# Frequently Asked Questions

Water pressure is measured in pounds per square inch–also known as psi. It is commonly referred to as “pressure”. Water pressure varies from home to home and it is important to know what your pressure is when buying new sprinklers.

Flow rate is measured in gallons per minute–known as gpm. Your flow rate is how quickly water–flows from your spigot or pump through the hose and to your sprinkler.

Friction loss is the loss of pressure that occurs in hose flow because of the fluid's friction near the surface of the hose.

The amount of friction loss increases the more gallons per minute you push through a fixed-size hose. To reduce friction loss, you need to increase your hose diameter to accommodate the desired flow rate and distance your water will be traveling to reach your sprinkler.

Buying the correct size sprinkler for your situation is important. If you do, the sprinkler will perform correctly and give you the best coverage.

A sprinkler head’s performance is based on the amount of water delivered to it (your flow rate or gpm) and the pressure (psi or pounds per square inch) at which your flow is delivered there.

All of our sprinklers are displayed with their performance chart on the website. The chart is broken down to show the coverage you can expect with a given flow rate (gpm) and pressure (psi).

This will primarily be determined by the total flow rate and pressure you have available at your source.

For example, you generally have a flow rate of 10 gpm from a ¾-inch spigot where you connect your hose. With your 10 gpm flow rate at your spigot, you could run two sprinklers at 5 gpm each.

The best set-up is to run two hoses from the spigot–each to one sprinkler. Suggested sprinklers for this set-up are the Residential Sled Base Sprinklers or the Tripod Sprinklers.

A garden hose connected to a spigot on city water or a domestic well usually has a flow rate of 10-12 gpm, with a working pressure of 40-60 psi.

We have sprinkler carts, sleds, and tripods, which will connect to a garden hose and accommodate common household flow and pressure.

*Note: Not all garden hose applications are the same and the above-mentioned specifications are a generalization. It is important to find out your flow rate and pressure are with a flow and pressure test kit available on our webstore.

**Models we offer that connect to a garden hose: **

- Sprinkler Carts – 750K, 750R, 1000F, and 1000R
- Residential Sled Base Sprinklers – Jumbo Sled, Wobbler Sled, Impulse Sled, and Rotator Sled
- Tripod Sprinklers – 1092K, 1085K and 1093K
- Travelers – RG20 and RG25

Our sprinklers come with a set of nozzle sizes, which are fitted to each specific sprinkler. We have a performance chart for each sprinkler that shows the distance that can be covered with a given flow and pressure through each nozzle size. You can use this to match your flow rate and pressure with the proper nozzle size for the area you want to cover.

Reaching a greater distance requires a larger sprinkler that can handle a larger flow amount. It takes a larger volume of water at high pressure for the stream to not dissipate before reaching its end point.

**Example:** A sprinkler with a 5-millimeter nozzle letting out 10 gpm at 60 psi will cover a 100-foot circle (+-). A bigger sprinkler with a 12-millimeter nozzle letting out 60 gpm at 60 psi will cover a 175-foot circle (+-).

It takes 27,154 gallons of water to irrigate one acre of land with an inch of water. This measurement is useful when you need to water one or more acres and need to evaluate whether your current flow rate is adequate for getting it done according to your schedule.

There is a significant difference between using a trash pump compared to a high-pressure pump when providing water to your big sprinkler(s).

A trash pump is designed to have a large flow rate with a low amount of pressure. A high-pressure pump is designed to move water with much higher levels of pressure.

For example, a two-inch trash pump pumps 50 gpm at 35 psi. While a two-inch high-pressure pump will pump 50 gpm at 65 psi. For your big sprinkler to run at its peak performance, the flow rate needs to be delivered to the sprinkler with high pressure.

The largest sprinkler we recommend using with a 2-inch trash pump would be the SIME K-1 sprinkler or the 1250K sprinkler cart, which has the K-1 sprinkler attached to it.This

This sprinkler has a set of nozzles that use a flow range of 10 gpm up to 50 gpm. If you choose a sprinkler that requires more flow, your trash pump will not be able to produce the proper flow with enough pressure.

This range of flow (10 – 50 gpm) from a two-inch trash pump will generally have enough pressure to give you a quality spray. A quality spray is achieved when the arc of water from your sprinkler has enough pressure behind it that it begins to break apart along the entire arc of water. When this happens, you get a “rain curtain” which results in even coverage from your sprinkler to the end of the arc.

There are three factors which affect the pressure in your irrigation or sprinkler system. These factors are the performance capability (or total flow rate), the diameter and total length of hose, and any elevation change between your water source and the sprinkler.

**Performance Capability or Total Flow Rate**

Performance capability is the first thing to consider when finding how far you can pump water and have pressure to run your sprinkler(s). How much water can your pump move and at what pressure? You should be able to find out from the manufacturer of the pump if you’re unsure.

What is the total flow rate or gpm needed to run the sprinkler? How much pressure (or psi) can your pump produce at that flow rate? Knowing this will give you the base pressure with which you are starting. From there you can calculate the other factors in that cause pressure loss.

**Hose Diameter and Length**

To choose the proper diameter of the hose, you need to know total flow rate (gpm) that will flow through the hose in order to calculate “friction loss”.

Friction loss is the loss of pressure that occurs in hose flow because of the fluid's friction near the surface of the hose.

The amount of friction loss increases the more gallons per minute you push through a fixed-size hose. To reduce friction loss, you will need to increase your hose diameter to accommodate the desired flow rate and distance your water will be traveling to reach your sprinkler.

Friction loss increases as hose length increases. There is a friction loss chart with the measurements calculated for you and are measured per 100 feet of hose.

Using this calculation, you multiply the friction loss factor by how many 100-feet of hose you will need from your pump to sprinkler. This is how you find your total friction loss through your hose.

**Elevation Change**

You must know the complete elevation change from your water source to your sprinkler or sprinklers. Elevation can change your pressure both positively or negatively. To push water uphill it will require pressure and if water goes downhill then you will gain pressure.

An easy calculation to know is that for every 10 feet of rise you lose -4.33 psi. For every 10 feet of fall in elevation, you will gain +4.33 psi.

Once you know your total pressure loss, you subtract it from your starting pressure. If you have enough remaining pressure and flow rate, you’re your pump will power your sprinklers with any given set-up.

*Note: You can increase hose diameter, if needed, to reduce pressure loss and adjust your numbers accordingly.

If you are going to be using a pump to supply the water to your sprinkler, it is important to get the right size pump for the intended performance level.

Each sprinkler comes with a performance chart. Use this to find out the pressure and flow rate needed to use that sprinkler to water the area you wish to cover.

Then, find the performance chart provided on the pump you’re interested in to find the option that will produce the required flow at adequate pressure to match the requirements of your sprinkler and the distance you wish to cover with water.

Don’t forget to account for friction loss and elevation changes between the pump and where the sprinkler will be sitting.

Every pump has a pump curve or performance curve--a graph of the overall performance capabilities of your pump. A pump curve may also be displayed in a chart format and can provide the same information.

Either way, a pump curve or performance chart displays a pump’s ability to sustain a certain flow rate (gpm) at a specific pressure (psi).

Not all pumps perform the same way, even if they are connected to the same engine. For this reason, it is important to look at a pumps performance chart or curve to know if the pump will work for your application.

If you are using one of the big sprinkler guns with your pump, the amount of water the pump will produce is all determined by the size of the nozzle on your sprinkler. The nozzle of the sprinkler(s) dictates the total flow produced by the pump.

Once you know the total flow needed by your sprinkler, the pump curve or performance curve will tell you if your pump can:

- Provide the necessary flow
- Produce the desired flow at a high enough pressure to get all the way out to your sprinkler.

Don’t forget, you want extra pressure to accommodate for the pressure losses between the pump and the sprinkler. This is where sizing your hose matters. You need to allow the total flow required to pass through with minimal friction loss and account for any significant elevation changes.

Matching your pump performance and sprinklers’ requirements to your hose size is important so your system operates at its best.

The factors you will need to know are:

- What is the performance capability of my pump?
- What is the desired flow rate (gpm) and pressure (psi) needed at the sprinkler for it to perform at its best?
- What is the farthest distance my sprinkler will be from my pump?
- Is there a significant elevation change – 15 inches or more – between the pump and sprinkler(s)?

The friction loss in your hose is the key factor. The last thing you want is for your high-pressure pump to provide the flow rate (gpm) and pressure you need at the sprinkler, but lose it pumping the water through the sprinkler because of an improperly sized hose. Using the friction loss chart will help you easily find the correct size hose.