Dry Powder Fire Extinguishers

[John T1594]

I have a couple of those dry powder fire extinguishers on board and every year the Coast Guard inspector says "Be sure to shake these good to loosen the powder". So I shake and shake until my arms are sore and my head feels like the after effects of a heavy metal concert. There must be a better way. Any suggestions?

 

[kloudie1]

You can feel when the powder is free by inverting the extinguisher. I usually invert mine and bump the mid point of the cylinder a couple of times then check to make sure the powder is moving inside. Bump, rotate, bump, rotate, etc until everything is loose and happy ! Usually only takes 3 or 4 bumps.

 

[Mikem]

You can also lightly rap the bottom with a rubber mallet.

 

[robertsapp]

Personally I think this idea that the powder is going to settle and cake up and thus fail to spray when you need it falls into the area of urban legend. I've never heard of a single case of such a thing actually happening. I just replaced a 1A10BC dry chemical extinguisher on our boat that had fallen out of the green zone on the pressure gauge. It had a date code on the bottom of 99, which tells me it was 14 years old. I know I had never touched it in the four years we've had the boat, and the previous owner was the type of guy who wouldn't even fix diesel leaks, so I doubt he was shaking the fire extinguishers on a regular basis. It probably hadn't been moved since the day it was mounted on the bulkhead back in the 20th century. I took it home and said to my wife "Here dear, I doubt you've ever operated one of these before, go ahead and discharge this so you can see how it works." It sprayed just fine, emitting a heavy stream of white power. And my wife had fun. But it did kill the grass where she sprayed it. Fortunately, it turned green again in a few weeks.

So seriously, I wouldn't worry about it. If you feel the need to do some safety gear preventive maintenance, I think your time would be better spent blowing up your inflatable PFD's occasionally.

 

[Mikem]

Hmmm. I have three on my boat. Not knowing any better I gave them a shake recently. Two of them I could hear (feel) the powder moving back and forth. The third one...nothing. A few raps and things seemed to loosen up. It sure did't take much time to do all three. Maybe there are different dry chemicals with slightly different "compacting" properties.

 

[robertsapp]

When I shook the fourteen year old extinguisher I mentioned above, nothing moved that I could tell. I turned it upside down and I couldn't feel any indication of a change in weight distribution that would indicate the powder moving. But when I activated it, it sprayed just fine. Anyway, there's certainly no harm in going all Carmen Miranda on your extinguishers occasionally. I'm just saying I don't think it's necessary based on my experience.