Things to know, |
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when sound is critical |
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Sound Data |
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SUGGESTED LIMITS FOR ROOM LOUDNESS | |||
The sound data shown in this catalog has been | |||
Sones | DBA | ||
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 | |||
| theatres, executive offices | ||
to provide a means of quickly evaluating the relative | |||
loudness of a fan selection. |
| wards and operating rooms | |
What is a sone? |
| houses, private homes (urban) | |
Sones are an internationally recognized unit of loudness. In |
| offices, banks | |
practical terms, the loudness of one sone is equivalent to the | |||
| lounges, washrooms and toilets | ||
sound of a quiet refrigerator measured from five feet away | |||
in an acoustically average room. A sone is a single number |
| supermarkets | |
Reprinted from AMCA Publication 302 (Application of Sone | |||
rating, which indicates the inlet noise derived from the eight | |||
Ratings for Non Ducted Air Moving Devices, with | |||
audible octave bands. Sones are a linear measurement of | |||
dBA correlations) with the written permission from the AMCA | |||
sound level. For example, a sound level of 10 sones is twice | International, Inc., 30 West University Drive, Arlington Heights, IL | ||
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as loud as 5 sones. |
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NOTE: Values above are for room loudness and are not sound | |||
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What is the difference in a AMCA Sone vs. HVI Sones? | ratings. Room loudness is the resulting level in a conditioned space | ||
after the acoustical qualities of the room have been accounted for. |
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 |
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designer greater flexibility in locating these fans for |
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lowest sound levels. In critical sound areas, insulated | Fiberglass | |
ductwork, flexible duct connections, or placing the | ||
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fan in a remote section of the ductwork (away from | Remote mounted | |
the critical area) offers the best means of meeting | ||
Model CSP with | ||
desired sound levels. | vibration isolators and | |
insulated ductwork | ||
When room sound levels are critical, such as in | ||
provides quietest | ||
executive offices, conference rooms, hospital | installation. | |
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operating rooms, and school study areas, a CSP |
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fan is the best choice. Shown here is a comparison |
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of SP and CSP fans of the same size, with equal |
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performance in typical installations. The CSP shows |
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lower sone values. |
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Model | CFM | WG | FRPM | Sones |
405 | 1/8 | 1000 | 3.7 | |
426 | 1/8 | 1000 | 2.1* |
*Sone value with insulated inlet duct.
Model SP mounted directly overhead may be too loud for sound critical applications.
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