Volume-2 - Delhi Metro Rail Corporation

BEARINGS:
TENDER NO. DMRC/ELECT./IT&PD/ILBS/HVAC-LV-FF-02
The pump shaft shall be adequately supported by the pump bearings to limit the shaft deflection to
0.002 inches.
Bearings shall be ball type, grease lubricated and locked to the shaft with positive locks of ample size
to withstand any axial thrust loads. Bearing shall provide a minimum life of 10years when calculated
at 50% of Best-Efficiency-Point for the scheduled pumps.
WORKING PRESSURE:
Maximum allowable working pressure (MAWP) for all the pressure containing parts shall in no case
be less than the maximum discharge pressure produced by the pump at shut off(including
tolerances), at the max suction pressure, for the maximum impeller diameter and the maximum
continuous speed.
Note: MAWP shall not be less than 16 kg/cm² for condenser water pumps and not be less than 25
Kg/cm2 for chilled water pumps of primary and secondary applications.
Volute shall have gauge tapping at the suction and discharge nozzles and vent and drain tapping at
the top and bottom.
VIBRATION:
The pump(s) vibration limits shall conform to Hydraulic Institute ANSI/HI 1.1-1.5-1994; section
1.4.6.1.1 or ISO 10816 for recommend acceptable unfiltered field vibration limits (as measured per
HI 1.4.6.5.2) for pumps with rolling contact bearings.
SOUND LEVEL:
The maximum permissible sound pressure level of the pump shall not exceed 85 dbA measured at
1m from pump surface for the recommended range of operation.
COUPLING:
A flexible type, with optional center drop-out (Spacer) design coupler, capable of absorbing torsional
vibration, shall be employed between the pump and motor. Pumps for variable speed application
shall be provided with a suitable coupler sleeve.
The coupling shall be shielded by a dual rated ANSI B15.1, Section 8 & OSHA 1910.219
Compliance coupling guard.
Base Plates:
Base plate shall be of structural steel or fabricated steel channel with fully enclosed sides and ends,
and securely welded cross members. Grouting area shall be fully open. The combined pump and
motor base plate shall be sufficiently stiff as to limit the susceptibility of vibration. The minimum
base plate stiffness shall conform to ANSI/HI 1.3.4-1997 for Horizontal Base plate Design standards.
PAGE No 29 of 204 Nov.2011