PARKING LOT VENTILATION and smoke removal
Extract from French technical instruction on parking lots ventilation and monitoring: The ventilation system has to efficiently remove even local harmful or flammable gas stagnation. In each car park compartment, carbon monoxide (CO) concentrations are set as follows*:
- Instant concentration shall not exceed 200 ppm
- Time-weighted average value (TWA) calculated upon 8 hours shall not exceed 50 ppm
- Exposure limit value (ELV) calculated upon 20 minutes shall not exceed 50 ppm.
Once a car park may contain diesel-powered vehicles on more than 30% of its surface, it is required to set limit values for pollutant gases like nitric oxide (NO) and nitrogen dioxide (NO2). The owner is responsible for complying with these standards. Emergency actions has to be set as well in case of above values are reached.
(*) Values to respect regardless to outdoor carbon monoxide concentration.
PARKING GAS DETECTION
European regulations on air quality in underground or enclosed structures recommends following values regardless to site size.
CO concentration (carbon monoxide)
NO concentration (nitric oxide)
Upon 15 minutes
Upon 30 minutes
Underground and existing car parks are regulated under classified installations and must be equipped with carbon monoxide (CO) gas detection system. Structures that may contain more than 500 vehicles must furthermore have a nitrogen oxides gas detection sytem – for nitric oxide (NO) or nitrogen dioxide (NO2).
All of these provisions also apply to road tunnels, underground roads and bus terminals equipped with a mechanical ventilation system. Gas detection systems control structures operating conditions in order to comply with quality requirements. This installation has to control:
- Ventilation actuators
- Emergency signal triggering
A gas detection system can also be required if the car park design, attendance or underground levels number justify.
Even for – and above all – micro-parkings like joint ownership, small buildings, garages, technical centers… gas detection controllers provide safety aspect with a gas concentration permanent monitoring and economic aspect with optimal ventilation and smoke removal activation.