Water-type extinguishers exposed to weather below 40 degrees require what to be added?

Water-type extinguishers are designed primarily for use on Class A fires, which involve ordinary combustibles such as wood, paper, and textiles. When such extinguishers are exposed to temperatures below 40 degrees Fahrenheit, the water inside can freeze, rendering the extinguisher ineffective. To counter this issue, anti-freeze is added to the water to lower the freezing point, ensuring that the extinguisher remains operational in cold weather conditions.

The addition of anti-freeze helps maintain the extinguisher's functionality by preventing ice formation, allowing the operator to deploy it effectively even in frigid temperatures. This practical alteration addresses environmental factors that could compromise safety during fire emergencies.