What are the dimensional and shape tolerances for EN10210 steel hollow sections?

EN 10210 is the European standard that governs hot-finished structural hollow sections made from non-alloy and fine grain steels. It is published in two parts: EN 10210-1 sets out the technical delivery conditions, while EN 10210-2 defines the tolerances on dimensions, shape, straightness and mass. For structural engineers, fabricators and procurement teams working with circular, square or rectangular hollow sections (CHS, SHS and RHS), knowing these tolerance values is essential. They decide how neatly sections fit together on site, how weld joints line up, and how predictably the finished structure behaves under load.

What EN 10210-2 covers

EN 10210-2 applies to hot-finished sections with wall thicknesses up to 120 mm, in the following size ranges:

Circular sections: outside diameters up to 2,500 mm
Square sections: outside dimensions up to 800 x 800 mm
Rectangular sections: outside dimensions up to 750 x 500 mm
Elliptical sections: outside dimensions up to 500 x 250 mm

The standard also covers the common steel grades used for structural hollow sections, from non-alloy grades such as S235JRH, S275J0H, S275J2H, S355J0H, S355J2H and S355K2H, up to fine grain grades like S275NH, S355NH, S420NH and S460NH.

Dimensional tolerances

The outside dimensions of the section are the first thing checked on delivery. For circular sections the outside diameter D, and for square and rectangular sections the outside dimensions B and H, are held to ±1% with a minimum deviation of ±0.5 mm. On circular sections the tolerance is additionally capped at a maximum of ±10 mm. Wall thickness T is permitted to be up to 10% below the nominal value, while the positive deviation is limited by the mass tolerance.

Shape tolerances

Shape control is where EN 10210-2 becomes specific. The table below summarises the key shape, straightness and mass tolerances for the different section types.

Characteristic	Circular sections	Square & rectangular sections
Outside dimensions (D, B, H)	±1%, min ±0.5 mm, max ±10 mm	±1%, min ±0.5 mm
Wall thickness (T)	-10%	-10%
Out-of-roundness	2% (D/T ratio not exceeding 100)	-
Concavity / convexity	-	1%
Squareness of side	-	90° ± 1°
External corner profile	-	3T maximum at each corner
Twist	-	2 mm plus 0.5 mm/m length
Straightness	0.2% of total length and 3 mm over any 1 m	0.2% of total length and 3 mm over any 1 m
Mass per unit length	-6% / +8% on individual delivered lengths	-6% / +8% on individual delivered lengths

Length tolerances

Length tolerances depend on the type of length ordered. Random lengths run from 4,000 to 16,000 mm with a range of 2,000 mm per order item, and up to 10% of supplied sections may fall below the minimum of the ordered range provided they are not shorter than 75% of that minimum. Approximate lengths carry a tolerance of ±500 mm. Exact lengths are supplied 0 to +10 mm for lengths up to 6,000 mm, and 0 to +15 mm for longer pieces. Common stock lengths are 6 m and 12 m.

How tolerances are verified

External dimensions are measured at a distance of at least D from the end of a circular section, or B or H from the end of a square or rectangular section, with a minimum of 100 mm. For welded sections, wall thickness is checked at least 2T away from the weld line so that the measurement is not distorted by the weld bead. Reputable mills back these checks with dimensional inspection reports and mill test certificates, which are worth requesting before material is released for fabrication.

Why tolerances matter on site

Tight dimensional control translates directly into cleaner fit-up at bolted and welded connections, fewer shims and reworks, and more predictable structural behaviour. Sections that drift outside tolerance can cause misaligned splices, excessive weld gaps and uneven load transfer. Those problems are expensive to correct once fabrication has started, so it pays to confirm the grade, dimensions, wall thickness, length type and required inspection documents at the enquiry stage.

Sourcing EN10210 sections that meet spec

For building frameworks, bridges and other load-bearing structure works, ordering EN10210 steel hollow sections from a manufacturer with in-house testing and quality control gives you confidence that dimensional and shape tolerances are met before the material reaches your workshop. A supplier that can document compliance across a wide size range, and that backs every delivery with mill test certificates, makes specification control far simpler. If your project also calls for large-diameter line pipe or foundation elements, a full-range big diameter steel pipe and structural supplier can consolidate several material requirements into a single, traceable order.