How close can you work to an open edge?For example an access tower is erected to a flat roof the top lift is level with the roof you then sail the stop ends into the flat roof to access the centre where you build a tempory hand railed section in the middle where the gear will be chained up to and the labourer will feed the scaffolders, you then use this to build your hand rails around the parimeter of the roof using restraint lanyards clipped on to the frame in the centre from the start you are never any more than 2m from an open edge is this acceptable.