Gas Detection for Garages

Cars today run on various types of fuel. Modern trends in alternative vehicle propulsion must also be reflected in the equipment of parking garages and underground garages. A significant number of people move around in underground garages, and at the same time, incoming cars produce toxic exhaust fumes. It is therefore necessary to protect people from the danger of poisoning. The most important elements we monitor when measuring emissions are carbon monoxide (CO), unburned hydrocarbons (HC), nitrogen oxides (NOx), and soot (PM). To maintain a safe environment, the garage must be equipped with forced ventilation and a detection system. According to the valid standard ČSN 73 6058 - Individual, row, and mass garages, the concentration of carbon monoxide CO is monitored. When allowing the entry of vehicles with alternative propulsion into an underground garage, the appropriate detection and ventilation system must also be present.

Detection of Carbon Monoxide in Garages

Carbon monoxide is a colorless, tasteless, and odorless gas, non-irritating. It is lighter than air but can mix with air. It is produced by incomplete combustion. There are two approaches, two possible solutions, for detecting carbon monoxide in underground garages. The first is a two-level detection according to ČSN 736058, where the concentration of CO is monitored at 26 ppm and 50 ppm. These values are derived from the maximum permissible limits for human health. The highest permissible concentration of CO is set for 30 minutes of human presence in the garage at 50 ppm. People in the garage must be informed about the maximum time of 30 minutes. The second value is prescribed with regard to an 8-hour working period of the staff, where the highest exposure limit (PEL) is 26 ppm. The standard prescribes the use of at least one sensor per 400 m2. It is assumed that the concentrations of other pollutants (nitrogen oxides, hydrocarbons, benzene C6H6, particulate matter) will be below the permissible limit with ventilation designed according to the airflow for CO removal.

Due to the high pressure on the ecology of cars, the amount of pollutants emitted from cars is decreasing. The current composition of vehicles is different, and the emissions of petrol engines are significantly lower than before. Nitrogen oxides have similar effects to carbon monoxide, attacking the lungs and mucous membranes. They are formed in the engine at high temperatures and pressures during combustion with an excessive surplus of oxygen. Some nitrogen oxides are harmful to health. Measures leading to fuel consumption reduction can lead to an increase in the proportion of nitrogen oxides in exhaust gases. The European standard EN 50 545-1 specifies limits in a more detailed structure than ČSN. This standard prescribes monitoring three levels of concentrations of CO, NO2, and NO.

In line with Czech and European normative requirements, Evikon detection systems can be used. To create a functional detection system, several components are needed. The basic component is the sensor itself for the concentration of the target gas. Individual sensors or combined sensors can be used. The information about the current concentration from individual sensors is processed by a suitable control panel, which signals the operator, activates operational, fire, and emergency ventilation. Last but not least, people in the garage are informed about the danger. As supplementary elements of the system, we offer a siren and light warning signs.

Detection System According to ČSN 73 6058 - Two-Level Detection

Detection System According to EN 50 545-1 - Four-Level Detection

Garages with Permission for Entry of Vehicles with Alternative Propulsion

Another major chapter is the issue of previously prohibited entries of vehicles with LPG, CNG, LNG, or hydrogen propulsion. Today's legislation and standards allow these entries if the garage is adequately equipped for these vehicles. The standard ČSN 73 6058 and ČSN 73 0804 describe the parking of vehicles on gaseous fuels in mass garages. The garage must be equipped with a detection system for the leakage of alternative fuel and effective forced ventilation. From the perspective of detecting hazardous gases, the standards prescribe switching levels at 10% LEL (Lower Explosive Limit), 20% LEL, and 50% LEL. At the first level, operational ventilation is activated, at the second, emergency ventilation, and at the third, a fire alarm is triggered. Considering the safety of people in garages, the fire alarm can be triggered already at 20% LEL.