A dual source
| Source | What it provides |
|---|---|
| Standardisation | sizing methods, definitions, systems |
| Regional energy regulation | binding force, performance requirements, checks |
The standard says how to size. The regulation says that it must be done and to what level.
That is a different configuration from acoustics, where the standard carries the whole, and from accessibility, where regulation carries the whole. Ventilation is therefore read in two schemes at once.
How ventilation became mandatory
A logical sequence explaining the current position. It starts from airtightness and ends at controlled ventilation.
Improved airtightness of buildings, driven by energy requirements, removed the incidental air changes that previously provided de facto ventilation. Without organised ventilation, indoor air deteriorates.
Tightening insulation without organising ventilation creates a health problem, humidity, condensation and degraded indoor air quality.
That is why regional energy regulations incorporated ventilation requirements, inseparable from those on insulation and airtightness. The two subjects are therefore treated together.
The regional energy framework is covered in the guide on construction costs per m². The thresholds are given region by region there.
What it imposes at design stage
Four consequences, all structural.
Flow rates determine sections. A correctly sized ventilation system requires ducts whose bulk must be allowed for, including in ceiling heights and suspended ceilings.
Routes cross structure. Openings and penetrations must be coordinated with the structure, not improvised during construction.
Supply and extract structure the plan. The principle of air transfer requires coherence between rooms, which constrains layout.
Noise from services is a requirement in its own right. The acoustic standard sets limits on noise produced by ventilation, which may require acoustic treatment, as the article on acoustics between dwellings recalls.
Why it is poorly verified after the fact
The point distinguishing this field from the other two in the branch. Ventilation is measured and adjusted after commissioning.
A ventilation defect is not visible. Unlike an insufficient clear width or failing acoustic insulation, it is not immediately established.
Its effects appear over time, as condensation, mould or discomfort, often after several heating seasons.
The causes are multiple, which complicates attribution: design, execution, commissioning or use may all be involved.
Hence the importance of commissioning and of documenting it at handover, and of informing the occupant, since a correctly designed system can be rendered inoperative by blocking or switching off.
How this interacts with other requirements
Three recurring tensions, to be resolved at design stage. They set ventilation against acoustics, energy and cost.
With acoustics, wall penetrations and equipment noise.
With fire safety, compartment penetrations and dampers.
With energy, the balance between adequate air change and limiting heat loss, which drives the choice of system.
What this means for a professional
Four rules.
Look for requirements at regional level, in energy regulation, not in federal texts.
Size before distributing, since sections govern bulk.
Document commissioning at handover, or attributing a later defect will be impossible.
Inform the occupant, since a deactivated system produces exactly the defects it was meant to prevent.
This article reflects the position of the rules at the date of checking and serves professional orientation. It does not constitute legal advice and does not replace consulting the applicable texts.