Mechanical Fastening

Fasten ducts with a minimum of three equally spaced galvanized or stainless steel mechanical fasteners

Fasten ducts with UL 181 approved tie bands using a tie band tensioning tool

Install a rigid metal coupling of the same size as the flex duct between the two sections

Fasten both joints with UL 181 approved tie bands using a tie band tensioning tool

Cut duct board edges to create an overlapping joint on all contact surfaces

Fasten joints with outward clinching (stitch) staples spaced every 2"

Cover joint with UL 181 rated mastic embedded fiber tape and additional mastic that laps at least 1" past the edges of the tape on all sides

Install a metal take-off collar on the duct board specifically designed for the thickness of the duct board

Bend all finger tabs down securely so collar shank is firmly seated against the exterior surface

Attach flexible duct to collar with UL 181 approved tie bands using a tie band tensioning tool

Fasten duct board to metal duct using metal channel and mechanical fasteners spaced evenly on all sides

Cover connection joint with UL 181 rated mastic embedded fiber tape and additional mastic that laps at least 1" past the edges of the tape on all sides

Fasten duct board to air handler cabinet using metal channel fastened with screws spaced a maximum of 6" with the duct board sandwiched between the channel flanges

In upflow air handler connections, install a flexible connection between supply plenum and unit that does not reduce the inside dimensions of the duct

Fasten boot to wood using a minimum of 1 stainless steel or galvanized fastener per side

If accessible, fasten a boot hanger to adjacent framing with mechanical fasteners

Connect boot to hanger with mechanical fasteners

If inaccessible, fasten boot to gypsum with UL 181 rated fiber tape and mastic

Install a flexible connection between plenum and unit that does not reduce the inside dimensions of the duct

Fasten plenum on all sides with mechanical fasteners spaces no more than every 6"