Airflow from ACH Calculator: worked example
This example is generated from PROFENG's own default input set and the implemented relationship. It is not copied from a cited publication.
Relationship
V̇ = ACH×room volume/3600
This calculator determines required airflow from target air changes, room volume. Use it for HVAC and building-services screening with transparent air, thermal or flow assumptions.
Inputs
- Target air changes (ach) = 6 ACH
- Room volume (volume) = 300 m³
Working
(6)*(300)/3600 = 0.5 m³/s
Required airflow: 0.5 m³/s
Assumptions and limits
- Air or fluid properties are represented by the entered values.
- The calculation represents steady operation unless the formula explicitly includes time.
- Room, duct or envelope geometry is idealized by the displayed relationship.
- ACH represents the target air-change rate for the effective room volume.
- The result is a steady average airflow and does not by itself establish ventilation-code compliance.
Formula source and acknowledgement
ASHRAE, ASHRAE Handbook—Fundamentals, 2025 volume, 2025, ASHRAE. Credit belongs to the cited author(s)/publisher; PROFENG presents its own implementation and does not imply endorsement.
Automated verification passed – 30 September 2026 – six numerical cases checked, with dimensional checks and an independent implementation where applicable.
This worked example is for engineering screening and education. Replace defaults with traceable project data and confirm the method, assumptions, standards and equipment information before design, procurement or operation.