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Off-the-grid fire fighting
Out There:
I read an old (2004) string, here, related to firefighting (brush fires seemed to be the primary concern). It sounded like the guy was off grid, as he had a halon extinguisher by his inverter. He had just purchased a diesel water pump. This subject has been on my mind, of late. I'd like to BEGIN planning for a fire-suppression system which would allow some automation (I'm thinking of a sprinkler system, actually), and wondered what people's thoughts were. If I had a dedicated pressure tank with a pressure switch (much like you have on a typical well), I was thinking I could set that up to (electrically) start a fossil-fueled pump to help keep up pressure. I'm hoping my water source can be a cistern (yet to be planned/built) or the year-round stream I have on my property.
Anyone have any experience with anything remotely like this?
-Brian
birdhouse:
i was actually doing fire suppression work today as a matter of fact. forklifts and sprinkler pipes don't mix well!
the pipe typically used in older systems is standard schedule 40 with npt threaded ends. new systems use a much thinner wall with a dedicated mechanical clamp/gasket system for joints. for DIY, i'd goe with threaded.
most systems run at ~60-90 PSI. these pressures will yield about 15' diameter spray per head. they're very water hungry! they thread into a 1/2" npt female threaded hole. there are also different temperature ratings on heads. i believe they come from ~ 160 degrees to 200 degrees for the auto spray feature to engage. so basically a fire has to be already burning before a head will spray. each head sprays individually. IE- if one sprays, they all don't. each head has to get to the temp brink before it will spray.
there's wet and dry systems. wet systems are always full of pressured water. dry systems are full of compressed air. they are used were a wet system could freeze and burst pipes. the compressed air in the pipes keeps a flapper valve shut at the base of the riser. if a head goes, the compressed air leaves, and the flapper valve opens, releasing the water. this is a bit scary, as when you have a fire with a larger system, your shooting 600+ gallons of ~35-40psi compressed air (oxygen) onto a fire before the water comes out!
if you have any other questions feel free to ask. i MAY be able to answer.
adam
madlabs:
I live off the grid an am a volunteer firefighter of 15 years. I have thought about a sprinkler system but instead have decided not to.
Instead, firstly, I practice good fire safety. Fuels, solvents, paints, etc. in a metal locker, keep the shop clean, good wiring, all that sort of stuff. Then I have fire extinguishers sprinkled around all over the place, total of 6 five pound ABC's. Then I have a 2600 gallon tank (setting another one soon) and a gas powered pump with 30' of suction hose and 300' of 1 1/2" fire hose, a good nozzle, and an inductor and 10 gallons of foam.
So nothing automated but I'm ready to rumble if I am here.
Jonathan
Out There:
Wow! Both EXCELLENT responses! I may actually tend toward (at least for now, in the planning stages) a balance between the two.
birdhouse, when you say "very water hungry", do you have any idea as to what that would mean? How much do I need to have in "reserve"? What would I need for a pressure tank? 60-90 psi seems do-able….
madlabs, I sincerely appreciate, and take to heart, your point regarding "good fire safety". Any potentially flammable liquids are not stored in the house. I don't actually have that much… wiring is well done (so far as I've investigated). I have several ABC extinguishers about the place, too.
My house is three levels (not three stories) totaling 2300 sq. ft. Once the soapstone stove is rebuilt, it will be in a room with a lot of combustible material (books on wooden shelves - lots!) which happens to sit on a concrete slab. At the opposite end of the house, connected to but not communicating with the interior of the home, is my electrical room (battery box, inverter, PV charge controller, etc.). I suspect these two rooms are going to be my biggest challenges.
A while back (when I was really broke and could not afford it) I saw what looked like an excellent deal on eBay: A self-contained, Halon, ceiling-mounted fire extinguisher with a sprinkler-style head. I thought about one of those for my electrical room. Any thoughts?
-Brian
birdhouse:
brian-
--- Quote ---"very water hungry"
--- End quote ---
a standard older home is if fed with water via a 3/4" water main. newer homes are typically 1" main.
a sprinkler head uses 1/2". i think you'd struggle to get full flow out of three heads from a 3/4" main.
risers for systems with a 100+ heads are in the 6-8" range. we're talking big time water flow at 75psi. then there's the FDC connection at the street. fire departments will hook a pump truck to a fire hydrant to push pressures above 100 psi to any blown heads to get them to "over flow".
i'm wondering a little why you're worried? a newer listed wood stove should be fairly safe, as long as the floor and wall protection/clearances are correct. i personally let my wood stove run while i'm sleeping and have never thought much of it.
is you battery bank vented? hydrogen can escape from batts while charging. it's very flammable.
if a sprinkler system goes off, the results are pretty damaging. obviously less damaging than the whole house going up in flames... but it's pretty bad. most times the "water" in the pipes is more like rusty sludge being thrown about.
i'd think money spent in the prevention/prepared realm would be the better bet. venting the electrical room at it highest point (hydrogen rises) and giving the wood stove a code plus clearance to combustibles.
adam
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