SHEV: Underground car parks
Our objective is to create a pleasant and healthy atmosphere in underground parking garages that enhances the safety of users (both individuals and emergency services). In RWA systems for parking garages, smoke gases and heat are extracted. Ventilating enclosed parking garages is a specialized field. Due to the building’s design (multiple levels below ground) and its specific function (parking vehicles), it deserves our particular attention.
To meet the specific requirements of parking garages, our ventilation systems for enclosed garages have been developed and refined through many years of experience.
The application of this ventilation system is twofold:
- Daily ventilation (optionally linked to a CO detection system)
- SHEV ventilation (controlled smoke and heat extraction in case of fire, linked to smoke detection).
The ventilation system optimally ventilates the enclosed garage and, due to its design, is much more effective and higher performing than conventional ventilation systems (based on smoke accumulation within smoke compartments).
1. Daily Ventilation
The ventilation is adapted to the actual occupancy rate of the car park and continuously monitors the air quality throughout all corners of the parking area. When vehicles circulate in a closed space, the CO level automatically increases. The proposed impulse ventilation system maintains constant air movement in the garage to ensure optimal air quality in all areas, including the farthest corners.
Air supply and extraction are achieved through structural shafts equipped with large axial fans. Impulse fans are mounted on the ceiling of each level to ensure a continuous and uniform airflow. The system is connected to a CO detection control unit. When the CO concentration in the parking area rises, the system will automatically switch from its standard daily ventilation to higher airflow levels.
2. SHEV Ventilation
In the event of a vehicle fire in the parking area, the generated smoke and heat will be fully and carefully extracted through predefined and calculated corridors (smoke zones). All evacuation routes that do not border these smoke zones will remain visible and accessible at all times. The optimal placement of air supply and exhaust points is carefully determined based on the layout of the parking facility. The air volume and the ideal configuration of the impulse fans are precisely calculated.
Air supply and extraction function in the same way as with CO ventilation, but are now fully concentrated on the area of the burning vehicle. All actions are taken to direct a maximum air flow over the fire at high speed. Only those fans that are strictly necessary for smoke extraction will be activated. Using aerodynamic principles, we create a virtual compartment that channels the smoke in a controlled manner to the extraction shaft. A smoke-free path up to 15 meters from the burning vehicle is maintained, enabling firefighters to intervene directly at the source of the fire. An addressable smoke detection system is essential. Smoke evacuation must comply with the NBN S 21-208-2 installation standard.
Benefits
The system offers many advantages in terms of the design and management of the parking garage compared to conventional ventilation systems based on smoke accumulation within smoke compartments in the event of fire.
Ventilation System Benefits
- Better mixing of ventilation air with polluted air, resulting in lower concentrations of contaminants in the mixed airflow.
- Improved ventilation in all areas and corners of the parking garage due to the induction effect of the impulse fans.
- No ductwork system required, resulting in significant space savings.
Benefits for Users
- Continued accessibility of the entire parking garage (including the fire source) for emergency and rescue services.
- Safe evacuation of customers is guaranteed.
- No major structural damage to the building above the fire source, due to the significant cooling effect of the high airflow rates.
CFD Simulation
To predict the situation in the parking garage during a car fire, a CFD (Computational Fluid Dynamics) simulation is carried out. A three-dimensional model of the parking garage is created for this purpose. The technical installations, fire source parameters, and the ventilation system are then integrated into the model. Once the model is equipped with the corresponding physical parameters, it is ready for simulation. Using the finite volume method, the mass, momentum, and energy balances are solved at each time step.
The simulation results are analyzed per time step for various variables.
