Design outdoor airflow calculator: inputs, result and limits
Which inputs are required?
n is simultaneous design occupancy, not average attendance. Select qp and qB from the agreed indoor-environment category and applicable national requirements. Defaults of 7 l/(s·person) and 0.7 l/(s·m²) represent German National Annex category II for a low-polluting single office; that classification must fit the project. AR is occupied-zone floor area. Net room volume is used only to express the result as air changes per hour.
What is returned?
Results include total design outdoor airflow in l/s and m³/h, separate people and building components, area-specific airflow, people share, and calculated air-change rate. Air changes per hour are a plausibility indicator, not an independent design criterion in this method.
Method and interpretation
DIN EN 16798-1 equation (1): qtot = n·qp + AR·qB. The people component dilutes occupant-related pollution and the area component addresses building emissions. Convert with 1 l/s = 3.6 m³/h; divide m³/h by net room volume for air changes per hour.
Calculator limits
This addition method is used here for occupied non-residential rooms. Dwellings, pollutant mass balances, CO₂ targets, intermittent occupancy, and purge ventilation require other methods. Supply/extract balance, transfer air, infiltration, diversity, heat recovery, fan power, acoustics, and ventilation heat load are excluded.
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Source: Locally held DIN EN 16798-1:2022-03, section 6.3.2.2, equation (1), and German National Annex NA.5, particularly tables NA.6 to NA.8. The defaults represent category II for a low-polluting single office.