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J. Clarke[_4_]

In article om,
says...

On 4/29/2017 7:37 PM, Puckdropper wrote:
Electric Comet wrote in newse2gq4$ajg$1
@dont-email.me:

current exitinguisher is old and have never used it

thinking about an upgrade but have not kept up with latest trends

what is the preferred style these days

I've got to wonder if that style that you could charge with shop air is
still around. It seems to me that as long as the chemical stays good,
shop air would be easy to maintain. Just keep it by the door and glance
at the gauge as you go out, and when it gets low just recharge it. (All
seals leak over time.)

If you define "over time" as eons, perhaps. If not, I can counter your
"All seals leak over time" with the 10lb Ansul ABC sitting in my
unheated garage. That went in service (or last inspected/charged)
November 1986.

Local service guy (fireman moonlighting) told me so long as it stays in
the green zone or slightly above AND you shake or invert it a couple
times every year or so it will do its job. If the chemicals get wet and
cake up it will not work regardless of holding pressure. If the service
tech does it properly, the air used to charge it has been through a
dryer and it won't cake up.

It's still ready to rock and roll after 31 years. Had another one with
a good 23 years on it. Accumulation of cut grass and crap on the mower
caught fire and SWMBO came running in the house screaming the mower was
on fire. It was but that extinguisher worked just fine after 23 years.

The problem with charging with shop air is that unless you have a really
good drying system you're likely to get some moisture in the extinguisher.

As for technology, there isn't any radically new fire extinguisher
technology. Extinguishers have ratings, A, B, C, D, or K. A is for dry
fuel fires, B for wet fuel, C for electrical, D for burning metal, and K
for cooking oil.

They also have a number associated with each rating--for A, the number is
the equivalent of multiples of 1.25 gallons of water, for the others it's
square feet of coverage under specified circumstances.

Example--a 10A80BC extinguisher is rated to put out dry fuel and wet fuel
fires and safe to use on powered electrical equipment ("safe" means the
fireman won't get electrocuted, not that the equipment will ever work
again) but not rated for burning metals or for fires involving cooking oil
and the like. On dry fuel it will work as effectively as 12.5 gallons of
water and on wet fuel it will cover 80 square feet under "typical"
conditions when expertly handled.

Typically at places like Home Depot you'll find ABC rated dry chemical
extinguishers. One of those in a size to cover whatever you expect to be
burning would be the best first option, but understand that if you use it
any tools or equipment that get hit will have to be cleaned after, possibly
involving disassembly, and that if they were hot at the time the dry
chemical may have melted into them.

Some of the cheaper ones have plastic valves--there has been at least one
recall over these and I would avoid them--go for a model with a brass or
aluminum valve.

Note that there are also "BC" rated dry chemical extinguishers, not rated
for type A fires. If you're running a gas station or the like where the
major danger is gasoline or oil fires a "BC-only" extinguisher might be a
better bet than an ABC, which is a compromise to some extent.

The "traditional" alternative is CO2--it's in general no good for class A
fires (i.e. wood fires) but it doesn't leave a residue that has to be
cleaned off of equipment.

The "old fashioned" type is a water extinguisher--it doens't really do
anything that a garden hose doesn't do except be ready to hand and work
when the power to the pump is off. These are type A only--shouldn't use
them on oil or gasoline fires or on powered electrical machinery.

An improvement on the water extinguisher is a foam extinguisher. These add
a foaming agent to the water and whatever other bits are necessary to
ensure that it foams properly. The advantage is that the foam is lighter
than oil or gasoline and and will float on top of it, so they can be used
on oil or gasoline fires as well as solid-fuel. But still, they are using
water and should not be used on electrical fires.

There are a couple of alternatives.

Something fairly new is the "water mist" extinguisher, which when used with
deionized water is rated for A and C fires--it's good for wood fires in
other words and safe on powered equipment.

You'll see something called "Halotron", which is the replacment for ozone-
depleting Halon and has about the same rating as CO2. Rarely you'll find a
real Halon extinguisher--if you find one for a reasonable price, charged,
grab it--Halon is highly effective and clean.

A class D is specifically for metal fires--the kind of thing you get when
somebody manages to light a barrel of magnesium swarf for example. If
that's not a likely scenario for you there's no need for one.

A class K (note--this is DIFFERENT from a "Purple K" extinguisher--"Purple
K" is NOT class K--some regulator really wasn't thinking when he picked
that letter) is intended for commercial kitchens and is intended to
supplement a permanently installed system. The main reason they exist is
that conventional dry chemical can interfere with the chemistry used in
permanently installed kitchen fire suppression systems--if you don't have
such a system and aren't likely to have a commercial deep fryer full of
vegetable oil light up on you a regular dry chemical extinguisher should be
fine.

The bottom line on all this--get as many decent ABC dry chemical
extinguishers as your shop has entrances and put one next to each (why?
Because if the shop is on fire and you're coming _in_ the extinguishers are
ready to hand and if you are already in the shop going for an extinguisher
will force you to move toward an escape route rather than possibly moving
you into a more dangerous location). Hang them on the wall where you can
see and reach them and they won't get lost in the clutter. And if you are
not going to have them professionally inspected, DO work out a schedule for
when you are going to check the pressure and shake them up.