Dupré Minerals’ AVD (Aqueous Vermiculite Dispersion) is a revolutionary fire extinguishing agent designed for flammable metal fires, specifically Magnesium powder and Magnesium swarf. It offers significantly superior performance across the flammable metal range and has key benefits over existing solutions.
Dupré have proven that AVD is more effective at extinguishing metal fires, especially Magnesium, than conventional extinguishing agents.
What is AVD?
AVD is an aqueous dispersion of chemically exfoliated Vermiculite. Vermiculite is the name given to a group of hydrated laminar aluminium-iron-magnesium silicates. Raw Vermiculite consists of thin, flat flakes containing microscopic layers of water. When Vermiculite is exfoliated, either thermally or chemically, the microscopic layers of water are removed and this either causes expansion (thermally exfoliated) or creates microscopic, individual platelets that are freely suspended in water (chemically exfoliated). AVD is approximately 20% Vermiculite / 80% Water with a viscosity of 3000 cPs and a D90 of 180 microns (0.18mm). AVD is non flammable and has excellent insulation properties.
How does AVD work?
Due to the reactivity between a flammable metal fire and water, AVD is applied in the form of a ‘mist’ or ‘foam’. The Vermiculite particles within the mist or foam are deposited on the surface of the burning fuel to create a film over the top of the fire. This film instantly dries and because the high aspect ratio platelet particles overlap and bind together, they produce a non flammable oxygen barrier between the fire and the atmosphere.
This process offers cooling to the surface of the fire and as the AVD platelets begin to build up they form an oxygen barrier over the fuel source, the fire is gradually cooled and brought under control. Unlike other Class D Extinguishing Agents where the fire has to be left for long periods of time before the fire is truly under control and completely burnt out, AVD offers quicker control to the fire.
What are the benefits of AVD?
AVD is suitable for both portable and fixed installations due to its fluid nature and a smaller volume of agent is required to extinguish the fire compared to conventional agents. The Vermiculite platelets within the AVD create a fire proof high insulation oxygen barrier that extinguish and not just suppress the metal fire whilst the water content cools the fire source.
AVD can be used in a Misted or Foamed format depending on the application and to date we have tested AVD in the following deployment systems:
- Portable Extinguisher Bottles
- Back Pack Extinguishers
- Trolley Based Extinguishers
- Fire Service Pump Systems
- Fixed Installation
In addition to its performance on metal fires AVD can also be used to extinguish Class A materials such as wood and plastic. The excellent re-ignition prevention properties of AVD provide a flame proof barrier to almost any substrate allowing the spread of fire to be contained.
For more information, go to www.avdfire.com