Manhole and Xxxxxxxx a) All manholes, xxxxxxxx, septic tanks and other such works as specified shall be constructed in XX Xxxxx Masonry (1:6) I.S. (1 cement: 6 coarse sand).
b) All manholes, xxxxxxxx, septic tanks, etc, shall be supported one base of cement concrete of such thickness and mix.
c) All manholes shall be provided with cement concrete benching in 1:2:4 mix (1 cement 2 coarse sand 4 stone aggregate 20 mm nominal size) The benching shall have a slope of 10 cms towards the channels. The depth of the channel shall be full diameter of the pipe. Benching shall be finished with a floating coat of neat cement.
d) All manholes shall be plastered with 25 mm thick cement mortar 1:3 mix (1 cement 3 coarse sand) in finished with a floating coat of neat cement inside. Manholes shall be plastered outside as above but with rough plaster.
e) All manholes with depths greater than 1 m shall be provide with Ferro Cement Foot Steps.
f) All manholes shall be provided with cast iron covers and frames and embedded in reinforced cement concrete slab. Weight of cover and frame shall be approximately chosen.
g) Size of Manhole should not be less than 1500 x 900 mm in normal circumstances. Circular manhole shall be construction with minimum 1 meter internal dia.
h) Drop Connection
(i) Drop connections shall be provided between branch sewer and main sewer or in the main sewer itself in the steep ground when the difference in the invert level of the two exceeds 45 cm of the required size.
(ii) Drop connections from the gully trap to main sewer on rectangular manholes shall be made inside the manhole and shall have H.C.I. special type door on top and heel rest bend at bottom connected by a H.C.I. pipe. This pipe shall be supported by holder bat clamp at 180 cm intervals with one clamp for each drop connection. All joints shall be lead caulked joints 25 cm deep.
(iii) Drop connections from branch sewer to main sewer shall be made outside the manhole wall with glazed stone ware pipe tee connection, vertical pipe and bend at the bottom. The top of the tee shall be finished up to the surface level and provided with a C.I. hinged type frame and cover 30 cm x 30cm. The connection shall be embedded in the cement concrete 1:2:4 mix 15 cm all round the pipe and tee upto the surface chamber of the tee.
(iv) Drop connection made from vertical stack directly into the manhole shall not be considered as drop connection.
Manhole and Xxxxxxxx. All manholes, xxxxxxxx, septic tanks and other such works as specified shall be constructed in brick masonry in cement mortar 1:4 (1 cement 4 coarse sand) or as specified in the schedule of quantities. Interior finishing shall conform to AIA Standard.
