[BC] KOMO, Seattle building fire

[Broadcast List USER]

There are a LOT of misconceptions.

First of all, neither Halon nor CO₂ remove oxygen from the air.  Both  
displace Oxygen, and because it takes so much CO₂ to suppress a fire,  
it makes the partial pressure of oxygen so low that human life cannot  
be supported.  Halon, on the other hand, suppresses fire at such a low  
concentration that there is enough partial pressure for us to survive.

CO₂ MUST displace enough oxygen to put out the fire, or life.  Halon  
doesn't need to do that.

I chose Halon for one simple reason, and the company bought off on it  
even thought it cost more because of the reason.  Imagine some worker  
falling from a ladder and dropping a soldering iron in a metal trash  
can.  The fire would burn up the trash in the can, and go out under  
normal conditions.  The guy who fell off the ladder and hit is head,  
would wake up later and cough a bit from the smoke he inhaled.  OK, no  
problem.

Then we put in a CO₂ system.  It senses the smoke from two sensors  
and discharges.  The alarm sounds.  No one hits the abort mushroom  
because the worker was knocked out from his fall.  The CO₂ system  
discharges, and puts out the fire that would have gone out anyway.   
The worker dies from lack of oxygen.

Instead, we put in a Halon system.  It senses the smoke from two  
sensors and discharges.  The alarm sounds.  No one hits the abort  
mushroom because the worker was knocked out from his fall.  The HALON  
system discharges, and puts out the fire that would have gone out  
anyway.  The worker lives because the partial pressure of oxygen is  
close enough to five pounds per square inch hat he is fine -- though  
maybe wakes up a few minutes later than he would have with no fire  
suppression.  Good for him in that he inhales less smoke.

SOLD!

There are other reasons to choose Halon over CO₂.  Halon can "dump"  
from only one nozzle in a large equipment room.  It will find its way  
into racks and other equipment.  CO₂ needs to be plumbed into each  
and every rack and cabinet in the room.

Someone wrote that his system was (imporperly) tested with Freon  
instead of Halon.  This is standard operating procedure for several  
reasons.  The first is cost.  The second is monitoring.  In most  
tests, the room is sampled, that is, sensors are placed around the  
room, and monitored.  I don't know the reason, but I was told that the  
Freon sensors were better at testing concentrations.  Also, the Freon  
can be seen.  I saw two tests in two rooms, and the gas kind of turned  
the room slightly purple.  It left no residue on anything.

One really frustrating problem is that people keep clinging to the  
"fire triangle" they learned in elementary school.  It is time go grow  
up.  Others have pointed this out, but there are not three, but FOUR  
things needed for fire.  Heat, fuel, oxygen, AND A MECHANICAL ACTION.   
Halon gums up the works on the fourth element.  It is like sand in the  
gears.

Sadly, Halon is falling out of favor because of the Ozone Hole.  It  
really works well.  In fact, one of the greatest demonstrations I have  
seen is with gasoline in a snow saucer (you know, the thing kids ride  
down the hill in show).  You have to really get CO₂ portable  
extinguishers to the base of the flames.  Same for dry chemical.  It  
has to get in there.  You can spray Halon 45° from the direction to  
the fire.  The stuff actually turns the corner and finds the fire.  It  
is an amazing thing to watch.  It just puts the fire out.

--chip

On Jul 5, 2009, at 1:00 PM, broadcast-request at radiolists.net wrote:

> Does Halon remove oxygen from the air?
>
> It is a common misconception that Halon, like CO2, "removes oxygen
> from the air."