Home Firefighting System
My neighbor has asked me to design a home firefighting system for her.
This is to protect the house in the event of a forest fire.
A hill rises up behind her house, it is some 30 feet high. I will go over and get the exact elevation of the hill.
I am planning to bury a plastic tank in the top of the hill, and run an underground pipe to the vicinity of the house, and install some spigots on either side of the house to fight a woods fire with. Could you do well with garden hoses, or would a special firefighting hose work better? How high would the tank need to be to get good pressure?
Also, I would want to have the tank accessible to the pump from a fire truck.
Another neighbor's house caught on fire, the fire truck came up and fought it for about ten minutes. Then, the firemen all set their hoses down and smoked a cigarette. They were out of water. Their truck carried 2,000 gallons. They had to wait about ten minutes for a backup truck to bring more water.
So I was thinking of a 2 or 3 thousand gallon tank.
This is to protect the house in the event of a forest fire.
A hill rises up behind her house, it is some 30 feet high. I will go over and get the exact elevation of the hill.
I am planning to bury a plastic tank in the top of the hill, and run an underground pipe to the vicinity of the house, and install some spigots on either side of the house to fight a woods fire with. Could you do well with garden hoses, or would a special firefighting hose work better? How high would the tank need to be to get good pressure?
Also, I would want to have the tank accessible to the pump from a fire truck.
Another neighbor's house caught on fire, the fire truck came up and fought it for about ten minutes. Then, the firemen all set their hoses down and smoked a cigarette. They were out of water. Their truck carried 2,000 gallons. They had to wait about ten minutes for a backup truck to bring more water.
So I was thinking of a 2 or 3 thousand gallon tank.
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might be better to prepare by clearing any fuels off the ground, ie brush, leaves etc.use a leaf blower to build a line, faster than a rake, clear any shrubs, leaf litter, away from the home, your type of fires are usally slow moving ground fires unless a lot of wind is involved,your idea would be a great back up, i doubt regular garden hose that is gravity fed will have much effect,unless its got some kind of pressure behind it, call your local fire dept, and ask what size fittings their brush trks and pumps use if your looking for them to hook into the storage tank, ask them for advice also, green will burn if it gets hot enough, Loko [:D] 0 -
Questions:
Do you live in an area that will freeze?
Do you/she want a system that must have one or more people there to use it?
How will you fill the tank and then keep it full over time?
Do you want to keep the house wet during a fire or put out the fire as it gets close?
What size and type of vegetation is around the house?
Things to consider:
We figure that you gain/loose 5 P.S.I./story or 10'
Most houses have 40-60 P.S.I. in the water systems.
You may need a longer pipe to get to where the Fire Trucks can fill off of it.
You will need to talk with the Fire Department and find out what size and type of fitting they will need on the pipe.
My thoughts:
Add a gas powered pump and a Class A foam. This will let you wet down the house and will "hold" the water in place longer.
This could be a very good thing to have set up. I think you will need some kind of pump. Definitely contact the local Fire Department and see if they already have plans or specs for what you are doing.
This is all I have for now, I'll check back and add anything I think of.0 -
I GI this (googled it) using "calculating water pressure". This is from the first link, you may want to research it further. Hope this helps.
Note: A 2 or 3K tank is mighty big. You're gonna need a backhoe or at least 5 Mexicans to bury it.
The static water pressure in a gravity-fed system is simply a function of
>the vertical distance between the opening of the hose and the top of the
>water level in the tank. The pressure of a column of water is one
>atmosphere (about 15 psi) for every 32 feet of height. So, if the water
>level in the tank is 16 feet above the hose nozzle, the water pressure at
>the nozzle will be half an atmosphere.
>Factors such as pipe size come only into play when you worry about flow
>rates. Then, the cross-sectional area of the pipe, the flow rate, and the
>viscosity of the fluid (water) will have an effect on the delivered
>pressure. I don't know the values of the constants you need to plug int eh
>equation, but the drop in pressure is inversely proportional to the
>cross-sectional area, directly proportional to the length of the pipe, and
>directly proportional to the flow rate.0 -
Do you live in an area that will freeze? Yes.
Do you/she want a system that must have one or more people there to use it? We want a system that one person could operate.
How will you fill the tank and then keep it full over time? She has a drilled well that is 605 feet deep, which, admittedly, has a low output, maybe 1 1/2 gallons per minute. This well holds about 400 feet of water, or 600 gallons. So, I figure you could fill the tank, 100 gallons a day, it wouldn't put much of a strain on the well. Check the firefighting tank every so often and see if it needs topping up, dump a couple gallons of Clorox in there to keep the bacteria/algae down.
Do you want to keep the house wet during a fire or put out the fire as it gets close? I was planning to put the fire out as it gets close. Twenty years ago, I was living in Georgia. I was off playing soccer. A neighbor saw lighting strike a pine tree in my yard, and catch the yard on fire. She immediately called 911. They scrambled the volunteer fire dept. The first firefighter arrived, the woods fire was twenty feet from my house, and thirty feet from my car. The fire truck was not there yet. This firefighter fought the fire with the garden hose for ten minutes, until the fire truck arrived. He saved my house and car. This is how I got the idea for the home firefighting system.
What size and type of vegetation is around the house? This is in the heavily wooded forests of the North Carolina mountains. When it is dry, like it is now, there are lots of forest fires, and there was one a mile and a half away, two weeks ago. When you are on top of the mountain, and the fire starts below, you know it is coming on up.
At my neighbor's house, there is a grassy yard that goes about 80 feet all around the house, and past that is thick woods and brush with 90 foot trees.0 -
If you do go with a gas powered pump make sure it is started at lease once a week and allowed to run for 5-10 minutes. We start the small equipment each morning at the station. This helps it to start when we need it to with one or maybe two pulls. This is not something that you will want to mess with when you see smoke.
Also keep fresh gas on hand. It should not take much to run the pump for an hour or two. Figure out how long the tank of water will last and the run time of the pump. It would be easy to get two cans and each month you take one and fill it and then dump the old one in a cars tank. This way you will always have one can with a month old or less gas.0 -
Freezing:
The tank will need to be well buried then. We have installed what is called a "Dry Hydrant" see picture. Also Google it and you will find good info. The insurance company might give her a break because of having the tank.
All lines will need to be able to be drained and blown out come cold weather. Some careful planning and pitching of the pipes will make this very easy to do.
Filling it and keeping it full:
Sound s like a good plan, I would run a line from the house so all she has to do is open a valve to fill it. This would also let you refill the tank while fighting a fire.
With the size and distance to the woods I would put some hose bibs out 10-20 feet from the tree line. Also have some closer to the house. As you start working out in the woods with the hose it will get wrapped around trees and you may have to drop it and run if the fire is moving to fast. This way you will have over lapping fields of fire, yeah spraying water not bullets, so someone can help you or if you loose a hose.0 -
Very important:
If you do put in a Dry Hydrant pipe contact the Fire Department and find out what size and type (male, female or Storz) fitting they need
We have some different ones in the county and have to make sure we get the right adapters before we try and hook up to them. We are now getting them all standard on any new ones. It was the first few that the departments weren't thinking about the other departments that might be using them.0 -
I measured the drop from the top of the tank to the lower edge of the house. It is 44 feet. This would give about 20 to 22 psi at that point.
This is the ideal place to put the spigot. What I have in mind in installing a frost proof spigot. This will not freeze even in the coldest weather.
At that point, the ground drops off sharply. The lawn is about 100 feet wide. So, to get to the woods, there would be a drop of another 10 to 15 feet. So you could install a spigot there at the edge of the house, put 200 feet of garden hose on it, and you would get a total drop of 55 to 60 feet to where you would be fighting a woods fire. This would give a pressure of around 30 psi.
I know that 30 psi is a minimal amount for household pressure. Would this be enough flow to fight a fire with?
I do not want to use a system that depends on a gasoline powered pump. My neighbors would not keep up with storing the gasoline, or maintenance for the pump, and I would not want to mess with it, either. I am hoping to design a system that would rely on gravity flow only.
If this is insufficient pressure, would it be of value to the fire dept. to have a couple thousand gallons of water there for them to pump onto a fire? The tank would be about 200 feet from the house, so I know the hoses would reach.
Do all fire trucks have a suction pump where they can pump from ponds?
If so, I could just make sure there was a big lid on the top of the tank, and the fire truck could drop their suction hose into the tank. Then, I would not have to worry about having a fitting that was compatible with the fire truck's fittings.0 -
While pressure is important in calculating a fire stream, you also need to concentrate on gpm or gallons per minute. Most 1 /34 handlines on fire trucks are pumped at roughly 120 psi and can flow anywhere from say 90 to 150 gpm. So the 30 psi that your getting will do some good, it obviously could be better. And you also have to figure in friction loss which is the pressure needed to overcome the hose restriction, and the longer and smaller the hose, the more the friction loss. So if you've only got 30 psi at the spigot, you'll have less at the nozzle. Probably your best bet is concentrating on prevention, ie clear the brush, trees and other litter that is close to the house. Not saying it can't be done, but if you've got much of a fire, especially in big pine timber, your pretty much pissin in the wind with a garden hose. 0 -
I spent 30 years inspecting public water systems and calculating pressure requirements. To achive a minimum of 35 psi from an elevated storage reservoir, the water level in that reservoir must be a minimum of 81 feet above your service area. I feel that you would need quite a bit more pressure than that to fight a forest fire. 0 -
average pump speed on an engine/pumper- 500-2000gpm
average tank size on an engine- 500-1500gal
even using the small pump and big tank(unheard of), you can see how its real easy to run out of water if you dont have a plug
btw, you need significantly more pressure to adequately fight a fire than 35psi0 -
Standard garden hose at 30 psi will get you around 5-8 gallons a minute. for 1.5 inch hoseline, (like you see on the firefighting rack in use in Lowes, Home Depot, etc) we figure 100-150 gpm. and that is rather minimal for fire fighting. Being able to wet down house and area right around house may help, but if fire is downslope, it WILL come up. REALLY wet vegetation can help- there are ground cover plants that are really little bags of water. Distance between fuel vegetation and the house will help. But at 30 psi, you need to ask how FAR you can spray water, and just how long you can stand THAT close to a wildfire. For private water supplies for fire sprinklers, we start at 10K gallons. 0 -
I understand that you need 2.3 feet of rise of the tank to get one psi.
In other words, a tank that is 23 feet high will give 10psi.
Does it make any difference how much water is in the tank?
It seems like a tank with 16,000 pounds of water in it would give more pressure than a tank with 40 pounds of water in it.
If the bigger tank does not give more pressure, then I am stuck with about 25 to 30 psi. Obviously this would not be worth the trouble to do, since there is a frostproof spigot in the yard, connected to the house water system, and it has 35 to 55 psi. She could just get a couple of 100 foot garden hoses, and at least could tamp down a yard fire until the fire dept. arrived.
I have seen on the internet a foam sprayer which attaches to the garden hose. Is this foam pretty effective in keeping the house from catching fire? It is a log house, but it has a steep metal roof, so it wouldn't be too hard to spray the foam on the logs. Can you wash the foam off with water after the fire?0 -
Your water pressure is measured by PSI. Volume has nothing to do with pressure, height or head pressure determines final pressure. That's why sometimes you see these tall skinny water tanks instead of the large round ones. If heighth didn/t matter, water towers wouldn't be towers, they would be ground water tanks. A tank one inch in diameter will have the same pressure as one twenty feet in diameter, if they are the same height, just not the same volume. 0
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