New Fine Woodworking magazin almost made me ill

[Eddie Munster]

No. Halon is still used and approved for aircraft. I don't remember what type number it is though. But they still have their place. I sit on a handheld one one!

John

[Eddie Munster]

[Joe Gorman]

snip

I learned of it as Shallow Water blackout, snorkeling class many years ago.

[Robert Galloway]

Always got to be some SOB wants to argue. Today, it's me. There are several inert gasses. Helium, Neon, Argon, Radon... Nitrogen is fairly non reactive but everything from ammonium nitrate fertilizer to nitric acid tends to show that is does react with a few things. Doesn't require extreme conditions, either. Check out the rhizobium bacteria attached to the roots of your alfalfa or clover.

bob g.

every thing else you said appears to be right on.

[Dave Hinz]

Get in line ;)

[Robert Bonomi]

Usually 1301, or a 1301/1211 'blend'.

It's still 'used and approved' for computer rooms, and other facilities, too. :)

The facts remain that it has been banned from manufacture since the early 1990s, that the *only* sources today are 'old stock' -- either manufactured before the ban, or 'reclaimed' from systems being de- commissioned. Even the hand-held ones that are on the market _today_ were actually manufactured a number of years ago.

*NOBODY* is building aircraft with in-frame fire-suppression systems using HALON these days, And havn't for a number of years. They all use one of the 'substitutes'.

[Robert Bonomi]

Such beasties are fairly inexpensive.

It's also _easy_ to home-brew one. all you need is: a) a 'trickle charger' for 12V batteries b) nominal 12V of rechargeable batteries (e.g. motorcycle-type gel-cell) c) a 12V light (automotive headlight, cigarette-lighter spotlight, even a camping fluorescent lantern, etc.) d) a relay across the 120V, that turns on the 12V lamp, when the power goes off.

Work at it, and you can spend $50 for the parts. Shop the surplus world, and you can probably do it for significantly under $20.

I think 'commercial' units are in the $100 ballpark.

[Charlie Self]

Robert Bonomi responds:

Some are under $30. I doubt I'd want to try making one for that!

Charlie Self "Health nuts are going to feel stupid someday, lying in hospitals dying of nothing." Redd Foxx

[Scott Lurndal]

USD 52 for 90 minutes.

scott

[Tim Douglass]

Just for one of those "for what it's worth" points, during the First World War the working ceiling for airplanes was between 20,000 and

25,000 feet. Those guys would fly up there, patrol for between 1 and 4 hours then descend, all in an open-cockpit plane w/o oxygen. Many reported that their entire body would tingle for hours after a flight. Of course the fact that the outside temperature was usually at least

-30f and maybe as cold as -50f had something to do with that. Still, it is amazing to me that they not only could fly that high without oxygen, but could function and fight under those conditions.

Tim Douglass

[Tim Douglass]

As far as making stuff cold goes, you can use just about any gas, straight propane works well and has been substituted for years, the problem is that gasses under pressure often leak, and flammable gasses tend to, well, *burn*, when they leak into very hot environments. Add to that the fact that and AC system repeatedly compresses the gas (raising its temperature notably) and you have a real disaster waiting to happen. While a dust collector explosion is virtually impossible, an explosion of an AC system charged with propane is a very real possibility and would have significant destructive capability, far beyond what you will get from any fuel system.

The propane mixtures are still often used in stationary applications where you don't have to worry about hot exhaust systems and suchlike setting leaking gasses on fire. As I understand it, propane actually has a greater capacity for cooling than does freon.

Tim Douglass

[Tim Douglass]

Most main breakers are not engineered for regular on/off duty. You can get switches that are designed for it and I would recommend looking into one of those if you decide to proceed this way.

Tim Douglass

[Brian Elfert]

$12,000 was the total cost to repair the fire suppression after the fire, but refilling the tank was most of the expense.

The entire system had to be recertified. All of the heat/smoke detector heads had to be replaced because of the oily smoke caused by burning plastic.

Damage was very minor. One of piece of hardware was melted and burned internally. We got all of the equipment online 2.5 hours after the fire. The longest wait was for an electrician to reset the power.

Brian Elfert

[Brian Elfert]

Emergency lights are as cheap as $36 at Home Depot with several more models at $45. An exit sign with emergency lighting jacks the price to $135.

Brian Elfert

[Robert Bonomi]

I agree totally. That's too cheap _not_ to buy!

I havn't had occasion to price such stuff for years -- memory said circa $60, circa 10 years ago. Was 'guessing' on current market. Glad to see I was wrong on the high side. :)