Tee 140×203×20 vs WT 8X13
Tee 140×203×20 is an Tees (from UB) section from the UK Blue Book (SCI P363); WT 8X13 is the closest equivalent in the American AISC Shapes Database. They are close to interchangeable in bending: 121 cm³ against 120.61 cm³ of plastic modulus, a difference of 0.3%. They weigh essentially the same, 19.5 kg/m and 19.3 kg/m. Both are about 199 mm deep, so either fits the same construction zone.
| Property | Tee 140×203×20 Tees (from UB) | WT 8X13 WT | Difference |
|---|---|---|---|
| Mass | 19.5 kg/m | 19.3 kg/m | +1.0% |
| Depth | 198.9 mm | 199.4 mm | -0.3% |
| Width | 141.8 mm | 139.7 mm | +1.5% |
| Web thickness | 6.4 mm | 6.4 mm | same |
| Flange thickness | 8.6 mm | 8.8 mm | -2.3% |
| Area | 24.8 cm² | 24.8 cm² | same |
| Second moment, major (Iy) | 979 cm⁴ | 978.1 cm⁴ | +0.1% |
| Plastic modulus, major (Wpl,y) | 121 cm³ | 120.61 cm³ | +0.3% |
| Elastic modulus, major (Wel,y) | 67.2 cm³ | 67.023 cm³ | +0.3% |
| Second moment, minor (Iz) | 205 cm⁴ | 199.4 cm⁴ | +2.8% |
| Plastic modulus, minor (Wpl,z) | 45.4 cm³ | 44.737 cm³ | +1.5% |
| Radius of gyration, minor (iz) | 2.87 cm | 2.84 cm | +1.1% |
| Torsion constant (It) | 5.33 cm⁴ | 5.41 cm⁴ | -1.5% |
Tee 140×203×20 to BS EN 10365:2017; WT 8X13 to AISC Shapes Database v16.0. Difference is expressed relative to WT 8X13.
How to choose between them
On stiffness, Tee 140×203×20 has the larger second moment of area: 979 cm⁴ against 978.1 cm⁴, a difference of 0.1%. 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 (6.2 against 6.2 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. Tees (from UB) sections are specified to BS EN 10365:2017 and WT 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.