Car parks are ubiquitous features of densely populated spaces. In fact, some national guidelines, like the Victoria Planning Provisions of Australia, require the provision of car parks to address the growing issue of street density. As integral as car parks are to urban infrastructure, recent events show, however, that there are emerging concerns with car park fires. Although fatality numbers are kept to a minimum as car parks are not expected to have several occupants at a given time, car park fires are still of concern since once spreading occurs, structural integrity is threatened.
Car park fires are attributed to numerous factors, one of which is increasing the demand for modern vehicles with batteries that have a superior power-to-weight ratio and recharging capabilities. As we began to power swankier and faster-processing mobile phones, we also started using these high-power-generating batteries for our vehicles. In part, we attribute the growing emergence of Electric Vehicle (EV) batteries or Lithium-Ion batteries (LIB) batteries to a wider global initiative to electrify vehicles to reduce greenhouse gas emissions. The technology, however, can pose a fire safety risk when incorrectly charged or damaged. It is important to assess if this has implications also for car park fire safety.
In this week’s issue of Burning Matters, we delve into the complex challenges posed by car park fires, emphasizing the importance of dealing with these through fire safety mitigations.
The discussion includes notable incidents such as:
The car park fire incident at the London Luton Airport Terminal 2, leading to a disruption of some 150 flights and around 30,000 stranded passengers;
An underground garage fire in an apartment complex in the Netherlands that caused 50 cars to be damaged and left 20+ apartments inhabitable and;
300 cars destroyed in the garage fire, which also resulted in a partial collapse, at the Stavanger Airport, Sola, Norway.
London Luton Airport and Stavanger Airport incidents
Are we still designing to the status quo?
On October 10, 2023, a vacationer returning from a family trip in Romania happened to dial 999 after spotting flames at the Luton Airport Terminal 2 [note (edit): multiple calls were received, also from the owner of the vehicle that was the origin of the fire]. Twelve hours later, the fire had spread through three levels of the airport garage, destroying around 1,500 cars, and causing a structural collapse of the multi-million-pound facility. This is not the first of car park fires in airports, as a similar incident was reported in 2017 of a parking garage fire at Stavanger Airport in Sola, Norway. Given that these two incidents are similar in nature, but occurred at different times and locations, it is crucial to reexamine our assumptions regarding car park design fires.
Garage Fire in the Netherlands
How safe are we designing for multi-use spaces?
Multi-use space garages pose higher challenges than open parking spaces due to the presence of residential and commercial zones, which increase the likelihood of people being present. There are not only concerns with passive and active fire protection but also a greater need to heighten security access against potential arson and increase emergency preparedness among residents. Unlike airport incidents, garage fires in apartment complexes require comprehensive fire safety protocols and detailed evacuation plans to ensure occupant safety.
Lessons learned
What then have been the lessons learned from these incidents?
1. Design Fire
Firstly, car park designs currently operate on the assumption that only 1-3 cars will be involved in the fires. Reports by NFPA (USA) [link], DBI (Denmark) [link] and RISE FR (Norway) [link] all point out that the design fire scenarios used for structural fire safety of car parks must be revisited. The reasons are:
A. Cars have become bigger while parking spaces have become smaller.
B. Modern cars have more plastic and thus a higher heat release rate (and are easier to ignite).
An interesting debate is thus whether one should aim for meeting the criterion of 1-3 cars burning or change the assumption to a larger number of cars burning. The former could possibly be achieved through larger spacing and installing sprinklers, while the latter would result in a need for higher fire resistance ratings of the structural elements, and system as a whole.
2. To sprinkler or not to sprinkler, that is the question
"Sprinklers may have made a positive impact on this incident." This quote was stated by the chief fire officer who arrived on the scene of the Luton Airport fire incident. The report by DBI in Denmark highlighted the need for sprinklers, and many argue that it is the obvious solution. That, however, depends on the objectives, which in some places are purely life safety based, while property protection (of key infrastructure) is considered elsewhere. A study that I was involved in found that sprinklers were not cost-beneficial if life safety was the objective (Alimzhanova, Spearpoint and Jomaas, 2022). Thus, it is not as simple as ‘well, sprinklers would have helped in this fire’ - there are many car parks, and the statistics and objectives will be the deciding factors for installing sprinklers or not.
3. Passive Fire Protection
A holistic approach requires that passive fire protection is evaluated. As it stands, some design guidelines recommend a structural fire resistance rating of 15 minutes. This must be increased to take into account the aspects from point 1, namely that the HRR is larger and that more than a few cars can be expected to burn. Different approaches to achieve higher fire resistance ratings are readily available, and they should be considered.
The design should also look to improve compartmentation in car parks to allow for large car parks to be divided into smaller sections by fire-resistant barriers.
4. Heat and smoke control
The car park fire near Engelen, the Netherlands, resulted in smoke and fire damage to a large number of apartments. For underground car parks, heat and smoke control is essential, and even more so when they are placed below housing or other infrastructure.
5. EV, ICE, Hybrid…
When discussing recent fire events in car parks, EVs are very quickly coming into focus. The fact, however, is that the fires in the Liverpool Echo Arena, the Sola Airport and the Luton Airport all started in a diesel car. In the extensive reports by DBI, RISE FR and NFPA, the main message has not been related to EV vs ICE cars. Rather, the general consensus is that bigger cars, smaller parking space, and more energy per car (due to plastics) result in easier spread and larger fires.
Thus, let us focus on achieving safer car parks rather than blaming the engine type of the cars that are parked there. This was also the opinion shared by Wojciech Węgrzyński. Note that the Fire Science Show has no less than 17 episodes on car park and tunnel fire safety.
What do you see as the best approach to improving car park fire safety?
More discussion will follow on this topic, and I am sorry to have left out all the discussion of firefighting solutions and active and passive devices that were promoted in the comments of the LinkedIn posts (see below). I am sure there will be time to evaluate these at a later point.
Grunde
I would love to hear your thoughts! Reach out through the Burning Matters feedback form.
Original LinkedIn Posts:
