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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On removal from the galvanising bath the resultant coating shall be smooth,<br />
continuous, free from gross imperfections such as bare spots, lumps, blisters and<br />
inclusions of flux, ash or dross. Edges shall be clean and surfaces bright.<br />
Bolts, nuts and washers shall be hot-dip galvanised and subsequently centrifuged in<br />
accordance with IS:2629. Nuts shall be tapped up to 0.4 mm oversize before<br />
galvanising and the threads oiled to permit the nuts to be finger turned on the bolt<br />
for the full depth of the nuts.<br />
During off-loading and erection the use of nylon slings shall be used. Galvanised<br />
work which is to be stored in Works or on Site shall be stacked so as to provide<br />
adequate ventilation to all surfaces to avoid wet storage staining.<br />
Small areas of the galvanised coating damaged in any way shall be restored by:-<br />
i. Cleaning the area of any weld slag and thoroughly wire brushing to give a clean<br />
surface.<br />
ii. The application of two coats of zinc-rich paint (not less than 90 per cent zinc, dry<br />
film), or the application of a low melting-point zinc alloy repair rod or powder to the<br />
damaged area, which is heated at 300 C.<br />
iii. Fastenings of galvanised steelwork shall be hot drip galvanised and subsequently<br />
centrifuged in accordance with IS:2629. Nuts shall be tapped upto 0.4 mm oversize<br />
before galvanising and the threads oiled to permit the nuts to be finger turned on the<br />
bolt for the full depth of the nuts.<br />
iv. Where surfaces of galvanised steelwork are to be in contact with aggressive solutions<br />
and\or atmospheres the galvanising shall receive further protection by painting.<br />
Fasteners:<br />
All bolts, nuts and studs with nominal diameters up to and Fasteners including<br />
39mm required to be made in carbon steel shall conform to BS.6104 and threaded in<br />
accordance with IS:1367. Bright steel washers 3.0mm in thickness shall conform to<br />
BS.4320 and shall be provided beneath bolt head and nut. The above items required<br />
to be supplied in stainless steel shall conform to IS:1570. These items together with<br />
holding-down bolts and anchor plates required to be supplied in high tensile steel<br />
shall conform to BS.970 Ref. Symbol T Drilled anchor fixings for use on concrete<br />
structures shall be of a type Fasteners approved by the Engineer's Representative.<br />
GTS : General Technical Specification. Page 143
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