ECN Forum Forums General Topics of the Trade General Discussion Area How do fire sprinklers really work? (OT?)

Poor draft from a non-existent chimney would keep the cook house upwind of the out house.

Throw in some smoky local timbers and the need for isolation would be smoke in your eyes.

Typicaly, the shunt trip operates on the water flow pressure switch.
This ensures no power cut until there is a need for water.

But I have seen some that go off on low air !!!!!!

Boy that makes a customer mad.

Only 1 head? Better than none at all, but isn't that a bit like putting an alarm system on just one door?

Thanks. I won't worry about code compliance right now, as I won't be building here in Minnesota. I'm going to move someplace warmer first.



If it keeps the house from burning down, I won't mind paying for the water!

Have you ever seen the mist type of sprinklers. The water is sprayed out in a really fine mist so that when it heats up, it turns to steam and smothers the fire. There is very little water damage, because very little water is used. Sometimes they will put these systems in computer rooms. (I was told by a salesman for these systems.)

The only systems I saw in computer rooms from the early 70s until the CFC police made them illegal was Halon.
I can imagine they are scrambling to find ozone safe replacements now but I am not really sure why a fire suppression system is even necessary in the modern computer room. They are rapidly becoming paperless, tapeless and cardless. There really isn't much in there to burn. These are not even attended in a lot of cases. It is just a few racks, humming away.
You will still need supression simply because these are commercially occupied areas but I don't see them actually operating.
Even when computer rooms were stuffed with paper, cards and mylar tape, paper dust coating everything, I still never heard of a fire in 30 years that operated the fire suppression. That was when people even smoked in the computer room ... eeek!

BTW I was in one Halon dump and heard of several others ... always a false alarm ... a $60,000 (and up) false alarm.

BTW the strangest fire suppression system I ever saw was a CO2 system that would make the computer room like the surface of Venus (lethal concentration) in about 2 seconds. This was Atomic Energy Commission Germantown Md
They also had the first "motion sensor" alarm system I ever saw. It was a couple 60w bulbs running on reduced voltage strategically placed and it looked for moving shadows with photo detectors.

The rumor was the CO2 was connected to the burglar system. Yikes! I never believed it but this was a "cold war" agency so who knows. I was always in there with an "escort" and my plan was to beat him to the door if the alarm went off.

FM200 is the "new Halon" for computer rooms.

At work the existing Halon system was pulled out for environmental reasons and a two stage suppression system was put in.

The first stage is a cross zone trip FM 200 system connected to the Emergency Power off system for the data centre and printer room.

The second stage is a dry pipe sprinkler system. The reasoning is if the FM200 malfunctions or does not put the fire out immediately, the heat of the fire will trip the sprinklers and save the rest of the office tower from the fire.

Our unmanned backup data center is strictly FM200 as its a standalone building out in the suburbs not on city water. It tripped this spring and the vendor is still not sure why it did that as there was no fire in the building.

A girl I was going out with in the early 1980's was caught in a Halon dump in the Provincial government data center as she could not make it out the exit door in time when the pre alarm sounded. She dived under a desk in the tape library as all the suspended ceiling blew apart as it was not clipped down properly. Parts of the cross tee's were embedded in the drywall from the discharge force when the fire department came to search for her. Other than being scared for her life while everything was blowing around she was ok.

I was just watching a tv program today on behind the scenes of the QE 2 cruse boat and they use the grey water from the ship for a fire fighting mist system on the decks as well as the regular hoses. Apparently this is a new way of fighting fires on cruse boats.

As to these supposed 'mist' sprinklers ... I would INSIST upon FM or UL approval of the system.

I've seen all manner of experiments done regarding droplet size, and it is my belief that a fine mist would not be an effective way to dampen a fire.

Likewise, I've been in all manner of situations where "instant experts" decided, simply using 'logic of the moment,' that sprinklers posed a greater risk than a fire posed - either from water damage after the fire was suppressed, or from an accidental discharge. One gent went so far as to defeat the alarms, and chain the water main shut, using his own good hands.

Such fears are founded upon emotion- not actual data. If there is an intolerable risk, it seems to be the result of a poorly designed work center - not of the sprinklers themselves.