QF In-Line Back Draft Damper


QF In-Line Back Draft Dampers are used to reduce backward air flow in the line. They are designed for use in a horizontal line. Please specify if a vertical operation and upward air flow is required in the application. Manufactured with 16 or 18 ga Galv. and 18 or 20 ga. 304SS.
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Quick Fit In-Line Back Draft Dampers are used to reduce backward air flow in the line. They are designed for use in a horizontal line. Please specify if a vertical operation and upward air flow is required in the application.
QF In-Line Back Draft Dampers are manufactured as follows
- In 3 to 24 inch diameters, with standard 16, and 18- gauge Galvanized or standard 18 and 20 gauge 304SS Stainless Steel
- The longitudinal seam is lapped, spot welded, and caulked
- Collars are located on the exterior side of each port and considered as air flow non-directional. A raised lap seam and spot weld are used for attaching the collar to the body and no caulking is used
- The 3 to 24 inch diameter Dampers come with standard QF ends, with diameters of 26 inches and larger come with standard Angle Flanged ends
- Standard QF ends can be changed to Raw with a defined ID dimension (RawID), Raw with a defined OD dimension (RawOD), No Fitting or just a raw end (NoFit), Flexible hose adapter (RawFlex), Flat Flange (FFL), Angle Flange (ANGFL), or Van Stone (VanStone).
Size
in. |
Galvanized
ga. |
304SS
ga. |
Weight
lbs. |
Length
in. |
Length (B)
in. |
Rolled Edge
nom.in. |
---|---|---|---|---|---|---|
3 | 18 | N/A | 2.25 | 17.5 | 7 | 0.2 |
4 | 18 | 20[18] | 3.00 | 18.5 | 7 | 0.2 |
5 | 18 | 20[18] | 3.50 | 19.5 | 7 | 0.2 |
6 | 18 | 20[18] | 4.00 | 20.5 | 7 | 0.2 |
7 | 18 | 20[18] | 4.50 | 21.5 | 7 | 0.3 |
8 | 18 | 20[18] | 5.00 | 22.5 | 7 | 0.3 |
9 | 18 | 20[18] | 10.00 | 23.5 | 7 | 0.3 |
10 | 18 | 20[18] | 20.00 | 24.5 | 7 | 0.3 |
11 | 18 | 20[18] | 25.00 | 25.5 | 7 | 0.3 |
12 | 18 | 20[18] | 30.00 | 26.5 | 7 | 0.4 |
13 | 18 | 20[18] | 36.00 | 32.5 | 12 | 0.4 |
14 | 18 | 18 | 42.00 | 33.5 | 12 | 0.4 |
15 | 18 | 18 | 49.00 | 34.5 | 12 | 0.4 |
16 | 18 | 18 | 59.00 | 43.5 | 20 | 0.4 |
17 | 18 | 18 | 63.00 | 44.5 | 20 | 0.4 |
18 | 18 | 18 | 72.00 | 45.5 | 20 | 0.4 |
20 | 16 | 18 | 78.00 | 47.5 | 20 | 0.4 |
22 | 16 | 18 | 85.00 | 49.5 | 20 | 0.4 |
24 | 16 | 18 | 90.00 | 51.5 | 20 | 0.4 |
26 | 16 | 18 | 100.00 | 57.5 | 24 | AF |
28 | 16 | 18 | 110.00 | 59.5 | 24 | AF |
30 | 16 | 18 | 115.00 | 61.5 | 24 | AF |
32 | 16 | 18 | 120.00 | 63.5 | 24 | AF |
34 | 16 | 18 | 130.00 | 65.5 | 24 | AF |
Galvanized Gauge Metal Thickness
Gauge | Inches | Millimeters |
---|---|---|
18 | 0.0516 | 1.31 |
16 | 0.0635 | 1.613 |
Stainless Gauge Metal Thickness
Gauge | Inches | Millimeters |
---|---|---|
20 | 0.0375 | 0.95 |
18 | 0.050 | 1.270 |

NOTES:
- At temperatures ranging between 390° F and 480° F, the zinc-iron alloy layers in the galvanized steel will continue to provide a high level of protection from corrosion. However, there may be some peeling, changes in mechanical properties, and reduction in the corrosion protection. Recommended maximum service temperature is 390° F.
- For 304 SS metal, bluing may occur at temperatures of 800° F and above.
- Rock River Silicone Sealant and Red Devil HVAC/R High Temperature Silicone Sealant are not able to be painted.
Item | Material | Compliance/Rating |
---|---|---|
QF In-Line Back Draft Damper | Galvanized | ASTM A653 with a G-90 Rating |
304 SS | Finish meets ASTM A240 | |
316 SS | Finish meets ASTM A240 | |
3M Scotch Seal Metal Sealant 2084 | Acetone blend | AAMA Specification 801.1 |
3M Polyurethane Sealant 560 | Polyurethane | ASTM E 162 Bombardier SP 800-C |
Rock River Silicone Sealant | 100% Silicone | ASTM C920 Class 25 TT-S-00230C Class A and TT-S-001543A FDA No. 421 CFR 117.2600, conforms to FDA requirements |
Red Devil HVAC/R High Temperature Silicone Sealant | Silicone | ASTM C920 Class 25 TT-S-00230C Class A and TT-S-001543A CEBTP 432.6 140-2 Mil Spec 46106A CGSB 19C9-9B DIN 18540 Part 2 OREX 150031-2 |