General Features:
• 360,000 CFM Air-Handling System
• four 90,000 CFM supply fans serving four individual riser networks filters, heaters, cooling coils and supply fans housed in a 40'x36'x12' plenum constructed from 4' acoustical panels
• ultra-quiet supply fan system featuring
- high insertion loss, aerodynamic inlet silencer
- high insertion loss regain outlet silencer
- acoustically lined flow duct system connecting fans to risers
• four ultra-quiet 90,000 CFM return fans featuring
- high insertion loss, aerodynamic inlet silencer
- high insertion loss regain outlet silencer
Supply Fan:
Joy 54-26 Series 1000, 1780 RPM
90,000 CFM 5.75 in. WG. total pressure
80.9% efficiency
100 HP
Return Fan:
Joy 66-26 Series 1000, 890 RPM
85,000 CFM 1.75 in. WG. total pressure
75.6% efficiency 40 HP
Test Report:
Chicago Police Headquarters
On Mar 5, 1999 a series of sound power measurements was performed to determine the insertion loss of the Coolbreeze inlet and discharge silencer system to be installed in the new Chicago Police headquarters building. The airhandler consists of an inlet silencer, an axial flow fan and a discharge silencer.
Sound power was measured using the procedure outlined in ISO 10494. A total of 32 measurement stations were surveyed: 16 for the inlet, 16 for the discharge. The general arrangement is shown in figure 1. Sound pressure levels were measured with a calibrated B&K 2230sound level meter with a 1625 1/3 octave filter set. Sound power levels were computed therefrom in accordance with ISO 10494. The insertion losses are computed by subtracting the measured sound power from the sound power levels generated by the New Philadelphia supply air fan. The fan sound data was provided by the fan manufacturer. The results are summarized in below.
|
63 |
125 |
250 |
500 |
1000 |
2000 |
4000 |
8000 |
Hz |
| Lw Fan |
103
|
106
|
113
|
121
|
121
|
116
|
112
|
105
|
dB
|
| Inlet |
|
|
|
|
|
|
|
|
|
| Lw Rad |
87.3
|
80.7
|
77.8
|
83.5
|
79.2
|
79.8
|
76.7
|
73.4
|
dB
|
| IL |
15.7
|
25.3
|
35.2
|
37.5
|
41.8
|
36.2
|
35.3
|
31.6
|
dB
|
| Prediction |
12
|
18
|
24
|
32
|
42
|
42
|
32
|
23
|
|
| Discharge |
|
|
|
|
|
|
|
|
|
| Lw Rad |
85.6
|
77.8
|
73.3
|
74.3
|
76.3
|
73.4
|
73.1
|
71.2
|
dB
|
| IL |
17.4
|
28.2
|
39.7
|
46.7
|
44.7
|
42.6
|
38.9
|
33.8
|
dB
|
| Prediction |
18
|
27
|
35
|
45
|
46
|
38
|
29
|
24
|
|
