Protecting against car park fires – How to Prevent and Minimize Risks

Different types of cars are associated with various risks, and nowadays, there is a higher likelihood of multiple vehicles being involved in a car park fire. This increase can be attributed to the demand for energy-efficient transportation, which has led to the use of lighter components, including more plastic. Consequently, the fire load of modern cars has increased. Additionally, the combination of more plastics on the exterior surfaces of vehicles and the fact that cars are now more tightly spaced due to their increased size while parking space remains unchanged promotes the propagation of fire across multiple cars. Moreover, it is important to note that many fuel tanks are made of plastic materials, which can result in the release of fuel if the tank is exposed to heat during a fire event. Furthermore, the introduction of electric vehicles and their charging process introduces new risks.

An uncontrolled fire in a modern car park has the potential to cause severe damage to the loadbearing frame, including structural collapse, even for heavy construction materials like concrete. In some cases, the damage may be so extensive that replacement becomes necessary. However, by implementing preventive measures and promoting safe parking practices, it is possible to save lives, protect vehicles, and preserve buildings.

 

How many cars may be involved in a car park fire?

In the past, car park fires typically involved only one car. However, recent experience has shown that car park fires can now potentially involve a significant number of vehicles. As observed in the example below, these incidents may result in the involvement of 100 or more cars.

 

 

What about electrical vehicles?

Electric vehicles, including hybrid cars, commonly utilize lithium-ion batteries with varying chemistries and capacities to store energy. Recent fire incidents have highlighted the challenges associated with handling fires involving these batteries, both for automatic fire protection systems and manual firefighting efforts.

 

When water is applied to extinguish and cool lithium-ion fires, it can lead to the release of hydrogen, hydrogen fluoride, and other toxic, corrosive, and flammable components. This presents an increased risk to firefighters and other individuals involved in fire suppression operations. In enclosed or below ground charging and parking areas, the presence of these toxic and flammable gases can create additional obstacles, potentially delaying or preventing effective manual firefighting.

 

Furthermore, the release and generation of chemical byproducts during such fires can cause contamination and corrosive effects, leading to increased property damage. It is crucial to be aware of these risks and take appropriate measures to address and mitigate them during firefighting operations involving electric vehicles and their lithium-ion batteries.

What considerations should be made for the fire protection of modern car parks?

Given the history of car park fires rarely involving more than one car there was a sense that automatic sprinklers were not always needed. Often, local codes do not require automatic sprinklers in aboveground, open-sided car parks. Local codes may require sprinklers in underground or enclosed car parks, and in car parks under or attached to other occupancies.

The current design requirement for sprinklers (wet-pipe) in car parks is often set at a low rate of 5.0 mm/min over 144 m². However, this design is based on car parks that do not account for the materials and layout of modern vehicles.

 

Considering the increased fire risks posed by modern cars, we recommend considering the provision of sprinkler protection designed for a higher rate of 12.5 mm/min over 260 m² when utilizing a wet-pipe system.

Research indicates that automatic sprinkler protection can be effective not only for conventional cars but also in containing lithium-ion battery fires within their area of origin, such as within a vehicle. Sprinkler systems offer the ability to initiate alarms, help prevent fire spread between vehicles, and limit damage to the building structure. However, due to the location of the batteries inside a vehicle, it is unlikely that sprinkler water will reach or cool the burning vehicle battery itself.

 

Guidance on automatic sprinkler protection for car parks is continuously evolving, and Zurich is actively engaged in ongoing research conducted by the NFPA Research Foundation.

What additional preventive measures should be considered for electrical vehicles?
When considering electric vehicle charging and parking areas located inside buildings, the following preventive measures should be taken:

 

• Charging and parking areas should be located as close as possible to the car park entrances or exits, preferably on the ground level, to facilitate public fire service access.

 

• When the building is not solely dedicated to car parking, the area should be provided with at least 1-hour fire-rated separations from other building occupancies to reduce the potential fire and smoke damage to other areas of the building.

 

• Electric vehicle charging and parking areas should be equipped with automatic fire detection systems. Fire detectors should be installed to monitor the charging stations and electric vehicles, and alarms should be automatically communicated to a constantly attended location where action can be taken to report the fire to the public fire service.

 

• Battery failure and thermal runaway events may involve the release of flammable gases. If this occurs in a confined area, such as inside buildings, the flammable gases may accumulate and create an explosion hazard. Mechanical exhaust ventilation systems should be installed to keep flammable vapours below 25 percent of their lower flammable limit, and these systems should operate continuously or be activated by combustible gas detectors.

 

When electric vehicle charging and parking is located outdoors, the charging should be located at least 10 meters from combustible walls or at least 7.5 meters from unprotected openings in non-combustible walls.

 

 

 

For more information on how Zurich Resilience Solutions can help your company meet tomorrow prepared by offering data-led risk engineering and risk management services, contact Mikael Karlberg.