1964_BUILDING_(CONSTRUCTION)_REGULATIONS

B 128

[Subsidiary]

CAP. 123] Building (Construction) Regulations [1985 Ed.

Minimum thickness of protection in mm for

period of

Construction and Materials 2 hours 3 hours 4 hours 5 hours Gypsum plaster on 19 mm gypsum plaster board with 1.6 mm diameter wire binding at 100 mm 4 12.5 19 25 2 layers of metal lathing plastered with gypsum plaster on each layer, each 2 Precast concrete consisting of 4 volumes of vermiculite to 1 volume of Portland cement, reinforced with expanded metal, wire mesh or with 1.6 mm diameter wire binding at 100 mm pitch 1 65 Beams Moulded asbestos bound in position with nicrome wire not less than 1.6 mm diameter in thickness, the wires to be sunk in grooves not less than 3 mm deep in the outer surface of the asbestos and the grooves and all joints in the asbestos to be filled with refractory cement $ 40 25 25 Cement plaster or cement-lime plaster on metal lathing 25 19 Cement plaster or cement-lime plaster on metal lathing with reinforcement over the rendering coat 22 16 Gypsum plaster on metal lathing Gypsum plaster on 9.5 mm gypsum plaster board with 1.6 mm diameter wire binding at 100 mm pitch Gypsum plaster on 9.5 mm gypsum plaster board supported on wood battens Gypsum plaster on 19 mm gypsum plaster board with 1.6 mm diameter wire binding at 100 mm pitch 12.5 Precast concrete consisting of 4 volumes of vermiculite to 1 volume of Portland cement, reinforced with expanded metal, wire mesh or with 1.6 mm diameter wire binding at 100 mm pitch 12.5 (neat, single coat) 5 25

In this Table:-

"Solid Protection" means casing which is bedded close up to the steel without any intervening cavities and with all joints in that casing made full and solid. "Hollow Protection" means that there is a void between the protective material and the steel. All hollow protection to columns shall be effectively sealed at each floor level.

Reinforcement--where reinforcement is required in this Table, that reinforcement shall consist of steel binding wire not less than 2.5 mm diameter, or a steel mesh weighing not less than 0.5 kg/m2. In the case of concrete protection, the spacing of that reinforcement shall not exceed 300 mm in any direction.