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Sustainability and fire safety – mitigating the hazards of new energy technology

Fire Engineering By Steven Reilly, Principal Engineer - Fire & Life Safety Lead MENA – 16 March 2023

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Steven Reilly

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Our world is changing rapidly, with actions to address the climate crisis bringing the development of an increasing number of new technologies to move us towards a more sustainable future.

We are seeing, for example, the development of entirely new and next-generation clean energy harvesting technologies. However, the safe storage of this energy is proving to be a very interesting challenge from a fire safety perspective. Inevitably, whether it is fuel storage for on-site generation or energy storage itself, these new technologies are resulting in the storage of new and denser sources of fuel in buildings. And as we know, fire is the release of energy.

One area where the risk is most apparent is the growing number of Electric Vehicles (EVs) we see on our roads, and more importantly, in our parking structures. It is generally thought that EVs have a comparable Heat Release Rate (HRR) to internal combustion engine vehicles (ICEVs). However, this does not take into account the unique, highly directional nature of the flames produced from EV batteries, or the fact EV battery fires generally cannot be extinguished easily. In some cities in Europe, EV's have been banned from parking structures altogether due to fears of the impact such a fire would have on structural integrity.

You may have heard the term Thermal Runaway (TR), where fires are caused by uncontrolled positive feedback following the abuse of the battery cells in lithium-ion batteries. Firefighters are still trying to work out how to deal with EV fires, working in many instances on a trial-and-error basis. Firefighters in Denmark were recently seen plunging a smouldering EV into a large water tank in order to extinguish the flames.

Fire is not the only problematic issue with lithium-ion batteries - the risk of vapour cloud explosion is also often understated or overlooked.

Thermal runaway does not always produce fire or explosions, cells can be in TR and generate a vapour cloud. This vapour cloud contains toxic gases such as carbon monoxide, hydrogen cyanide and hydrogen chloride. Vapour cloud deflagrations have also occurred with residential lithium-ion battery energy storage systems such as e-scooters and e-bikes. While such instances are still rare, the increasing popularity of lithium-ion batteries in the built environment, design standards and people's behaviour increase the risks.

There are a range of mitigation systems present in all lithium-ion batteries, from physical protection, to alerts for operating at high temperatures and preventing overcharge. Unfortunately, the development of lithium-ion batteries has outpaced the development of appropriate standards, at least in the UK and large sections of Europe. However, in the US, Underwriters Laboratories (UL), have developed UL1973 ‘’Batteries for Use in Light Electric Rail (LER) and Stationary Applications’’, which is being adopted in many countries across the world.

A universally implemented set of standards addressing the specific risks should be the first step in a strategy to ensure safety.

Another issue in the built environment is the growing number of photovoltaic (PV) panels being installed on homes, buildings and even facades. PV systems may also include batteries for storing current and inverters that change the current into usable electricity. One of the most hazardous components of a PV system is the actual panel, which continuously produces electrical current when exposed to the sun, even when they are disconnected from the rest of the system. While the design and installation of PV systems are covered under the electrical codes, it is important to design arrays with proper spacing to allow for firefighter access to the roof and to evaluate the impact arrays will have on the roof or façade fire rating.

Additionally, it is important to consider the placement and protection of electrical systems such as inverters and battery systems in the event of a fire, as they can pose a threat to first responders.

In conclusion, new low-carbon technologies have huge potential to improve the overall sustainability and energy efficiency of the built environment. However, appropriate measures must be put in place to ensure the safety of occupants and first responders. This includes proper standards and codes, as well as training and education for fire safety professionals, building owners and operators.