David Morris wrote:

G'day from DMRH

Having worked in the fire protection industry for some time now. (yes I
have a day job) I have experienced a number of gas drops including both
1301 & 1211 Halon.

To give a practical experience. Once (1989) I accidently discharged 6
"100 kg" 1301 bottles into a
5 x 10 metre computer room with no major form of ventilation. Walking
into the room whilst the Halon was discharging (to ask the confused
operaters to leave) I didn't have any problems with breathing straight
away. Staying in there after about 3 min gave me a very high pitched
voice (Mickey mouse style) not unlike when you breath in helium ballons
as a party trick. Obviously the Halon didn't disperse 100% of the oxygen
from that room for even a short period of time but it doesn't need to
either to be effective.

I can remember one of those training films from some time back saying
the oxygen doesn't need to be totally dispersed or maintained away from
a room (cockpit!!) to work effectively. The oxygen level just needs to
be brought down to a certain threshold level before a fire ceases to
function. It went into a set of complex formula's to calculate the
required amount of Halon for a given volume of space which at the time I
failed to take notice of. (due to it not being part of my particular
field)

BTW, Halon gases (all types) have been banned in Oz for many years now.
Does the U.S have the same enviromental policy???

REgards
             David Morris

Yes I think they are. Kind of stupid because it is not released unless
there is a fire.

I know you are in Austraila Dave and not New Zealand. Was it my
imagination
or are the ultra violet rays stronger in New Zealand? The 
sun seemed brutal down there. 

Paul Lamar
 
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