How accurate are the material takeoff and cost calculations?

Calculations are grounded in industry-standard engineering formulas (such as compacted density multipliers, ASTM standards, and CSI MasterFormat divisions), with customizable local material unit costs and compaction waste factors.

What waste allowance factor should be added to material orders?

For commercial and residential trade installations, standard engineering practice recommends including a 5% to 10% material waste and compaction contingency factor.

Can I export these takeoff sheets for client bidding?

Yes, you can export full itemized material schedules and bid breakdowns directly to CSV or printable takeoff summaries.

ACCA Manual D Mechanical Engineering

HVAC Duct Sizing & Airflow (CFM) Sizer

Calculate duct dimensions based on volumetric airflow (CFM), target air velocity (FPM), static friction loss (0.08 - 0.10 in. w.g.), and equivalent rectangular aspect ratios.

Airflow & Velocity Parameters

Volumetric Airflow (CFM)

Duct Application & Design Velocity

Friction Rate (in. w.g. per 100 ft)

Duct Sizing Recommendation

Round Spiral / Flex Duct Diameter

Equivalent circular cross section

16" Round Duct

Equivalent Rectangular Duct Size

Based on standard 10" ceiling depth

22" x 10" Sheet Metal

Actual Air Velocity in Duct

Velocity = CFM / Area (sq ft)

859 FPM (Quiet)

Flexible duct exhibits up to 30% higher friction loss than rigid galvanized steel sheet metal due to spiral wire ribbing and sag.