Originally Posted by
simonl
At work, start of every shift :q At home I have 2 vaporizing liquid extinguishers. These are the ones that replaced the ozone depleting BCF (Bromo,chloro,Difluromethane) which are OK to use but a little expensive to buy. Vaporising liquid are the go in the shed as it does not create a mess that costs more to clean up than the fire! That white powder makes a lovely grinding paste! Also, vaporising liquid extinguishers are "reasonably" easy to test as you can tell with a shake how much liquid is there which is a backup to just relying on the gauge. As it requires pressure to store it in the liquid phase, you know it must be charged. WRT Dry powder, once they are discharged even the smallest amount of powder, they will go "flat" very quickly since the valve cannot seat properly as it has powder in it, within hours the charge of dry nitrogen will escape and you will end up with an extinguisher with near on 9Kg of powder but no pressure. While the gauge should reflect this, if the extinguisher is old it's not unusual for the needle to stick and still show "full" in the green zone. Best way to check is to look in the nozzle or give it a tap. It should be clean and have no sign of powder, if it has then it's been used. Of course nothing beat water for A class fires.... as long as any electrical hazard has been isolated. Cheers, Simon