HVAC Procedure and Performance Guide

Measure CFM air-flow in duct

Training for this procedure can be found in these courses:

                         131 – Oil Heat l  and  161 – Boilers l


Air-flow in duct must be measured by averaging traverse measurements as recommended in recognized publications for size, shape and type of duct.  Applicable safety procedures must be followed.


  1. Review manufacturer’s specifications and job specifications.
  2. Collect tools, equipment and materials.
  3. Put on safety and protective equipment and apparel.
  4. Select desired measuring instrument.
  5. Prepare duct openings for probe insertion.
  6. Take air-velocity measurements and calculate average velocity.
  7. Determine duct size and calculate area.
  8. Calculate CFM air-flow.
  9. Record measurements and calculations.
  10. Reseal duct openings.
  11. Leave equipment in required operating status.
  12. Remove safety and protective equipment and apparel.
  13. Gather tools, equipment and leftover materials, and leave work site clean.