The employer shall ensure at a construction site of a building or other construction work that,-
(a) no trestle scaffold is constructed with more than three tiers or if its working platform is more than 4.5 metres above the ground or floor or other surface upon which such scaffold is erected, such trestle scaffold is designed by professional engineer and has the approval of Chief Inspector of Inspection of Building and Construction before being taken into use;
(b) no trestle scaffold is erected on a suspended scaffold;
(c) no cantilever or jib scaffold is used unless it is adequately supported, fixed and anchored on opposite side of its support has outriggers of adequate length and where necessary sufficiently supported and braced to ensure safety and stability of such scaffold:
and
(d) no working platform resting on bearers let into a wall at one end and without other support is used unless such bearers are of adequate strength, braced through the wall and securely fastened on the other side.