Available in Perforated (Acoustical) Liner or
Solid (Thermal Insulation) Liners
Insulation
Impregnated to
inhibit air born
fibers
Duct liner absorbs equipment and air rush noises over a broad spectrum of sound. Glass fiber construction traps noise and dissipates it within the fiber matrix. Air is delivered, not noise. It also performs as a thermal insulation to conserve energy.
Three l-beam spacers minimum at approx. 120° centerline spot welded to inner duct.
Application Note
Zinc on galvanized pipe melts at 788° F.
The Manual of Industrial Ventilation Recommended Practice, 23rd Edition, suggests that operating temperatures not exceed 400° F.
Standard duct liner maximum temperature rating 250° F.
R-value of duct liner per inch of thickness = 3.6.
Aluminized Type 1 - 1250° F.
Performance Characteristics
(Sound Absorption)
Perforated
Section
(Actual Size)
3/32”@ 3/16” centers (staggered).
33 holes per sq.
inch. Open area 23%.
DENSITY lbs. cu. ft.
Thick- ness
Noise Reduction Coefficients at Frequencies
125
250
500
1000
2000
4000
NRC
1.5
1"
.17
.52
.57
.69
.82
.86
.65
1 1/2"
.23
.62
.74
.82
.87
.88
.75
2"
.32
.70
.83
.91
.92
.91
.85
2.0
1/2"
.08
.42
.35
.46
.61
.75
.45
1"
.19
.54
.61
.74
.86
.90
.70
1 1/2"
.25
.64
.78
.87
.94
.92
.80
2"
.33
.76
.88
.94
.95
.94
.90
3.0
1/2"
.10
.40
.37
.53
.68
.79
.50
1"
.21
.57
.70
.89
.95
.97
.80
1 1/2"
.27
.66
.85
.94
.97
.98
.85
2"
.36
.79
.96
.99
.98
.99
.95
# Overall Noise Reduction Coefficient (NRC)
Thermal Conductance
DENSITY lbs. cu. ft.
K
R
1.5
.29
3.4
2.0
.27
3.7
3.0
.24
4.2
All values are measured at 75° mean temperature
K factor is expressed as Btu/in./ft²/°F
R is the reciprocal of K.
Dual Wall 60° & 90° Elbows, Dual Wall Plain
Tee & Dual Wall Reducing Tee.
Dual Wall Fittings
Dual Wall 60° Elbow
(DW-E-4-60)
Dual Wall 90° Elbow
(DW-E-5-90)
All 90° elbows are of 5 piece construction, and all 45° elbows are of 3 piece construction. Elbow centerline radius is not less than 1-1/2 times the inside duct diameter.
When ordering, list dimensions in order of: D¹, D²
When ordering, list dimensions in order of: D¹, D²
Dual Wall Plain Tee
(DW-T-1)
Dual Wall Reducing Tee
(DW-T-1-R)
When ordering, list dimensions in order of: A ¹, A ², D¹, D²
When ordering, list dimensions in order of: A ¹, A ², B ¹, B², D¹, D²
All fittings in this catalog are available in dual wall construction. See examples above.
Product Selection Schematic
Standard Physical Properties of Spiral Pipe
