The section families
| Family | Examples of designation | Typical use |
|---|---|---|
| Hot-rolled I / H beams and columns | IPE 300, HEA 200, HEB 300 (European); UB 406×178×60, UC 203×203×46 (British); W12×26 (American); H 300×150×6.5×9 (Asian) | Beams, columns, crane beams, mezzanines |
| Built-up (welded) I-sections | Written by plates: web 500×6, flanges 200×10 – or as I H×B×tw×tf | PEB columns and rafters, often tapered |
| Channels | UPN 200, PFC 180×75, C 200×75 | Trimmers, bracing, secondary framing |
| Angles | L 75×75×6 (equal), L 100×75×8 (unequal) | Bracing, cleats, edge trims |
| Hollow sections | CHS 114.3×4 (circular), SHS 100×100×5 (square), RHS 150×100×6 (rectangular) | Columns, trusses, struts, handrails |
| Plates and flats | PL 12×250 (thickness × width), FL 50×6 | Connection plates, stiffeners, base plates, built-up members |
| Cold-formed purlins / girts | Z 200×2.0, C 150×65×20×2.0 | Roof purlins and wall girts |
| Round bars | RB 20, Ø20 | Rod bracing, tie rods, anchor bolts |
Reading a dimension string
Each family has its own order. For an I-section, H×B×tw×tf is overall depth × flange width × web thickness × flange thickness, in mm. A plate is t×W (and × L when the length matters). A circular hollow section is Ø×t, outside diameter × wall thickness. PEB Studio writes part dimensions in exactly this form in the Parts list, so the BOM can be read without opening the drawing.
Weight per metre
Steel has a density of about 7,850 kg/m³. The mass of any prismatic member is therefore its cross-section area × length × 7,850. Two quick checks every estimator should know:
- A plate weighs 7.85 kg per m² per mm of thickness – a 10 mm plate is 78.5 kg/m².
- A round bar weighs about 0.00617 × d² kg/m (d in mm) – a Ø20 bar is about 2.47 kg/m.
Rolled sections are listed in the producer's tables; the BOM uses the section properties from the model, so totals match the IFC exactly.
Coating area
Painting and galvanising are priced per m² or per tonne. The painted area of a section is roughly its perimeter × length; for a plate it is both faces plus the edges. PEB Studio reports the coating area per part, assembly, group and project.
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حُدّث في 01 Nov 2026