Single-Wall, Round Duct

Single-Wall, Round and Flat Oval Duct and Fittings
McGill AirFlow's single-wall, round duct is fabricated to exacting tolerances that make it easy to assemble and essentially leak free. Round duct costs less to install than rectangular duct and because of its efficiency, a round duct system offers lower operating costs. Three standard types of single-wall, round duct are available: spiral lockseam, spiral lockseam with a standing rib, and longitudinal seam.
Uni-Seal™ Duct
Spiral lockseam duct is available with a standing rib. This external stiffening rib gives the duct strength and rigidity equal to that of heavier gauges of standard spiral lockseam duct.
Longitudinal Seam Duct (fully welded or pipelock)
Longitudinal seam duct is available for applications that require very heavy gauges or large diameters. The longitudinal seam of the duct is solid welded. Construction meets or exceeds HVAC Construction Standards, 1995 Sheet Metal and Air Conditioning Contractors National Association (SMACNA).
A pipelock construction is used for some lighter gauge duct (residential and light commercial) and some PVC-coated metal duct.
Single-Wall, Round Duct Available Sizes, Materials, and Thicknesses
Uni-Seal™ Duct
(spiral lockseam)
Diameters1 Lengths2 Materials3,6 Thicknesses
3-84 inches 1-20 feet Galvanized Steel 28-14 gauge
Stainless Steel 26-20 gauge
3-60 inches4 1-20 feet Aluminum 0.025-0.063 inch
Uni-Seal™ Duct
(spiral lockseam)
Dia.1 Len.2 Matl.3,6 Thickness
3-84 inches 1-20 feet Galvanized Steel 28-14 gauge
Stainless Steel 26-20 gauge
3-60 inches4 1-20 feet Aluminum 0.025-0.063 inch
Uni-Rib®
(spiral lockseam with standing rib)
Diameters1 Lengths2 Materials3,6 Thicknesses
9-60 inches 1-20 feet Galvanized Steel 28-22 gauge
Aluminum 0.025-0.050 inch
Uni-Rib®
(spiral lockseam with standing rib)
Dia.1 Len.2 Matl.3,6 Thickness
9-60 inches 1-20 feet Galvanized Steel 28-22 gauge
Aluminum 0.025-0.050 inch
Longitudinal Seam Duct
(solid welded)
Diameters1 Lengths2 Materials3,6 Thicknesses
8-90 inches5 1-6 feet Galvanized Steel 20-10 gauge
Stainless Steel 22-10 gauge
8-60 inches Aluminum 0.040-0.090 inch
Longitudinal Seam Duct
(solid welded)
Dia.1 Len.2 Matl.3,6 Thickness
8-90 inches5 1-6 feet Galvanized Steel 20-10 gauge
Stainless Steel 22-10 gauge
8-60 inches Aluminum 0.040-0.090 inch
Notes
  1. McGill AirFlow's single-wall, round duct is available with the following diameters: 3-inch through 15-inch diameters in 1/2-inch-diameter increments, 16-inch through 38-inch diameters in 1-inch-diameter increments, and 40-inch through 90-inch diameters in 2-inch-diameter increments.
  2. Standard lengths of round Uni-Seal and Uni-Rib duct are 10, 12, and 20 feet; longer lengths are available. Standard lengths of round longitudinal seam duct are 5 and 6 feet.
  3. Single-wall, round duct is also available in nongalvanized carbon steel and paintable galvanized steel. Stainless steel is generally type 304 or 316. Aluminum is generally type 3003-H14. Uni-Coat single-wall, round duct (polyvinyl-chloride-coated galvanized steel) is available on special order.
  4. Aluminum single-wall, round duct is available in diameters greater than 60 inches on special order.
  5. Single-wall, round longitudinal seam duct is available in diameters smaller than 8 inches on special order.
  6. SilverGuard™ single-wall, round duct (pre-coated with an antimicrobial) is available on special order.

Single-Wall, Round Lined Duct

Single-Wall, Round Duct with Acousti-Line™ Insulating Liner
Single-wall ductwork is available with an Acousti-Line insulating liner coated to protect against erosion and microbial growth. This acoustical/thermal liner can be used with air velocities up to 5,000 fpm and temperatures up to 250°F. It is available in thicknesses of 1 and 1 1/2 inches and has a maximum thermal conductivity (k) factor of 0.24 BTU/hour/square foot/°F/inch thickness. Formulated with an antimicrobial agent that is EPA registered, the liner's acrylic coating resists the growth of fungus and bacteria (tested in accordance with ASTM C 1071 and ASTM G21 and G22). The liner's surface can be cleaned according to procedures detailed in the North American Insulation Manufactures Association (NAIMA) Duct Cleaning Guide.

Single-Wall, Round Fittings

Single-Wall, Round Fittings
A complete line of fittings designed for low leakage and efficient performance is available for use with McGill AirFlow's single-wall, round duct. Each fitting is sized accurately to allow easy field assembly. Fittings are available in gaskted and non-gaskted profiles in solid welded, spot or tack welded and sealed, lap rivited (or screwed) and sealed, and Uni-Seam™ standing seam constructions. Single-wall, round fittings can be supplied with and Acousti-Line™ insulating liner to match our single-wall, round lined duct.
Single-Wall, Round Fittings Available Sizes, Materials, and Thicknesses
Uni-Seal™ Fittings4
Diameters1 Materials2,5 Thicknesses
3-90 inches Galvanized Steel 26-10 gauge
Stainless Steel 26-10 gauge
30-60 inches3 Aluminum 0.032-0.090 inch
spot or tack welded and sealed, lap and riveted/screwed and sealed, solid welded, or standing seam
Uni-Gasket® Fittings
Diameters1 Materials2,5 Thicknesses
3-24 inches6 Galvanized Steel 26-22 gauge
Notes
  1. Except as noted, McGill AirFlow's single-wall, round fittings are available with the following diameters: 3-inch through 15-inch diameters in 1/2-inch-diameter increments, 16-inch through 38-inch diameters in 1-inch-diameter increments, and 40-inch through 90-inch diameters in 2-inch-diameter increments.
  2. Single-wall, round fittings are also available in nongalvanized carbon steel and paintable galvanized steel. Stainless steel is generally type 304 or 316. Aluminum is generally type 3003-H14. Uni-Coat® single-wall, round fittings (polyvinyl-chloride-coated galvanized steel) are available on special order.
  3. Aluminum single-wall, round fittings are available in diameters greater than 60 inches on special order.
  4. Fittings that are 16 gauge (Aluminum-0.090 inch) or heavier are fully welded.
  5. SilverGuard™ single-wall, round fittings (pre-coated with an antimicrobial) are available on special order.
  6. Except as noted, McGill AirFlow's single-wall, round Uni-Gasket fittings are available with the following diameters: 3-inch through 12-inch diameters in 1-inch-diameter increments, and 14-inch through 24-inch diameters in 2-inch-diameter increments.

Single-Wall, Flat Oval Duct

Single-Wall, Flat Oval Duct
For applications in which space restrictions prohibit the use of round duct, McGill AirFlow offers flat oval duct in spiral lockseam and longitudinal seam constructions. Flat oval duct provides a more efficient alternative to rectangular duct in these applications. McGill AirFlow manufactures flat oval duct with the same techniques used to make round duct. As a result, flat oval duct shares many of the performance characteristics of round duct. Compared with rectangular duct, it provides lower installation costs and, because of reduced leakage and pressure loss, lower operating costs.
Spiral lockseam duct is constructed with an interlocking helical seam that runs the length of the duct. As with round spiral lockseam duct, the flat oval type combines efficient performance with a structural strength equal to that of heavier gauges of other types of duct.
Flat oval duct is available with a longitudinal seam construction for applications that require very heavy gauges or large sizes. The duct's longitudinal seam is solid welded.
A pipelock construction is used for some lighter gauge duct (residential and light commercial) and some PVC-coated metal duct.
Single-Wall, Flat Oval Duct Available Sizes, Materials, and Thicknesses
Uni-Seal™ Duct (spiral lockseam)
Lengths1 Materials2,3 Thicknesses
1-12 feet Galvanized Steel 28-18 gauge
Stainless Steel 26-20 gauge
Aluminum 0.025-0.063 inch
Longitudinal Seam Duct (solid welded)
Lengths1 Materials2,3 Thicknesses
1-6 feet Galvanized Steel 20-10 gauge
Stainless Steel 22-10 gauge
Aluminum 0.040-0.090 inch
Notes
  1. Some standard sizes of flat oval Uni-Seal duct are available only to lengths of 6 feet; longer lengths are available on special order. Standard lengths of flat oval longitudinal seam duct are 5 and 6 feet.
  2. Single-wall, flat oval duct is also available in nongalvanized carbon steel and paintable galvanized steel. Stainless steel is generally type 304 or 316. Aluminum is generally type 3003-H14. Uni-Coat® single-wall, flat oval duct (polyvinyl-chloride-coated galvanized steel) is available on special order.
  3. SilverGuard™ single-wall, flat oval duct (pre-coated with an antimicrobial) is available on special order.
Minor Axis (inches) Major Axis (inches)
Minimum Min Maximum Spiral Lockseam Maximum Longitudinal Seam or Fitting Size
3 8 22 30
4 7 21 40
5 8 21 46
6 8 59 59
7 10 21 62
8 10 77 77
9 12 23 89
10 12 79 99
11 14 25 109
12 14 81 119
14 20 80 139
16 22 79 143
18 23 81 134
20 26 80 140
22 35 82 134
24 37 81 141
26 29 not available 137
28 31 not available 144
30 43 84 141
32 35 not available 139
34 37 not available 138
36 39 not available 136
38 41 not available 136
40 43 not available 143

Single-Wall, Flat Oval Fittings

Single-Wall, Flat Oval Fittings
A complete line of fittings designed for low leakage and efficient performance is available for use with McGill AirFlow's single-wall, flat oval duct. Each fitting is sized accurately to allow easy field assembly. Fittings are available in solid welded, spot or tack welded and sealed, lap and riveted (or screwed) and sealed, and standing seam constructions.
Single-Wall, Flat Oval Fittings Available Materials, and Thicknesses
Uni-Seal™ Fittings2
Materials1,3 Thicknesses
Galvanized Steel 26-10 gauge
Stainless Steel 26-10 gauge
Aluminum 0.032-0.090 inch
spot or tack welded and sealed, lap and riveted/screwed and sealed, solid welded, or standing seam
Notes
  1. Single-wall, flat oval fittings are also available in nongalvanized carbon steel and paintable galvanized steel. Stainless steel is generally type 304 or 316. Aluminum is generally type 3003-H14. Uni-Coat® single-wall, flat oval duct (polyvinyl-chloride-coated galvanized steel) is available on special order.
  2. Fittings that are 16 gauge (Aluminum-0.090 inch) or heavier are fully welded.
  3. SilverGuard™ single-wall, flat oval duct (pre-coated with an antimicrobial) is available on special order.
Minor Axis (inches) Major Axis (inches)
Min Minimum Maximum Spiral Lockseam Maximum Longitudinal Seam or Fitting Size
3 8 22 30
4 7 21 40
5 8 21 46
6 8 59 59
7 10 21 62
8 10 77 77
9 12 23 89
10 12 79 99
11 14 25 109
12 14 81 119
14 20 80 139
16 22 79 143
18 23 81 134
20 26 80 140
22 35 82 134
24 37 81 141
26 29 not available 137
28 31 not available 144
30 43 84 141
32 35 not available 139
34 37 not available 138
36 39 not available 136
38 41 not available 136
40 43 not available 143