Water Pressure

125' vertical?

Horizontal. Using for fire suppression.

If you want to reach 125' maximum, I would estimate that you would need about 90 feet to the breakover point which equates to about 90 feet of head or about 40 psi as the water leaves the nozzle.

You will have to calculate (or measure) friction loss in your hose and nozzle and add roughly 40 psi.

I don't think so. Once the water leaves the nozzle, there is nothing to push it any further except inertia. Remember, it's not confined inside the pipe any longer.

At that point it starts to lose energy and slow down and spread out.

It's much more complex than that.

Yep, good point, I should have thought that through more before I posted.

Is all 125 ft is a rise in elevation that's one thing. If the 125 ft travel length is down a 100 ft by -25 ft slope of a ramp then gravity by a stream or siphon will work fine. Then there are the questions of desired end point pressure, flow rate, flow restrictions, etc.

Here's a big hint for you, the density of water at 70°F is 62.31 lb/ft^3. This should be enough information to get you started.

I should have put what I am going to use it for in the question.. I am going to use it for fire suppression. To cool landscape to below the flash point to keep a forest fire from burning down my cabin.

I used to live in a hilly/canyon area of Calif. you cant beat this, but wind blows right over it

I guess you need an answer pretty quick then.

Just for grins, go turn on your water hose. Most residential water is supplied at around 50 PSI and on a good day you can shoot a 3/4 inch stream out of a 50 foot hose about 8 feet.

Next, fill a 5 gallon bucket with that hose and see how long that takes.

You're going to need a lot of water to supply that stream. Forget the pump for a minute ask yourself if you even have the water for this. If you can't pull from at least a 4 inch supply you may have issues with pump starvation.

Then, there's the electrical service needed for a motor to drive that pump.

Pumping Water - Horsepower Requirements

You may be better off using a sprinkler system than a deluge gun.

Have you asked your insurance company for help designing a system?

I'm not trying to discourage you. Many items you have there are surly irreplaceable.

Good luck.

Thanks for your concerns. I get about 15 feet from my garden hose at full city pressure. The water supply is a 5000 gallon tank and the pump is driven by a gasoline engine.

I hate it when I'm so negative.

5,000 gallons of water will buy you maybe a half hour. An hour if you can limit the flow to 75 GPM. Then you're out of water, unless you have some way to replenish the tank.

Rethink your approach and how to protect the property.

Sounds like a good excuse to install a swimming pool!

I would surely be surly also if some wanted to replace me.

TO be honest if it was me I would be planning around a system that can supply at least 150 PSI at the nozzle with a flow rate of 50 GPM or better.

I have a 3 HP multistage electric pump I used to use for watering my lawn on the dry years and if I am recalling things correctly it could maintain about 70 PSI at somewhere around 25 GPM through 10 or so feet of half inch line resulting in a solid stream that could reach about 50 - 70 feet.

Based on that I would be shooting for a minimum of at least double that PSI at double the flow rate for a base line.

The people who have managed to save their homes in the path of forest fires or big suburban fires like the Oakland California Hills fire had swimming pools for a supply and big gasoline driven pumps. A 2" fire hose and nozzle would be a great addition to the kit assuming you can hold the thing down under pressure. But at least a 1" hose. No standard garden hose or house plumbing is going to supply enough volume, no matter the pressure.

Personally, I'd cut the underbrush and burnable items away from the cabin by about 100 feet as well. If you have combustible objects close to the cabin, it probably will not matter what you have for fire suppression, it will burn.

Maybe 4-6 big golf course rain birds and a goodly sized pump would do it too. Then you could turn it on and leave (a really good idea).

Don't forget you have to breathe in the midst of a fire and would probably need some protective clothing much like foundry workers wear. I don't know if the surplus market has OBAs but you likely can find the compressed air supply setups the fire departments use.

Frankly, I'd just sign up for insurance and rebuild.

Go talk to a forest ranger, especially one of the fire fighting specialists and see what they say.

Now a days the lack or shortage of city water supplies in California should be your initial concern. The amount / volume of water needed for your project, to make it a success may not be available?

Thank you all for participating in the project. I now have enough information that I can proceed.

Byron

Not so fast!

I think I speak for the group when I ask that you share with us what you intend to do and how you accomplish it. Could be a "how I built my fire protection system" blog.

One word of caution swimming pools are expensive and require either a "pool man" or dedication.

You need to look up the technology of a water canon. Most used for fire fighting reach about 90 ft. The D&E model nozzles a McMaster Carr 3/4 orifice at 100 psi will consume 168 gpm. Gives you about 30 minutes with a 5000 gal tank.

Spray your yard with fire suppressant gel. After the fire, use your hose to rinse off the gel.