Parking lots standards and regulations

It is the technical instruction of March 3, 1975 relating to the ventilation and monitoring of the atmosphere in parking lots (regulation of parking lots or enclosed spaces where thermal vehicles are used) which regulates the safety rules to be implemented. Also to be taken into account, the notice of December 14, 1998 (published in the BO n° 99/7) on the limit concentrations of the exhaust gases present (carbon monoxide, nitrogen oxides, LPG and since recently hydrogen).

Ventilation of parking lots and smoke extraction

Extract from the technical instruction of March 3, 1975 relative to the ventilation and monitoring of the atmosphere in parking lots: Ventilation must be carried out in such a way as to efficiently prevent the stagnation, even locally, of noxious or flammable gases. In each compartment of the park (as defined in article 2) the limit values of carbon monoxide (CO) concentration are fixed as follows*: 

  • The instantaneous level shall not exceed 200 ppm; 
  • The exposure average value (EEV) calculated over a period of 8 hours shall not exceed 50 ppm;
  • The exposure limit value (ELV) calculated over a period of 20 minutes shall not exceed 100 ppm. 

When a fleet is likely to have more than 30% of its surface area covered by diesel vehicles, a limit value for other pollutants such as nitric oxide (NO) or nitrogen dioxide (NO2) may be imposed. The operator is responsible for compliance with these objectives. The operator will have to anticipate the emergency measures to be applied if the above-mentioned levels are reached. 

(*) Values to be respected whatever the carbon monoxide content of the air taken from outside.

Gas detection in parking lots 

By the notice of December 14, 1998 published in the French Official Bulletin n° 99/7, the French Superior Council of Public Hygiene on air quality in underground or covered structures recommends the following limit values whatever the size of the structure.

  CO concentration (carbon monoxide NO concentration (nitric oxide)
Instant value 150 ppm 150 ppm
Upon 15 minutes 90 ppm 2 ppm
Upon 30 minutes 50 ppm -

Underground parking lots and existing parking lots subject to the parking regulations for classified facilities must be equipped with a carbon monoxide (CO) detection system, and for those with a capacity of more than 500 vehicles also with a nitrogen oxide (NO) or nitrogen dioxide (NO2) detection system. 

All these measures are also applicable to road tunnels, underground roads and bus stations equipped with a mechanical ventilation system. The gas detection devices control the operating conditions of the structure in order to ensure that the quality criteria are respected. This installation must also allow : 

  • The control of the ventilation
  • The activation of the emergency signal

This installation can also be imposed when the geometry of the park, its attendance or the importance of the number of underground floors justify it. 

Even (and especially) for small parking lots (condominiums, small buildings, garages, technical centers, etc.), gas detection systems for parking lots offer a safety aspect with a permanent analysis of gas concentrations as well as an economic aspect with an optimum control of ventilation and smoke extraction systems.