Tools — Duct Pressure Loss

Duct pressure loss

Draw a ventilation duct system diagram and get per-branch pressure loss, air velocity, required static pressure, and the critical path. Compare the result with the fan's P-Q curve to see both the pressure the fan can deliver at the target airflow and the actual operating point.

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What it does

01Draw the system as a tree (fan → branches → terminals), placing ducts, reducers, filters, air conditioners, and terminals as parts
02Per-branch velocity, pressure loss, and cumulative loss are computed automatically, with the critical path highlighted
03Shows the required static pressure (upstream + downstream critical) and the operating point on the catalog P-Q curve, side by side
04Multiple systems in one file (SA / RA / EA, multiple fans) — handle supply and exhaust together
05Built-in diagnostics flag unconnected parts, zero airflow, size mismatches, and terminal-type inconsistencies
06Pick a catalog part and you get its loss coefficient ζ; computation uses Darcy-Weisbach + ζ (based on PHJ 2026 duct seminar v1.0)

A few things to know

Guest mode does not save your work. Screenshot the result or export to PDF if you need to keep it
The catalog ships with representative parts. To use a specific fan, enter `airflow,static-pressure` points in the fan's P-Q field, one per line
The model is incompressible and isothermal. High pressures or extreme temperatures need separate consideration