I have photos of the incident in question, and the fault was that the barrier _was_ right at the edge of the shaft, so when the IP leaned out to steady a tub of cement, it fell over and he fell with it. Nothing secured the barrier to the walls or floor. Edge 'demarcation', set a *significant* distance back from the edge to prevent access by administrative means, can be of any form that makes itself obvious, therefore streetworks kit is fine (as is a chain, or hazard tape and poles). Edge 'protection' is a physical safety barrier placed at the edge itself, and must be of suitable strength to stay in place even if you throw yourself at it, as defined in the WAHR.

If you can get hold of a copy of HSW magazine Aug 2009, we have some photos on page 8. 'Significant' varies - it's the distance needed to ensure nobody can be at risk from or by the edge (falling over it, dropping a spanner on someone below, etc.) even if they fall against the demarcation barrier itself. On a horizontal surface I'd make it 2m to 3m as a minimum, but if there's a slope it may not be possible at all. Structural edge barriers can of course be right at the edge, and usually are. The rule-of-thumb for WAH near unprotected edges is that PFPE is required if approaching closer than *about* 2m, i.e. a little more than the distance you could fall if you tripped over something. The distance isn't defined in law, only via the concept of "being able to fall". Setting demarcation a fraction further back ensures even if someone trips over the barrier itself, or it bends in the wind (as with a chain or rope), they're still safe.