We have a lot of fire extinguishers we're using in our company, and I'm wondering why fire extinguishers become depressurized even they're not being used, just on standby. I want to know why it's happening and what are the common reasons? What can I do to avoid depressurization?

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    I'm voting to close this question as off-topic because fire extinguisher characteristics and management are not related to DIY home improvement.
    – Steven
    Jan 28, 2015 at 17:24
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    @Steven -- homeowners have fire extinguishers too! Jan 29, 2015 at 1:25
  • Higher quality commercial grade extinguishers will probably give you better performance over time. The cheapo ones at the big-box stores are not well constructed and are considered disposable. Good ones can be recharged. Jan 30, 2015 at 19:18

1 Answer 1


No man-made container will ever be 100% leak proof over time. Even a Mylar balloon (the more expensive fancy ones) will lose it's helium over time and no longer stay afloat. Most fire extinguishers are charged with nitrogen under pressure as their propellant. Nitrogen is an extremely small molecule and given enough time will slowly seep or leek out of the fire extinguisher.

Changes in temperature and barometric pressure would be the culprits making this loss faster over time. Keeping them out of direct sunlight and away from heat sources may help prolong the amount of time until they need to be recharged. However, keep in mind there may be laws or regulations governing where a fire extinguisher should be located.

This is one Example

My father and uncle worked for years installing fire and security systems. Along with a schedule for systematically checking smoke detectors, you should include checking the charge on your fire extinguishers.

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    +1 but not sure your example is a helium balloon is the best. Helium extremely small and can escape/diffuse into nearly any container very rapidly. Containing almost any other gas is easier than helium.
    – s0rce
    Jan 28, 2015 at 23:19
  • out of curiosity - why are they charged with N2 instead of CO2?
    – warren
    Feb 3, 2015 at 20:11
  • Warren - Some 'dry' or powder style fire extinguishers are charged with CO2. I would believe it's a matter of what the extinguisher is primarily doing. If you are simply trying to propel a liquid chemical to put out the fire, nitrogen works great. If you are trying to chemically suffocate a fire, CO2 is the way to go. Feb 4, 2015 at 13:24

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