BU LLETI N QD / SI L.000
„
CERTI FI ED PERFO RMAN CE DATA
„
SDS 3.6
QUIET-DUCT SILENCERS
TYPE: ML
with FORWAR D and R EVE R S E FLOW Ratings
IAC has produced Quiet-Duct HVAC silencers for more than 50
years, and has developed many of the terms and test standards
for rating silencer performance that are used today. These standards are dynamic documents that continue to change based on
new developments and discoveries in the field of acoustic engineering. Today we continue our involvement in several of the
industry’s governing agencies, and we remain committed to
ensuring that we are always providing product that is in accordance with all of the latest standards. All published acoustic and
aerodynamic performance results are based on tests conducted
in strict accordance with ASTM E477-99 in IAC America's
NVLAP-Accredited laboratory.
H
DESIGNATING A SILENCER
L
W
Model: 5 ML 36 x 18
Length: 5'
Type: ML
Width: 36"
Height: 18"
Table I. Dynamic Insertion Loss (DIL) Ratings: Forward (+) / Reverse (-) Flow
IAC
MODEL
Octave Band
Hz
Face Velocity,
fpm
1
63
2
125
3
250
4
500
5
1K
6
2K
7
4K
8
8K
3ML
-5000
-2000
0
2000
5000
4
3
3
3
2
5
5
5
4
4
12
10
10
9
8
20
19
19
18
16
18
18
18
17
17
11
12
12
12
13
7
8
9
9
10
5
6
7
8
9
5ML
-5000
-2000
0
2000
5000
6
5
5
4
3
9
8
8
7
6
18
16
15
14
14
32
31
31
30
28
32
31
31
30
29
17
17
19
20
22
9
10
12
13
13
6
7
9
10
11
7ML
-5000
-2000
0
2000
5000
6
6
6
5
5
12
11
11
10
9
22
21
20
19
17
42
41
39
37
36
43
40
40
39
38
24
23
25
26
28
14
15
16
16
16
10
10
11
12
12
10ML
-5000
-2000
0
2000
5000
9
8
8
7
7
18
17
16
15
15
28
27
26
25
23
46
47
46
45
44
47
50
50
49
50
34
33
35
36
36
19
20
20
20
21
11
12
12
12
14
(+) Forward Flow / (-) Reverse Flow. Aero-acoustic performance data based on NVLAP accredited laboratory tests
conducted in strict accordance with ASTM E477-99. Contact IAC if attenuation in excess of 50 dB is required.
IAC: MAKING THE WORLD A QUIETER PLACE
69
Table II: Weights and Measures
Nominal
Length
W/ In
H/ In
9
18
9
24
9
30
9
36
9
42
9
48
18
18
18
24
18
30
18
36
18
42
18
48
36
18
36
24
36
30
3 feet
5 feet
7 feet
10 feet
Wt/ lb.
35
60
84
118
41
71
100
141
52
82
116
167
57
95
133
190
65
107
150
240
73
119
167
215
52
87
122
174
61
103
144
205
71
121
168
239
84
142
200
284
94
158
223
-
104
175
247
-
69
119.5
168.5
237.5
103
175
246
349
120
201
283
403
Nominal
Length
W/ In
H/ In
36
36
36
42
36
48
54
18
54
24
54
30
54
36
54
42
54
48
72
18
72
24
72
30
72
36
72
42
72
48
3 feet
5 feet
7 feet
10 feet
Wt/ lb.
138
239
337
475
153
265
374
-
168
291
411
-
121
206.5
290.5
411.5
164
278
390
554
191
322
451
642
222
381
537
759
247
423
597
-
272
466
658
-
138
239
337
475
206
350
492
698
240
402
566
806
276
478
674
950
306
530
748
-
336
582
822
-
0.24
0.28
0.36
0.44
0.28
0.34
0.42
0.52
0.33
0.40
0.50
0.61
0.38
0.46
0.58
0.71
0.44
0.53
0.66
0.82
0.50
0.60
0.75
0.93
0.57
0.68
0.85
1.05
0.64
0.76
0.95
1.18
0.71
0.85
1.06
1.31
0.78
0.94
1.18
1.45
Table III: Aerodynamic Performance
Model L/ Ft
3
5
ML
7
10
Static Pressure Drop, i.w.g.
0.05 0.07 0.10 0.13 0.16
0.06 0.08 0.12 0.15 0.19
0.07 0.11 0.14 0.19 0.24
0.09 0.13 0.18 0.23 0.29
0.20
0.24
0.29
0.36
Silencer Face 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 3200 3400 3600 3800 4000
Velocity, fpm
Table IV: Self-Noise Power Levels, dB re: 10-12 Watts
IAC
Model
Octave Band
Hz
Silencer Face
Velocity, fpm
1
63
2
125
3
250
4
500
5
1K
6
2K
7
4K
8
8K
-3,000
-2,000
-1,000
1,000
2,000
3,000
64
56
42
39
58
71
59
53
42
35
52
61
59
52
41
30
46
55
63
53
38
27
43
53
60
56
49
26
42
51
62
58
50
28
45
55
63
52
37
28
45
56
59
44
20
20
39
52
ML
All
Sizes
(+) Forward Flow / (-) Reverse Flow. Aero-acoustic performance data based on NVLAP accredited laboratory tests conducted in strict
accordance with ASTM E477-99.
TAKE NOTE!
THE IAC SNAP FORM
• Silencer Face Area is the cross-sectional area at the
silencer entrance.
The IAC Snap Form helps evaluate the entire HVAC
system and is now available on CD. The analysis starts
with the acoustic criterion for the occupied space and
then accounts for the system effects of each component
such as terminals, mixing boxes, branch take-offs, elbows,
ductwork, fan sources, plus room characteristics. Request
a copy of the CD at [email protected]
• Face Velocity is the CFM of airflow divided by the Face
Area (in sq. ft.)
• Pressure Drop for any velocity can be calculated from
this equation:
PD = (Actual FV/Catalog FV)2 x (Catalog PD)
• Self Noise values shown are for a three-square-foot face
area silencer.
• For each doubling of the face area add 3 dB to the
self-noise values listed.
• For each halving of the face area subtract 3 dB from the
self-noise values listed.
• Weights and measures are listed for limited number of
available sizes.
70
IAC America 1160 Commerce Avenue Bronx, New York 10462-5599
Tel: (718) 931-8000 Fax: (718) 863-1138
E-mail: [email protected] Web: www.IACsilencers.com
Specially designed silencers
and full-scale or model testing
is available on request.