HVAC Procedure and Performance Guide

TASK: Install branch duct takeoff from main using round metal duct and fittings.


Duct and fittings must be installed according to job specifications.  Duct joints must be tight with minimum air leakage and duct noise.  Applicable safety procedures must be followed.


  1. Review job specifications.
  2. Collect tools, equipment and materials.
  3. Put on safety and protective equipment and apparel.
  4. Fit longitudinal seams of duct sections together to form round duct.
  5. Prepare duct penetrations and register openings.
  6. Locate main (trunk) duct.
  7. Install branch duct from main. Locate takeoff point and determine size of takeoff branch.

a. Mark center of takeoff point and scribe opening; cut opening in main.

b. Insert takeoff fitting and secure, using fitting tabs or sheet-metal screws.

c. Install manual balancing damper in duct section.

d. Connect duct section to takeoff.

e. Connect remaining duct sections using required hangers and supports.

f. Install register transition.

8. Seal duct joints.

9. Install duct insulation.

10. Remove safety and protective equipment and apparel.

11. Gather tools, equipment and leftover materials and leave work site clean.