Roof fans - Troges

RF Fans
Technical information
Using general equation (2), which is valid for total sound
pressure in a closed room, the octave sound pressure
level L pokt
can be calculated from the values of sound
power L wokt
radiated into the room.
L P
= L W
+ 10 log [ Q / (4π r 2 ) + 4.(1 - α m
) / ( S.α m
)] (4)
L P
L W
sound pressure level [dB]
sound power level [dB]
Q Directional coefficient for the given direction (1–8) [-]
r Distance (source – person) [m]
α m
mean coefficient of sound absorption capacity [-]
S room enclosing area [m 2 ]
Then, the total sound pressure level in the room can
calculated using the following relationship
Dimensions, Weights and Performance
For the most important data and dimensions of RF fans,
refer to figure #3 and table #5.
Table 5 – Basic dimensional Range
Designation
Base dimensions
A [mm]
Max. width
B [mm]
Figure 2 – Basic dimensions of the fan
Height
C [mm]
RF 40/ .. 408 560 400
RF 56/ .. 568 780 590
RF 71/ .. 718 960 690
RF 100/ .. 1008 1360 900
L PA
= 10.log ∑10 0,1(Lpokt + KAokt) (5)
For the values of correction factor K Aokt
for particular
octave bands, refer to table #4.
If the calculated sound level in the checked place is not
satisfactory, it is necessary to take additional anti-noise
measures, e.g. complete the air-handling assembly with
an additional attenuator.
Table 4 – A-weighting filter correction values
Octave band
mean frequency
A-weighting filter
correction
A-weighting filter correction
A-weighting filter correction curve
Octave band mean frequency (Hz)
For operating fan parameters and the allocation of output
controllers, refer to table # 6.
Legend:
V max.
.... Maximum air flow rate
n .... Fan speed measured at the highest efficiency working
point (5b), rounded to tens
U .... Nominal power supply voltage of the motor without control
(all values in the table are related to this voltage)
P max.
.... Maximum power input of the motor
I max.
.... Maximum phase current at voltage U
(this value must be checked)
t max.
.... Maximum permissible transported air temperature
at air flow V max.
C .... Capacitor capacity of single-phase fans
regul. .... Recommended fan output controller
FM .... Recommended frequency inverter
m .... Weight of the fan (±10%)
5