eliminators shall conform to requirements specified for fill.
2.5.9
Cold Water Basin and Accessories
Basin shall be constructed of steel [, and shall be sized for dry-basin
operation] [, and shall be sized to have sufficient water capacity and
free-board to prevent [pump cavitation,] air-entrainment and to accommodate
run-back without overflow]. Basin assembly shall be water-tight.
[Multiple basins shall operate as one basin with common water level and
shall be complete with interconnecting piping.] Basin outlet screen shall
be constructed of galvanized, 13 mm 1/2 inch square mesh hardware cloth,
reinforcement, and framing. Basin shall be fitted with overflow and valved
drain. [Manufacturer's standard modulating float-controlled makeup valve
shall be provided.] [A nonmodulating, pilot actuated, float-controlled,
diaphragm type makeup valve shall be provided where a water meter is
indicated or specified in the makeup supply line.] Makeup shall discharge
50 mm 2 inches or two pipe diameters, whichever is greater, above maximum
attainable basin water level during overflow condition, or as required to
preclude backflow. A drainable 20 mm 3/4 inch hose bib connection shall be
provided with a vandalproof vacuum breaker for makeup line mounting.
[Basin shall be fitted with indicated heaters.]
2.5.10
Access and Safety Provisions
Unit shall be fitted with access provisions as indicated to facilitate
inspection, maintenance and replacement of components. Guard screens shall
be provided at unducted fan inlets and far discharge. Guards shall be
provided for moving power transmission components.
2.5.11
Fans and Drives
[Induced draft counter-flow and cross-flow cooling tower fans shall be
propeller type and drive shall be [gear type with motor out of wet
airstream] [or] [belt type with motor [in] [out of] wet airstream].]
[Induced draft evaporative [water cooler] [condenser] fans shall be
propeller type and drive shall be [gear] [belt] type with motor out of wet
airstream.] [Forced draft fans shall be propeller or centrifugal type,
with multiple V-belt drive and motor out of wet airstream.]
2.5.11.1
Propeller Fans
Shall be airfoil section type with fixed or adjustable pitch blades
fabricated from solid aluminum alloy, except fans sized 1220 mm 48 inches
and under may be manufacturer's standard. Fixed pitch fans combined with
gear drives are not acceptable. Adjustable pitch fans, with pitch set at
or near maximum pitch, combined with gear drives, are not acceptable. Fans
shall be statically or dynamically balanced to limit imbalance forces on
drive shaft.
2.5.11.2
Centrifugal Fans
Shall be forward curve, double-inlet, drainable scroll type with
streamlined inlets, constructed of galvanized or stainless sheet steel or
aluminum. Fan shaft shall be corrosion protected. Bearings shall be
double-shielded, grease lubricated, self-alining, ball or roller, cast iron
(split-bolted), pillow block housed, antifriction type. Sleeve bearings
may be used in conjunction with one or more antifriction bearings at
locations other than drive-end. Sleeve bearings shall be oil-lubricated,
grooved, cast iron housed, antifriction metal liner type, with an effective
SECTION 15602N
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