a TABLE OF CONTENTS - UNDP

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12) Wrinkles over than 3% of the surface area and individual wrinkles
more than 2 mm deep.
19.1.8 Cast Iron Pipes and Fittings
Cast iron pipes and fittings for sewers, rising mains, drains or other purposes
may be grey iron or ductile iron, to the approved standard unless either
material is specifically detailed on the drawings.
Unless a "higher" pressure rating is necessary for the pipe duty cast iron pipes
shall be rated for 10 bar working pressure.
Unless detailed to the contrary to suit existing pipework, flanges for cast iron
pipes shall be rated for 10 bar working pressure and drilled accordingly.
19.1.9 Clay Pipes and Fittings
Clay pipes and fittings shall be normal pipes of standard strength unless extra
strength or chemically resistant pipes are specifically called for on the
drawings or in the Bills of Quantities.
Pipes may be glazed or unglazed.
19.1.10 Pipes for Land Drains
Pipes for land-drains shall be uPVC pipes for gravity duty complying with the
requirements of this Specification. The pipes shall be perforated with holes or
slots to a configuration subject to approval by the Engineer's Representative.
The minimum cross-sectional area of the perforations, at the inside surface of
the pipe barrel, shall be 2700 mm2 per meter run of pipe.
19.1.11 Stone for Land Drains
Stone for land drains shall be nominal single size 20 mm and/or nominal
single size 63 mm in accordance with the following table and placed as
shown on the drawings. The stone shall also comply with the requirements
the specifications.
Percent by Weight Passing Test Sieve Nominal size of
single size stone
mm
63 mm 20 mm
75 100 -
63 85 - 100 -
37.5 0 - 30 100
20 0 - 5 85 - 100
14 - -
10 - 0 - 25
5 - 0 - 5
2.36 - -
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