Edge protection
Guardrail and toe board lengths with height and gap check
- where
- edge length per lift (m)
- run length of each protected lift (m)
- open ends to return
- platform width (m)
- guardrail tube, main and intermediate (m)
- lifts needing edge protection
- toe boards
- toe board length (m)
- main guardrail height (mm)
- intermediate guardrail height (mm)
- toe board height (mm)
Explain this equation
Works out the guardrail tube and toe boards for the working lifts, and checks the largest gap in the edge protection.
The edge to protect is the run plus a return across the platform at each open end. Each lift needs a main and an intermediate guardrail along that edge, hence 2 × L_p per lift. Toe boards run the same length in whole boards. The gaps are between the main and intermediate rails, and between the intermediate rail and the top of the toe board; the larger one is what matters.
Lengths add up along the edge; the gap check compares heights.
Sense check: a 21 m run with both ends returned on 1.25 m platforms is 23.5 m per lift, 94 m of rail for two lifts and 14 toe boards. With a 1000 mm main rail, 530 mm intermediate and 150 mm toe board the biggest gap is 470 mm, the maximum allowed.
Watch out: the Work at Height Regulations require the main guardrail at least 950 mm high and no gap over 470 mm.
Measures the main and intermediate guardrails and toe boards for the open edges of each working lift, and checks heights and gaps against the Work at Height Regulations.
Enter your values to see the result.
Good to know
Work at Height Regulations 2005, Schedule 2: the top guardrail at least 950 mm above the edge, intermediate protection so no unprotected gap exceeds 470 mm, and suitable toe boards. BS EN 12811-1 asks for a toe board top at least 150 mm above the platform. A guardrail at about 1000 mm, an intermediate at about 530 mm and a 150 mm toe board meets both. Where materials are stacked above toe-board height, fit brick guards or mesh. Inside edges more than about 225 mm from the building also need protection.
Common mistake
Fixing the intermediate rail halfway between platform and top rail without allowing for the toe board, or leaving the ends of the run open.
Limits
Outer edge plus chosen end returns only. Guardrail tube is counted as continuous length; add laps, joints and couplers. Stair and ladder access openings need their own protection. For planning and estimating only. This does not replace TG20:21 compliance (a TG20 compliance sheet or eGuide output) or a scaffold design by a competent person.
Sources
- Work at Height Regulations 2005 (SI 2005/735) Schedule 2: guard-rail at least 950 mm, gap not exceeding 470 mm, suitable toe-boards
- BS EN 12811-1:2003 Temporary works equipment. Scaffolds. Performance requirements and general design (Table 3 load classes; 5.5 side protection; Annex A cladding force coefficients)
- Health and Safety Authority (Ireland), Code of Practice for Access and Working Scaffolds (sole boards ≥ 1000 cm², ties ≥ 6.1 kN, façade bracing at least every six bays, tower height to least base ≤ 3, toe-boards ≥ 150 mm)
- NASC TG20:21 Good practice guidance for tube and fitting scaffolding (Operational Guide, Design Guide, User Guide and eGuide compliance sheets)
Results are calculations from the published methods and figures shown, and depend on the data you enter. For planning and checking only. Scaffolds must be erected to NASC TG20 or a bespoke design by competent persons, and lifting operations planned under LOLER by a competent person. Never rely on these results instead of a design, a lift plan or manufacturer ratings.