NATIONAL ALUMINIUM COMPANY LIMITED - Rites

drains of minimum size of 300 mm width and 300 mm depth all around the periphery. All
drains shall be of R. C. C. construction. All open drains shall have removable steel grating
designed for loads as specified under loading cclause.
lause. Minimum thickness of grating
(Galvanised to 610 gm/m) 2 shall be 12 mm. However at entry or road crossing point’s
minimum thickness shall be 40 mm. The opening size of grating shall not be more than 90
mm x 35 mm. All drains as well as pre - cast covers vers shall be provided with edge protection
angles and lifting hooks. However, drains in coal stockyard area shall have pre cast R. C. C.
covers. RCC pre - cast cover weight shall not be more than 65 Kgs. RCC pre pre-cast covers near
entry or at road crossings shall be designed for 10 T wheel load at centre. RCC pre – cast
covers shall be designed for central point load of 75 Kgs. The scope for foul water from
toilets shall include layout and laying of sewers up to the Employer’s main sewer line for
sewerage system stem together with all fittings and fixtures and inclusive of ancillary works such
as connections, manholes and inspection chambers within the building and from the
building to the Employer’s sewer line. For rain water down comer and those to be used for
conveying onveying water / coal slurry generated from cleaning of conveyor gallery and buildings
floors, Galvanised MS pipes conforming to IS: 1239 (for 150 mm NB Medium grade pipes)
with welded joints shall be used for MCC buildings, pump houses, penthouse, contro control
rooms. Galvanised steel ERW pipes (273mm OD, 4mm thk) of steel grade Fe330 conforming
to IS: 3589 with welded joints shall be used for all TP’s, and Conveyor galleries. Galvanising
shall be as per IS: 4736. The minimum mass of zinc coating shall not be less than 400
gms/sq.m. as per IS:6745. The zinc coating shall be smooth and shall be subjected to testing
as per IS: 2633, for uniformity of coating. The zinc coating shall be free from all defects as
per IS: 2629. All rain water down comers shall be prov provided ided with roof drain heads and
complete with shoes bends, junctions, sockets, adapters, brackets and finished with anti
corrosive painting over a coat or primer. For design of building drainage system IS: 1742 shall
be followed. For sanitary / sewerage pip pipes es above ground, sand cast iron pipes conforming to
IS : 1729 with leak proof lead joints. For underground drain pipes, minimum class NP - 2
pipes conforming to IS: 458. At road crossings, concrete pipes of class NP 3 conforming to IS:
458 and at rail crossing sing R.C.C. box culvert to be provided. For sewerage below ground
stoneware pipes conforming to IS: 651 with concrete bedding and haunch.
6.0 COLOUR COATED AND OTHER SHEETING WORK
Permanently colour coated sheet of approved shade and colour using galvanize galvanized mild steel
sheet of minimum 0.6mm BMT(bare metal thickness i.e. metal thickness excluding thickness
for coating and galvanizing) galvanised to grade 275 as per IS 277,of minimum yield strength
of 250 Mpa of drawing grade as per IS 513 or high tensile st steel eel of minimum 0.5mm
BMT(bare metal thickness i.e. metal thickness excluding thickness for zinc aluminium
coating and colour coating ) coated with zinc aluminium alloy @ 150gm/sq.m.of minimum
yield strengthof 350 as per AS1397. Steel shall be colour coate coated d with total coating thickness
of 35 microns (nominal) comprising of silicon modified polyester (SMP with silicon content of
30% to 50%) paint or Super Polyester paint, of minimum 20 microns (nominal) dry film
thickness (DFT) on external face on 5 microns (nominal) primer coat and 5 microns (nominal)
SMP or super polyester paint over 5 microns (nominal) primer coat (or 10 micron SMP/super
polyester paint) on internal face. SMP and Super polyester paint systems shall be of category
3 as per AS2728. Coated su surface rface shall be provided with a protected guard film (polyethylene)
of about 40 microns to avoid any damage to the coating during handling. For metal deck,
minimum 0.8 mm (bare metal thickness i.e. metal thickness excluding thickness for coating
and galvanizing) izing) galvanised to grade 275 as per as per IS 277, of minimum yield strength of
250 Mpa of drawing grade as per IS 513, troughed profile having nominal trough depth 44
mm and pitching of 130 mm shall be used. However alternative profile meeting the stren strength,
defection and other functional requirements such as sections modulers and moment of
inertia shall be provided. To minimize the number of joints, the length of the sheet shall
Technical Specification:Sec-7, Civil
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