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

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?

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.
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

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)

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.