Single-Wall, Round and 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.

Single-wall, flat oval duct

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.

Flat Oval Duct
Available Lengths, Materials, and Thicknesses

UNI-SEAL™ Duct (spiral lockseam)
Lengths (1)	Materials (2,3)	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)
Lengths (1)	Materials (2,3)	Thicknesses
1-6 feet	Galvanized Steel	20-10 gauge
	Stainless Steel	22-10 gauge
	Aluminum	0.040-0.090 inch

(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.

Flat Oval Duct and Fittings—
Available Size Ranges

Minor Axis (inches)	Major Axis (inches)
Minor Axis (inches)	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

McGill AirFlow's Single-Wall, Round and Flat Oval Duct and Fittings:

Single-Wall, Round Duct
Single-Wall, Round Lined Duct
Single-Wall, Round Fittings
Single-Wall, Flat Oval Duct
Single-Wall Flat Oval Fittings

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