shall be located adjacent to float controls.
2.5.7
Louvers
Air inlets for each cooling tower shall be provided with individually
removable louvers arranged to prevent the escape of water. Louvers shall
be zinc-coated steel, [Type 304 stainless steel,] [FRP,] or lumber.
Materials provided for casings and louvers shall be compatible; one
material shall not produce stains upon the other. Louvers constructed of
lumber shall be of a thickness to withstand alternate wetting and drying
without cracking or splitting. Air intakes shall be provided with 25 mm 1
inch zinc-coated steel mesh.
2.5.8
Fan Deck and Cylinder
Each fan shall be mounted in a fan cylinder (or stack) to elevate the fan
discharge air. Total extension height shall not exceed the fan diameter.
Each fan cylinder shall be provided with a zinc-coated steel 2.75 mm (12
gauge) 12 gauge wire mesh securely mounted to the top of the cylinder in
accordance with manufacturer's recommendations. Fan decks shall be
designed to withstand a live load of not less than [1.9] [2.9] kPa [40]
[60] psf in addition to the concentrated or distributed loads of equipment
mounted on the fan decks. [Fan deck and cylinders shall be constructed of
zinc-coated steel, lumber, Type 304 stainless steel, or FRP and be
compatible with the entire tower construction.] [Fan deck shall be
constructed of precast, reinforced lightweight concrete, in multiple
sections, forming a complete, vibration-free base for mounting fan, speed
reducer, drive shaft, motor, and fan stacks. Fan cylinders (or stacks)
shall be constructed of precast, reinforced lightweight concrete in
multiple sections, constrained with bands of zinc-coated steel conforming
to ASTM A 123/A 123M, not less than 3 x 75 mm 1/8 x 3 inches, and bolted to
form a compressive load on stack perimeter. Fan cylinder shall be secured
in place on the fan deck with Class A mortar.]
2.5.9
Fans
**************************************************************************
NOTE: When the density of the ambient air to be
handled by the fans differs substantially from the
density of the standard air value of 1.2 kg per
cubic m (0.075 pound per cubic foot) at 21 degrees C
(70 degrees F) and 101 kPa (29.92 inches mercury),
the density of the air and/or the elevation above
mean sea level will be shown on the drawings.
**************************************************************************
Fans shall be the [centrifugal] [or] [adjustable-pitch propeller] type,
constructed of zinc-coated steel, Type 304 stainless steel, aluminum or an
aluminum alloy, or FRP. Propeller type shall have a maximum tip speed of
330 m/minute 10,800 fpm. Fan blade assembly shall be both statically and
dynamically balanced after assembly of the cooling tower. Fan hub shall be
constructed of [zinc-coated steel] [stainless steel] [cast aluminum] with
adequate surface protection against corrosion. Complete fan assembly (fan
and mounting) shall be designed to give maximum fan efficiency and long
life when handling saturated air at high velocities. Each cooling tower
fan shall be provided with a ball and pedestal type vibration limit switch
which shall stop the corresponding fan motor in the event of sensing
excessive fan vibration.
SECTION 15645A
Page 13
Previous Page
