Monthly
Check that the arrow in the gauge is pointing on the green which means it’s charged
Check that that there is nothing blocking the nozzle
Check that there is no changes (bulges, rust) to cylinder
Check that it has not been dropped and / or damaged
Annually - It is recommended that you perform annual checks of your extinguisher(s) as follows: (when you test your smoke detectors)
Perform you normal monthly inspection
Remove extinguisher from the wall bracket
Turn the extinguisher upside down and use a rubber mallet and tap the bottom of the extinguisher, this will prevent the powder from settling
Return the extinguisher to the bracket
