HVAC Ductwork Quantity Take off for Quantity Surveyors

Explore the basics of hvac ductwork, including circular, rectangular, and oval shapes, common materials, key fittings, and the roles of supply, return, fresh air, and exhaust in air handling systems.

Clarify the difference between an air handling unit and a fresh air handling unit, detailing how outside air enters the supply and how return air recirculates within separate streams.

Learn to measure duct lengths using the centerline method in AutoCAD, handling rectangular, offset, reducer, and transition pieces, with fittings either included or enumerated separately, and record in Excel.

Learn to calculate ductwork area for quantity surveying by applying formulas for straight, elbow, offset, reduce, and transition sections using AutoCAD measurements and rectangular fittings.

Calculate duct weight by deriving the area and multiplying by the unit weight per area from standard gauge tables, with low and medium pressure classes defined by pressure and velocity.

Learn POMI standards for duct measurement, including rectangular ducts weighted by area, centerline length, and inclusion of fittings, supports, and insulation, with gauge-based classification per Spagna and Ashleigh standards.

Perform a pre-takeoff check by zooming to reveal duplicates and extra drawings, verify accurate counts, and remove unnecessary drawings to ensure precise ductwork quantity takeoffs.

Learn how to use the overkill command to remove overlapping lines and ensure accurate total length measurements in ductwork quantity takeoffs.

Download the templates and documents, and apply HVAC ductwork quantity take off skills in professional practice. Practice by adapting formulas and templates to save time and improve accuracy.