Fire Engineering & Electric Vehicles
Electric vehicles (EVs) are now a permanent part of the world we live in. Across Australia, certifiers and designers are increasingly being asked to approve EV charging infrastructure in residential buildings, commercial developments and public car parks.
One important point should be stated clearly: cars have always caught fire.
In fact, when adjusted for fleet size, global studies indicate that petrol and diesel vehicles are more likely to catch fire than EVs. So EVs are not introducing vehicle fire risk into buildings for the first time. What they are introducing is a different fire behaviour, which requires different engineering considerations and firefighting strategies.
Why do EVs Catch Fire
EV fires can originate from failures within the lithium-ion battery system. Common causes include:
- Battery manufacturing defects
- Physical impact (such as high-speed collisions)
- Internal short circuits
- External exposure to another fire
- Charging failures or overheating
- Water ingress
- Internal cell damage
When battery failure occurs, it can trigger a process known as thermal runaway. Thermal runaway is a self-sustaining chemical reaction inside the battery cells. Once initiated, the battery continues to generate heat and release flammable gases as it decomposes internally.
The National Construction Code Context
The NCC already includes EV-ready provisions for carparks, primarily within the energy efficiency sections. These provisions focus on electrical readiness rather than fire behaviour.
Car park fire design assumptions within the NCC were largely developed based on internal combustion engine vehicle fires. As EV adoption increases, this creates a potential gap between emerging hazards and prescriptive design guidance.
The Role of Fire Engineering
Fire engineering can incorporate emerging technologies and ensure not only life safety, but also property protection. Performance-based fire engineering can allow of testing of scenarios not explicitly addressed by DTS. This includes plume behaviour, detection timing and ventilation performance. It provides an evidence-based pathway where prescriptive guidance is limited.
Where prescriptive provisions are limited, fire engineering provides a structured, evidence-based pathway.
This webinar recording provides more insight into EV fire risks, statistics and assessment pathways. The full webinar is available for purchase here.
If you require fire engineering advice, risk assessment or performance-solutions for EV parking in your building, contact CJK Fire & Safety.