System Solutions From McQuay
Quiet Condenser Fan Option
How can I reduce the noise that radiates from air-cooled,
packaged rooftop units for sound-sensitive applications?
For many applications, low radiated sound is a critical factor
in the selection and installation of air-cooled, packaged
rooftop units. In response to the need for quieter units,
McQuay offers a Quiet Condenser Fan option for
RoofPak™ applied rooftop systems. When this option is
employed, sound power at the unit is reduced by an average
of 11dB when compared to standard condenser fans. To the
human ear, that translates into a perceived reduction in
sound of over 50%.
This reduction in sound power can also impact where the
unit can be located relative to the lot line. For example, if
local code requires a maximum of 50 dB sound pressure at
the lot line, the standard condenser fan must be located 298
feet from the lot line to comply. With McQuay Quiet
Condenser Fans this distance is reduced to 94 feet.
Features
McQuay Quiet Condensor Fans are specially engineered to
provide high levels of sound attenuation without reducing
overall system performance or increasing energy
requirements. Special features of these fans include:
• An airfoil blade design that increases fan efficiency.
• Heavy-duty fan shrouds that smooth airflow and reduce
inlet and outlet air turbulence.
• A reduced fan speed that lowers turbulence at the fan
tip (850 RPM for Quiet Fans vs. 1140 RPM standard).
• Heavy-gauge steel fan and motor assemblies that
minimize vibration and breakout noise.
Engineered for flexibility and performance. TM
Bibliotheque CH Blais, Quebec City, Canada, Photo Courtesy Of Guillemette Inc
Benefits
The benefits of specifying Quiet Condensor Fans include:
• Stringent outdoor noise requirements for high-density
locations can often be met without employng other
attenuation methods.
• Units can be placed closer to lot lines and still meet
outdoor noise requirements.
Contact your local McQuay sales representative for more
information on how your building environment can
benefit from innovative McQuay air handling systems, or
visit www.mcquay.com.
Heavy-guage fan shrouds are
employed with this option to
smooth air flow and reduce
turbulence and vibration.
Quiet Condenser Fan Option
Condensing Unit Performance
The use of quiet condenser fans does not affect the unit capacity. They deliver the same airflow volumes as our standard
fans and—due to greater efficiency—run at slightly lower motor brake horsepowers and amp draws.
Standard Condenser Fans
Motor HP RPM Voltage FLA
1.0
1140 208-230
4
460
2
575
1.7
Quiet Condenser Fans
Motor HP RPM Voltage FLA
1.0
850 208-230 3.6
460
1.8
575
1.7
Sound Performance
The table below shows the sound power levels, in decibels, of the standard McQuay Packaged Rooftop units and the same
units when fitted with the new Quiet Condenser Fan option.
Fan Type
Quiet
Standard
Quiet
Standard
Quiet
Standard
Quiet
Standard
Quiet
Standard
Quiet
Standard
Quiet
Standard
Quiet
Standard
Quiet
Standard
Quiet
Standard
Quiet
Standard
Quiet
Standard
Unit Size 125 Hz
015C
72.3
015C
90.6
018C
72.4
018C
90.6
020C
72.4
020C
90.6
025C
74.1
025C
92.4
030C
74.1
030C
92.4
036C
75.4
036C
93.6
040C
75.5
040C
93.6
045C
75.5
045C
93.6
050C
75.3
050C
93.6
060C
77.1
060C
95.4
070C
77.3
070C
95.4
075C
78.3
075C
96.6
250 Hz
73.8
88.5
73.8
88.5
73.8
88.5
75.5
90.3
75.5
90.3
76.8
91.5
76.8
91.5
76.8
91.5
76.8
91.5
78.5
93.3
78.6
93.3
79.8
94.5
500 Hz
78.7
87.8
78.4
87.7
78.4
87.7
80.4
89.5
81.5
89.7
81.4
90.7
82.0
90.8
82.0
90.8
83.0
90.9
85.8
92.9
83.8
92.6
85.5
93.9
Octave Band
1000 Hz
2000 Hz
79.2
71.2
85.3
81.9
79.0
71.5
85.3
82.0
79.0
71.5
85.3
82.0
81.1
75.3
87.1
84.0
81.2
75.4
87.2
84.0
82.0
74.5
88.3
85.0
82.0
76.4
88.3
85.2
82.0
76.4
88.3
85.2
82.8
80.5
88.5
86.0
84.4
80.7
90.2
87.4
83.8
78.1
90.0
86.9
85.5
82.3
91.4
88.7
© 2004 McQuay International • (800) 432-1342 • www.mcquay.com
4000 Hz
67.9
81.2
68.0
81.3
68.0
81.3
73.2
83.3
71.4
83.1
71.0
84.3
72.1
84.3
72.1
84.3
78.1
85.0
75.9
86.2
73.8
86.1
79.9
87.8
8000 Hz
61.6
79.6
69.9
80.0
69.9
80.0
72.7
81.9
72.6
81.9
72.9
83.0
66.5
82.7
66.5
82.7
67.0
82.7
66.8
84.4
68.2
84.4
69.2
85.7
Total
83.4
95.0
83.4
95.0
83.4
95.0
85.7
96.8
86.0
96.8
86.4
98.0
86.7
98.0
86.7
98.0
88.2
98.2
89.7
99.9
88.5
99.8
90.6
101.1
A/SP 31-193