CAFS & Lithium-Ion Fire Suppression FAQs
RML AU provides engineered Compressed Air Foam System (CAFS) solutions for BESS, lithium-ion batteries, electric vehicles, electrical infrastructure, waste and recycling, mining, data centres, wind energy and other high-risk applications across Australia.
These frequently asked questions explain how CAFS works, where it may be applied and the important distinction between fire suppression, cooling and lithium-ion battery thermal runaway.
Compressed Air Foam Systems
What does CAFS stand for?
CAFS stands for Compressed Air Foam System.
A CAFS combines water, a selected foam concentrate and compressed air within the system to produce a controlled aerated suppression medium.
The finished compressed air foam can then be delivered through hose, pipework or fixed discharge systems to the fire hazard.
How does CAFS work?
CAFS combines three principal components:
Water + Foam Concentrate + Compressed Air → Compressed Air Foam
Water provides cooling and heat absorption.
The selected foam concentrate supports wetting, surface coverage and foam formation.
Compressed air creates the controlled bubble structure before the finished foam is discharged.
The resulting suppression medium can provide rapid flame control, sustained cooling, effective surface coverage and efficient use of firefighting water.
Is CAFS the same as conventional aspirated foam?
No.
With CAFS, compressed air is mechanically introduced into the water and foam solution within the system.
The resulting finished foam is then transported through the hose or pipework.
This differs from conventional aspirated foam systems where air is typically entrained at or near the discharge device.
Does CAFS still use water?
Yes.
Water is an important part of CAFS and provides valuable cooling and heat absorption.
RML AU does not position CAFS as a way to eliminate water.
The objective is to use water more effectively.
Does CAFS always use less water than conventional suppression?
Not necessarily.
Water consumption depends on the hazard, fire size, application method, system design and required cooling.
RML AU/EZCAFS testing has demonstrated water reductions of approximately 75–85% under defined test configurations compared with the conventional water application used as the relevant test benchmark.
Those results are test-specific and should not be interpreted as a universal reduction for every fire or project.
Lithium-Ion Batteries and Thermal Runaway
What is lithium-ion battery thermal runaway?
Thermal runaway is a self-heating process within a battery cell where increasing temperature drives further reactions and heat generation.
It can result in high temperatures, gas generation, venting, fire and potentially propagation to neighbouring cells.
Can CAFS stop thermal runaway?
CAFS should not be described as stopping the internal electrochemical process within a cell that has already entered thermal runaway.
The suppression strategy is instead to:
control flaming combustion → remove heat → cool the affected area → reduce thermal energy transfer → help limit propagation and escalation.
This distinction is important when assessing any lithium-ion battery fire-suppression technology.
Can CAFS extinguish a lithium-ion battery fire?
CAFS can be used to control flaming combustion and provide cooling in appropriate lithium-ion battery fire applications.
However, visible flame extinguishment does not necessarily mean that all internal battery reactions have stopped.
Continued cooling and post-suppression monitoring may still be required.
Why is cooling so important?
Heat is central to lithium-ion battery propagation.
An affected cell or module can transfer thermal energy to neighbouring cells, potentially contributing to additional thermal runaway.
Removing heat and reducing thermal energy transfer can therefore help limit escalation and propagation.
Can a lithium-ion battery re-ignite?
Yes.
Residual heat or continuing internal reactions can result in further battery activity or re-ignition after visible flames have been controlled.
Post-fire monitoring and appropriate emergency procedures remain important. We suppres any reignition.
BESS Fire Suppression
What makes a BESS fire different?
Battery Energy Storage Systems can contain substantial quantities of stored electrical energy and large numbers of lithium-ion cells arranged into modules, racks and enclosures.
A fire strategy may need to address:
thermal runaway;
propagation;
flammable and potentially hazardous gases;
cooling;
re-ignition;
adjacent equipment;
firefighting-water demand; and
potentially contaminated firewater.
Can CAFS be used for BESS fire suppression?
CAFS can be considered as part of an engineered BESS fire-protection strategy.
The appropriate solution depends on battery chemistry, system configuration, detection, access, fire scenario, manufacturer information and available fire-test evidence.
Explore BESS Fire Suppression →
Does CAFS prevent propagation in BESS?
The objective is to reduce heat transfer and fire exposure to neighbouring cells, modules or equipment, helping manage propagation.
The degree of propagation control must be demonstrated under relevant test conditions and should not be assumed from flame extinguishment alone.
Electric Vehicles
Why are EV fires difficult to manage?
The traction battery is commonly installed beneath or within the vehicle and protected by a structural enclosure.
This can make direct access to affected battery cells difficult.
A response may need to address:
external flaming combustion;
battery cooling;
application access;
propagation;
re-ignition; and
post-fire monitoring.
Has CAFS been tested on an EV battery?
RML AU/EZCAFS testing has included a 42.7 kWh lithium-ion vehicle battery pack at 100% state of charge.
Testing examined fire control, cooling, water consumption and post-suppression behaviour under defined test conditions.
The results apply to the tested configuration and should not be interpreted as guaranteeing identical performance for every EV or battery.
Explore Electric Vehicle Fire Suppression →
What about EV fires in underground car parks?
Underground and enclosed car parks introduce additional issues including smoke and gas accumulation, adjacent vehicles, structural exposure, evacuation, firefighter access, drainage and contaminated firewater.
These risks need to be considered as part of the building's complete fire-safety strategy.
Explore Underground Car Park & EV Charging Fire Protection →
Electrical Infrastructure
Can CAFS be used around electrical equipment?
CAFS may be suitable for defined electrical fire-protection applications where supported by appropriate engineering and test evidence.
RML AU/EZCAFS has undertaken independent electrical testing under defined high-voltage conditions.
The results apply to the particular voltages, standoff distances, discharge conditions and configurations tested.
Is CAFS safe to use at 110 kV?
It is not appropriate to make a blanket statement that CAFS is simply “safe to 110 kV”.
Electrical performance depends on the specific test configuration, voltage, standoff distance, discharge characteristics and other conditions.
RML AU can provide applicable electrical test documentation for engineering review.
Can CAFS be used for transformer fires?
CAFS can be considered for appropriate transformer and electrical infrastructure applications to provide rapid flame control, cooling, surface coverage, vapour suppression where applicable and exposure protection.
The system must be engineered around the transformer, electrical conditions, fuel, separation and applicable fire-protection requirements.
Explore Transformer & Electrical Fire Suppression →
Water and Environmental Management
Why does water demand matter?
High firewater demand can affect:
water storage;
pumps;
pipework;
drainage;
bunding;
containment;
treatment; and
emergency operations.
Where lower design water demand is technically supported, it can reduce the wider infrastructure required to supply and manage firefighting water.
Does using less water mean less contaminated runoff?
Potentially.
Reducing the quantity of firefighting water can reduce the volume of potentially contaminated runoff requiring containment and management.
It does not mean the runoff is uncontaminated, nor does it eliminate the need for firewater management.
Is CAFS environmentally friendly?
Environmental performance depends on the specific foam concentrate, fire scenario and application.
RML AU assesses the selected foam chemistry and supporting product documentation for the intended application.
Any PFAS-free, fluorine-free or chemical-compliance claim should relate specifically to the concentrate being supplied and its current technical documentation.
Testing and Evidence
What evidence supports RML AU's CAFS systems?
RML AU/EZCAFS has undertaken testing across defined fire scenarios relevant to applications including lithium-ion batteries, EVs and other industrial fire risks.
Depending on the test, data may include:
fire configuration;
pre-burn period;
application method;
flow rate;
flame-control time;
cooling;
water consumption;
propagation observations;
electrical performance; and
post-suppression behaviour.
RML AU's approach is:
Evidence before claims. EZ-CAFS - YouTube
Why are test conditions important?
A fire-test result only demonstrates performance under the conditions actually tested.
Variables such as battery chemistry, state of charge, fire size, fuel, application method, flow rate, distance and cooling duration can materially affect the outcome.
For this reason, RML AU does not assume that a result from one test automatically applies to every fire scenario.
Standards and Engineering
Is there one Australian Standard covering lithium-ion battery fire suppression?
Lithium-ion battery fire protection involves multiple regulatory, standards and engineering considerations depending on the application.
BESS, EVs, buildings, mobile mining equipment and electrical infrastructure are different hazards and should not be treated as though one standard provides a universal suppression design.
Project requirements should be determined from the applicable Australian regulatory framework, standards, fire authority requirements, manufacturer information and project-specific fire engineering.
What is UL 9540A?
UL 9540A is a test method used to evaluate thermal runaway fire propagation in battery energy storage systems.
It provides information that can assist fire-safety assessment and system design.
It should not be described as a fire-suppression-system certification.
What is NFPA 855?
NFPA 855 is the US Standard for the Installation of Stationary Energy Storage Systems.
It may be relevant to some Australian projects where adopted as part of the design basis, insurer requirements or engineering assessment.
It does not replace applicable Australian regulatory requirements.
Is AS 5062 relevant to battery-electric mining vehicles?
AS 5062:2022 addresses fire prevention and protection for mobile and transportable equipment and may be relevant to aspects of mining mobile-equipment fire protection.
Lithium-ion BEVs can introduce additional battery-specific issues such as thermal runaway, cooling, propagation and post-fire monitoring that also need to be considered.
Working with RML AU
Where can RML AU CAFS systems be used?
Potential applications include:
BESS;
electric vehicles;
underground car parks and charging facilities;
transformers and electrical infrastructure;
waste and recycling;
underground mining and BEVs;
data centres;
wind turbines; and
other high-risk industrial applications.
Every application should be assessed against its specific fire hazards and engineering requirements.
Does RML AU provide fixed and mobile CAFS?
Yes.
Depending on the application, CAFS may be configured as fixed, mobile or other purpose-designed arrangements.
The appropriate system depends on the hazard, required response, water supply, application method and operating environment.
How do I know whether CAFS is suitable for my project?
Start with the fire risk rather than the suppression technology.
RML AU's approach is:
Understand the risk → Detect early → Intervene rapidly → Control flaming combustion → Remove heat → Limit propagation or escalation → Use water efficiently → Manage environmental consequences → Support the solution with evidence.
The appropriate fire-protection strategy can then be developed around the actual asset and hazard.
Discuss Your Fire Protection Requirements
RML AU works with asset owners, developers, engineers, insurers, emergency-response organisations and fire-safety professionals across Australia.
Have a project or technical question? Talk to RML AU about your fire-protection requirements.