Edge Protection Calculator

The Work at Height Regulations 2005 removed the previous 2 metre threshold — edge protection is required wherever a person could fall any distance and be injured (the test is risk-of-injury, not a fixed height). Falls from less than 2m (e.g. into excavations, onto sharp rebar, into water) absolutely require protection. WAH Regs require collective protection (guard rails) before personal protection (harnesses).

The Work at Height Regulations 2005 (Schedule 2) require the top guard rail to be at least 950mm above the working platform (910mm is only allowed for protection already fixed before the Regulations came into force). Any gap between the top rail and the next means of protection must not exceed 470mm, so at least one intermediate rail is normally fitted between the top rail and the toe board. Toe boards retain people and materials. Note BS EN 13374 (temporary edge-protection equipment) sets a higher 1000mm principal guard-rail and a 150mm toe board, and BS 6180 (permanent barriers) requires 1100mm — meet whichever standard applies to your system.

Post spacing depends on the system, but 2.0m is standard for most proprietary edge protection. Some systems allow up to 2.4m. Posts must be secure - typically clamped to scaffold or fixed to the structure. Check the manufacturer's instructions for your specific system.

BS EN 13374 grades temporary edge protection by the slope it suits and the load it resists. Class A: flat surfaces and roofs pitched up to 10 degrees, where loads are mainly static (a person leaning against the rail). Class B: slopes up to 30 degrees that must also resist a low dynamic load, often needing mesh or solid infill. Class C: steeply pitched roofs from 30 up to 45 degrees (with no fall-height limit), or from 45 up to 60 degrees where the fall height is under 5m — here a falling person gains momentum, so the system must absorb that energy. Most general construction edge protection is Class A or B; steep-pitch roofing uses Class C.

Scaffold boards can be used as toe boards but should not be the sole guard rail. Proprietary guard rail systems with steel or aluminium rails are preferred as they provide consistent strength. If using timber, it must be of adequate cross-section and properly secured.