CHS 323.9×14.2 vs PIPE 14XS
CHS 323.9×14.2 is an CHS Hot-finished section from the UK Blue Book (SCI P363); PIPE 14XS is the closest equivalent in the American AISC Shapes Database. They are close to interchangeable in bending: 1360 cm³ against 1355.2 cm³ of plastic modulus, a difference of 0.4%. They weigh essentially the same, 108 kg/m and 107.4 kg/m. PIPE 14XS is deeper, 355.6 mm against 323.9 mm, which matters where the floor zone is tight.
| Property | CHS 323.9×14.2 CHS Hot-finished | PIPE 14XS Pipe | Difference |
|---|---|---|---|
| Mass | 108 kg/m | 107.4 kg/m | +0.6% |
| Depth | 323.9 mm | 355.6 mm | -8.9% |
| Width | 323.9 mm | 355.6 mm | -8.9% |
| Web thickness | 0 mm | 11.8 mm | -100.0% |
| Flange thickness | 0 mm | 0 mm | same |
| Area | 138 cm² | 123.9 cm² | +11.4% |
| Second moment, major (Iy) | 16,600 cm⁴ | 18,314 cm⁴ | -9.4% |
| Plastic modulus, major (Wpl,y) | 1,360 cm³ | 1,355.2 cm³ | +0.4% |
| Elastic modulus, major (Wel,y) | 1,030 cm³ | 1,030.7 cm³ | -0.1% |
| Second moment, minor (Iz) | 16,600 cm⁴ | 18,314 cm⁴ | -9.4% |
| Plastic modulus, minor (Wpl,z) | 1,360 cm³ | 1,355.2 cm³ | +0.4% |
| Radius of gyration, minor (iz) | 11 cm | 12.17 cm | -9.6% |
| Torsion constant (It) | 33,200 cm⁴ | 36,628 cm⁴ | -9.4% |
CHS 323.9×14.2 to BS EN 10210-2:2006; PIPE 14XS to AISC Shapes Database v16.0. Difference is expressed relative to PIPE 14XS.
How to choose between them
On stiffness, PIPE 14XS has the larger second moment of area: 18,314 cm⁴ against 16,600 cm⁴, a difference of 9.4%. 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 (12.6 against 12.6 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.
These come from different catalogues, so treat the swap as a design change rather than a like-for-like substitution. CHS Hot-finished sections are specified to BS EN 10210-2:2006 and Pipe to AISC Shapes Database v16.0; the steel grades, tolerances and available lengths differ, connection details and bolt gauges are set out differently, and the two are rarely both stocked in the same market. Check availability before changing a section on a drawing to save a marginal amount of weight.
In short, these two are genuine equivalents. Pick whichever your supplier stocks and the rest of the frame already uses.