Delta Commissioning
HVAC Field Tools

Duct Traverse

Duct Geometry

Pitot Depths AUTO
5
Access Holes AUTO
5

Traverse Method

Equal Duct

📏 Measurement Positions

Enter duct dimensions above to see where to mark your pitot and drill access holes.

Average Velocity

Flow
—
Enter readings & calculate flow (optional)
Tap + to switch to − for return / extract.
Density correction
Apply correction
Off: assumes ρ = 1.2 kg/m³

Valve Calculator

Variable Orifice DRV

For T/A STAD, STAF, Danfoss balancing valves and similar. Set the turns, measure ΔP, get flow.

Airflow / Speed

Fan affinity law. Enter any three values; the missing one solves.

Speed units cancel — use Hz, RPM, or % consistently.
FormulaQ₂ = Q₁ × (N₂ ÷ N₁)

Pressure / Flow

Square law. Enter any three values; the missing one solves.

FormulaP₂ ÷ P₁ = (Q₂ ÷ Q₁)²

Reference

Flow vs speedQ₂ = Q₁ × (N₂ ÷ N₁)
Pressure vs speedP₂ = P₁ × (N₂ ÷ N₁)²
Pressure vs flow (square law)P₂ = P₁ × (Q₂ ÷ Q₁)²
Power vs speedkW₂ = kW₁ × (N₂ ÷ N₁)³

🔥 Air Heating Capacity

kW = Q(m³/s) × 1.2 × ΔT

❄️ Air Cooling Capacity

Stable plant required. Measure DB/WB close to coil for accuracy.

kW = Q(m³/s) × 1.2 × Δh

💧 Water Capacity

kW = Q × ρ × Cp × ΔT (Cp adjusts with glycol %)

Inlet Cone — Plug Fan Airflow

Calculate plug-fan airflow from the inlet-cone differential pressure and manufacturer K-factor.

D 0.5×D Direction of air flow Δp

Measure ΔP between the inlet-cone pressure barb and the inlet-side of the cone. Do not reference against the fan discharge plenum.

Air density assumption Calculations use the manufacturer's published K-factor formula q = k × √Δp (q in m³/h, Δp in Pa). Manufacturer K-factors are typically derived at standard conditions: ρ = 1.2 kg/m³ (air at 20 °C, sea level). For non-standard altitudes or temperatures, apply a manufacturer-specific correction or note the uncertainty on the result.
If the model name contains a size (e.g. "250"), Fan Size auto-selects below.

Inlet Guard?
Affects K-factor reliability

Cautions

  • AHU-supplied inlet guard: if the guard is supplied by the AHU manufacturer (e.g. GJ Walker), the published fan K-factor may not apply. Treat the result with caution and check unit documentation.
  • Packaged units (e.g. Actron Air with ebm-papst fans): K-factor may differ from the published ebm-papst data. Always cross-check against the unit-specific manual where possible.
  • Backdraft / non-return dampers: if installed at or near the inlet, the cone method is generally unreliable — damper position is not repeatable and the K-factor with damper is usually unknown.
  • Pressure reference: never measure against the fan discharge chamber or high-pressure plenum.
  • Multi-fan total: the total airflow shown is the per-fan flow × N. This is an estimate. Where practical, measure each fan individually and compare against a duct traverse.

Settings

Units
Metric (SI)
Theme
Follows iOS unless overridden
Density correction default
Apply on every duct traverse by default
Review EULA
Re-open the licence terms
Clear saved settings
Reset units, theme, EULA acceptance

Offline Mode

The app itself works offline once you've added it to your home screen. Tap below to also pre-download every manufacturer datasheet so PDF links keep working when you're on site without coverage.

Stuck on an old version? If PDFs aren't loading after an update, the phone may be serving old cached files. Use this to wipe the offline cache and pull everything fresh from the server.

About

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Powered by Delta Commissioning. Built for internal use. Web prototype — iOS / TestFlight build to follow.

Results are calculation estimates. Cross-check against manufacturer data before use in commissioning certificates. The developer accepts no liability for losses arising from use of this app.

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