Daikin VAM-FA8VE Technical Data Manual page 261

• HRV • VKM-GA(M)V1
11.2.4 Operating Sound
As well as the required airflow and static pressure, the operating sound (noise level) is an important factor
for determining the type of ventilating fans. The noise level allowable limit may have been defined
depending on the use of the room to be ventilated. Select an appropriate type of ventilating fans according
to the noise requirements.
Operating sound unit : dB
A-weighted sound pressure level measured using a sound level meter is the measure of sound produced
by an operating ventilator fan. There has been many units used : phon(A), phon, dB(A) and dB. This
catalogue uses the internationally unified unit "dB." Note that the sound pressure level in "phon" can be
directly converted into "dB" without changing the numerical value. Use sound level meters in the A-
weighted mode.
Allowable noise level
Building codes specify the allowable noise level for each type of room. See Table 1 for selecting.
Table 1 Allowable noise level depending on the type of room
Use of room
Broadcasting studio
Music hall
Theater (about 500 seats)
School room
Meeting room
Apartment
Hotel
Residential housing (living room, etc.)
Notes for noise level
The noise ratings shown on the nameplate of a product are those measured in an anechoic room per the
relevant JIS standard that specifies measuring procedures including the distance between the noise source
under test and the sound level meter. To select types of ventilating fans, observe the following three notes.
1. The environment affects the noise level.
The nameplate values are those measured in an anechoic room. Actual buildings have echoes from the
walls, floors and ceilings, so that the noise level depends on the building materials used and how wide
the room is. Use appropriate echo coefficients to determine the actual noise level and available fan
types.
2. Vibration
Motor driven fans, a type of rotating machine, inevitably produce vibration, though our largest efforts to
reduce such vibration have been made. To minimize vibration (propagation and resonance), the
product should be firmly mounted on the wall.
3. Synthesis of sounds
When using two or more ventilating fans in a room, consider the synthesized effect of sounds.
Other noise
•
Echoes
Depending on the type or material of the wall and ceilings of the room, and in small room, echoes occur.
•
Vibration
Vibrating objects produce vibrating sound by moving their surrounding air. 20Hz or higher frequency
sounds are audible.
•
Noise due to duct's resistance
Higher static pressures acting on the fan will produce larger sounds.
• HRV • Heat Reclaim Ventilation
dB Use of room
25 Cinema
30 Hospital
35 Library
40 Small office room
40 Restaurant
40 Gymnasium
40 Large office room
40 Factory
2
11
dB
40
35
40
45
50
55
50
70
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