1. Tell us about EV fire risk
Electric vehicles (EVs) are still a relatively new technology and there’s little published data on how they perform in a fire. While there’s plenty of research being done globally, we’re largely unaware of the fire hazards, the most appropriate mitigation measures and what’s an acceptable level of risk.
What we do know about EV fires
At the time of writing – June 2023 – the occurrence of EV fires is low compared to internal combustion engine vehicle fires. However, the industry is moving at a rapid rate and new battery manufacturers, battery chemistry and battery quality are emerging daily.
In simple terms, we know that fires are caused by the battery in an EV. When a battery undergoes thermal runaway, significant heat and combustible gas is produced which can result in rapid fire growth with an intense flame jet and high temperatures. The fires release a toxic smoke due to metal oxides from the battery.
We also know the potential fire size is greater due to the increased possibility of fire spread from the initiating vehicle. Reignition of the batteries after the initial extinguishment may also take place.
What don’t we know about EV fires
There’s a lot that we don’t know, including the impact of:
- the rapid increase in number of EVs in the built environment
- different battery manufacturers, battery chemistry and quality
- ageing vehicles and batteries, including minor impacts and mechanical damage
- the range of charger types and their combination with various battery types.
Businesses, authorities and researchers around the world are studying EV fire behaviour to better understand how a fire interacts with other vehicles, its impact on fire safety systems and building structure.
2. What are the building regulations my business needs to follow when it comes to electric vehicles?
Australia
The Australian regulations, published as part of the National Construction Code (NCC), require new buildings to include electrical infrastructure which accommodates the installation of EV charging stations. They don’t currently include additional measures to address the potential fire safety risks associated with EVs and EV chargers.
EVs present different challenges to building fire safety because the fire characteristics are very different to a traditional internal combustion engine that building design and fire testing is based on.
The Australasian Fire and Emergency Service Authorities Council – the national body for fire and emergency services – has identified the potential gap in the NCC by requesting that EV charging stations are considered by design teams as a ‘special hazard’. This would typically require a fire risk assessment or performance-based fire engineering solution.
In response to this, the Australian Building Codes Board has recently (June 2023) issued a guidance document on recommendations to address some risks associated with EV chargers. However, this guidance is non-committal with respect to any required enhancements or minimum requirements for detection, occupant warning, sprinkler protection, smoke exhaust or minimum structural fire ratings and suggests specialist fire safety assessment.
United Kingdom (UK)
In the UK, the current regulations (Part S of Schedule 1 of the Building Regulations) suggest that EV charging points pose a fire safety risk and therefore discourage their installation inside buildings. Although the risk is acknowledged, there is a growing demand for charging units to be provided within buildings. The introduction of Part S and its accompanying guidance document, Approved Document S, does not provide any specific guidance on fire safety aspects related to electric vehicle charging within buildings. However, there are research documents, guidance documents and recommendations from insurers that offer guidance on the location of charging units for electric vehicles. Furthermore, some non-UK national agencies have also published documents highlighting issues with electric vehicles and their charging. It’s important to note that this topic is continuously evolving, and this publication aims to reflect the available information as of June 2023.
New Zealand
Similarly, New Zealand does not have formal prescriptive requirements for the fire safety provisions for EV chargers. How this is addressed will therefore be on a case-by-case basis and subject to review by the fire safety engineer on the project, until more formal guidance is released.
All regions
The installation of EV chargers will therefore require an assessment by a suitably qualified fire safety engineer, in consultation with the respective design team. Fire safety requirements differ depending on:
- whether the building is new or existing
- building classification
- building layout
- existing and proposed fire safety systems
- number of EV chargers proposed
- location of EV chargers
- local brigade requirements.
3. Are the current EV regulations likely to change?
We believe the regulations globally will evolve to pick up a consistent set of national fire safety measures. The driver for this will be to ensure buildings:
- achieve a minimum level of safety and performance
- are not over-designed and incur costs for onerous provisions that are disproportional to the benefit.
4. What’s the fire risk for my building?
Risk is a combination of the likelihood of an event and the consequence of that event occurring. We consider both life safety and property protection when carrying out risk assessments with building owners.
Likelihood
The likelihood of an EV fire depends on:
- the number of vehicles in circulation
- the quality of battery manufacturers and battery chemistry
- how vehicles and batteries age, including minor impacts and mechanical damage
- the range of charger types and their combination with various battery types.
As technology is moving so quickly and we have insufficient sample size to provide any meaningful historical data, the likelihood of a fire isn’t easy to predict.
Codes and regulations will take time catch up with the emerging technology and for a standardised approach to be established. This will be driven by the need to fully understand the risk. Until that time, the assessment of that risk will be left to the project design team, largely led by a fire safety engineer, with stakeholder consultation that includes the fire brigade, building owners and insurers.
Consequence
The consequence of an EV fire can vary significantly depending on:
- fire resistance levels of building structures
- the effectiveness of traditional fire sprinkler systems
- the ability for fire spread to other vehicles
- the effectiveness of traditional car park smoke hazard management and exhaust systems to facilitate egress and brigade intervention.
Recorded cases of EV fires have fortunately not resulted in any fatalities or major property loss. However, based on the nature of the rapidly developing fires and temperatures involved, these could be potential consequences if not properly considered.
We don’t, yet, have sufficient information or real life examples to fully understand the consequences of fires in different situations. The industry is still carrying out testing to better understand the interaction of EVs with traditional building fire safety systems and firefighting methods.
5. What should I look for in an EV risk assessment?
A risk-based approach to identifying and addressing EV hazards is a valid approach, given the limited prescriptive requirements for chargers.
- A risk assessment can identify some EV fire risks, based on our current knowledge. However, the acceptable level of risk can be different depending on the fire safety advisor and their role. It’s therefore important to have as many stakeholders involved in a risk assessment as possible.
- With any risk assessment and fire safety strategy, weigh up the proposed fire provision costs with the potential benefits. A good building design will avoid over-design that incurs costs for onerous provisions that are disproportional to the benefit.
- You should also consult with the building’s insurer during the risk assessment process to make sure your level of cover is sufficient for the risk proposed. Certain design elements may be viewed as high or low risk to insurers and this could impact ongoing insurance premiums or even invalidate a building’s insurance. It’s important a building owner is across this to help with their decision-making process.
- Codes and regulations differ across the world and they’re taking time to catch up with the emerging technology. You should always carry out an assessment, largely led by the fire safety engineer, with stakeholder consultation that includes the fire brigade, building owners and insurers.
- Be wary of a fire safety professional who promises definitive answers – this is an emerging sector and there’s still so much that’s unknown. This ranges from suppliers of products or practitioners that provide a one size fits all approach.
6. Is it safe to install EV charging stations in my basement car park?
There’s no such thing as zero risk, unless you ban EVs from buildings altogether. However, with the push from governments to encourage the adoption of EVs, combined with consumer uptake, this doesn’t seem to be a feasible option in the long term.
There’s an existing risk to life safety in any car park, even without EVs. However, internal combustion engine cars have been around for over 100 years. Fire testing and real-life fires have been used to develop fire safety provisions for these cars based on society’s acceptance of the risk of fatalities and major injuries in car parks, which is low. These provisions were developed over many years as both the vehicles and buildings evolved over time.
To establish an acceptable level or risk, we need to assess real-life events, their frequency and consequences. EVs are a new technology and there are currently insufficient statistics and data to provide a reliable probabilistic risk assessment that can determine an equivalent level of risk.
We recommend carrying out a risk assessment and developing a fire strategy for your car park that considers life safety as well as the specific property protection drivers for the project. Life safety will be a universal consideration, however the importance of property protection and business continuity can vary depending on the type of building, size of building, owner and insurer.
7. How can I reduce the likelihood of an EV fire?
The likelihood of an EV fire in your building increases with the number of EVs. EV chargers will increase the number of EVs parked in your car park. While some building owners are considering no EV or EV chargers in their buildings until more information is available, the trend for EV sales, government incentives and building code requirements makes this impractical in the long term.
Building owners have very limited control over a tenant’s EV and its maintenance. Consequently, the primary measures that can be done by a building owner to reduce the likelihood of an EV fire are:
- install slow or medium chargers in lieu of fast chargers which add energy at a slower rate to the battery. This increases the charge duration and likelihood of overcharging that could lead thermal runaway
- install chargers from reputable companies with charge management monitoring and safety cut offs and isolation.
Building owners and body corporates could also consider creating management procedures and policies for their buildings. For example, in an apartment building this could include a building registration scheme to register all EVs with an obligation on EV owners to submit documentation to demonstrate service history and battery health.
8. Will a fire safety strategy (and its execution) be expensive?
An EV fire safety strategy isn’t expensive as you think. A risk assessment for both new and existing buildings should look to implement measures that are cost effective, with each recommended measure adding real value.
It’s important to include as many stakeholders as possible in a risk assessment to help identify potential mitigation measures and consider their practicality, buildability and effectiveness. This can include both engineering measures and controls as well as management controls.
Example fire mitigation measures include:
- choosing locations away from exits and close to smoke exhaust points, or above ground and naturally ventilated
- enhanced fire safety systems including smoke detection, suppression or smoke exhaust
- using additional fire breaks to contain a fire.
The outcome of any risk assessment will be subject to the specific building and stakeholders involved.
9. How will fire safety measures impact the design of my building and car park?
Any recommended fire safety measures will be tailored to your building and its specification. A large, modern building which already includes a majority of the fire safety systems available will likely only need minor improvements to engineering and management controls.
Older buildings are likely to require more upgrades, particularly if the existing car park has no automatic fire sprinklers or has had the fire rating to structure reduced.
There are a number of fire detection and suppression solutions being developed and tested to combat the risk of EV fires. However, the effectiveness of these varies. Any bespoke solution will also take time to be ratified in standards or codes, based on no current test standards to demonstrate effectiveness against EV fires. Therefore, none of the new technologies would be certified or used as part of a prescriptive approach. The use of any such systems should include a cost-benefit analysis and may require performance-based solutions, recommended by a fire engineer.
10. What should I do about e-bikes, scooters and skateboards?
E-bikes, e-scooters and e-skateboards present a similar hazard to EVs due to their batteries. Their batteries are smaller than EV batteries, however, and any fire will be smaller.
The obvious hazard associated with thermal runaway of the battery is the rapid development of a fire and the risk it poses with respect to occupant evacuation. If a fire occurs near an exit, this could result in a blocked exit much faster than a typical fire which smoulders longer before transitioning to flames.
Similarly, where fire strategies require strict fuel load and ignition source controls, the introduction of e-scooters and the like could compromise such strategies. An example of this is in trains and stations. In London, e-scooters have been banned from the underground network due to the potential risk attributed to the varying quality and type of those vehicles.
Another challenge with e-bikes and e-scooters in buildings is managing or controlling where they’re located in a building as they are portable and many include removable batteries that can be charged through any available power socket. A key mitigation in office buildings, for example, could be to provide dedicated charging facilities within a fire isolated end-of-trip facility, away from egress routes.
A fire safety engineer can help you establish fire safety measures and policies tailored to your building and its specification.
