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CHS 114.3×4 vs CF CHS 114.3×4

CHS 114.3×4 is an CHS Hot-finished section from the UK Blue Book (SCI P363); CF CHS 114.3×4 is the closest equivalent in the UK Blue Book (SCI P363). They are close to interchangeable in bending: 48.7 cm³ against 48.7 cm³ of plastic modulus, a difference of 0.0%. They weigh essentially the same, 10.9 kg/m and 10.9 kg/m. Both are about 114 mm deep, so either fits the same construction zone.

Section properties side by side. Bold marks the more favourable value where one is.
PropertyCHS 114.3×4
CHS Hot-finished
CF CHS 114.3×4
CHS Cold-formed
Difference
Mass10.9 kg/m10.9 kg/msame
Depth114.3 mm114.3 mmsame
Width114.3 mm114.3 mmsame
Web thickness0 mm0 mmsame
Flange thickness0 mm0 mmsame
Area13.9 cm²13.9 cm²same
Second moment, major (Iy)211 cm⁴211 cm⁴same
Plastic modulus, major (Wpl,y)48.7 cm³48.7 cm³same
Elastic modulus, major (Wel,y)36.9 cm³36.9 cm³same
Second moment, minor (Iz)211 cm⁴211 cm⁴same
Plastic modulus, minor (Wpl,z)48.7 cm³48.7 cm³same
Radius of gyration, minor (iz)3.9 cm3.9 cmsame
Torsion constant (It)422 cm⁴422 cm⁴same

CHS 114.3×4 to BS EN 10210-2:2006; CF CHS 114.3×4 to BS EN 10219-2:2006. Difference is expressed relative to CF CHS 114.3×4.

How to choose between them

On stiffness, CF CHS 114.3×4 has the larger second moment of area: 211 cm⁴ against 211 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 (4.5 against 4.5 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 114.3×4 has a plastic modulus of 48.7 cm³ and CF CHS 114.3×4 has 48.7 cm³, a difference of only 0.0% - within the margin that section choice normally turns on. Compare stiffness and availability instead.

Neither meaningfully: CHS 114.3×4 is 10.9 kg/m and CF CHS 114.3×4 is 10.9 kg/m. On a tonnage basis they cost the same.

Structurally it is the closest equivalent we hold: CF CHS 114.3×4 gives 48.7 cm³ of plastic modulus and 211 cm⁴ of inertia against 48.7 cm³ and 211 cm⁴. Re-check deflection and the connection details before swapping, since the flange and web thicknesses differ.

CF CHS 114.3×4, with a second moment of area of 211 cm⁴ against 211 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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