Morgan
International Hazard
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Fire extinguisher shimmering mystery
I was discharging what I believed to be an old CO2 fire extinguisher, one with a long horn at the end of a rubber tube with rusted wire mesh
reinforcement underneath the rubber discovered when I later cut the tubing off. I just wanted the tank for another experiment. As an aside, I got
shocked a few times and decided to put a cloth over the handle in order to continue emptying it. It only took two good shocks to decide to this wasn't
going to work. I had the tank on the ground as well when discharging it.
There was the typical white cloud of vapor and white snowy flakes that form, but at the very end when the gas was barely coming out I noticed a
mirage-like vapor just at the tip of the horn, as if the light were being distorted by gasoline vapors. It doesn't seem like CO2 would do that but I
don't know. Not that I tried to breathe the gas but there was no odor to it either. Also, there were several more distinct discharges of static that
could be heard in the horn, like shorting a capacitor.
In reading about CO2 static from fire extinguishers, a few articles said that if the braided wire inside the rubber hose was damaged, that that could
create a shock. ha
"Anyone that is trained to use CO2 should also be trained in the hazard associated with static discharge. Large wheeled units have knocked down
operators when the hose bonding wire had been damaged."
http://www.linkedin.com/groups/Have-u-ever-experienced-stati...
"CO2 fire extinguisher discharge hoses are manufactured with a braided continuous wire inside. If the wire in the hose is damaged, the buildup of
static electricity can't be dissipated and the operator may experience a shock. This is particularly true if the fire extinguisher is being discharged
while being carried up off the ground. That is why NFPA 10 requires that a continuity test be performed on the hose at the time of maintenance to
ensure the wire braiding remains capable of dissipating any static buildup. A label is then attached to the hose as an indication that the continuity
test has been performed."
http://www.linkedin.com/groups/Have-u-e ... S.72405014
My tank was painted red and about 7 inches in diameter with the letters PD painted on it. This tank in the barge scenario looks just like my tank with
the same shape of the horn and wavy bottom on the tank.
https://www.youtube.com/watch?v=2sSqzLPMb4s#t=13m58s
So I don't know if they make a blended CO2 and something gas mixture or what that made the mirage gas effect.
TIdbits
• Two navy firemen were killed in an explosion while attempting to inert an 18,9 m3 Jet Fuel tank by use of portable CO2 fire extinguisher.
• Four persons were killed in an explosion on board the tanker Alva Cape while inerting naphtha tanks using CO2 cylinders.
• Twenty nine persons were killed in an explosion while witnessing the demonstration of a newly installed CO2 fire-extinguishing system for a
partially filled 5000 m3 jet fuel tank, in Bitburg, Germany.
http://indiaprocesssafety.blogspot.com/2011/08/static-electr...
[Edited on 18-10-2014 by Morgan]
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unionised
International Hazard
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The refractive index of CO2 is different from that of air, so it's perfectly possible that CO2 caused the "mirage" effect.
http://en.wikipedia.org/wiki/List_of_refractive_indices
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Morgan
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I think there's a chance it may have been this stuff. I typed the words "halon shimmering" and found this work of fiction below. Good thing I didn't
breathe the gas and it went well away from me. If it's heated as in a fire it makes even worse crap. I swear so often when you are doing something fun
in chemistry there's some caveat waiting for you. That's what I get for buying an unmarked fire extinguisher.
"Now the ear splitting gas discharge under the raised floor was so massive and fast, it blew about half of the floor tiles up out of their framework.
It came up through the floor into a communications rack and blew the cover panels off, decking an operator. Looking out across that vast computer
room, we could see the air shimmering as the halon mixed with it."
http://www.hactrn.net/sra/vaxen.html
"Multiplier effect of mixed agents of trifluorobromomethane (halon 1301) and inert gases on flame extinction has been investigated, for the purpose of
minimizing the use of halons. The inert gases examined are argon, nitrogen and carbon dioxide."
http://www.iafss.org/publications/fss/5/901
http://www.iafss.org/publications/fss/5/901/view
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macckone
Dispenser of practical lab wisdom
Posts: 2168
Registered: 1-3-2013
Location: Over a mile high
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Halons refractive index is much different from air as is CO2. The reduced temperature of the gas also
enhances the effect. A mirage is caused by a temperature
difference between the air close to a surface (like a road)
and the larger body of air above it. So yes it could be CO2
.
In a raised floor data center, halon discharge under the floor
can be quite impressive. Think of hundreds of 24"x24" corks
popping at once. I have seen pictures but never been in one
when it happened. Independent discharge below the floor and
not above it is no longer allowed due to the hazard. In some
cases where insufficient vents are placed in the data center
walls have even been blown out.
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Morgan
International Hazard
Posts: 1694
Registered: 28-12-2010
Member Is Offline
Mood: No Mood
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Quote: Originally posted by Morgan  | I was discharging what I believed to be an old CO2 fire extinguisher, one with a long horn at the end of a rubber tube with rusted wire mesh
reinforcement underneath the rubber discovered when I later cut the tubing off. I just wanted the tank for another experiment. As an aside, I got
shocked a few times and decided to put a cloth over the handle in order to continue emptying it. It only took two good shocks to decide to this wasn't
going to work. I had the tank on the ground as well when discharging it.
There was the typical white cloud of vapor and white snowy flakes that form, but at the very end when the gas was barely coming out I noticed a
mirage-like vapor just at the tip of the horn, as if the light were being distorted by gasoline vapors. It doesn't seem like CO2 would do that but I
don't know. Not that I tried to breathe the gas but there was no odor to it either. Also, there were several more distinct discharges of static that
could be heard in the horn, like shorting a capacitor.
In reading about CO2 static from fire extinguishers, a few articles said that if the braided wire inside the rubber hose was damaged, that that could
create a shock. ha
"Anyone that is trained to use CO2 should also be trained in the hazard associated with static discharge. Large wheeled units have knocked down
operators when the hose bonding wire had been damaged."
http://www.linkedin.com/groups/Have-u-ever-experienced-stati...
"CO2 fire extinguisher discharge hoses are manufactured with a braided continuous wire inside. If the wire in the hose is damaged, the buildup of
static electricity can't be dissipated and the operator may experience a shock. This is particularly true if the fire extinguisher is being discharged
while being carried up off the ground. That is why NFPA 10 requires that a continuity test be performed on the hose at the time of maintenance to
ensure the wire braiding remains capable of dissipating any static buildup. A label is then attached to the hose as an indication that the continuity
test has been performed."
http://www.linkedin.com/groups/Have-u-e ... S.72405014
*****
There was this story that seemed like it might fit here with the above previous post. There's a boatload of comments on the page if you scroll down.
"We are scratching our head over an incident that happened at one our our sawmills the other day."
https://cr4.globalspec.com/thread/62968/Mysterious-Shock-Rec...
[Edited on 14-9-2021 by Morgan] |
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