SPX Cooling Technologies SS-NC-08A - Manual (Page 19)

Specifications Specification Value
Marley / NC Class Stainless Cooling Tower / Specifications: Options
19
Inlet Flow Control Valves:
8.2: Add the following to the end of the
paragraph: Heavy-duty flow-regulator
valves shall be provided at the hot
water inlet connections. These valves
shall be disc-type, with cast iron
bodies and stainless steel operating
stems. There shall be a locking handle
to maintain the valve setting in any
position. Valves shall be right-angle
configuration, precluding the need for
inlet elbows.
Equalizer Flume Weir Gates:
11.2: Add the following paragraph under
Cold Water Collection Basin: The
interconnecting flume between cells
shall be equipped with a removable
cover plate to permit the shutdown of
one cell for maintenance purposes, or
to permit independent cell operation.
Sound Control
1.2 Add the following paragraph under
Base: The cooling tower shall be quiet
operation, and shall produce an overall
level of sound not higher than _______
dB(A) measured at _______ m from the
locations in the table below. All low
noise options and combinations shall
be CTI Certified for thermal perfor-
mance.
Inlet Sound Attenuation
1.3 Add the following paragraph under
Base: The cooling tower shall be
equipped with inlet sound attenuation
baffles positioned and spaced verti-
cally. The baffles will be spaced across
the entire length and extend the full
height of the air inlet. The baffles will
be constructed of perforated sheet
metal and contained within a steel
■ Marley flow-control valves have been a
favorite of users since the 1950s. They
remain serviceable for the life of the tower
and provide a continuing means of flow-
regulation between hot water basins—and
between cells of multicell towers as well.
■ Where it is your intention to be able to operate both cells of the tower
while the flume cover plate is installed, separate outlet connections,
float valves and overflows must be provided for each cell. Likewise, this
would require separate sensors and controls for basin heater systems,
if installed.
■ Sound produced by a
standard NC Cooling
Tower operating in an
unobstructed environ-
ment will meet all but
the most restrictive
noise limitations—and
will react favorably to
natural attenuation.
Where the cooling
tower has been sized
to operate within an
enclosure, the enclosure itself will have a damping effect on sound.
Sound also declines with distance—by about 5 or 6 dB(A) each time the
distance doubles. Where noise at a critical point is likely to exceed an
acceptable limit, you have several options—listed below in ascending
order of cost impact:
• Where only a slight reduction in noise will satisfy—and the source of
concern is in a particular direction—merely turning the cooling tower
may be the answer. Less sound emanates from the cased face of the
cooling tower than does from the air intake face.
• In many cases, noise concerns are limited to nighttime, when ambi-
ent noise levels are lower and neighbors are trying to sleep. You can
usually resolve these situations by using two-speed motors—operating
the fans at reduced speed without cycling “after hours”. The natural
nighttime reduction in wet-bulb temperature makes this a very feasible
solution in most areas of the world, but the need to avoid cycling may
cause the cold water temperature to vary significantly.
• A Marley Variable Speed Drive automatically minimize the tower’s
noise level during periods of reduced load and/or reduced ambient
Location 63 125 250 500 1000
Discharge
Air Inlet
Cased Face
Location 2000 4000 8000 Overall dB(A)
Discharge
Air Inlet
Cased Face
➠