(1) Empirically constructed brick parapet-walls shall have a thickness of not less than one sixth of their height or 215 millimetres, whichever is the greater, and shall be laid in class A mortar.

(2) They shall be reinforced in the highest four bed-joints with reinforcement consisting of two stands of steel wire of a diameter or not less than 3,55 millimetres, or two steel strips of equivalent cross-sectional area per bed-joint, and such reinforcement shall be lapped over a distance of at least 150 millimetres with the anchors to the supporting-columns required by section 27.

(3) Empirically constructed brick balustrade-walls shall be not less than 100 millimetres in thickness, and shall be laid in class A mortar and reinforced as required by subsection (2).