How can you determine when a CO2 bottle is empty?

The best method to determine when a CO2 bottle is empty is through the audible sound it makes, specifically when it begins to produce a hollow or whistling noise. This sound indicates that the pressurized gas is nearing depletion, as the sound is often associated with the escape of the remaining gas being utilized to extinguish a fire.

Other methods, such as checking the pressure gauge or assessing the temperature of the cylinder, may not provide reliable indicators. A pressure gauge reading zero could suggest that the bottle is empty, but it is also possible for gauge malfunctions to occur. Similarly, a warm cylinder does not correlate directly with the fill level of the CO2; it can be affected by environmental factors. A visually cracked extinguisher could indicate damage and potential failure, but it does not provide specific information about the gas level.

Focusing on the sound emitted by the extinguisher provides a more immediate and tangible signal concerning its operational status, making it a practical approach for users in emergency situations.