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CHS 219.1×16 vs CF CHS 219.1×16

CHS 219.1×16 is an CHS Hot-finished section from the UK Blue Book (SCI P363); CF CHS 219.1×16 is the closest equivalent in the UK Blue Book (SCI P363). They are close to interchangeable in bending: 661 cm³ against 661 cm³ of plastic modulus, a difference of 0.0%. They weigh essentially the same, 80.1 kg/m and 80.1 kg/m. Both are about 219 mm deep, so either fits the same construction zone.

Section properties side by side. Bold marks the more favourable value where one is.
PropertyCHS 219.1×16
CHS Hot-finished
CF CHS 219.1×16
CHS Cold-formed
Difference
Mass80.1 kg/m80.1 kg/msame
Depth219.1 mm219.1 mmsame
Width219.1 mm219.1 mmsame
Web thickness0 mm0 mmsame
Flange thickness0 mm0 mmsame
Area102 cm²102 cm²same
Second moment, major (Iy)5,300 cm⁴5,300 cm⁴same
Plastic modulus, major (Wpl,y)661 cm³661 cm³same
Elastic modulus, major (Wel,y)483 cm³483 cm³same
Second moment, minor (Iz)5,300 cm⁴5,300 cm⁴same
Plastic modulus, minor (Wpl,z)661 cm³661 cm³same
Radius of gyration, minor (iz)7.2 cm7.2 cmsame
Torsion constant (It)10,600 cm⁴10,600 cm⁴same

CHS 219.1×16 to BS EN 10210-2:2006; CF CHS 219.1×16 to BS EN 10219-2:2006. Difference is expressed relative to CF CHS 219.1×16.

How to choose between them

On stiffness, CF CHS 219.1×16 has the larger second moment of area: 5,300 cm⁴ against 5,300 cm⁴, a difference of 0.0%. This matters more often than the strength comparison, because on normal floor spans deflection rather than bending capacity sets the beam size - so if the two are close on modulus but apart on inertia, the stiffer one is usually the better answer even when it is not the stronger one.

Measured as bending capacity per kilogram, the two are equally efficient (8.3 against 8.3 cm³ per kg/m), so on a pure steel-tonnage basis there is nothing to choose between them. The decision comes down to availability, connection detailing and what the rest of the frame uses.

In short, these two are genuine equivalents. Pick whichever your supplier stocks and the rest of the frame already uses.

Common questions

They are effectively equal in bending. CHS 219.1×16 has a plastic modulus of 661 cm³ and CF CHS 219.1×16 has 661 cm³, a difference of only 0.0% - within the margin that section choice normally turns on. Compare stiffness and availability instead.

Neither meaningfully: CHS 219.1×16 is 80.1 kg/m and CF CHS 219.1×16 is 80.1 kg/m. On a tonnage basis they cost the same.

Structurally it is the closest equivalent we hold: CF CHS 219.1×16 gives 661 cm³ of plastic modulus and 5,300 cm⁴ of inertia against 661 cm³ and 5,300 cm⁴. Re-check deflection and the connection details before swapping, since the flange and web thicknesses differ.

CF CHS 219.1×16, with a second moment of area of 5,300 cm⁴ against 5,300 cm⁴ (0.0% more). Deflection under a uniform load goes as 5wL⁴/384EI, so it is inversely proportional to I - on a span where the deflection limit governs rather than strength, this is the number that decides the section.

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