A GRP round tube is a hollow circular section drawn from a heated die in one continuous length, so the diameter and the wall thickness are the same on the last metre as on the first. NA-ME pultrudes 23 standard round sections, from Ø20 mm to Ø58 mm, with walls between 2 and 7.5 mm. This page sets out what the section is good at, what it is deliberately not sold for, how the product codes are read, and which resin belongs in which environment.
The first thing to settle is what this product is for. A pultruded round tube is a structural profile that happens to have a circular cross-section. It is specified the way an angle or a square tube is specified: by span, by load and by environment. It carries no pressure class, and we do not publish one, because a pultruded structural section is not designed or rated for containing pressurised fluid. If your job is a pressurised line, that is filament-wound pipework, which is a different product and not something we pultrude.
What the circular section does give you is a closed profile. Closing the wall all the way round is what separates a tube from an angle or a channel, and it changes the behaviour in two useful ways. The section responds much the same whichever direction the load arrives from, so a free-standing post does not have a weak axis to worry about. And a closed section is far stiffer in torsion than any open one of similar weight, which is why round tube is the default for anything that gets twisted, leaned on or knocked: stanchions, handrail infill, guard frames.
There is a third, quieter advantage. A round section has no flat face and no inside corner. Water runs off it, dust does not settle in a groove, and it is comfortable in a gloved hand. That is the reason handrails have been round for two hundred years, and it has not stopped being true in composite.
The same product is called an FRP tube in much of the wider industry, a fiberglass round tube in North America and a GFK tube in German-language specifications. For a glass-fibre profile all of those names describe this section, and we read your specification the same way whichever one you use.
| Code | Outside dia. Ø (mm) | Wall t (mm) | Weight (kg/m) |
|---|---|---|---|
| CPP-O-101 | 20 | 3 | 0.30 |
| CPP-O-102 | 25 | 2 | 0.30 |
| CPP-O-103 | 25 | 2.5 | 0.33 |
| CPP-O-104 | 25 | 3 | 0.41 |
| CPP-O-105 | 30 | 2 | 0.33 |
| CPP-O-106 | 30 | 3 | 0.53 |
| CPP-O-107 | 30 | 4 | 0.68 |
| CPP-O-108 | 32 | 2.5 | 0.45 |
| CPP-O-109 | 34 | 3 | 0.51 |
| CPP-O-110 | 37 | 2 | 0.41 |
| CPP-O-111 | 37 | 3 | 0.75 |
| CPP-O-112 | 40 | 2.5 | 0.56 |
| CPP-O-113 | 40 | 4 | 0.84 |
| CPP-O-114 | 40 | 6 | 1.31 |
| CPP-O-115 | 40 | 7.5 | 1.40 |
| CPP-O-116 | 44 | 2 | 0.50 |
| CPP-O-117 | 50 | 2.5 | 0.68 |
| CPP-O-118 | 50 | 4 | 1.06 |
| CPP-O-119 | 50 | 5 | 1.31 |
| CPP-O-120 | 50 | 6 | 1.50 |
| CPP-O-121 | 50 | 7 | 1.68 |
| CPP-O-122 | 51 | 2 | 0.58 |
| CPP-O-123 | 58 | 2 | 0.67 |
Weights are per metre for the orthophthalic grade. The same section number carries the same dimensions and the same weight in every resin system, so a CPP-V-118 measures exactly what a CPP-O-118 measures.
Need a diameter or a wall that is not in the table? NA-ME cuts its own dies, so a non-standard round section is a question of quantity and lead time rather than a flat no. Send the dimension you actually need and we will tell you where it sits.
Every pultruded profile we make carries a three-part code, and once you know the pattern you can read any of them off a packing list. Take CPP-O-118:
In practice that means you choose the section first and the resin second, and the two decisions do not interfere with each other. CPP-O-118 and CPP-VA-118 are both Ø50 mm with a 4 mm wall at 1.06 kg/m. One is a general-purpose tube; the other is a vinyl ester tube with a flame-retardant grade, for a chemical plant with a fire clause in the specification.
The resin is the part of the profile that meets the environment. The glass carries the load; the resin decides how long the profile survives what is around it. We pultrude these tubes in six systems, and the choice is usually straightforward once you describe the site honestly.
These are separate product codes on our list, not a coating or an option ticked at the end. Which one suits your site, and what each system actually resists, is set out at length on resin systems. The outer surface matters too: a surface veil is what protects the resin from UV and keeps the fibre pattern from showing through after a few seasons outdoors, and that is covered on surface veil, UV and fire.
The round section is the natural handrail: comfortable to grip, nothing to catch a sleeve on, and stiff in torsion where the rail meets the post. It works with our purpose-made handrail sections and with composite grating on the same walkway.
Run the cable inside the tube and the tube takes the abuse. Because the profile is electrically non-conductive, a damaged cable inside it does not turn the sleeve into a live part — which is the whole point in substations and solar plants.
Rollers, spacers, spindles, frame members and stand-off supports: anywhere a round bar section is wanted for the geometry and the load is mechanical rather than internal pressure.
Posts and rails that will not rust at the ground line, will not need repainting, and can be cut and drilled on site with ordinary tools. Weight is roughly a quarter of steel, so a run goes up by hand.
GRP is a directional material. Along the length of the pull it is strong; across the section it is much weaker, because that is where the fibres are not. Its modulus of elasticity is low to medium compared with steel, which means that on most spans deflection, not strength, is what settles the section — the tube will bend visibly long before it is anywhere near failure. Design to the deflection limit and the strength looks after itself. It does not rust, rot or attract insects, it is electrically non-conductive, its thermal conductivity is low, and it stands up to UV and weather. The full picture, with the numbers that matter for a calculation, is on mechanical properties.
Buyers in Europe and the United Kingdom often write standards into a tube specification, and it is worth knowing what each one actually measures before you copy it across.
NA-ME holds ISO 9001, ISO 14001 and ISO 45001 certification for the design and manufacture of composite products. We explain the standards above because they appear in tender documents; we do not present them as certifications we hold. What we test in house and what we do not is set out plainly on quality, standards and testing.
Round GRP tube cuts with a diamond or carbide-tipped blade and drills with ordinary masonry-type bits. It does not weld — every joint is mechanical, made with bolts, clamps, saddles or bonded connections. That changes the sequencing of a job more than most people expect the first time, so installation and fastening is worth ten minutes before the first delivery arrives. Cut ends should be sealed; the reason and the method are on the maintenance and service life page.
If the load has a clear direction, a square section may serve you better than a round one — see FRP square tube. If you want the same circular geometry solid rather than hollow, for pins, dowels and connectors, that is GRP rod. For plates, straps and edge trim, see GRP flat bar. The whole range sits together on GRP and FRP structural shapes, and complete assemblies are shown on handrail and platform systems.
Tell us the outside diameter, the wall thickness, the length and the quantity, and describe the environment in a sentence — outdoor, coastal, chemical, fire clause. That is enough for us to confirm a section from the table or tell you a die is needed. We have been pultruding in Ankara since 1982, around half of what we make is exported, and an EU destination is 3 to 7 days away by road with no customs duty on industrial goods under the EU–Turkey Customs Union. Small and mixed orders are welcome.