| S.No. |
Description |
Heavy/Extra-Heavy
duty HD/EHD |
Medium-duty
MD |
Light-duty
LD |
| 1. |
Clear
Opening-matching the top opening of manhole chamber
(C) |
560
mm dia or 600 mm dia. or square |
450
mm dia/480 mm 500 mm dia or 560mm dia or square 450
x 900 mm (Rectangular) |
600
x 450 Rectangular 450 mm dia or 350 mm dia or square |
| 2. |
Precast
Polycrete slab with integral frame (D/T) |
900
mm dia x 180 mm or square corners cut 1000 mm dia x
200 mm or square corners cut |
800mm
dia x 130mm, 800mm dia x 150mm, 700 x 1150 x 130 mm,
900 dia x 150 mm |
850mm
x 700mm x 100mm 625mm dia x 100mm, or 575mm dia x 100mm
or square |
| 3. |
Thickness
of cover/Depth of Frame (T) |
100mm
or 110/130mm/175 to 200mm |
60/70/80mm/125
to 160mm |
50mm/100mm |
| 4. |
Matching
manhole cover (B) |
685/660mm
or 735/710mm dia or square |
585mm
dia or 645mm dia or square 535x985x70mm (Rectangular) |
685
x 535 mm 515mm dia or square 435 mm dia or square |
| 5. |
Edge
protection of covers inside of frames/lifting facility |
Polycrete
manhole covers, and inside of frames are designed and
provided with MS Rims of 2/2.5/3.15 mm thickness, depending
upon the grade of manhole cover system, welded around,
with provision of two lifting hooks welded at appropriate
locations. |
| 6. |
Chequered
pattern n operative surface/Colour finish |
The
MS Rims along with the edges of Polycrete manhole covers
and their operative surface are suitably coated/finished
using Polyutherane enamel of the desired shade,
for improved corrosion resistance, besides providing
chequered pattern : Chocalate Brown/Olive green/
Black/ Grey to facilitate colour condification.
MS Rims can also be supplied galvanised on demand and
at additional cost. |
| 7. |
Marking
on the covers |
Polycrete
manhole covers/precast slabs suitably marked on the
operative surface with the following letters, unless
specified otherwise :
Name of the Department / Sewer / SWD / Grade /
Date of Mfr. / Trade name etc.
|
| 8. |
Performance
requirment
|
When
tested for ULTIMATE breaking load using 300 m dia block,
as per the method described in IS : 1726-1991 for cast-iron
& IS : 12592 (1981 & 1991), Polycrete (PFRC)
manhole covers shall be with in the follwing range.
|
|
(I)
Test-load |
| Light-duty
: |
2.5
tonnes(LD-2.5) |
Medium-duty
: |
10
tonnes (MD-10) |
| Heavy-duty
: |
20
tonnes (HD-20) |
Extra-heavy-duty
: |
35
tonnes(EHD-35) |
|
|
(II)
Improved Abrasion resistance of operative |
Polycrete
(PRFC) Heavy-duty and extra-heavy-duty manhole covers
can be provided with Polymer concrete operative
surface with a view to obtain improved abrasion resistance
over conventional cement ceoncrete surface, on demand,
and at additional cost. |
