After the recent fire and also a thread talking about expired fire extinguishers I decided to do a little more research. I stopped by the local Simplex-Grinnell office and spoke with one of their techs.
He says that if you have a pressure gauge in the green and you can feel the powder shaking around that is good but really means nothing. The real issue is the release valve. He says that the valves will corrode and freeze up so when you go to use the extinguisher, you cannot press the handle and on the cheap ones the handle then just breaks.
The powder rarely turns to a solid if the cylinder has not been breached and the gauge will still be in the green if the valve freezes up.
So I would put these in the same category as expired flares. Maybe keep one on board as an extra if the primary runs out. Of course, make sure you do so in such a way that the primary is always the first one used.
I keep 4 on board. One in the stern locker that can be accessed without going into the cabin. One next to the engine compartment, one in the galley and one in the V berth.
Stay tuned for MS's post when he splits a fire extinguisher in half to demonstrate this failure.


He says that if you have a pressure gauge in the green and you can feel the powder shaking around that is good but really means nothing. The real issue is the release valve. He says that the valves will corrode and freeze up so when you go to use the extinguisher, you cannot press the handle and on the cheap ones the handle then just breaks.
The powder rarely turns to a solid if the cylinder has not been breached and the gauge will still be in the green if the valve freezes up.
So I would put these in the same category as expired flares. Maybe keep one on board as an extra if the primary runs out. Of course, make sure you do so in such a way that the primary is always the first one used.
I keep 4 on board. One in the stern locker that can be accessed without going into the cabin. One next to the engine compartment, one in the galley and one in the V berth.
Stay tuned for MS's post when he splits a fire extinguisher in half to demonstrate this failure.