(1) The edge of all steps, landings, balconies, bridges, flat roofs and other places from which there is danger of a person falling shall be provided with parapet-walls, guard-railings or balustrades, unless access by persons to such places has been excluded by an adequate physical barrier satisfactory to the local authority.

(2) Such parapets, railings or balustrades shall have a height of not less than 850 millimeters, measured from the floor or from the center of a tread vertically to the top of the parapet, railing or balustrade.

(3) Balustrades or railings to internal stairs shall have the same minimum height, and, in addition, the balusters, rails or other parts shall not have openings in or between them which permit the passage of a 125-millimetre-diameter ball.2