The full multilayer composite system, supplied in Kuwait: five-layer PE-RT and aluminium pipe from 16 to 110 mm, with metal press fittings, PPSU composite fittings, and a modular riser system. It bends like plastic and behaves like metal. Quotes returned in one working day.
Corrosion-free jacket. No scale, no rust, nothing to paint
Permanent bond
100% oxygen barrier · holds the bend · one-seventh the expansion of PP-R
Permanent bond
Hygienically smooth at k = 0.0004 mm, so full flow lasts the life of the system
All five layers are permanently bonded. Cut the pipe anywhere and the wall behaves as a single material. Bend it and the aluminium keeps the shape; heat it and the aluminium keeps the length.
The pipe carries the system; four fitting families and a prefab range cover everything from a 16 mm basin tail to a 110 mm riser main.
Inner and outer high-temperature PE-RT bonded to a longitudinally welded aluminium core. It bends by hand and stays bent, blocks oxygen completely, and moves a seventh as much as PP-R when the temperature swings.
The standard joint, 16-50 mm. Inspection windows confirm insertion depth, and the coloured stop ring breaks off as the jaw closes, so an unpressed joint is visible from across the room.
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The economy fitting, 16-50 mm. A PPSU insert and stainless sleeve make the joint, and the run can still be realigned right up to the pressure test.
Learn moreThirty-nine components cover every 63-110 mm riser, manifold, and main. Press at the bench, insert, lock. Nothing is tooled overhead in the shaft.
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Screw fittings, 16-25 mm, including ¾" eurocone, for radiator, fan coil, and appliance tails that must stay demountable for service.
Learn moreWall-outlet elbows, plates, angles, and rails, positioned and fixed one-handed. The U-profile elbow keeps flow rate up on loop installations.
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Multilayer composite sits between PEX and copper by design. The aluminium core gives it the shape stability, low expansion, and oxygen barrier of a metal pipe; the PE-RT skins give it the corrosion immunity, smooth bore, and cold jointing of a plastic one.
Movement, oxygen, hot work, and corrosion are the four things that cost money on a Kuwait plumbing or HVAC package. A composite pipe with a welded aluminium core answers all four, which is why it keeps appearing on tower and hospital specifications here.
Bend it by hand and it stays bent. There is no snap-back to restrain, so a run needs far fewer fixing points than an all-plastic pipe, and an installer can set out a route around structure instead of buying an elbow for every deviation.
Over 50 m at a 50 K swing, composite moves 62.5 mm where PP-R moves 450 mm. On a Kuwait riser that alternates between chilled and hot service, that is the difference between an expansion strategy and a set of ordinary sliding clamps.
Every joint is pressed or screwed cold. On an occupied hotel floor or a live hospital wing that removes the permit, the fire watch, and the shutdown window, usually the real constraint on a refurbishment programme in Kuwait.
The welded aluminium layer is the oxygen barrier, not an extra film that can be scored or omitted. That matters on chilled water, fan coil, and heating circuits where dissolved oxygen quietly corrodes the steel components downstream of the pipe.
Chlorinated municipal supply and saline groundwater pit copper and eat galvanised steel. The pipe bore here is PE-RT. It does not corrode, does not scale, and the aluminium never touches the water.
Ten dimensions from 16 to 110 mm under one jointing philosophy: press fittings up to 50 mm, modular riser fittings above. A contractor stocks one system and trains one crew instead of splitting the package between materials at the riser.
Composite is the default choice when a project needs one material to run from the smallest branch to the main riser, and when hot work is either restricted or simply too slow.
Concealed hot and cold distribution through walls and screed for villas across Mishref, Salwa, Bayan, and Abu Fatira. Hand-bent routes hold their shape through the pour, and pre-insulated pipe up to 25 mm removes a whole lagging trade from the programme.
The 63 to 110 mm modular riser system for towers in Kuwait City, Salmiya, and Hawally. Fittings are pressed at the bench and locked into place in the shaft, with no heavy tool work overhead and no welding in a confined riser.
Loop and serial layouts for guest floors, where stagnation in a rarely-used bathroom is a genuine hygiene risk. Cold jointing means a floor can be reworked without a hot work permit or a fire watch.
Loop installations that keep water turning over, prefabricated wall outlets that shorten time in occupied areas, and a jointing method that never introduces a flame onto a live clinical floor.
Long horizontal distribution above ceilings where expansion would otherwise dominate the design. Low movement and generous clip spacing of up to 2.4 m on the larger sizes mean fewer supports over a very long run.
Fan coil tails and secondary chilled water circuits, where the diffusion-tight core protects steel plant downstream and eurocone compression tails keep the unit demountable for service.
The honest version of the comparison we give consultants every week. Composite is not always the answer, but where movement, oxygen, or hot work restrictions drive the design, it usually is.
| Criterion | Multilayer composite | PEX (PE-Xa) | PP-R | Copper |
|---|---|---|---|---|
| Expansion, 50 m at Δt 50 K | 62.5 mm | ≈375 mm | 450 mm | 41.3 mm |
| Shape after bending | Holds the bend | Springs back | Rigid, fittings only | Holds the bend |
| Oxygen diffusion barrier | Built in (AL core) | Needs an EVOH layer | None | Not applicable |
| Fixing points needed | Few | Many, restrains snap-back | Many, rigid | Moderate |
| Jointing on site | Press / compression | Cold expansion / press | Heat fusion | Solder / braze / press |
| Hot work permit | Not required | Not required | Required (hot plate) | Required (torch) |
| Size range supplied | 16-110 mm | 16-63 mm typical | 20-125 mm | 12-108 mm |
| Chloride / scale attack | Immune | Immune | Immune | Pits in saline water |
| Bore at the same OD | Largest of the plastics | Comparable | Smallest, thick wall | Largest overall |
| Where it fits best | Branch and riser, one system | Coiled branch runs | Rigid distribution | Exposed and legacy work |
Composite figures come from the system data published on this page. PEX, PP-R, and copper figures use published material coefficients and standard dimension tables. Final selection depends on the consultant specification, water analysis, and pressure regime. Send us the brief and our technical team will comment.
Total movement over 50 metres at a 50 K swing. The same run in PP-R moves 450 mm.
Everything below is reference data for planning a multilayer composite installation: dimensions and weights for the support design, bore comparisons for the hydraulic check, and bending and clearance figures for the site.
Length change over a 50 m run at Δt = 50 K. The aluminium core is what holds multilayer composite to 62.5 mm, roughly one-seventh of PP-R over the same run, and within striking distance of copper.
Water-filled weight is the figure to use when sizing clamps and hangers. It is what the support actually carries.
| Dimension OD × s | Inner Ø | Water volume | Weight, empty | Weight, water-filled | Supplied as |
|---|---|---|---|---|---|
| 16 × 2.0 | 12.0 mm | 0.113 l/m | 105-118 g/m | 218-231 g/m | Coil 100 / 200 / 500 m · 5 m straight |
| 20 × 2.25 | 15.5 mm | 0.189 l/m | 148-160 g/m | 337-349 g/m | Coil 100 / 200 m · 5 m straight |
| 25 × 2.5 | 20.0 mm | 0.314 l/m | 211-240 g/m | 525-554 g/m | Coil 50 / 100 m · 5 m straight |
| 32 × 3.0 | 26.0 mm | 0.531 l/m | 323 g/m | 854 g/m | Coil 50 m · 5 m straight |
| 40 × 4.0 | 32.0 mm | 0.800 l/m | 508 g/m | 1,310 g/m | 5 m straight |
| 50 × 4.5 | 41.0 mm | 1.320 l/m | 745 g/m | 2,065 g/m | 5 m straight |
| 63 × 6.0 | 51.0 mm | 2.040 l/m | 1,224 g/m | 3,267 g/m | 5 m straight |
| 75 × 7.5 | 60.0 mm | 2.827 l/m | 1,788 g/m | 4,615 g/m | 5 m straight |
| 90 × 8.5 | 73.0 mm | 4.185 l/m | 2,545 g/m | 6,730 g/m | 5 m straight |
| 110 × 10.0 | 90.0 mm | 6.362 l/m | 3,597 g/m | 9,959 g/m | 5 m straight |
Where two weights are shown, the first is coiled pipe and the second is straight length. Pipe roughness k = 0.0004 mm, thermal conductivity λ = 0.40 W/(m·K), expansion coefficient α = 25 × 10⁻⁶ m/(m·K) across the whole range.
At the same outside diameter, a composite pipe carries more water than PP-R because the wall is thinner, which often lets a designer drop a size, or hold pressure at the far end of a long run.
| Composite OD × s | Composite bore | PP-R SDR 6 bore | PP-R SDR 7.4 bore | Copper bore |
|---|---|---|---|---|
| 16 × 2.0 | 12.0 | n/a | n/a | 13.6 (Ø15) |
| 20 × 2.25 | 15.5 | 13.2 (Ø20) | 14.4 (Ø20) | 20.2 (Ø22) |
| 25 × 2.5 | 20.0 | 16.6 (Ø25) | 18.0 (Ø25) | 26.2 (Ø28) |
| 32 × 3.0 | 26.0 | 21.2 (Ø32) | 23.2 (Ø32) | 32.6 (Ø35) |
| 40 × 4.0 | 32.0 | 26.6 (Ø40) | 29.0 (Ø40) | 39.6 (Ø42) |
| 50 × 4.5 | 41.0 | 33.4 (Ø50) | 36.2 (Ø50) | 51.6 (Ø54) |
| 63 × 6.0 | 51.0 | 42.0 (Ø63) | 45.8 (Ø63) | 64.3 (Ø66.7) |
| 75 × 7.5 | 60.0 | 50.0 (Ø75) | 54.4 (Ø75) | 73.1 (Ø76.1) |
| 90 × 8.5 | 73.0 | 59.0 (Ø90) | 65.4 (Ø90) | n/a |
| 110 × 10.0 | 90.0 | 73.4 (Ø110) | 79.2 (Ø110) | 105.0 (Ø108) |
All values in mm. Copper to BS EN 1057 R250, matched to the nearest standard outside diameter, shown in brackets. Copper carries more water per outside diameter than any plastic. The trade-off is corrosion behaviour, jointing method, and cost.
Sizes 16 to 32 mm can be formed by hand. Below the minimum radius, use a press elbow rather than forcing the pipe.
| Dimension | By hand | Inner spring | Outer spring | Bending tool |
|---|---|---|---|---|
| 16 × 2.0 | 80 (5 × OD) | 64 | 64 | 46 |
| 20 × 2.25 | 100 (5 × OD) | 80 | 80 | 80 |
| 25 × 2.5 | 125 (5 × OD) | 100 | 100 | 83 |
| 32 × 3.0 | 160 (5 × OD) | 128 | n/a | 111 |
| 40 × 4.0 | n/a | n/a | n/a | 160 |
| 50 × 4.5 | n/a | n/a | n/a | 200 |
| 63 × 6.0 | n/a | n/a | n/a | 252 |
All values in mm. Hot bending over an open flame, heat gun, or industrial dryer is prohibited, and the same point must never be bent twice. Pipe passing through ceiling recesses and wall cut-outs must never be bent over the edge.
Maximum distance between clips. Coiled pipe is spaced more closely than straight length because it carries residual curvature.
| Dimension | Horizontal, coil | Horizontal, straight | Vertical | Load on support |
|---|---|---|---|---|
| 16 × 2.0 | 1.20 m | 1.60 m | 1.70 m | 0.231 kg/m |
| 20 × 2.25 | 1.30 m | 1.60 m | 1.70 m | 0.368 kg/m |
| 25 × 2.5 | 1.50 m | 1.80 m | 2.00 m | 0.557 kg/m |
| 32 × 3.0 | 1.60 m | 1.80 m | 2.10 m | 0.854 kg/m |
| 40 × 4.0 | 1.70 m | 2.00 m | 2.20 m | 1.310 kg/m |
| 50 × 4.5 | 2.00 m | 2.00 m | 2.60 m | 2.062 kg/m |
| 63 × 6.0 | 2.20 m | 2.20 m | 2.85 m | 3.265 kg/m |
| 75 × 7.5 | 2.40 m | 2.40 m | 3.10 m | 4.615 kg/m |
| 90 × 8.5 | 2.40 m | 2.40 m | 3.10 m | 6.741 kg/m |
| 110 × 10.0 | 2.40 m | 2.40 m | 3.10 m | 9.987 kg/m |
Load shown is straight pipe filled with water at 10 °C, excluding insulation. Size the support from pipe weight plus contents plus insulation, and set clips close to fittings and connectors where practical. We supply the matching clamps and channel from our pipe supports range.
The three site dimensions that decide whether a joint can physically be pressed where it is drawn.
| Dimension | Min. free pipe between fittings | Clearance to wall (A) | Clearance to next fitting (B) |
|---|---|---|---|
| 16 × 2.0 | 50 mm | 15 mm | 45 mm |
| 20 × 2.25 | 55 mm | 18 mm | 48 mm |
| 25 × 2.5 | 70 mm | 27 mm | 71 mm |
| 32 × 3.0 | 70 mm | 27 mm | 75 mm |
| 40 × 4.0 | 100 mm | 45 mm | 105 mm |
| 50 × 4.5 | 100 mm | 50 mm | 105 mm |
| 63 × 6.0 | 150 mm | 80 mm | 98 mm |
| 75 × 7.5 | n/a | 82 mm | 125 mm |
| 90 × 8.5 | 160 mm | n/a | n/a |
| 110 × 10.0 | 160 mm | n/a | n/a |
Clearances are for the compact press tools; larger jaws and manual tools need more room. A manual pressing tool for 16 and 20 mm needs roughly 510 mm of swing. Pipe ends must be bevelled before insertion. Ask us for the clearance sheet matching the tool on your site.
Composite is forgiving on site, but three things are not negotiable: bevel the pipe, respect the bending radius, and give the thermal movement somewhere to go. Everything else is quicker than the material it replaces.
On the 63 to 110 mm riser system, all the heavy work happens at the bench. Only one of these four steps needs a tool, and it is not the one done overhead in a shaft.
Cut the pipe square and bevel the end, then push it into the press adapter. Bevelling is mandatory. A raw cut edge will damage the O-ring on insertion.
Press the adapter onto the pipe at the workbench, jaw seated in the guide groove on the sleeve. Comfortable working height, no confined space, no overhead load.
Push the pressed adapter into the base element of the fitting. No tool, no heat, no torque setting, and the assembly is still adjustable at this point.
Push the locking element into the fitting opening until it clicks home. A locking pin is single-use: once released it must be replaced, not refitted.
Sizes 16 to 32 mm form by hand and hold their shape. A spring or bending tool takes the radius tighter; 40 to 63 mm needs a powered bender.
Rigid installation is not possible with composite pipe. The movement has to be either absorbed or controlled. Compensation always happens between two fixed points, across a change of direction.
Lines are measured centre to centre along the axial line, and the pipe length between two fittings is the centre distance less each fitting's Z-dimension (Lᵣ = Lᴳ − Z₁ − Z₂).
The three layouts differ mainly in what happens to water that sits still. On hotels, hospitals, and anywhere with rarely-used outlets, that difference is the whole decision.
Most composite failures on site are handling failures, not material failures. The rules are short and worth enforcing.
Concrete floor work follows the ordinary rules of technology, plus a short list specific to a pipe that moves with temperature.
These are typical planning values for the multilayer composite range we supply. Always confirm against the manufacturer's installation instructions for the make of fitting and the pressing tool actually used on your project. Send us the specification and we will supply the matching document set.
Straight answers to the questions that come up in project correspondence, in the order they usually arrive.
A five-layer pipe. An aluminium tube is folded around and welded along its length with a safety overlap, then bonded by adhesive layers to an inner and outer skin of high-temperature-resistant polyethylene (PE-RT). The plastic gives you a corrosion-free bore and cold jointing; the aluminium gives you an oxygen barrier, low thermal expansion, and a pipe that stays where you bend it. It is also sold as PEX-AL-PEX or composite pipe, the same idea with the skins varying by manufacturer.
Three practical differences. Composite holds its shape after bending where PEX springs back, so composite needs far fewer fixing points. Composite has a built-in oxygen barrier from the aluminium; PEX needs an added EVOH layer to achieve the same thing. And composite expands about a quarter as much as PEX for the same temperature change. PEX still wins on long coiled branch runs and on the very tightest bends. Many Kuwait projects use both: composite for risers and distribution, PEX for coiled branch work.
Ten dimensions: 16×2, 20×2.25, 25×2.5, 32×3, 40×4, 50×4.5, 63×6, 75×7.5, 90×8.5, and 110×10 mm. Small sizes come coiled up to 500 m as well as in 5 m straight lengths; from 40 mm up it is straight lengths only. Press and composite fittings cover 16 to 50 mm, the modular riser system covers 63 to 110 mm, and compression fittings cover 16 to 25 mm. Send the take-off and we will confirm stock and lead time in writing.
No. The aluminium core is the barrier, and it is diffusion-tight by construction rather than a coating that can be scored or left off. That is the main reason composite gets specified on fan coil tails and secondary chilled water circuits: oxygen ingress through an ordinary plastic pipe corrodes the steel components downstream long before the pipe itself shows anything.
No permit is needed, because nothing is heated. Up to 50 mm, joints are pressed with a jaw: metal press fittings with a fixed sleeve, or PPSU composite fittings as the economy option. From 63 to 110 mm, the modular riser system is pressed at the bench, then inserted and locked in place by hand. Compression and eurocone fittings cover radiator and appliance tails. All four methods are cold, which is usually the deciding factor on occupied hotel and hospital floors.
Two independent checks are built into the fitting. Each press fitting carries a coloured stop ring that breaks off and falls away as the jaw closes, so a ring still in place is visible from several metres away. And the fitting is designed to leak deliberately at the prescribed pressure test if it has not been pressed, so an unpressed joint shows itself during commissioning rather than after handover. Inspection windows also let you confirm insertion depth before pressing.
By hand, 16 to 32 mm bends to five times the outside diameter, so 80 mm on 16 mm pipe. A bending spring takes that to four times the diameter, and a bending tool gets 16 mm pipe down to a 46 mm radius. From 40 to 63 mm you need a powered bender. Hot bending is prohibited, and the same point must never be bent twice. If the radius cannot be achieved, fit a press elbow.
The full pack for the make supplied on your project: manufacturer certification and approval certificates, declarations of conformity, material safety data sheets, technical and installation manuals, and pressure test documentation, packaged in the submittal format the specification calls for. Certification varies by manufacturer, so tell us the specification clause you need to satisfy and we will confirm before you order.
Layout, sizes, and riser diameters are enough. We come back with a priced, stock-checked, submittal-ready package, pressing tools confirmed.
