What type of water is used in water mist extinguishers?

Water mist extinguishers utilize distilled water. The reason for this is that distilled water is free from impurities and minerals that could potentially leave residues or cause corrosion in the extinguisher system. Distilled water has a uniform composition and evaporates quickly, which is essential for creating fine mist droplets that can effectively suppress fires. When the mist is released, it helps displace oxygen around the fire and cools the combustible material by absorbing heat.

Using alternatives like tap water or saltwater may introduce contaminants or minerals that can interfere with the extinguisher's effectiveness and maintenance. While rainwater might seem like a viable option due to its natural presence, it can carry pollutants and bacteria depending on the environment, making it unsuitable for use in fire extinguishing systems. Thus, distilled water is the ideal choice to ensure optimal performance and longevity of water mist extinguishers.