PACKAGE : I Bid Document VOLUME : II - Public Health Engineering
PACKAGE : I Bid Document VOLUME : II - Public Health Engineering
PACKAGE : I Bid Document VOLUME : II - Public Health Engineering
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Aluminium and aluminium alloys shall not be utilised unless alternative materials<br />
are considered unacceptable. The use of aluminium requires the approval of the<br />
Engineer in all cases. Bars and extruded sections shall be as per relevant IS.<br />
Aluminium and Aluminium Alloy Castings shall be manufactured as per<br />
IS:617:1994 and subjected to a chill cast to increase tensile strength. Immersed<br />
structures or structures that are periodically immersed shall not be constructed from<br />
aluminium or aluminium alloys. All chromium plating shall comply with IS 1986.<br />
Painting and Metal Protection:<br />
The surface preparation and painting or application of corrosion protection coatings<br />
to the following materials shall be carried out in accordance with relevant IS for the<br />
particular environmental conditions where the materials are used.<br />
Mild Steel<br />
Cast and Duct Iron<br />
Aluminium<br />
Nonferous Parts<br />
Other small parts<br />
Galvanising:<br />
Where steel or wrought iron is to be galvanised, it shall be carried out by the hot-dip<br />
process and shall conform in all respects with IS:2629. Adequate provision for<br />
filling, venting and draining shall be made for assemblies fabricated from hollow<br />
section. Vent holes shall be suitably plugged after galvanising.<br />
All surface defects in the steel including cracks, surface laminations, laps and folds<br />
shall be removed in accordance with IS:6159. All drilling, cutting, welding, forming<br />
and final fabrications of unit members and assemblies shall be completed before the<br />
structures are galvanised, The surface of the steelwork to be galvanised shall be free<br />
from welding slag, paint, oil, grease, and similar contaminants. The articles shall be<br />
pickled in dilute sulphuric or hydrochloric acid, followed by rinsing in water and<br />
pickling in phosphoric acid. They shall be thoroughly washed, stoved and dipped in<br />
molten zinc and brushed, so that the whole of the metal shall be evenly covered and<br />
the additional weight thereof after dripping shall not be less than 610 grams per<br />
square metre of surface galvanised, except in the case of tubes to BS.1387 when it<br />
shall be 460 grams per square metre.<br />
GTS : General Technical Specification. Page 142
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