PFC 300×90×41 vs PFC 300×90
PFC 300×90×41 is a PFC section from the UK Blue Book (SCI P363); PFC 300×90 is the closest equivalent in the European (Continental) range. They are close to interchangeable in bending: 568 cm³ against 568 cm³ of plastic modulus, a difference of 0.0%. They weigh essentially the same, 41.4 kg/m and 41.4 kg/m. Both are about 300 mm deep, so either fits the same construction zone.
| Property | PFC 300×90×41 PFC | PFC 300×90 PFC | Difference |
|---|---|---|---|
| Mass | 41.4 kg/m | 41.4 kg/m | same |
| Depth | 300 mm | 300 mm | same |
| Width | 90 mm | 90 mm | same |
| Web thickness | 9 mm | 9 mm | same |
| Flange thickness | 15.5 mm | 15.5 mm | same |
| Area | 52.7 cm² | 52.7 cm² | same |
| Second moment, major (Iy) | 7,220 cm⁴ | 7,218 cm⁴ | same |
| Plastic modulus, major (Wpl,y) | 568 cm³ | 568 cm³ | same |
| Elastic modulus, major (Wel,y) | 481 cm³ | 481 cm³ | same |
| Second moment, minor (Iz) | 404 cm⁴ | 404 cm⁴ | same |
| Plastic modulus, minor (Wpl,z) | 114 cm³ | 114 cm³ | same |
| Radius of gyration, minor (iz) | 2.77 cm | 2.77 cm | same |
| Torsion constant (It) | 28.8 cm⁴ | 28.8 cm⁴ | same |
PFC 300×90×41 to BS EN 1993-1-1:2005 / BS 4-1:2005; PFC 300×90 to Continental Steel. Difference is expressed relative to PFC 300×90.
How to choose between them
On stiffness, PFC 300×90×41 has the larger second moment of area: 7,220 cm⁴ against 7,218 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 (13.7 against 13.7 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. PFC sections are specified to BS EN 1993-1-1:2005 / BS 4-1:2005 and PFC to Continental Steel; 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.