One thing to watch out for is with the dry powder ABC rated fire extinguishers, the contents can 'clump and solidify' over time and many manufacturers say to turn them upside down or rotate them on their side periodically (often as little as every three months) to prevent this from happening...
Otherwise you can have 'pressure' but if you try to use it- nothing comes out but the pressurised air!!!
(some people say this isn't necessary, but I know that the one in my tilt tray (5 years old when I used it, gauge in the green') did NOT work- hissed but no powder came out (which when I checked online was told 'oh you never shook it regularly did you'- um no- first I had heard of it...
The guy who was to refill it later took one look at it inside and told me, just buy a new one- the ammonium phosphate??? inside was a single solid 'block' and it would take hours to 'break it up' enough to get it out of the tanks neck...
Luckily I had a second 'fire extinguisher in a can' I have carried in my workpack ever since a car I was in caught fire while driving along!!!) and it was (just barely) big enough for the job (crashed car's wiring shorted out and the bonnet was too damaged to open to disconnect the battery- it started smoking and glowing while being winched off the tree...
(I now have TWO separate extinguishers- one each side- and both are shaken and tipped upside down every three months)
Makes you wonder just how effective most peoples powder extinguishers would really be in an emergency...
