PRODUCT FAMILY 01 · ROUND TUBE

Round steel tube, Ø21.3 to 114.3 mm, for posts, bracing and wire frames.

Nine outside diameters in stock sizes, wall 1.0–4.0 mm, in Q235B or Q355B. Used where a round section is cheaper than an oval, where the member is in compression, or where the tube has to pass through a clamp.

Round tube is the workhorse. It is what a buyer means when they ask for “greenhouse pipe”: the post under the gutter, the diagonal brace in the end frame, the rail that carries crop wire, the frame of the door. It is rarely the arch — arches are oval for a reason explained on the oval page.

Round tube — family specificationXY-RT / FAMILY

Outside diameter: Ø21.3 / 26.7 / 33.5 / 42.2 / 48.3 / 60.3 / 76.1 / 88.9 / 114.3 mm
Wall thickness: 1.0 / 1.2 / 1.5 / 1.8 / 2.0 / 2.5 / 3.0 / 4.0 mm
Length: 6 m / 12 m standard, up to 16 m, cut to order
Steel grade: Q235B standard, Q355B on request
Tolerance: EN 10219, ±1 % on OD, ±10 % on wall
Straightness: ≤ 2 mm per metre
Coating: Pre-galvanised Z275, or hot-dip ISO 1461 after forming
Ends: Plain, bevelled, or swaged for a socket joint

Stock sizes: 9 OD × 8 walls
Cut tolerance: ±1 mm
Bundle: Hexagonal, 37–61 pcs
Marking: Bundle tag + heat no.
Loading: 40HQ for 6 m

Nominal weights on the size pages are calculated from geometry; the mill certificate carries actual figures per heat.Rev. 2026-11

Which size is bought for what

Typical duty by diameter — a starting point, not a design
OD	Wall usually bought	Used for
21.3 mm (1/2″)	1.5–2.0 mm	Crop wire supports, light trellis, small tunnel hoops
26.7 mm (3/4″)	1.5–2.0 mm	Tunnel hoops, low tunnels, light bracing
33.5 mm (1″)	1.8–2.5 mm	Side posts, door frames, internal partitions
42.2 mm (1-1/4″)	2.0–2.5 mm	Gutter posts on small spans, end-frame bracing
48.3 mm (1-1/2″)	2.0–3.0 mm	Posts, truss chords on lighter houses
60.3 mm (2″)	2.0–3.0 mm	Main posts, heavy bracing, machinery protection
76.1–114.3 mm	2.5–4.0 mm	Structural columns, large clear spans, non-greenhouse work

If your engineer specifies a section not listed, we will quote it: the mill runs Ø6–1,200 mm.

Coating, cutting and ends

Pre-galvanised coil (Z275) is the default because it is cheaper and keeps the inside of the tube coated. Hot-dip after fabrication is the upgrade for coastal sites, for welds, and for buyers whose inspection procedure names ISO 1461. The two are not interchangeable on a purchase order, and the coating standard page explains what to write.

Open selection list

Size pages

Price this against your take-off

Send the sizes, wall thicknesses and quantities you need. We reply with a line-by-line offer, bundle weights and the loading plan for your container.

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