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Things to know,
when sound is critical
Things to know,
when sound is critical
Sound Data
The sound data shown in this catalog has been
presented to aid the system designer in selecting a
fan which will meet the desired sound criteria. Sone
levels have been included on the performance pages
to provide a means of quickly evaluating the relative
loudness of a fan selection.
What is a sone?
Sones are an internationally recognized unit of loudness. In
practical terms, the loudness of one sone is equivalent to the
sound of a quiet refrigerator measured from five feet away
in an acoustically average room. A sone is a single number
rating, which indicates the inlet noise derived from the eight
audible octave bands. Sones are a linear measurement of
sound level. For example, a sound level of 10 sones is twice
as loud as 5 sones.
What is the difference in a AMCA Sone vs. HVI Sones?
In general, the AMCA (Air Movement and Control Association)
sone value is focused on commercial markets, whereas the
HVI (Home Ventilating Institute) sone value is focused on residential markets. Both calculate their sone data from
the same raw test data (eight octave bands), however an AMCA sone applies a hemispherical correction factor
to the sound power and rounds to the nearest 0.1, whereas HVI applies a spherical correction factor to the sound
power and rounds to the nearest 0.1 under 1.5 sones and to the nearest 0.5, 1.5 sones and greater. There are no
conversions from one sone to the other, each must be calculated. In every instance the same fan will have a lower
HVI calculated sone rating than an AMCA calculated sone rating.
Can radiated noise increase the sound levels?
Radiated noise from fan housings can cause unacceptable sound levels, on any brand of fan. The size of these
fans allows them to be placed in areas where this noise will be transmitted to the conditioned space through walls
or ceilings. Where possible, cabinet fans should be located in remote parts of the ventilation system.
When should a SP or CSP fan be used?
Model SP and CSP fans are designed for the lowest possible sound levels. Forward curved wheels, insulated
housings, and vibration isolators between the motor and housing contribute to quiet, efficient operation.
Applied and installed as recommended, SP and CSP sound levels will fall well within the ranges shown in
the chart above. For applications where sound levels are critical, a remote mounted CSP with ductboard is
recommended. Placement of SP/CSP fans should take into account the desired sound level at the location of
the listener. Their compact size allows the system
designer greater flexibility in locating these fans for
lowest sound levels. In critical sound areas, insulated
ductwork, flexible duct connections, or placing the
fan in a remote section of the ductwork (away from
the critical area) offers the best means of meeting
desired sound levels.
When room sound levels are critical, such as in
executive offices, conference rooms, hospital
operating rooms, and school study areas, a CSP
fan is the best choice. Shown here is a comparison
of SP and CSP fans of the same size, with equal
performance in typical installations. The CSP shows
lower sone values.
SUGGESTED LIMITS FOR ROOM LOUDNESS
Sones DBA
1.3-4 32-48 Private homes (rural and suburban)
1.7-5 36-51 Conference rooms
2-6 38-54 Hotel rooms, libraries, movie
theatres, executive offices
2.5-8 41-58 Schools and classrooms, hospital
wards and operating rooms
3-9 44-60 Court rooms, museums, apartment
houses, private homes (urban)
4-2 48-64 Restaurants, lobbies, general open
offices, banks
5-15 51-67 Corridors and halls, cocktail
lounges, washrooms and toilets
7-21 56-72 Hotel kitchens and laundries,
supermarkets
Reprinted from AMCA Publication 302 (Application of Sone
Ratings for Non Ducted Air Moving Devices, with room—sone—
dBA correlations) with the written permission from the AMCA
International, Inc., 30 West University Drive, Arlington Heights, IL
60004-1893.
NOTE: Values above are for room loudness and are not sound
ratings. Room loudness is the resulting level in a conditioned space
after the acoustical qualities of the room have been accounted for.
Remote mounted
Model CSP with
vibration isolators and
insulated ductwork
provides quietest
installation.
Model SP mounted directly
overhead may be too loud for
sound critical applications.
Fiberglass
Model CFM WG FRPM Sones
SP-A410 405 1/8 1000 3.7
CSP-A410 426 1/8 1000 2.1*
*Sone value with insulated inlet duct.