Centrimaster LF2500, LF2503, LF2505, LF2507, LF2510 User Manual
Model LF2500
Low Frequency
Sound Silencer
The SEMCO Model LF2500 low frequency sound
silencers are specifi cally designed to solve noise problems
in the lower frequency range and will provide excellent
low band attenuation in low to medium velocity ranges
with a moderate pressure drop.
INDEPENDENTLY CERTIFIED TEST DATA
Published data is derived from Independent Certifi ed Testing conducted in accordance with ASTM E477. For testing purposes,
specifi ed lengths of straight duct are used both upstream and downstream of the silencer. Static pressure losses must therefore
be adjusted when the unit is installed, at or near transitions, elbows, or at the intake or discharge of the system. Consult SEMCO
for adjustment values. All data published herein was obtained from a 24” x 24” production run unit.
Model Length
LF2503
LF2505
LF2507
LF2510
36”
60”
84”
120”
Forward Airfl ow Performance applies when both noise and airfl ow are traveling in the same direction.
Reverse Airfl ow Performance applies when noise and airfl ow are traveling in opposite directions.
Face
Velocity
0
500
1000
1500
2000
0
500
1000
1500
2000
0
500
1000
1500
2000
0
500
1000
1500
2000
Dynamic Insertion Loss (dB)
Forward Airfl ow Performance
Octave Band/Frequency (hz)
Press.
Cv
Drop16321253250450051K62K74K88K16321253250450051K62K74K88K
0
4
12
23
24
22
21
9.11
9.95
13.50
16.90
.14
.57
1.28
2.27
0
.16
.62
1.40
2.48
0
.21
.84
1.89
3.37
0
.26
1.06
2.37
4.21
12
10
15
15
13
13
4
12
22
24
2
13
12
11
17
16
15
15
15
22
22
23
22
21
32
31
32
30
28
22
21
20
32
31
29
28
26
40
40
40
38
37
48
49
49
47
40
5
2
9
9
6
8
7
9
9
7
5
23
23
23
30
31
32
31
31
42
42
43
43
43
49
50
50
51
47
22
23
23
23
30
30
31
32
32
33
33
34
33
34
40
40
41
42
39
21
21
23
23
31
31
32
33
34
31
32
32
32
33
37
37
38
40
35
17
17
18
18
18
26
27
28
29
28
28
29
30
29
30
35
35
36
36
31
Reverse Airfl ow Performance
Octave Band/Frequency (hz)
17
4
12
23
18
17
18
17
24
25
26
27
26
24
25
28
26
26
29
29
32
31
31
10
11
14
13
15
14
17
17
18
20
19
5
14
6
14
4
15
5
17
9
17
8
17
9
19
9
19
20
22
26
27
28
29
30
33
33
34
35
25
25
25
26
32
34
34
35
36
39
41
41
44
45
48
48
49
50
46
24
24
25
25
25
28
29
30
31
32
36
37
38
39
40
48
48
49
51
49
20
21
22
23
24
27
26
27
28
29
28
29
30
32
34
42
42
43
44
41
18
18
19
19
19
29
29
29
30
30
28
29
30
31
31
39
40
40
40
35
14
15
16
15
14
24
23
22
23
24
28
27
26
25
23
38
38
36
32
31
14
15
17
15
13
21
21
21
21
21
23
20
19
20
16
30
28
26
23
21
Pressure Drops for velocities not shown above can be calculated using the following formula:
P.D. = Cv x Hv
where: P.D. = Pressure Drop
Cv = Silencer Flow Coeffi cient
Hv = (V/4005)
Hv = Velocity Pressure in Inches w.g.
V = Face velocity in Ft./Min.
2
LF2500
Low Frequency Sound Silencer
Model LF2500
STANDARD CONSTRUCTION:
Shell and Nose: 22 Gauge Galvanized Steel
Perforated Metal: 24 Gauge Galvanized Steel
Fill Material:
Fiberglass
FIRE RATINGS:
Fire Hazard Classifi cation Ratings in
accordance with ASTM-E84 is FHC 25/20.
Additional materials, gauges, and confi gurations are available, such as stainless or aluminum, with mylar or polyethylene
liners or bagging. Please contact SEMCO for details.
Standard Sizes & Weights
(EIGHT
7IDTH
Std.
Height
12”
24”
36”
48”
,ENGTH
Non-standard height dimensions are available within the following restrictions:
3’-0” Length
Standard Width
5’-0” Length
Standard Width
7’-0” Length
Standard Width
Standard Width
12” 24” 36” 48” 12” 24” 36” 48” 12” 24” 36” 12” 24” 36”
31 52 68 81 51 85 110 133 71 120 154 101 171 218
49 78 101 118 78 125 161 186 109 172 222 140 207 278
67 105 135 154 105 165 210 238 145 226 288 190 280 366
85132168191133204260291------
Non-standard sizes are available.
48” heights are not available in 7’ through 10’ lengths.
Self Generated Noise (dB)
Model Length
LF2503
LF2505
LF2507
LF2510
36”
60”
84”
120”
Forward Airfl ow Performance
Octave Band/Frequency (hz)
Face
Velocity16321253250450051K62K74K88K16321253250450051K62K74K88K
500
1000
1500
2000
500
1000
1500
2000
500
1000
1500
2000
500
1000
1500
2000
47
59
70
80
53
59
75
83
52
63
77
86
47
65
78
87
46
46
54
64
47
44
58
68
44
51
62
71
40
53
62
72
39
46
55
63
39
45
59
65
42
52
61
69
42
54
63
70
42
45
55
62
34
45
57
63
38
50
60
68
40
52
61
68
40
48
56
63
34
48
57
64
41
50
61
69
42
52
61
68
37
51
59
64
31
52
59
63
41
54
61
66
41
55
63
69
28
47
60
66
26
47
61
66
29
51
62
69
32
52
64
70
Reverse Airfl ow Performance
Octave Band/Frequency (hz)
24
48
45
37
38
53
62
27
36
54
62
24
43
56
65
25
45
59
67
54
66
74
48
52
64
74
50
55
63
68
45
56
65
67
48
55
60
48
50
51
57
47
52
57
61
49
52
59
64
50
55
60
42
52
56
60
45
53
58
62
43
54
61
65
39
49
56
61
41
51
56
61
44
53
60
63
44
53
62
66
42
54
57
62
44
55
58
61
45
54
60
65
43
53
62
67
41
59
63
65
45
59
63
65
45
57
62
66
41
57
64
69
30
54
66
69
30
55
65
70
33
55
64
70
29
53
66
70
10’-0” Length
24
45
57
66
25
46
57
66
27
48
59
68
24
46
60
70
Face Area Adjustment for Self Noise
Attenuator Face Area (sq. ft.)
PWL Adjustment Factor dB re 10
-12
Watts
0.5 1 2 4 8 16 32 64 128
-9 -6 -3 0 +3 +6 +9 +12 +15
Add or Deduct From Power Level Above.
For intermediate face areas, interpolate to nearest whole number.
1800 East Pointe Drive Columbia, MO 65201-3508 phone: 573/443-1481 fax: 573/443-7749
www.semcoinc.com
S ML 001 0606
Model LF5000
Low Frequency
Sound Silencer
The SEMCO Model LF5000 low frequency sound
silencers provide excellent low frequency performance
across all bands coupled with low to medium pressure
drops for use in low and medium velocity applications.
INDEPENDENTLY CERTIFIED TEST DATA
Published data is derived from Independent Certifi ed Testing conducted in accordance with ASTM E477. For testing purposes,
specifi ed lengths of straight duct are used both upstream and downstream of the silencer. Static pressure losses must therefore
be adjusted when the unit is installed, at or near transitions, elbows, or at the intake or discharge of the system. Consult SEMCO
for adjustment values. All data published herein was obtained from a 24” x 24” production run unit.
Model Length
LF5003
LF5005
LF5007
LF5010
36”
60”
84”
120”
Forward Airfl ow Performance applies when both noise and airfl ow are traveling in the same direction.
Reverse Airfl ow Performance applies when noise and airfl ow are traveling in opposite directions.
Face
Velocity
0
500
1000
1500
2000
0
500
1000
1500
2000
0
500
1000
1500
2000
0
500
1000
1500
2000
Dynamic Insertion Loss (dB)
Forward Airfl ow Performance
Octave Band/Frequency (hz)
Press.
Cv
Drop16321253250450051K62K74K88K16321253250450051K62K74K88K
0
3
10
16
18
18
15
3.00
3.55
3.97
4.50
.06
.19
.42
.75
0
.06
.22
.50
.89
0
.06
.25
.56
.99
0
.07
.28
.63
1.12
1
9
16
18
1
10
14
12
12
12
12
18
18
18
16
15
24
22
23
22
22
15
9
15
9
14
22
22
21
20
19
33
32
32
30
29
45
43
43
42
40
3
2
6
5
5
5
4
7
6
4
5
5
9
8
6
7
6
18
17
17
26
25
25
24
24
38
37
37
36
35
45
45
46
45
44
19
19
19
19
29
28
28
28
30
32
32
32
33
33
39
39
40
40
40
15
15
15
15
24
24
24
24
25
27
27
28
28
28
35
34
35
36
36
13
13
14
14
13
18
19
18
18
19
19
19
21
20
20
25
24
26
26
26
Reverse Airfl ow Performance
Octave Band/Frequency (hz)
14
3
9
16
14
14
14
13
18
18
18
17
18
17
17
20
18
18
20
19
23
22
21
10
11
12
11
3
11
3
10
3
11
2
11
5
16
6
16
5
16
5
16
5
18
7
18
8
19
9
20
9
21
9
21
6
21
25
26
26
26
18
18
18
18
25
26
26
25
27
33
34
35
35
35
40
44
44
44
44
18
19
20
21
20
26
27
27
28
28
35
36
36
37
37
39
43
43
45
45
17
18
19
19
19
25
26
25
26
27
30
31
31
32
32
35
39
39
40
41
13
14
14
14
14
22
22
21
21
21
26
27
27
27
26
35
37
36
35
33
11
13
11
11
10
18
19
17
15
18
21
22
21
21
18
24
26
24
25
21
12
15
14
15
12
17
18
15
13
15
18
19
19
19
14
18
20
18
19
16
Pressure Drops for velocities not shown above can be calculated using the following formula:
P.D. = Cv x Hv
where: P.D. = Pressure Drop
Cv = Silencer Flow Coeffi cient
Hv = (V/4005)
Hv = Velocity Pressure in Inches w.g.
V = Face velocity in Ft./Min.
2
LF5000
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