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Scaffolding Design Engine & Calculator

Per BS EN 12811 / OSHA 1926.451 — Multi-Page PDF with MTO & Scafftag

System
Geometry
Site

Scaffold System & Duty Rating

Project Details (for PDF)

Step 1 of 3

The scaffolding design calculator computes leg loads, sole board sizing, wall tie-in frequency, and material take-off for tube-and-coupler and system scaffolds. It generates a 4-page PDF design brief with 2D elevation drawings, 3D model renders, and a Green Scafftag inspection certificate. This tool is designed for scaffold designers, HSE officers, and QA/QC engineers working to BS EN 12811 and OSHA 1926.451 standards.

How Leg Load Is Calculated

The maximum leg load per standard is: (Duty Rating × Tributary Area × Number of Lifts) + Dead Load, all multiplied by the enclosure wind factor. The tributary area per leg equals bay length × bay width. Each lift is 2.0 m per BS EN 12811. The enclosure type (open, debris netting, or tarpaulin) applies a wind factor of 1.0×, 1.1×, or 1.5× respectively.

Sole Board Sizing

The required sole board area = Maximum Leg Load / Ground Bearing Capacity. For uncompacted soil (100 kN/m²), a 10 kN leg load needs 0.10 m² of sole board — roughly a 316 mm square. For concrete (500 kN/m²), the same load needs only 0.02 m². The calculator recommends the minimum square sole board size in millimeters.

Wall Tie-In Matrix

  • Open structure: ties every 4 m vertically, 6 m horizontally.
  • Debris netting: ties every 4 m vertically (wind factor 1.1×).
  • Tarpaulin sheeting: ties every 3 m vertically (wind factor 1.5×) — closer spacing is mandatory.
  • Ties must be verified against the structure's capacity to resist the tie load.

Material Take-Off (MTO)

The MTO counts every component per bay: standards (vertical posts), ledgers (longitudinal horizontals), transoms (transverse horizontals), diagonal braces, deck boards, guardrail boards, toe boards, base plates, sole boards, clamps/couplers, and tie rods. Quantities are calculated from bay geometry and lift count. The PDF includes a complete MTO table for procurement and erection planning.

The Green Scafftag System

A Green Scafftag certifies that a scaffold has been erected per the design calculation, inspected by a competent person, and is safe for use. It must be displayed on the scaffold and re-inspected every 7 days or after any modification. Red tags mean do not use; yellow tags mean restricted use. The PDF includes a pre-handover inspection checklist and sign-off roster for the erector, inspector, and client HSE representative.

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