What is Aqueous Vermiculite Dispersion (AVD)?

Aqueous Vermiculite Dispersion (AVD) fire extinguishing agent is a new, revolutionary technology that uses fixed and portable delivery techniques to effectively combat lithium-ion battery fires.

Lithium battery failure can be caused by the following:

  • Physical impact or penetration
  • Overheating
  • Short circuits
  • Internal cell failure
  • Manufacturing defects

With the rise in technology that uses lithium batteries, comes the added risk of lithium battery fires. How prepared are you for a lithium battery fire? And are lithium batteries dangerous?

The consequences of lithium battery fires are severe, so having the right precautions in place is critical. AVDfire offers a unique solution that can be used across a range of applications to effectively tackle the blaze.

What is AVD made of?

AVD is an aqueous dispersion of chemically exfoliated vermiculite. It is applied to lithium battery fires as a mist, extinguishing them and preventing the propagation of the fire.

Vermiculite is the name given to a group of hydrated laminar aluminium-iron-magnesium silicates. It consists of thin, flat flakes containing microscopic layers of water. The chemical exfoliation of vermiculite produces microscopic, individual platelets that are freely suspended in water. This yields a stable aqueous dispersion of vermiculite to be used as a lithium battery fire extinguishing agent.

Is AVD environmentally safe?

Vermiculite is a naturally occurring mineral that is exempt from REACH regulations. It is chemically and physically inert, only releasing steam when exposed to raised temperatures. It is also non-toxic to humans, plant life and animals.

How does AVD work?

The vermiculite particles within the mist are deposited on the surface of the burning fuel to create a film over the top of the fire. The film instantly dries and, because the high aspect ratio platelet particles overlap and bind together, a non-flammable oxygen barrier between the fuel and the atmosphere is produced.

This process has a cooling effect on the fuel source and, as the water content in AVD is evaporated, the vermiculite platelets begin to build up and the fire is brought under control.

When lithium-ion batteries are exposed to heat, physical/impact damage or overcharging, they go into thermal runaway.


The cells are sufficiently swollen, releasing hot flammable gases (hydrocarbons) that are formed as the electrolyte dissociates.


The hydrocarbons burn vigorously at high temperatures and rapidly spread the fire to the surrounding cells and flammable materials.


AVD is applied as a fine mist, which instantly cools the batteries and extinguishes the flames.


AVD encapsulates the fuel source and insulates the cells, preventing further propagation of thermal runaway – bringing the fire under control.


What are the benefits of AVD?

The AVD lithium battery fire protection agent is a unique product that provides a solution to an otherwise unsolved problem. AVD’s exceptional performance includes the following:

  • Water content cools the fire source
  • Vermiculite platelets encapsulate the fuel source creating an oxygen barrier
  • The vermiculite film is not electrically conductive
  • AVD is nearly twice as effective as water on a class A fires
  • AVD can be applied as a fire break to prevent the propagation of fire
  • AVD can be deployed using standard fire-fighting equipment
  • AVD is environmentally friendly

AVD Testing

AVD has been third-party performance tested against a set of battery fire criteria and certified at ZSW in Germany (see our downloads for the relevant document and information). We have tested AVD using the following application methods:

  • Portable extinguisher bottles
  • Backpack extinguishers
  • Trolley-based extinguishers
  • Fixed installations

We have also completed several trials on lithium-ion and lithium polymer batteries. The following table demonstrates the AVD testing that has been carried out to date:

Battery TypeChemistryDescription
LFPLiFePO4Lithium Iron Phosphate
NMCLi(Ni0.45Mn0.45Co0.10)O2Nickel Manganese Cobalt Oxide
LCOLiCoO2Lithium Cobalt Oxide
NMC/LCOLiCoO2 and Li(Ni0.50Mn0.25Co0.25)O2Blend of LCO and NMC
NCALix(Ni0.80Co0.15Al0.05)O2Nickel Cobalt Aluminium Oxide

The results from these lithium-ion battery fire tests are as follows:

  • AVD is practically effective when applied in a form of a mist
  • AVD is suitable for application for both portable extinguishers and fixed systems
  • AVD encapsulates the fuel source and insulates the cells preventing further thermal runaway; this prevents the propagation of the fire
  • The system can be designed to suit the specific requirements of the location and application
  • AVD is Dielectric Test approved in line with BS EN 3-7: 2004 + A1: 2007 (download the certificate)

What makes AVD unique?

Do you know what type of fire extinguisher is needed for lithium battery fires? With AVD, you are equipped with a unique agent that is specifically designed to effectively extinguish lithium battery fires. AVDfire provides the best, most versatile solution to battery fires across a wide range of applications.

Take a look at our lithium battery fire extinguishers and product bundles to find out more about the protection that AVDfire can offer.

Want to know more?

Get in touch to discuss the functions of the AVD extinguishing agent.

Ready to make AVD part of your fire protection?

Contact one of our distributors to start building your own lithium battery fire protection system.


While every reasonable effort is made to ensure that the information provided in this document is accurate*, no guarantees for the accuracy of information are made. AVD Fire’s website and material data relating to information, products or services (or third part information, products and services) is provided ‘as is’. It is provided without representation or endorsement and made without warranty of any kind, whether express or implied, including but not limited to the implied recommendations or warranties of satisfactory quality, performance or fitness for a particular purpose, non-infringement, compatibility, security or accuracy.

*The technical data provided herein reflects typical indicative results of testing of products under controlled conditions, to provide the best information to allow end users, specifiers, installers, contractors, retailers and alike to determine the suitability of AVD Fire products for intended application.

Proven results on lithium ion batteries

Effectively extinguishes Class A fires

Prevents the propagation of fire

Environmentally-friendly product