A car park is not just a place to park vehicles motor; staff work there all day long; the public enters and leaves it at will. Ventilation must be carried out in such a way as to oppose effectively to the stagnation, even local, of harmful or flammable gases.

Depending on the size of the car park, it is highly recommended, even mandatory, install a carbon monoxide (CO) detection system, and nitrogen oxides (NO and NO2) to regulate a ventilation system and / or to provide an indication, an alarm or any other warning signal from a danger of toxicity. National and local regulations may not require detection of NO or NO2 (in the case of Germany for example) but impose the detection of LPG gas (case of the Netherlands).

Permanent mechanical ventilation is expensive and ventilation by the hour fixed does not provide effective security. An automatic detection installation improves efficiency, safety and saves operating costs.