Of for the safe erection and use of scaffolding

oth, for securing vertical members together laterally. Horizontal, diagonal orcross-bracing must be provided immediately above the wheels or castors (seefig. 18).Castors should be of the swivel type and have a minimum wheel diameter of125 mm. Wheels or castors must be fixed to scaffold uprights, or be socketedinto the scaffold uprights, a minimum length of 150 mm, to avoid becomingdislodged during movement on uneven floors.BaseHorizontal diagonal bracesas near bottom as possible(a) Mobile frame(a) Mobile tubeHorizontal diagonal bracesas near bottom as possibleFig. 18 Free-standing mobile scaffolds.When the scaffold is in use, the wheels or castors must be effectively lockedand should be turned outwards to increase base width.A mobile scaffold must be used only on a firm level surface. Where the surfacehas a slight cross-fall, the level of the wheels must be adjusted to bring thescaffold back to plumb. Mobile scaffolds should not be used closer than 1 m toany slab edge or partition unless the edge is protected to prevent the wheelsand scaffold from falling.Access between working platform and base must be provided by means ofsecurely fixed ladders or purpose-built rungs. Cross braces must not be usedas a means of access. Work platforms must be fully decked and be providedwith guardrails and toeboards in accordance with general requirements forscaffolding.52 SAFE ERECTION AND USE OF SCAFFOLDING