Detect, Douse, Defend: Tackling Electric Vehicle Fires
- March 20, 2024
- 12:10 pm
Iain Hoey
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Siemens sheds light on the critical importance of early smoke detection and innovative suppression in preventing electric vehicle fire disasters in parking structures
The shift towards electric vehicles (EVs) marks a transformative era for transportation, bringing with it a host of benefits and a set of challenges, particularly around fire safety within parking garages.
A recent white paper from Siemens titled ‘Fire safety in parking garages with electric vehicles’, produced in collaboration with Danfoss Fire Safety and contributions from the Danish Institute of Fire and Security Technology, provides an authoritative guide on the nuanced risks associated with EV battery fires, such as thermal runaway, which leads to explosive combustions and the emission of intensely toxic smoke.
The white paper outlines strategies for fire safety, focusing on proactive measures like early detection and innovative suppression methods, including the use of high-pressure water mist systems.
It also explores the integration of these fire safety solutions into smart building management systems, aiming for an optimal blend of safety and operational efficiency.
Electric Vehicle fire risks
The risks of EV battery fires are distinct from those associated with traditional Internal Combustion Engine (ICE) vehicles due to the unique behaviour of lithium-ion batteries.
The white paper details the nature of these risks, including the heightened intensity of EV battery fires and the challenges in suppressing them.
The toxicity of smoke from EV battery fires poses severe health hazards, necessitating swift action to mitigate the risks to human health and the environment.
The release of heavy metals and toxic chemicals during these fires calls for rapid suppression and careful management of firefighting water to prevent environmental contamination.
Understanding thermal runaway is crucial for tackling EV fire safety effectively.
Siemens highlights the need for specialised fire suppression strategies as traditional methods, such as water sprinklers, are less effective,
The importance of early smoke detection
Early smoke detection is a fundamental aspect for safeguarding parking garages.
This capability to detect smoke is essential for prompt response and suppression, crucial in mitigating fire spread and protecting both garage occupants and the structural integrity of the facility.
Siemens also points out the effectiveness of early detection paired with high-pressure water mist in: “Preventing multi-vehicle fires and avoiding the high temperatures that might lead to structural damage.”
The white paper suggests integrating fire safety systems into smart building management, enhancing the safety and efficiency of response to these potential emergencies.
Through advanced detection technologies like aspirating smoke detectors (ASD) and point detectors with ASAtechnology, Siemens advocates for early detection strategies tailored to the unique challenges presented by EV battery fires, ensuring the protection of both individuals and properties in parking garage environments.
High pressure water mist
Siemens identifies high-pressure water mist as an innovative suppression method for EV fires, noting its effectiveness due to unique cooling and oxygen-displacing properties.
For centuries water has been used to fight fires.
The breakthrough that high pressure water mist represents is to use the same method as traditional sprinklers but to add the effect of converting the water into a mist or fog.
This approach allows the mist to significantly cool the fire and interrupt the combustion process, similar to gas-based suppression systems.
An example highlighted in the document is Danfoss’s SEM-SAFE system, which can propel clean water forced by Danfoss high pressure water mist pumps through a stainless-steel piping network and specially engineered nozzles.
The system’s fine water droplets quickly evaporate while expanding a minimum of 1700 times, enhancing its ability to cool fires effectively and prevent spread.
Siemens underscores water mist’s suitability for EV battery fires, noting its ability to directly cool battery cells and halt fire development: “The combined cooling and oxygen displacement provide a cooling capacity up to seven times greater than sprinklers.
“The water consumption is reduced by up to 80% compared with traditional sprinklers.”
Test results
Collaborative tests carried out by Siemens, Danfoss, and the Danish Institute of Fire and Security Technology (DBI) have confirmed the efficacy of high-pressure water mist systems in extinguishing EV fires, addressing the specific challenges they pose.
The primary aim was to demonstrate the feasibility of using high pressure water mist triggered by early detection as an effective EV fire suppressant, allowing enough time for the fire service to arrive.
In simulations conducted within steel shipping containers, both electric and conventional vehicles were tested, employing point-type smoke detectors and temperature sensors to evaluate the system’s performance.
The findings were clear: “The tests resulted in intense fires and verified that under these test conditions detection with point detectors is fast and reliable.
“In addition, high-pressure water mist performs well, allowing sufficient time for the fire service to arrive (typically 30 minutes), preventing multi-vehicle fires and avoiding the high temperatures that might lead to structural damage.”
These tests, exclusive to Siemens and Danfoss, underline the high-pressure water mist system’s capacity to safeguard adjacent vehicles from the extremities of EV fires, marking a step forward in fire safety strategies for environments housing electric vehicles.
Smart building management systems
Smart building management systems are also playing a role in the approach to fire safety in EV parking structures, integrating advanced detection, control, and response mechanisms.
These unified management platforms enhance the safety of garage occupants and infrastructure preservation.
As outlined in the Siemens white paper, the evolution of parking garages towards incorporating smart charging infrastructure necessitates a holistic approach to fire protection, becoming an integral component of a broader smart building management system.
When a fire in an EV charging station is detected, an integrated system can promptly alert the fire control system, which then notifies emergency services and the facility manager, besides initiating evacuation and extinguishing protocols.
This seamless integration extends beyond fire detection and suppression, facilitating interaction with other building management subsystems, such as Totally Integrated Power (TIP) and HVAC systems.
The fire safety system’s interaction with a TIP subsystem, for instance, enables it to cut off power to the buffer storage system and affected EV charging stations, enhancing safety measures.
Similarly, a signal to the HVAC system to activate smoke extraction further aids in managing the building environment during a fire, emphasising the system’s capability to provide a comprehensive response to fire incidents.
The integration of fire safety systems into platforms, like Siemens’ Desigo CC, allows facility managers to remotely monitor and manage the EV charging infrastructure, alongside other critical functions such as security, access control, power management, and climate control.
This holistic view afforded by smart building management systems like Desigo CC demonstrates their potential role in enhancing emergency response efficiency and proactively managing fire risks, offering a significant advantage in ensuring the safety and operational continuity of EV parking structures.
Operational Safety
Siemens also details the transformation in emergency response and operational safety through the integration of fire safety systems within smart charging and building management frameworks.
The outlined approach enhances the management of fire risks in EV parking structures, providing a coordinated and comprehensive response to incidents, ensuring the safety of occupants and the preservation of property.
It gives a scenario example where, upon fire detection in an EV charging station the fire control system is immediately alerted, triggering a sequence of responses, where a fire in an EV charging station is detected alerting the fire control system which calls the emergency services and notifies the facility manager as well as initiating evacuation and extinguishing.
This quick action minimises potential harm and damage by ensuring emergency services are promptly informed, evacuation starts swiftly, and fire suppression efforts commence without delay.
The integration with building management subsystems like TIP and HVAC adds a layer of safety.
For instance: “The fire safety system also interacts with the totally integrated power (TIP) subsystem which sends a signal to turn off the buffer storage system and the affected EV charging stations.
“Similarly, a signal is sent to the HVAC system to switch off the normal ventilation and switch on the smoke extraction.”
This tackles the fire directly, optimising building conditions to support occupant safety and fire containment efforts.
Utilising platforms such as Siemens’ Desigo CC, facility managers can oversee the fire safety aspects along with other critical functions from a remote location.
“EV fire safety is an integral part of an overall building management system,” says Siemens.
“In this way the facility manager is able remotely to monitor and operate the EV charging infrastructure in addition to building security access, power management, fire safety, lighting, and climate control.”
This comprehensive management capability ensures a unified response to fire risks, highlighting the advanced solutions smart building management systems offer for enhancing safety in EV parking structures.
Preventing false alarms
The white paper also highlights the crucial importance of ensuring reliable fire detection while minimising false alarms in maintaining safety and operational continuity.
Siemens highlights the effectiveness of ASAtechnology in overcoming the challenges posed by environments with high levels of dust and exhaust: “Point detectors with Siemens ASAtechnology are specially designed to avoid false alarms in parking garages and other harsh environments.
“It is very important that ICE exhaust gases or other air pollution do not cause false alarms resulting in unnecessary extinguishing evacuations or call-out of the fire service.”
These advanced detectors, including Siemens point detectors FDOOTC241 or OOHC740, are engineered to distinguish between actual smoke and deceptive phenomena like dust and pollution.
Their detection parameters can be finely tuned to ensure they only respond to genuine fire indicators, thereby: “Avoiding false alarms by distinguishing between smoke and deceptive phenomena such as dust and air pollution.”
Siemens recommends strategic placement of these detectors, with a suggestion to position them above parking spaces and not above access lanes to prevent dilution of smoke near the detectors.
