On 6/29/2011 9:43 PM, Ned Flanders wrote:
The Daring Dufas wrote:
On 6/26/2011 9:57 PM, Ned Flanders wrote:
The Daring Dufas wrote:
On 6/26/2011 9:08 AM, Ned Flanders wrote:
Nate Nagel wrote:
On 06/25/2011 06:58 PM, The Daring Dufas wrote:
On 6/25/2011 1:46 PM, bob wrote:
I live in an apartment with several fire sprinkler in the ceiling.

If the sprinkler goes off due to fire or malfunction, can I turn it
off
after the fire is out? Is it the same valve near the water heater
or is
there a different one?

Im more worry about water damage (to electronics and computers)
than
fire damage. Perhaps because Ive never had a fire before and
this is
the first time I moved to a place with fire sprinklers.

Alternately, is there a switch to cut off power to computers or
other
devices when it senses water? This would reduce short-circuits
caused by
water when the device is powered.

It's not like in the movies and TV where you see all the sprinkler
heads
start spraying water at the same time. It doesn't work like that if
that
worries you. Only the sprinkler head tripped by flames releases
water.
Many systems are dry, meaning there is no water, only compressed
air in
the pipes which keeps the main water valve shut until a sprinkler
head
is activated by fire. The wet pipe systems have to be drained to
flush
them out on a regular basis to keep crud out of them, the dry
systems
don't have that problem and the maintenance folks have to keep an
eye on
the air pressure in the system which is usually remotely monitored
through the alarm system. If you are in a multi-floor apartment
building
, each floor may have a maintenance closet where there is a valve
for
your floor.

TDD

Dry systems are typically only used where ther eis a risk of
freezing.
The vast majority of residential sprinklers are wet pipe.

nate


Dry systems are a bitch to maintain and they tend to rust faster
than a
wet system due to the oxygen and moisture contained in the pipes. I
used
to keep an eye on a system that had two risers and compressors. I
can't
tell you how many times I had to scramble to trouble shot a compressor
before it tripped and charged the system. Rust, pin holes, bad
connections... dry systems tend to develop small leaks and the
compressors have to work harder and harder to keep up as the system
gets
older. If the diaphragm trips unintentionally due to a drop in
pressure
there is always a chance some of the heads may fail due to the hammer
effect.


The dry systems I'm familiar with had compressed air dryers for the
compressors to keep moisture at a minimum. I've repaired many a
compressor and air dryer system. The dry air was to prevent the exact
problems you mentioned. An engineer I was working with on the first
indoor cooling tower type setup in The Southeast, bumped a sprinkler
head with his hardhat and lucky for us it simply leaked so I tend to
believe the things are quite tough as far as resisting water hammer.

TDD


Around here, all new dry fire suppression systems must be tested for a
minimum delay from when the sprinkler head is tripped to when the water
starts spraying at the furthest head. This testing guarantees the system
will be wet inside. Blow the lines all you want but you will never get
all of the moisture out.


I suppose I should have written that the air dryers minimize the
introduction of more moisture from the compressed air source. I'm
curious as to how often the time to spray water has to be tested?

Just once when the system is installed. After that it just has to be
serviced by a licensed fire protection co.

Is it a one time certification or is it an annual test? I know the
guys from the fire protection company don't want water pooling in
the unheated warehouse sprinkler systems so I don't what their
procedures are but I've taken automotive antifreeze and blown it
through pneumatic systems that were freezing up in cold weather.
If it was extremely critical, I'm sure they could blow denatured
alcohol through the system to get rid of residual water like I've
done on some pneumatic systems. I'll have to ask one of the guys
about it. I guess a fire would melt an ice plug? :-)

In the 17 years I lived there both systems tripped many times due to
malfunctions, accidental contact, vandalism, and car fires. Keeping the
pipes dry would have been a hell of a challenge.

After a watching the fire prevention company a few times. I could pretty
much have the system drained and compressor back up and running.

All they had left to do was blow out the low points one final time, shut
the main valve from the city water, drain the diaphragm check valve and
pressurize it from the sprinkler side, open the valve to the city water,
and sign off on it.

One time the malfunction was caused by a flaw in a seam of a pipe. The
pin hole got progressively bigger until the compressor could not keep
up. The system tripped (naturally on the weekend). By the time the fire
prevention guys got there on the Monday the small hole was about a
centimetre in diameter and the water was gushing out.


Darn, defective pipe. I saw a lot of that 20 years ago when I was
working for a big construction corp. when the black pipe came from third
world countries because they had the best price. There were all sorts of
pinholes and casting flaws in the pipe and fittings. I have to wonder
how long that stuff lasted.

TDD