Technical Booklet H Stairs Ramps Guarding and Protection from Impact·Page 38·4.18
Raised kerbs on ramps
Ramps with open sides must have a raised kerb at least 100 mm high (except where it would obstruct normal use). The kerb must be visually distinct from the ramp and landing surfaces.
A ramp should have a raised kerb on any open side (except where it would obstruct normal use). The raised kerb should –
(a) be not less than 100 mm high; and
(b) be distinguishable, through suitable visual contrast, from that of the surface of the ramp and landings.
Source — /Users/richardhill/Documents/planning-arch-project/data/documents/regional/Technical Booklet H - Stairs Ramps Guarding and Protection from Impact.pdf