Tee 140×203×27 vs WT 8X20
Tee 140×203×27 is an Tees (from UB) section from the UK Blue Book (SCI P363); WT 8X20 is the closest equivalent in the American AISC Shapes Database. They are close to interchangeable in bending: 155 cm³ against 154.53 cm³ of plastic modulus, a difference of 0.3%. Tee 140×203×27 is the lighter of the two at 26.6 kg/m against 29.8 kg/m, a saving of 10.7% on steel weight. Both are about 203 mm deep, so either fits the same construction zone.
| Property | Tee 140×203×27 Tees (from UB) | WT 8X20 WT | Difference |
|---|---|---|---|
| Mass | 26.6 kg/m | 29.8 kg/m | -10.7% |
| Depth | 203.3 mm | 203.5 mm | -0.1% |
| Width | 143.3 mm | 177.8 mm | -19.4% |
| Web thickness | 7.9 mm | 7.7 mm | +2.6% |
| Flange thickness | 12.9 mm | 12.8 mm | +0.8% |
| Area | 34 cm² | 38 cm² | -10.5% |
| Second moment, major (Iy) | 1,320 cm⁴ | 1,378 cm⁴ | -4.2% |
| Plastic modulus, major (Wpl,y) | 155 cm³ | 154.53 cm³ | +0.3% |
| Elastic modulus, major (Wel,y) | 87 cm³ | 87.671 cm³ | -0.8% |
| Second moment, minor (Iz) | 317 cm⁴ | 599.4 cm⁴ | -47.1% |
| Plastic modulus, minor (Wpl,z) | 69.5 cm³ | 104.22 cm³ | -33.3% |
| Radius of gyration, minor (iz) | 3.06 cm | 3.96 cm | -22.7% |
| Torsion constant (It) | 14.4 cm⁴ | 16.48 cm⁴ | -12.6% |
Tee 140×203×27 to BS EN 10365:2017; WT 8X20 to AISC Shapes Database v16.0. Difference is expressed relative to WT 8X20.
How to choose between them
On stiffness, WT 8X20 has the larger second moment of area: 1,378 cm⁴ against 1,320 cm⁴, a difference of 4.2%. 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 of steel, Tee 140×203×27 is the more efficient section: 5.8 against 5.2 cm³ per kg/m, 12.4% better. Over a floor of repeated beams that difference is real tonnage, though it is often outweighed by whichever section the fabricator can actually source.
The two diverge much more about the minor axis: WT 8X20 has 104.22 cm³ of minor-axis plastic modulus against 69.5 cm³, 33.3% more. If the member sees any minor-axis bending, or if it is unrestrained over a long length and lateral-torsional buckling governs, that gap decides the comparison even though the major-axis numbers looked equivalent.
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 10.7% weight.
In short, Tee 140×203×27 is the stronger section and Tee 140×203×27 is the lighter one; where those are the same section, it is the clear choice, and where they are not, decide on whether your design is governed by capacity or by tonnage.