A6 dash fires

[Brett Dikeman]

At 5:25 PM -0800 3/24/04, William Magliocco wrote:
>Halon?  Mike, where have you been?
>
>Stuff is obsolete, first replaced by "Inergen" now by
>"FM-200".

Inergen is actually superior to FM-200 in a few ways, but requires 
more suppressant(and hence bigger tanks, and hence more floor space, 
which costs a lot of $/sq ft in a datacenter) so it's not as popular.

a)the manufacturer will sometimes give you free refills for a few 
years, which can be worth huge sums of money for even a small room if 
there's a discharge event.

b)the gas mix causes faster breathing, which compensates for lower 
oxygen content.  Inergen is also more inert than FM-200, which can 
decompose in a fire and become poisonous.

c)it is much lighter than FM-200, which sinks fast and requires 
literally sealing the room so it is effective. I believe FM-200 
removes oxygen from the room, whereas Inergen lowers the oxygen 
concentration and flash-cools the room(could be mistaken about that).

I don't recall which required less plumbing changes for existing 
halon systems(diameter, jet heads, etc).

All in all, even though they're superior to sprinkler systems, 
gas-based suppression systems have so much more regulation it's not 
even funny.  Generally at least one, often two or three, room seal 
tests are required.  In some states/cities, you're even required to 
do a full release test of the system which is colossally expensive. 
The same fire department that bitches to you about failing the room 
seal test by a few millibars will happily sign off on a sprinkler 
system which would destroy all your equipment and quite likely start 
fires or at least present a major electrocution hazard.

Incidentally, the #1 cause of server room fatalities- smoke 
inhalation.  Cause?  Staff re-entering a room after a fire(which 
often has been completely put out by the system) to fetch backup 
tapes foolishly stored in the same room and succumbing, nearly 
instantly, to the highly poisonous toxic fumes from whatever was 
burning.

Backup tapes should NEVER be stored in the same room as equipment, 
and off-site rotation is critical.  It's sad how many companies will 
spend gobs of money on a tape backup system but neglect to pay for 
regular purchase of new tapes(they wear!), a proper media safe(paper 
will survive to close to 400 degrees; tapes will survive up to about 
150 or 200 at most) and off-site rotations(one ISP found out the hard 
way when a tornado levelled the place to the foundation and they had 
no off-site backups).  Some managers will insist staff take tapes 
home instead of paying a company to store them in climate-controlled, 
secure facilities with asset tracking systems and all-hours 
access/delivery.

Brett
(crawls back under the off-topic rock)
-- 
"They that give up essential liberty to obtain temporary
safety deserve neither liberty nor safety." - Ben Franklin
http://www.users.cloud9.net/~brett/