Foremost Duct

35901 Schoolcraft Road, Livonia, MI 48150

Phone - 734-793-4000 - Fax - 734-793-4001 Toll Free Phone Number - (800) 521-9316

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Flat Oval Duct Construction Standards

All flat oval duct and fittings by Foremost Duct, L.L.C. meet or exceed SMACNA standards for flat oval duct construction. See pages 3.13 and 3.14 of the

1995 SMACNA Duct Construction Standards for clarifications. For dual wall applications, the listed gauges are for the outer shell. The inner shell is typically

perforated galvanized, but it can be solid if desired. The outer shell may be joined by slip-fit, angle flanges, Ductmate's Ovalmate™ rings, or

AccuFlange™. When using AccuFlange™, the insulation and inner liner are enclosed within the flange. Flat oval is available in standard galvanized as

well as phosphatized, P.C.D., aluminum, aluminized and stainless steel.

Maximum duct length is 12'-0" for oval sizes up to and including 34" minor axis.
Maximum duct length is 8'-0" for oval sizes larger than 34" minor axis.
35" round major axis and larger can be rolled and fabricated with longitudinal welds. Maximum of 5'-0" length.
Welds on fittings and longitudinal welded ducts are painted with corrosion resistant paint.
Reinforcement(s) per 1995 SMACNA for positive pressure systems.

FITTINGS AND LONGITUDINAL SEAM DUCT

Major Dimension:	up to 36"	- 20 gauge
	37" to 60"	- 18 gauge
	61" & larger	- 16 gauge

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