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Posted By: BrianP How do fire sprinklers really work? (OT?) - 08/21/07 09:58 PM
This is mostly off-topic, but somewhat related, I think. Anyway, I know there are at least a few firefighters on the board, and probably others that know details about fire sprinklers and their history.

In many movies, TV shows, etc., a fire alarm will trigger all of the sprinklers in the building. I know that on modern systems, each head activates separately. (I think there are some systems for special applications that activate multiple heads at once, but my question is about standard systems that you'd find in office areas.)

Did building sprinkler systems ever activate all the heads at once, or is this purely a Hollywood invention?
Posted By: jay8 Re: How do fire sprinklers really work? (OT?) - 08/21/07 10:28 PM
I think what you may be referring to is a deluge system where the heads are all open, pipes are dry, and there is a control valve that responds to a device to flood the entire area. Probably wouldnt be found in the areas that the movies are showing them in ie offices, malls etc. but they do exist.
Posted By: iwire Re: How do fire sprinklers really work? (OT?) - 08/21/07 10:49 PM
Originally Posted by BrianP
or is this purely a Hollywood invention?


Other than the rare deluge systems I say pure Hollywood.

In most cases it would be bad design to have all heads open at once, to much water damage also the sprinkler main would have to be HUGE to supply all the heads at once in a large building.
Posted By: BigB Re: How do fire sprinklers really work? (OT?) - 08/21/07 11:22 PM
As a point of interest here I can verify that a case of frozen peas, thrown across a grocery store walk in freezer, missing the intended target employee and hitting a sprinkler head, will break off and flood a 20 x 20 walk in freezer in just a few minutes, resulting in many hours with an ice chipper. None of the other heads will open, however the fire alarm will activate and the fire dept will respond.

Seems foolish to put fire sprinklers in a freezer.
Posted By: leland Re: How do fire sprinklers really work? (OT?) - 08/22/07 12:36 AM
most likely a dry system.
with these the pipes are filled with air on a closed pipe system, the air holds a valve closed, when the head pops the air releases and the valve operates sending water in the pipe. these systems are very common in cold climates, overhangs garages etc...

I meant to say "Hi", New here, this site is great you cover it all.
Posted By: BrianP Re: How do fire sprinklers really work? (OT?) - 08/22/07 01:06 AM
Originally Posted by leland
most likely a dry system.
with these the pipes are filled with air on a closed pipe system, the air holds a valve closed, when the head pops the air releases and the valve operates sending water in the pipe. these systems are very common in cold climates, overhangs garages etc...


Those aren't necessarily deluge systems, though, are they?
No, Brian.

A "Dry" system will only have water come out the specific head that has been tripped.

A 'deluge" system has nothing in the heads to stop water from coming out; when a seperate trigger opens the valve, they all spray.

"Deluge" systems might be found in an aircraft hanger. "Dry" systems are often found on loading docks.
Posted By: BrianP Re: How do fire sprinklers really work? (OT?) - 08/22/07 01:16 AM
Thanks everyone for your replies. I knew I'd get some good info here. laugh

http://www.reliablesprinkler.com/pdfs/products/500%20Model%20BX%20Deluge%20Valves.pdf

Here is one type of deluge valve. I wish that we had these in some of our fueling areas. Unfortunately, we have the ones without the external reset knob which require cover removal to reset the flapper. We use solenoid activation from FACPs but you can see that other methods can be used. I'm more used to chasing electrons around so these instructions remind me of the old Mousetrap game.
Joe
Posted By: leland Re: How do fire sprinklers really work? (OT?) - 08/22/07 01:52 AM
Brian, Saw your bio and here's some more info you may find interesting.

Mainly 4 types of sprinkler systems.
1) wet system- these are your typical office type sys.
Operation: pipes are always full of water,heads are thermal devices tripped by heat, only the affected head will release the water.

2) dry system- These are primarily found in areas that will be suseptable to freezing, load docks ,parking structures etc. (see other post)

3)Deluge system- this is an open pipe system, These are used in tank farms ,Aircraft hangers and the like, they are controlled by an electric solonoid that when triggerd by a detection device (heat,smoke,flame etc)releases the valve and the water (and sometimes assisted with foam) flows out ALL heads, to.... Deluge the area.

4) Pre-action- These are typical in areas that are sensitive, Elec/Data rms and such,areas that need confirmation of an event before release.
Operation:Closed pipe system,The pipes are filled with air (this is for pipe integrity supervision only).An electric solonoid is activated by a detection device (smoke, heat etc), releasing the valve and the system is "charged" with water, No water flow will occur in the space until a sprinkler head thermal is tripped (melts). This ensures or limits accidental discharge into the area.

Hope this helps. This is just the beginning, Fire suppresion is way cool, and there is a ton of concepts and products out there.
Posted By: BrianP Re: How do fire sprinklers really work? (OT?) - 08/23/07 04:25 PM
Originally Posted by leland
Brian, Saw your bio and here's some more info you may find interesting.

(snip)

Hope this helps. This is just the beginning, Fire suppresion is way cool, and there is a ton of concepts and products out there.


Thanks. I appreciate it. How do residential systems (single family dwelling) typically work? I hope to someday build a house, and I plan on putting a sprinkler system in it.
My new place only came with 1 head (near the furnace), but it's a wet system.
Check out this foam test. Impressive photo sequence. Contrary to the story the test went as it was supposed to. It filled the hanger quicker than expected but was left running on purpose.
"The Air Force required a minimum of one meter of foam to be achieved in four minutes or less. For testing purposes, the foam was allowed to disperse for the full four minutes. "

http://www.boreme.com/boreme/funny-2006/foam-test-p1.php

The real story.

http://www.af.mil/news/story.asp?id=123019117
I put a sprinkler system in my Md house, It was the common "split foyer" design you see a lot up there and the thought of a fire in the utility room under the stairs scared the hell out of me. That is a choke point for he whole house. I slept better with a wet pipe system that had heads in the utility room, the downstais hall (below the upstairs hall to the bedrooms) and on the stairs. It was really a fairly small amount of pipe with 5 heads but it did wet down the choke points.
In pioneer times, it was common for the 'kitchen' to be a separate 'cookhouse,' and not part of the main house at all. The reason? A fire there would not leave everyone homeless.

So ... if you were to have only one sprinkler head .... which room would get it? Which room is the source of most home fires?
Posted By: Trumpy Re: How do fire sprinklers really work? (OT?) - 08/24/07 06:49 AM
From the perspective of a Fire Officer,
There are multiple systems in use, depending upon the risk, how the installation is set out, the closeness of a Fire Department.
Usually here in NZ, most sprinkler systems are charged (ie: full of water and pressurised), a drop in pressure at the pump end will trigger the fire alarm, even if it is a leak.
In larger buildings here, there is always a dry riser installed in multi-level buildings, this is usually empty and has a coupling that will fit the feeders from the Fire Service here, because we take "riser packs" on our backs as well as a BA set.
A riser pack is a standard 2 length's of hose (usually 45mm) being 50m (150ft).
You carry the branch with you. smile
Hollywood has a LOT to answer for regarding fire movies, look at Backdraft, Ladder 42, et al.
If fires where really like that, us FF's would have a pretty sweet number.
Fact of the matter is, it isn't like that at all.
This could be the reason why we are pulling idiots out of houses that have re-entered to try and save material things.
Get out and stay out!.
Brian:

I don't know if this is code compliant in your area but Uponor (use to be called Wirsbo) makes a residential system that is part of your home plumbing system. It's a pex pipe system so the labour to install it is less than the normal iron or copper system.

I have seen it installed here in the house of a plumber as a retrofit after his house had a fire.

Here is a link to the cut sheets for it. http://www.uponor-usa.com/index.php?id=122&pid=29

The only downside I can see with this is if it does activate, you would be charged for the water that passes through the water meter. I think, but am not sure that sprinklers if dedicated are not metered.
A wet sprinkler system protecting freezers may have an antifreeze loop or dry heads.

An antifreeze loop is filled with antifreeze, but hopefully not automotive antifreeze. Automotive antifreeze is flammable. A non-flammable antifreeze is used, and there are supposed to be check valves and backflow valves to prevent the antifreeze from getting into the potable water.

Dry heads are charged with nitrogen and used in freezers, coolers and other areas that are subjected to freezing. When the sprinkler head is subjected to high temperatures, the fusible link or glass bulb activates and the nitrogen is realesed, then a plug is pushed out by the water pressure and water flows.

Sprinklers have a success rate of approximately 93%. The failure rate is usually attributed to lack of proper mainentenance.

Hollywood shows all the sprinklers going off at the same time because is makes for ticket sales, similar to the big sparks when electrical someone plugs in an extension cord. Not based on fact, but is impressive, never mind the false impressions of the general public.

Fireguy
Posted By: leland Re: How do fire sprinklers really work? (OT?) - 08/24/07 09:36 PM
Jdevlin- Great link.

And to think.. if that's a bladder tank it's only 250 Gallons of foam.

I personaly would'nt want all that stuff on me.. Knowing where it comes from.. Yek! (bio degradable Protein)
Posted By: Tesla Re: How do fire sprinklers really work? (OT?) - 08/26/07 02:32 AM
AND...

4a) the pre-action detection device typically shunt trips the MAIN breaker feeding the critical loads which begins a controlled power down.... as UPS/Server logic begins to shut down affected loads.
Posted By: Tesla Re: How do fire sprinklers really work? (OT?) - 08/26/07 02:39 AM
Originally Posted by renosteinke
In pioneer times, it was common for the 'kitchen' to be a separate 'cookhouse,' and not part of the main house at all. The reason? A fire there would not leave everyone homeless.



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.
Posted By: leland Re: How do fire sprinklers really work? (OT?) - 08/26/07 04:03 AM
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.
Posted By: BrianP Re: How do fire sprinklers really work? (OT?) - 08/27/07 05:06 PM
Originally Posted by ghost307
My new place only came with 1 head (near the furnace), but it's a wet system.


Only 1 head? Better than none at all, but isn't that a bit like putting an alarm system on just one door? wink
Posted By: BrianP Re: How do fire sprinklers really work? (OT?) - 08/27/07 05:09 PM
Originally Posted by mbhydro
Brian:

I don't know if this is code compliant in your area but Uponor (use to be called Wirsbo) makes a residential system that is part of your home plumbing system. It's a pex pipe system so the labour to install it is less than the normal iron or copper system.

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. smile

Quote
The only downside I can see with this is if it does activate, you would be charged for the water that passes through the water meter. I think, but am not sure that sprinklers if dedicated are not metered.


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. wink
Originally Posted by gfretwell
I can imagine they are scrambling to find ozone safe replacements ...


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.
Originally Posted by harold endean
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.)


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.
Reno:
After reading your response I was wondering if there were listings for these type of sprinklers as they don't seem to be in general use in my city. Here is what I found on the Internet.

International ships appear to be under the Safety rules of the International Maritime Organization which is one of those UN groups. Boat mist sprinklers have to meet rule IMO 800(19) and I think the coast guard of the flag country is the final AHJ for this.

For building sprinklers the UL listing number is 2167 and at least one major manufacturer had one shown for sale on their web page.

According to the page I was looking at FM and UL worked with the IMO on the tests so sprinklers may be listed meeting both standards.

Regarding your views on the instant experts I agree.

Our data center had salad bar cough shields installed over all the servers, tape silo's and disk packs to prevent water from hitting them if the sprinklers went off. The director of data processing did not want his equipment getting wet in a fire if the sprinkler(s) went off.

He is under the impression that with a dry pipe system all the heads go off as soon as the water hits the pipe. We tried to explain to him if one of the covered units has flames coming out the top, the plastic would catch fire, melt and make sure the sprinkler head over it opened.
Don't underestimate misting fire suppression systems. On a bet I put out a 5 gallon bucket full of water with burning diesel on top using nothing but a ZEP spray bottle. This was flames 5' high.
I had the nozzle cranked all the way down so it was shooting a fine mist. That water just sucks the heat out of the fire until it can't burn anymore.
It is something they taught me in the military to fight fires on ships. We used low velocity fog to control a diesel oil fire in a swimming pool sized tank and in a mock up of a ships compartment.
Posted By: leland Re: How do fire sprinklers really work? (OT?) - 09/03/07 01:12 PM
Supression is not life safety, Its main intent is property protection.

I've seen water mist work very effectivly. Very popular in the power industry for the gas turbines. It must be very well calibrated, (air/water mix).

The new data rms, paper is not protected, rather the electronics. This is the reason behind the gasses.

Halon is still out there. the systems can still be recharged, (if you can find and afford it). The systems can not be modified, no athaurity will honor the calculations.

Fm-200 ( AKA FE-227) Is the replacement. All new calcs and modifications are needed so basicaly a new system.
Halon takes 13 million yrs to break down, FM takes only 9 million.

A nice product out there is "Inergen", The draw back is it takes up a lot of space.

This is an inert gas combo. @ 2500 psi it must be throttled down on discharge.
It operates by displacing the room air with the gas (+- 80%)
It drops the oxogyn level to +- 12% and raises the co2 level to +- 8%, This will susstain life (no PI) but not support flame.

Due to the percentage pres. releif must be present (like dropping an ice cube in a glass, the excess (rm. air) has to be moved out. Hence the need for space, all those tanks.

dis claimer: I've been out of this end for 3 yrs, some things are newer, and my % may not be exact.

I may be going back to it soon coz it's one exiting feild.
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