Permanent work platform requirement
The depth of the platform must be at least 350 mm (measured out from the chimney). The centre of the work platform must be at least 350 mm from the surface of the chimney. Guardrails shall be able to serve as anchor points for personal fall protection. The guardrails on work platforms shall be at least 1.0 m high and be positioned so that they do not impede work done while standing on the platform. The guardrail must have at least an upper rail and an intermediate rail.
The standing platform must not impede ascent (not protrude past the ladder rungs below). The step up to the standing platform must not have a negative slope, rather it should be 70-90 degrees positive.
The opening in the work platform, for example, between the handrails or the guardrails, must be about 600 mm.