Foster® 32-16 Fiber-FAS™ Duct Sealant

• Fiber-FAS™ Duct Sealant may be pressure tested within 16 hours dry time above 70°F (21°C) and below 60% RH. It quickly forms a strong bond to galvanized, aluminum or mild steel metal ducts. It has a mild odor when wet.
• Fiber-FAS™ Duct Sealant will meet all SMACNA pressure classes up to 10" w.g. and SMACNA seal classes A, B and C on ducts constructed to SMACNA standards.
• Fiber-FAS™ Duct Sealant contributes to USGBC LEED credits for SCAQMD Rule 1168 Compliance and Ozone Transport Commission (OTC) Compliance.

Material Preparation

DO NOT THIN. Apply only to clean, dry, oil-free surfaces. Keep container closed when not in use.

Application

UL 181B MASTIC CLOSURE OF UL 181 FLEXIBLE AIR DUCTS: Apply to clean, dry, oil-free surfaces by brush, trowel, or power extrusion. Uniformly brush out a 2” wide coat over the joint, at the nominal rate of 2 gal./100 sq. ft. (0.8 l/m²). Total coverage rate to be 45 – 55 sq. ft./gal. (1.1 – 1.4 m² /l). Allow the completed joint to dry at least 24 hours above 70°F (21°C) before pressure testing. High humidities (over 70%) and/or cooler temperatures may retard drying. Total wet film thickness to be 32 mils +/- 3 mils.

Other Sealing Applications

Apply a continuous film of FOSTER® Fiber-FAS™ Duct Sealant over all areas of the indoor or outdoor duct system where air leakage may occur. A brush may be used to work the sealant into joints and remove excess. On spiral ducts, apply a coat to the male end of the coupling prior to fitting the straight run of spiral duct over it. Brush excess sealant over the joint to complete the seal. Screw holes and flanges should also be sealed with a coat of Fiber-FAS™ Duct Sealant. It may be applied to the inside or outside of the duct.

Power Extrusion

Fiber-FAS™ Duct Sealant may be applied using a wide variety of power (pressure) extrusion equipment suitable for use with water-based sealants. It is a soft buttery gel with a typical viscosity range of 130,000 - 160,000 cps. Corrosion resistant pumps are fittings are suggested.

Top Coating
After it is completely dry, Fiber-FAS™ Duct Sealant may be top coated with good quality water-based paint.

Clean Up

Use fresh water to clean brushes and equipment before product dries. Dry product may be removed with hot soapy water or strong solvent such as chlorinated solvent (non-flammable) or xylol (flammable).

• Always test foil and paper facings for acceptable adhesion. Outdoor horizontal surfaces must always drain completely.
• A pitch of at least 1/2 inch per foot (4 cm/m) is required. If used between impermeable surfaces, drying time will be extended.
• Mechanical fasteners of the type and number normally used for duct assemblies are required to provide rigidity to the duct system.

¹ - Tested as applied in two 2 in. wide strips spaced 8 in. on center at a coverage rate of 25 sq. ft./gal. Applied to 1/4 inch (6.4 mm) inorganic reinforced cement board. The flame spread may vary at different product thicknesses and/or when applied over other surfaces.