PART 10
CONVEYANCE OF SURFACE WATER TO DRAIN OR WATERCOURSE
20. Curtilage to be Kept Free From Static Water
Static water shall not be permitted other than in specially constructed water tanks and where the impermeability of the curtilage renders such a precaution necessary the surface shall be graded, levelled or otherwise altered to permit of the effective discharge of surface water to gully traps or impervious watercourse or to soakaways.
21. Roof to be effectually drained
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(1) The roof of a building (whether flat or pitched) shall be so constructed as to drain effectually to—
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(a) a sufficient system of rainwater pipes and gutters connected with a suitable number of pipes discharging into gully traps or to a water tank; or
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(b) an impervious watercourse.
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(2) A sufficient system of rainwater pipes and gutters shall consist of—
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(a) eaves gutters downpipes and fittings formed of pressed steel or conforming to British Standard 1091 for pressed steel gutters pipes fittings and accessories;
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(b) eaves gutters downpipes and fittings of asbestos cement conforming to British Standard 569 for asbestos cement spigot and socket rainwater pipes, gutters and fittings;
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(c) eaves gutters downpipes and fittings formed of cast iron conforming to British Standard 460 for cast iron spigot and socket rainwater pipes fittings and accessories;
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(d) eaves gutters downpipes and fittings formed of aluminium conforming to British Standard 1430 for aluminium rainwater goods cast and extruded;
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(e) eaves gutters downpipes and fittings formed of copper or zinc conforming to British Standard 1431 for wrought copper and wrought zinc rainwater goods; or
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(f) eaves gutters downpipes and fittings formed of other material as approved by the Sewerage Authority.
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(3) Rainwater pipes shall be of adequate size to prevent surcharging and overflowing and shall not project beyond the limits of the curtilage of the building except by agreement with the parties concerned and in any case the rainwater downpipes shall not project over a public footway at any point which is less than 10 feet from the ground. Pipes shall be securely fixed to the wall of the building and shall terminate either below the cover of a water tank or over a gully trap or impervious watercourse by means of a shoe.
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(4) All eaves gutters shall be supported at intervals not exceeding 3 feet by suitable brackets and shall be properly aligned so as to provide continuous and even fall to the point of discharge in such a manner that no part of such eaves gutters shall be more than 30 feet of eaves gutters from a point of discharge save that with the approval of the Sewerage Authority such distance may be exceeded when the rainwater downpipes are connected to storage tanks. The eaves gutters shall be of adequate size to prevent surcharging and overflowing and shall be provided with proper stopped ends and shall discharge by proper outlet nozzles to rainwater pipes.