We spend 80 to 90% of our time indoors. Indoor air quality (IAQ) has become a major public health issue, brought into sharp focus by the pandemic. The HVAC commissioning engineer plays a central role: they are the ones who ensure ventilation systems deliver the regulatory fresh air rates.
Indoor pollutants
- • CO₂ (carbon dioxide): an indicator of poor ventilation. The recommended threshold is 1,000 ppm (French order of 2 May 2023). Above that, concentration drops and drowsiness sets in.
- • VOCs (volatile organic compounds): emitted by building materials, furniture and cleaning products. Formaldehyde is the most closely monitored (threshold: 30 µg/m³).
- • Fine particles (PM2.5, PM10): from outdoors (traffic, industry) or indoors (cooking, printers).
- • Radon: a naturally occurring radioactive gas, mainly in granite areas. The threshold is 300 Bq/m³.
Regulations and fresh air rates
- • Order of 24 March 1982 (French regulation): sets minimum ventilation rates in dwellings (e.g. 135 m³/h peak rate for a 4-room home).
- • French labour code (R4222-6): minimum 25 m³/h per person in offices, 45 m³/h in workshops.
- • NF EN 16798-1: the European standard that classifies IAQ into 4 categories (I to IV) and defines the associated airflow rates.
- • Decree no. 2015-1000: mandatory IAQ monitoring in public-access buildings (schools, nurseries) with CO₂ and formaldehyde measurement.
The commissioning engineer's role
- • Check fresh air rates at every supply terminal (flow hood, anemometer).
- • Check ductwork air-tightness to prevent leakage of polluted air.
- • Check that motorised dampers and fresh air dampers work correctly.
- • Measure CO₂ levels in occupied rooms to validate the air change rate.
- • Make sure filtration is appropriate (ISO ePM1 55% minimum in commercial buildings according to EN ISO 16890).
FIELD TIP
Install a CO₂ sensor in meeting rooms during commissioning: it is the simplest way to prove the ventilation is working properly and to persuade the facility operator not to cut airflow rates.