Ventilation Duct Systems for Marine Applications

The Marine Catalog includes product sheets and ordering examples single and double wall products side-by-side. The catalog also includes specifications, tolerances, and assembly instructions.
Marine Catalog | Marine Specifications | Tolerances and Gauges

Single Wall Marine Ductwork and Fittings

Duct is of spiral lockseam construction with a mechanically formed seam locking indentation evenly spaced along the spiral seam. All spiral duct greater than 8 inch (200 mm) diameter incorporates multiple corrugations between the spiral seams.

All fitting ends shall come factory equipped with a double lipped, U-profile, rubber gasket. The gasket is to be mechanically attached to the fitting using a spot welded stainless steel metal band located in a groove at the end of the fitting. All fitting ends shall be calibrated to manufacturer’s published dimensional tolerance standard and associated spiral duct. All fitting ends shall have rolled over edges for added strength and rigidity.

Fittings shall be manufactured using one or more of the following construction methods:

● Overlapped edges stitch welded along the entire length of the fitting
● Standing seam gore locked and internally sealed
● Button punched and internally sealed
● Elbows 3″ through 12″ (75 mm – 315 mm) diameter will be die stamped and continuously stitch welded

Double Wall Marine Ductwork and Fittings

Double wall duct and fittings shall consist of: an outer pressure shell; an inner perforated liner (available in G60 only) on duct and a solid liner on fittings; fiberglass insulation; retaining fabric (when a perforated inner liner is specified); and EnergyX™ insulation stops as a factory supplied
integral assembly.

The outer shell shall be the pressure shell. The outer pressure shell diameter shall be two times the insulation thickness larger than the inner liner.

The duct size shall be reflected as the nominal clear inside (airside) diameter or the nominal diameter of the inner liner.The perforated liner on the spiral duct shall be integrally wrapped with a retaining fabric between the perforated inner liner and the glass fiber insulation. The retaining fabric shall be securely held by the spiral lockseam of the inner liner. This is to prevent the glass fibers tearing into the airstream and at the same time maintains the desired acoustical properties.

Spiral duct shall have heavy duty spring clips evenly spaced around the duct circumference to maintain the inner liner concentric to the outer pressure shell.

The ductwork assembly shall be classified by Underwriters Laboratories (UL) for a flame spread index and smoke developed index of 0/0 in accordance with ASTM E84-91a.

Perforated Metal Liner (duct only) consists of 0.125″ (3 mm) perforations on 0.250″ (6 mm) staggered centers and 23% open area. Perforated liner is available in galvanized G60 only. All double wall fittings are manufactured with a solid inner liner; a perforated inner is available upon request.

Insulation (Linx Gasketed only) is USCG/IMO certified glass fiber insulation will have a maximum conductivity factor (k) of 0.26 BTU-in/hr x ft² x °F at 75°F mean ambient temperature (R=3.8). Insulation shall be 1” thick standard. 2” insulation thickness is an available option. The outer pressure shell diameter shall be two times the insulation thickness larger than the inner liner.

EnergyX™ Insulation stop system (Linx Gasketed only) is constructed of a closed-cell elastomeric foam with a maximum conductivity factor (k) of 0.28 BTU-in/hr x ft² x °F and an operating temperature range of -70°F to +220°F. Retaining fabric shall be 0.008” thick, 15.6 lb/ft³ density non-woven polyester fabric with an air permeability rate of 9.2 ft³/ft² x s.

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