PACKAGE : I Bid Document VOLUME : II - Public Health Engineering

vi) Avoidance of sudden change in the direction of flow by provision of a stilling
chamber to reduce the velocity gradually to about 0.3 m/s near the suction bellmouth.
v) Avoidance of dead spots by keeping rear clearance from the center line of the
pump.
vi) Avoidance of mutual interference between two adjoining pumps by maintaining
sufficiency clearance.
(vii) Avoidance of dead spots at the suction bellmouth by maintaining the bottom
clearance.
viii) Provision for adequate submergence of the inlet of pump under the LWL, so as to
prevent entry of air during draw down and to satisfy NPSHr.
ix) Provision for overflow arrangement from the inlet stilling chamber.
x) Provision for drainage system from both inlet and main chamber of the sump.
xi) Provision for free board.
17.5 Clear water pump house. For construction of pump house, the
following factors are to be considered.
i) The clear water pump house shall be rectangular and shall be constructed at the
same level and adjacent to RCC sump. The floor of Pump House shall be designed for
installation of 3 numbers of pumps, motors, delivery pipes, common header, valves and
other electrical accessories, H.O.T. crane etc.. The pump floor and RCC beams shall be M-
25 concrete and HYSD/TMT bars (Fe - 415). The walls of the Pump House shall be
250mm thick 1 st class brickwork with 1:4 cement mortar (1 cement and 4 sand). Adequate
numbers of RCC columns along the centre line of periphery of the circular brick wall and
equally spaced for the support of 2 (two) nos. of Rolled Steel Joists (RSJ) and RCC Roof
beams. The columns shall be constructed to support the RSJs over which HOT crane shall
be fixed for lifting the Pumps, Motors, Pipes, Valves, and Electrical Accessories as well as
to support RCC roof beams. The columns, bracings, Ties, Lintels, Chujja, RCC roof beams
and roof slab shall be of RCC concrete of not leaner than M-25 and HYSD/TMT (Fe - 415)
bars.
ii) The availability of sufficient space between two adjoining pumps/motors.
iii) Provision of sufficient space for the control panels as per the Indian Electricity
(I.E.) Rules.
iv) Provision of service bay in the station with different space to accommodate
overhauling and repairs of the largest equipment.
v) Provision of a head room and material handling tackle with adequate clearance to
lift the motor clear off the face of the coupling and also carry the motor to the service bay
without interference with any other apparatus including adequate clearance to dismantle
and lift the largest assembly.
DTS : Detailed Technical Specification. Page 164