), Pro-FAST elsewhere) to balance pump duty.
The tube is one part of the floor's heat-transfer system. Output depends on the actual tube, floor construction, pipe spacing, covering resistance and operating conditions. A material conductivity value alone cannot establish the installed floor's Kh or heat output.
Use the applicable thermal design method and product data for the proposed build-up. Keep a modelled result distinct from measured installation performance. Source: underfloor selection and design evidence.
Pro-FAST 15 is fully compatible with standard 15/16 mm PEX overlay boards from any manufacturer. That is the point of the size. It drops into existing board systems (XPS, gypsum, structural chipboard, tile-over) without modification. If a job is specced around PEX overlay boards and the contractor wants to upgrade to Ridgeline, Pro-FAST 15 is the swap.
Pro-FAST 17 and Eco-MAX require boards routed for their specific outer diameter, 17 mm and 22 mm respectively. Ridgeline supplies boards in all the standard build-up types (XPS overlay, structural chipboard, Gypdeck dry-screed system, tile-over) with CNC-routed channels at common pipe centres (50/75/100/150/200 mm depending on board type). Resonate Systems is one external supplier with established Ridgeline-routed XPS and Heatbacker boards.
Summary table:
| Method | Pro-FAST 15 | Pro-FAST 17 | Eco-MAX |
|---|---|---|---|
| Clip down (screed) | ✓ | ✓ | ✓ |
| Castellated panels | ✓ | ✓ | . |
| Standard 15/16 mm PEX overlay boards | ✓ | ( | ) |
| Pro-FAST 17 / Eco-MAX-specific boards | . | ✓ | ✓ |
Yes. Every Ridgeline Underfloor tube connects directly to any standard 3/4" manifold port. There is no need to specify a Ridgeline-branded manifold.
Pro-FAST 15 and Pro-FAST 17 connect via Pro-FAST connector cores (sold in sets of 2) or, when the manifold already has PEX connector cores fitted, by removing the inside of the existing PEX core and dropping a Pro-FAST adapter into the same housing. The nut from the existing PEX core is reused. That makes retrofit / mixed-system installs straightforward. Replace PEX runs with Ridgeline on the same manifold without changing the manifold itself.
Eco-MAX uses an Eco-MAX connector core set with a thread increaser sized to the 3/4" port (Eco-MAX has a slightly larger OD than the standard PEX cores can accommodate without the increaser).
Connection procedure (Pro-FAST):
Eco-MAX is a similar 6-step procedure with a thread increaser, 3 cm of cover removed and 4-5 corrugations exposed.
The half-turn rule matters. Over-tightening can deform the corrugations and create a leak path. Hand-tighten to seat, then half a turn for seal.
Choose pipe centres and circuit length from the room duty and complete floor design. Check output, permitted surface temperatures, covering resistance, design flow and circuit pressure loss for the chosen tube and manifold.
Do not replace a polymer design with a wider stainless spacing or longer circuit on material name alone. Ask the technical team to assess the actual build-up and duty.
Sources: underfloor selection and design evidence; underfloor datasheet.
Plan for the lift, especially on upper floors. Coil weights from the data sheet:
| Length | Pro-FAST 15 | Pro-FAST 17 | Eco-MAX |
|---|---|---|---|
| 100 m | 12 kg | 17 kg | 24 kg |
| 200 m | 24 kg | 34 kg | 48 kg |
| 500 m | 67 kg | 95 kg | 110 kg |
500 m coils give the best material efficiency (cut down on site, less waste) and are recommended on most jobs. But a 110 kg Eco-MAX 500 m coil needs handling: spool roller kits are available for all 500 m sizes, and on upper floors 200 m coils are often the practical choice.
100 m and 200 m coils ship in box format and are compatible with any standard PEX de-spooler.
Highly recommended for every Ridgeline Underfloor install. Ridgeline tube is more flexible than PEX, which is great for laying down, but means it can tangle more easily off a static coil if the tube is pulled at an angle. A de-spooler keeps the coil rotating cleanly, prevents tangle, and is the difference between a 1-person fast install and a 2-person tug-of-war.
Equipment options:
For sizing the day's lift: a 500 m Eco-MAX coil at 110 kg is the heaviest single item, and on multi-room jobs it makes sense to set the de-spooler centrally and route to multiple manifolds.
5 bar maximum pressure when pressure-testing Ridgeline Underfloor systems. Do not exceed.
This is not the burst pressure. Burst pressure is significantly higher. The 5 bar test ceiling exists because pressures above 5 bar can elongate the corrugations in the tube, which permanently changes the geometry and could affect long-term performance.
All Ridgeline Underfloor systems must be pressure-tested before being placed into commission, in line with BS EN 1264 and CIBSE underfloor heating practice. Standard test procedure (typical UK practice):
If the system you are testing also includes the heat-pump primary or a higher-pressure plumbing run, isolate the underfloor circuits at the manifold for the pressure test phase and test them separately at ≤5 bar.
Yes, and it is the standard install method. Tube ships in 100 m, 200 m or 500 m coils, and the recommended workflow on most jobs is to cut to length on site rather than buy pre-cut.
Tooling: a metal wheel pipe cutter (the standard plumber's tube cutter that handles copper). Avoid hacksaws. They leave burrs and a non-circular cut, both of which can compromise the seal at the manifold connector.
Procedure:
Sharp protrusions of stainless on the cut face must be removed before fitting the adapter. They can cut the rubber tongue inside the connector and cause a leak.
Two cases. Outer-sleeve damage, and corrugated-tube damage. They are handled differently.
Outer PE sleeve damaged (no hole in the steel). In screed. Repair with self-amalgamating silicone tape (available from Ridgeline). The PE sleeve's job is to keep chlorides in the screed away from the stainless steel; tape restores the chloride barrier. The repair is straightforward and the screed can go down on top.
Outer PE sleeve damaged. In engineered or chipboard floor (no screed). At the installer's discretion. If the damage is in a location that may contact chloride-bearing materials (plaster, cement, dampproofing) repair with self-amalgamating silicone tape. If it is in a clean, dry timber-floor zone, the practical risk is low and tape may not be needed.
Corrugated tube damaged (hole through the steel). As with all underfloor systems: the entire circuit should be removed and replaced. This is not a Ridgeline-specific limitation; it is standard practice for any UFH system because reliable in-screed repairs are impossible to verify and a slow leak in a buried circuit is catastrophic.
The flip side of this rule is the install-time advantage: Ridgeline coils are long (up to 500 m), continuous, and impossible to kink. The risk of mid-circuit tube damage during install is materially lower than with PEX, where kinking from rough handling is a common cause of circuit failure.
Start with the public underfloor product and selection page and underfloor datasheet. For detailed output data, provide the tube, floor build-up, covering resistance, pipe centres and operating temperatures to the technical team.
Request data and a calculation appropriate to that construction. A table for one screed or spreader arrangement should not be transferred to a different floor build-up without the design check.
Cost & comparisons
The honest answer on per-metre price, the case for total installed cost, and how Ridgeline lines up against every alternative on the merchant counter.
On smaller sizes, yes. Copper is cheaper per metre at the merchant counter. On larger sizes (R-28 and up), the gap closes quickly, and from R-35 upward Ridgeline frequently works out cheaper on materials alone.
The per-metre price is not where the cost comparison ends, though. A copper system needs elbows at every change of direction, soldered or compression joints at every connection, and a skilled installer prepared to put a flame to the wall. Each elbow is material cost, labour time, two potential leak points, and a future maintenance risk in itself. Ridgeline eliminates almost all of those. Long continuous runs replace dozens of soldered joints. From R-28 to R-54, Ridgeline delivers significant savings over copper on total system cost, because you can pull continuous runs like electrical cable and skip the fittings entirely. The actual time and cost saving on any given job depends on the size mix, the route, and the fitting density.
So the per-metre answer is "sometimes yes, sometimes no, but it's the wrong question." The right question is total installed system cost, which includes pipe, fittings, labour, hot-works overhead, and risk. On that comparison, Ridgeline competes hard.
Yes. Ridgeline is more expensive than PEX per metre. We're not going to pretend otherwise. PEX is a high-volume commodity polymer pipe and the per-metre price reflects that.
What we will tell you honestly is what each system gives you for the money. PEX is plastic, with documented industry-wide concerns around chloride stress cracking, microplastic shedding, leaching of organic compounds into the water, and a typical service life in the 20-30 year range. Ridgeline is corrugated 316L stainless steel (the same family of stainless used for marine fittings and surgical instruments) engineered for a 100+ year design life with no plastic in contact with drinking water.
On total installed cost, the gap narrows considerably. Ridgeline's flexibility means fewer fittings (often dramatically fewer. Long continuous runs replace cut-and-fit PEX sections joined with elbows), faster install times on smaller and especially larger sizes, and dramatically lower future failure risk. Some merchants and contractors find that on the 15-28 mm range, once the labour and fitting savings are accounted for, Ridgeline lands close to or better than PEX on total job cost. From 28 mm upward, the elbow-elimination effect compounds and the system-cost picture shifts further in Ridgeline's favour.
The per-metre conversation is the one PEX wins. The total-system conversation is the one we want to have.
This is the conversation that matters, and it's the one we want every contractor to have before they make the call.
The brochure puts it plainly: each fitting on a job adds material cost, labour time to install, two potential leak points (each side of an elbow or union), and future maintenance risk. Ridgeline's flexibility eliminates fittings. Long continuous runs, no elbows, faster installation, fewer leak points.
Add up the components on a typical job:
The honest summary: pipe per metre is the cheapest line item. Fittings, labour, and future failure risk are where the system cost actually lives. Ridgeline wins on those three. We've published a System Cost Analysis page in the Long Brochure precisely to make this visible, and we have tools and worksheets available to help calculate true installation cost for a specific project.
Three structural reasons, all baked into the product.
One. No hot works. No soldering, no flux, no flame, no fire-watch, no fire-permit overhead, no waiting for joints to cool. The connection is mechanical: cut, slide, tighten with two spanners. A plumber's standard kit covers the entire install.
Two. Fewer fittings. Ridgeline bends past obstacles by hand and stays in place. Adjacent (back-to-back) bends are achievable. Every elbow you don't fit saves the cut, the prep, the fit, the leak test, and the future inspection. On a typical whole-home plumbing project the fitting count drops sharply.
Three. Pull it like cable. Larger sizes (R-28 upward) feed through joists, voids and risers in long continuous runs. Point-to-point routing rather than cut-fit-cut-fit. The biggest time savings sit on the parts of the job where copper would have demanded soldering and elbow-fitting at every direction change.
The net effect: significantly faster installs vs both copper and plastic, and a labour line that drops on every job sheet where Ridgeline replaces a fitting-heavy alternative. We don't publish a multiplier. Every job is different and the saving compounds with the number of direction changes, the run length, and the size of pipework.
Yes, and the mechanism is straightforward. Every joint is a potential leak point. Every elbow is two joints. Fewer fittings = fewer leak points = lower call-back risk.
Ridgeline's flexibility lets a single continuous run replace what would have been a chain of cut-and-fitted sections joined by elbows. On a whole-home plumbing job the joint count drops sharply, and most remaining joints are brought out from behind the wall to accessible locations.
The downstream effect is real money. A concealed leak in a Victorian terrace doesn't just cost the price of a fitting. It costs the plaster, the floor, the redecoration, and the contractor's reputation. Ridgeline doesn't eliminate leaks (no system can), but it removes the structural cause of most of them: the sheer count of mechanical joints sitting in inaccessible places.
The materials science backs the same conclusion. 316L stainless steel doesn't pit, doesn't suffer chloride stress cracking under UK domestic conditions, and doesn't shed material into the water over time. Lancaster University's independent study found no measurable corrosion on Ridgeline tube under accelerated test conditions, while copper tested in identical conditions actively shed material. The pipe itself is engineered for 100+ year design life. Orders of magnitude beyond plastic alternatives.
Lower call-back risk is one of the strongest reasons specifiers and developers move to Ridgeline once they see the system-level economics.
Evidence: independent testing at Lancaster University (2022).
Ridgeline's continuous flexible tube can help reduce intermediate fittings and concealed joints on a suitable route. Count those joints and plan access, support, testing and commissioning as part of the installation.
A lower joint count does not by itself establish a measured reduction in leaks, insurance claims, premiums or excesses. Industry-wide escape-of-water figures cannot establish a comparative failure rate for a particular product. Cover and terms depend on the insurer, policy and installation.
Compare the complete approved systems and the actual route. Ridgeline's 100+ year design-life position is not a promise that an installation cannot fail. Sources: same-route comparison guide; current installation instructions; current certificates and schedules.
Material choice can affect a project's exposure to theft, but a scrap-price comparison does not establish a measured reduction in theft or a guaranteed project saving. Prices, quantities, storage and site conditions change.
Ridgeline uses corrugated 316L stainless tube. If theft is material to a specification decision, use current local quotes and the actual quantities for each system, and record the assumptions. Secure storage and site controls remain necessary whatever the pipe material.
Use the selected size's published dimensions and weight when planning handling and logistics. Source: P1 datasheet, Rev 2, July 2026.
The honest answer: it depends on the size mix and the fitting count, and we'd rather you do the maths than take our word for it.
A few rules of thumb from real merchant and contractor conversations:
On smaller, simple jobs Ridgeline is a quality and longevity decision more than a cost decision. On larger and more complex jobs it's increasingly a cost decision in its own right. The Long Brochure's System Cost Analysis page lays the framework out, and we have tools and worksheets to help cost a specific project. Talk to your merchant or to us directly if you'd like that done for a real BOQ.
Yes. Ridgeline has both list and net (trade) pricing tiers, and additional discounts are available on volume orders. Trade accounts and project-volume pricing are standard.
For project pricing, larger merchant orders, or structured supply on multi-phase developments, contact your merchant or speak to us directly at sales@RidgelineTubes.com / 01625 70 71 72. We're a UK-based distributor; we can structure pricing on volume, on framework supply, and on multi-product packages (Plumbing + Underfloor + Flexis combinations).
Both can be used for water services when the selected system is appropriate for the duty. Ridgeline uses corrugated 316L stainless tube; copper systems use copper tube with the chosen connection method.
Routing and installation: Ridgeline bends by hand within its installation limits and can replace intermediate fittings on long or awkward runs. Copper can also use formed bends. Copper connections include soldered, compression and press systems, so hot works are not required by every copper installation. Compare the actual method and permitted bends.
Selection: compare tube and fitting losses, water conditions, supports, insulation, operating limits and approval scope. Stainless steel's corrosion resistance is not immunity to every environment. A laboratory study applies to its tested conditions, not every building.
Installed cost: use the same route, current supplier quotes and a complete labour and component schedule. Ridgeline is worth assessing where continuous routing reduces fitting work and concealed joints; the result depends on the project. Sources: P1 datasheet, Rev 2, July 2026; current installation instructions; same-route comparison guide.
PEX is cross-linked polyethylene. Ridgeline plumbing tube uses corrugated 316L stainless steel. The material difference concerns the tube: the complete systems also contain fittings, seals and other wetted components.
Both can use flexible routing. Credit permitted bends in each system and compare the actual fittings, support requirements, insulation, hydraulic data and installation process on the same route. Do not assume every PEX direction change needs an elbow.
Check each manufacturer's specific approval, temperature/pressure limits, design assumptions and warranty terms. A design life and a warranty are different measures. A material label alone does not establish the installed system's water quality, leak risk or insurance cost.
Ridgeline offers a stainless tube water path and long continuous runs with P1 or, on the scheduled smaller sizes, RidgeLock connections. Select the exact assembly against the duty and total installed cost. Sources: Ridgeline products and connection systems; current certificates and schedules; same-route comparison guide.
Push-fit describes a connection method. Plastic plumbing systems can combine flexible tube with push-fit fittings; suitable tube can follow bends within the manufacturer's limits. Assembly still requires the specified preparation, insertion, support and checks.
Ridgeline uses corrugated 316L stainless tube with its selected P1 or RidgeLock connection system. Continuous routing can reduce intermediate fittings and concealed joints. Compare the same route and credit permitted bends for every option.
Check the exact components, approval scope, operating limits, installation requirements, access and total installed cost. Neither the joining method nor a joint count alone establishes comparative leak probability, lifetime or insurance claims. Sources: Ridgeline products and connection systems; current certificates and schedules; current installation instructions; same-route comparison guide.
Press-fit describes a joining method. It is used with different pipe materials, including metal and multilayer composite systems. Compare the actual tube, fittings and installation requirements together.
Ridgeline corrugated 316L stainless tube can follow bends within its installation limits, helping reduce elbows and concealed joints along a route. Other systems also permit bends; credit those when comparing the same layout. Branches and connections still require suitable fittings.
Press systems require compatible tools and jaws. Compare tools the installer owns or can hire, rather than assuming a new purchase for every job or one jaw per size in every system. RidgeLock uses a tube cutter, knife and spanners with the specified Ridgeline tube and approved assembly. Follow the preparation and tightening instructions.
Choose against flow, hydraulic resistance, pressure, temperature, approval scope, accessibility and total installed cost. Sources: current certificates and schedules; current installation instructions; same-route comparison guide.
MLCP combines polymer and aluminium layers. Ridgeline uses corrugated 316L stainless tube. Both can offer routes with fewer elbows within the chosen system's bending and jointing limits.
For heat-pump primary flow and return, compare hydraulic resistance, required flow, insulation, operating conditions and pump duty for the complete route. Tube conductivity alone does not establish a higher heat-pump COP or an annual energy saving.
Underfloor heating is a separate design comparison. Output and required water temperature depend on the complete floor construction, tube size and spacing, floor covering, flow and operating temperatures. Use evidence for that assembly and have the design checked before making a performance claim.
Compare the specific approval scope, installation method, maintenance access and total installed cost. Sources: current certificates and schedules; same-route comparison guide; underfloor selection and design evidence.
Stainless steel pipe has been the durability gold standard in water service for decades. Tokyo and Seoul both replaced their municipal plumbing networks with stainless and the leak rate fell by orders of magnitude. The single objection has always been: rigid stainless is hard to install, slow on site, and expensive in fittings.
Corrugating the steel solves all three.
Flexibility. Engineered corrugations let the tube bend by hand to a radius equal to its outer diameter. Adjacent (back-to-back) bends, no kinking, no special tools, no benders. Bends past obstacles like a flexible cable, holds the bend, routes through concealed spaces.
Fewer fittings. Because the pipe bends, elbows aren't required. Long continuous runs replace cut-and-fit sections. Far fewer joints than copper on a typical whole-home install.
Faster install. No hot works, mechanical connections only, two spanners and a pipe cutter. Significantly faster than copper on like-for-like jobs, particularly on the larger sizes where elbow-elimination compounds.
Same material durability. All the corrosion resistance, longevity, and water-quality benefits of solid 316L stainless, without the rigid-pipe install penalty.
The category gives you the long-life durability of stainless (Tokyo / Seoul-grade municipal experience) with the install speed of plastic. That combination didn't exist as a commercial product line in UK plumbing until very recently.
Corrugated stainless steel tubing has an established UK presence on the gas side, with several UK-Kitemarked CSST gas systems (Flexigas being our own. Over a decade in market). On the water side the UK CSST category is much newer and far less established, and Ridgeline is one of the products in that emerging space.
A small number of European CSST manufacturers offer water variants and cross-market into UK plumbing applications in limited quantities. The category is genuinely emerging on the water side and we expect more entrants over the next few years.
What we lead with on Ridgeline:
We're confident in where Ridgeline sits within the category on material, certification, fitting compatibility, and UK build-out.
Ridgeline and Flexigas are related brands for different services. Ridgeline provides water systems, including plumbing, heating, underfloor heating and final connections. Flexigas provides corrugated stainless steel tubing systems for gas.
Use the correct brand's tube, fittings, approvals and installation instructions for the service. A gas approval does not approve a water assembly, and water certification does not authorise gas use. Do not mix tube and connection systems unless the relevant manufacturer explicitly approves the assembly.
Ridgeline's plumbing range is R-15, R-22, R-28, R-32-HP, R-35, R-42 and R-54. P1, RidgeLock, Flexis and Underfloor have their own product and approval scopes. Check the selected assembly rather than transferring a rating across the range. Sources: Ridgeline products and connection systems; current certificates and schedules; current installation instructions.
Both, but for different reasons. The decision drivers are slightly different.
New-build. This is where Ridgeline's strongest case lands. On a new-build you control the spec, the design, and the install sequence. The advantages stack:
Refurb / retrofit. Ridgeline still wins, but the case is different:
When Ridgeline is less obviously the right call: very small, short-run plumbing repairs where the fitting count is low and a copper compression repair would do the job with no system advantages to capture. Even there it works fine, but the system-level benefits are diluted on jobs with no continuous run to exploit.
It can do either, and that's deliberate.
Whole-system option. Ridgeline plus P1 fittings can handle the entire H&C / heating / ASHP / UFH plumbing system. The size range (R-15 through R-54) covers everything from short terminal runs to commercial risers. P1 fittings provide complete proprietary assemblies. On a Ridgeline-throughout install, you get the maximum benefit of "Eliminate Elbows," fewest fittings, longest continuous runs, and the simplest specification.
Hybrid / partial replacement. Equally valid, and often the right call on retrofit jobs. Ridgeline RidgeLock is fully compatible with any standard EN 1254 compression fitting. That means Ridgeline can be specified for the long routes, the ASHP feed-return, the underfloor heating, the concealed continuous runs, and integrated mid-run with copper at every interface. Use copper compression bodies (universal merchant availability), replace the olive with the RidgeLock sealing ring on the Ridgeline side, and you have a leak-free transition. Same for plastic systems via male/female BSP threaded connections.
Practical patterns we see contractors specifying:
The product line is engineered to integrate, not to demand a wholesale rip-and-replace. That flexibility is a deliberate part of the commercial proposition.
If your question isn't answered above, the technical team will get back to you within one working day.