3.1601.6 Preparation and Mechanical Fastening—Low Rise

Topic: 
Ducts
Subtopic: 
Duct Preparation
Desired Outcome: 
Ducts and plenums are properly fastened to prevent leakage
For supporting material, see Referenced Standards.
TitleSpecification(s)Objective(s)
3.1601.6a
Preparation

Surrounding insulation will be cleared to expose the joints being sealed

Duct surface that accepts sealant will be cleaned

Gain access

Achieve proper adhesion for airtight seal

3.1601.6b
Metal to metal

Ducts will be fastened with a minimum of three equally spaced screws or acceptable mechanical connections

Ensure joints are durable

3.1601.6c
Flex to metal

Joints will be fastened with tie bands using a tie band Tie band A strap, often made of nylon, that mechanically squeezes a flexible duct to a fitting. Must have a minimum performance temperature rating of 165° (per UL 181A-type test) and a minimum tensile strength rating of 50 pounds tensioning tool or mechanical band, and sealed with approved mastic and UL181B tape

Ensure joints are durable

Reduce air leakage

3.1601.6d
Duct board to duct board

Joints will be fastened with a clinch stapler, rated tape, and mastic

Ensure joints are durable

Reduce air leakage

3.1601.6e
Duct board to flexible duct

An appropriate take-off collar in accordance with NAIMA NAIMA North American Insulation Manufacturers Association, www.naima.org standards will be used and sealed with approved mastic

Ensure joints are durable

Reduce air leakage

3.1601.6f
Metal plenum to air handler cabinet

Plenum will be fastened with a minimum of three equally spaced screws on each side

Canvas connection between plenum and unit will be installed so that it does not reduce the inside dimensions of the duct

Ensure joints are durable

Reduce air leakage

Optimize airflow

3.1601.6g
Duct board plenum to air handler cabinet

Termination bar or metal strip will be fastened with screws

Duct board will be installed between the screw and the termination bar

Ensure joints are durable

Reduce air leakage

3.1601.6h
Terminal boot to wood

Screws or nails will be used to fasten boot to wood

Seams and boot to subfloor will be sealed with mastic

Ensure joints are durable

Reduce air leakage

3.1601.6i
Terminal boot to gypsum

Boot hanger will be fastened to adjacent framing with screws or nails

Boot will be connected to boot hanger with screws

Integral snap boots will be installed

Seams of boot will be sealed with mastic

Boot to gypsum will be sealed with caulk in accordance with local code and standards

Ensure joints are durable

Reduce air leakage

3.1601.6j
Duct board to flex

An appropriate take-off collar in accordance with NAIMA NAIMA North American Insulation Manufacturers Association, www.naima.org standards will be used

Ensure joints are durable

Reduce air leakage

3.1601.6k
Replacement of insulation

Insulation will be returned or replaced with equivalent R-value

Maintain insulation value