Design built-in underground parking begins with an analysis of the planning restrictions of the site and determination of the structural fire hazard class of the building. According to the updated editions of the codes of practice, the placement of parking spaces directly under residential sections requires strict adherence to zoning and the use of fireproof materials for floors. Utility networks passing through the parking area must be protected from mechanical damage and have access for maintenance without vehicles entering. Errors at the preliminary design stage often lead to the impossibility of agreeing on documentation during the examination, since the requirements for evacuation and smoke removal are a priority.
The construction of such facilities is regulated by strict standards that dictate the number of floors, floor area and the type of design solutions used. SP 113.13330 establishes that built-in parking lots can have up to three underground floors, but only if they are equipped with automatic fire extinguishing systems. Each level must be divided into compartments by fire walls and gates, ensuring the localization of the fire within one zone. In this case, it is important to take into account the hydrogeological conditions of the site, since the presence of groundwater requires enhanced waterproofing and a drainage system.
The primary task when creating underground parking is to ensure the safety of people and the safety of cars in the event of an emergency. Fire requirements dictate the need to divide the building into fire compartments using structures with a fire resistance limit of at least REI 150. Exits from staircases should lead directly outside, bypassing the parking area, or through a vestibule with air pressure. Particular attention is paid to materials for finishing walls and ceilings, which must be non-flammable and not emit toxic substances when heated.
System smoke removal designed based on the area of the room and the number of parking spaces. Mechanical exhaust ventilation should turn on automatically when smoke detectors are triggered, ensuring the removal of combustion products and the supply of fresh air for fire crews. Fans must be designed to operate at 400°C for a specified period of time. Smoke exhaust ducts are made of steel with a thickness of at least 1.5 mm and are protected with a fire-retardant coating.
Emergency lighting and public address systems play a critical role in organizing an evacuation. Lamps must operate from independent power sources and provide illumination at floor level of at least 0.5 lux. The sound warning should be audible at any point in the parking lot, drowning out the noise of running engines and ventilation systems. Fault tolerance of security systems is checked upon acceptance of the object and during annual tests.
⚠️ Attention: It is prohibited to place storage rooms, workshops and any premises with permanent occupancy of people not related to parking maintenance in the built-in underground parking lots.
Classification of parking lots by capacity
Small parking lots (up to 50 parking spaces) have simplified evacuation requirements. Medium (51-100 m/m) require two emergency exits. Large ones (more than 100 m/m) are subject to mandatory equipment with automatic fire extinguishing and crushing systems into compartments with an area of no more than 3000 sq.m.
The structure of the underground part of the building experiences significant loads from the weight of the overlying floors and soil pressure. The foundation slab is made of concrete of a class not lower than B30 with waterproof mark W8-W12 depending on the groundwater level. Columns and walls are designed taking into account the possible impact of a car, therefore corners and protruding parts are protected by bumpers no less than 0.5 meters high.
For floors above a parking lot, a beamless structure or slabs with voids are often used, which allows the floor height to be reduced and the necessary communications to be placed in the ceiling space. The thickness of the slab is determined by the calculation of column punching. Expansion joints divide the building into compartments, compensating for thermal expansion and uneven soil settlement. Seams are sealed with elastic materials that are resistant to deformation.
Waterproofing is key to the longevity of an underground car park. A combined protection method is used: penetrating concrete waterproofing, adhesive insulation of external walls and injection systems for concreting working joints. A drainage system around the foundation moves water away from the structure, reducing hydrostatic pressure. Internal gutters and gutters must be made of corrosion-resistant materials.
Use fiber-reinforced concrete for floors and floor slabs of underground parking lots - this significantly reduces cracking and increases the water resistance of the structure without increasing the thickness of the protective layer.
| Parameter | SP requirement | Note |
|---|---|---|
| Room height | Minimum 2.0 m (to the bottom of structures) | For passenger cars |
| Passage width | Single sided: 3.5 m | Double sided: 6.0 m |
| Seat size | 2.5 x 5.3 m (standard) | For disabled people 3.6 x 5.3 m |
| Ramp slope | Maximum 15% (1:6) | With grooves across the movement |
Engineering support for an underground parking lot includes a complex set of systems operating in automatic mode. Ventilation is carried out according to a scheme that provides for the removal of polluted air in the lower zone and the influx of fresh air. Carbon monoxide concentration sensors CO regulate fan performance, saving energy during idle hours. In the event of a fire, the system switches to smoke removal mode, closing the supply valves in the fire zone.
Electricity supply is carried out according to the first category of reliability, since stopping the ventilation and drainage systems is unacceptable. Cable routes are laid in trays with a fire-retardant coating or in grooves. Switchboard equipment is located in dry rooms with a separate exit. System automatic fire extinguishing (most often sprinkler or aerosol) must cover 100% of the area of parking areas.
Water disposal and sewerage require the installation of oil and petrol separators before discharging wastewater into the city network. Stormwater from entry ramps is also treated. In low areas of the floor, ladders are installed with gratings that can withstand the load from the wheels of the car. Forced drainage pumps are equipped with level sensors and backup pumps in case of failure of the main ones.
The organization of traffic inside the parking lot should exclude the intersection of traffic flows of cars and pedestrians. The markings are applied with wear-resistant paints; retroreflective elements are required for marking columns and corners. Signs and indicators are placed at a height that prevents them from being damaged by oversized vehicles. Entrance and exit ramps are equipped with anti-icing systems and enhanced ventilation to remove exhaust gases.
Operational safety is ensured by a video surveillance system covering all areas, including blind spots. Access to the territory is controlled by barriers and card readers. Lighting should be uniform, without sharp transitions from light to shadow, which is especially important for CCTV cameras. Emergency exits for special equipment must always be free of temporary barriers.
⚠️ Attention: Operation of the built-in parking lot is prohibited if the smoke removal system or automatic fire extinguishing system is faulty, even if the parking lot is partially filled with cars.
☑️ Checking parking readiness
Compliance with all regulatory requirements when designing and constructing built-in underground parking lots guarantees not only the successful completion of the examination, but also the safe operation of the facility for decades. Integrating a parking complex into the structure of a residential building requires an integrated approach that takes into account the interaction of all engineering systems. Modern technologies make it possible to create comfortable and safe conditions for storing vehicles even in dense urban areas.
Regular maintenance of the life support systems of the parking lot is a prerequisite for its functioning. Owners of premises must provide access to services to carry out routine maintenance. Only the joint responsibility of designers, builders and operators allows us to maintain a high level of safety.
The main principle of designing a built-in parking lot is the priority of fire safety and the ability to quickly evacuate people over the convenience of accommodating the maximum number of cars.
Frequently Asked Questions
What is the minimum ceiling height in an integrated underground car park?
According to the joint venture, the minimum height from the floor level to the bottom of protruding structures (ventilation, pipes, beams) must be at least 2.0 meters for passenger cars. For mechanical parking or special equipment, the height is calculated individually.
Is it necessary to have an automatic fire extinguishing system?
Yes, for built-in underground car parks with an area of more than 3000 sq.m or when located on more than two underground floors, the presence of an automatic fire extinguishing installation (AFE) is a mandatory requirement.
Is it possible to store gasoline and oils in the garage?
Storing flammable liquids (gasoline in cans, oils) in quantities exceeding the needs of one car (usually no more than 20 liters in a sealed container) in built-in parking areas is prohibited by fire regulations.
Is there a need for a vestibule at the exit from the staircase?
Exits from staircases leading from residential floors must have a vestibule with air pressure when exiting into the parking lot in order to prevent smoke from evacuation routes.
What slope is allowed for entry ramps into underground parking?
The maximum longitudinal slope of ramps for vehicle traffic should not exceed 15% (1:6). On straight sections, it is allowed to increase the slope to 10-12% with appropriate justification, but with obligatory corrugation of the surface.