The flow rate of Rain Bird sprinklers refers to the volume of water that is discharged from the sprinkler head over a period of time. It is an important specification to consider when designing an efficient irrigation system. The flow rate is measured in gallons per minute (gpm) or liters per minute (lpm).
How flow rate affects irrigation system performance
The flow rate of the sprinklers used in an irrigation system determines how quickly an area can be watered. Sprinklers with higher flow rates will be able to cover more area in less time. However, the flow rate must be properly matched to the water pressure available and the spacing of the sprinklers to achieve uniform coverage.
If the flow rate is too high for the water pressure, the sprinklers will produce a mist that is susceptible to evaporation and wind drift. Water will be wasted as a result. If the flow rate is too low, the sprinklers will need to run longer to apply the desired amount of water, increasing water use and operational costs.
Manufacturers provide flow rate specifications to guide proper sprinkler selection based on the available water supply. Flow rates may be adjusted on individual sprinkler heads using built-in regulation components to fine-tune system performance.
Typical flow rate specifications of Rain Bird sprinklers
Rain Bird provides a wide range of sprinkler models for different environments and applications. Flow rates generally range from around 0.5 gpm for small, specialty sprinklers up to over 30 gpm for high flow models used on golf courses and athletic fields.
Some common flow rate specifications for standard Rain Bird sprinklers are:
- 1800 Series rotors – 0.5 to 8 gpm
- 5000 Series rotors – 2 to 15 gpm
- 5004 Series rotors – 3.5 to 14.5 gpm
- Falcon rotors – 2.2 to 12.6 gpm
- Hunter rotors – 0.9 to 32.3 gpm
- 8005 Series spray heads – 1.5 to 8 gpm
- Xeri-Bug emitters – 0.5 to 35 gpm
- XB Series bubblers – 0.5 to 2 gpm
Adjustable flow rate sprinkler models
Many Rain Bird rotors and spray heads feature adjustable flow rates to optimize watering patterns. Common adjustable models include:
- 5004 Series – adjustable from 3.5 to 14.5 gpm
- 5000 Plus rotors – adjustable from 2.5 to 15 gpm
- 3500 Series – adjustable from 1.5 to 8 gpm
- 8005VS spray heads – adjustable from 1 to 8 gpm
- 1806 spray heads- adjustable from 0.5 to 4 gpm
The flow is regulated by replacing the nozzle or adjusting an integrated flow control. Lower flow rates can be selected to reduce radius or match precipitation rates across the irrigation system.
Measuring sprinkler flow rate
To determine the actual flow rate of an installed sprinkler, a simple catch can test can be performed:
- Place an empty can directly under the trajectory of the sprinkler spray.
- Turn on the sprinkler zone and let it run for a set amount of time such as 1 minute.
- Measure the amount of water collected in the can in inches.
- Convert the depth of water to gallons using the surface area of the can.
- Divide the number of gallons by the run time to get the flow rate in gallons per minute.
This test should be repeated a few times for each type of sprinkler head to obtain an average flow rate. The results can be used to adjust irrigation run times accordingly.
Factors influencing Rain Bird sprinkler flow rate
The published flow rate specifications for Rain Bird sprinklers are tested under ideal laboratory conditions. There are several site-specific factors that can impact the flow rate in real-world installations:
- Water pressure – Higher water pressure increases flow rate while lower pressure decreases it.
- Nozzle size – Larger nozzle diameters allow higher flow rates.
- Elevation changes – Elevation gains in the irrigation system reduce the water pressure and flow rate.
- Friction loss – Longer pipe runs increase friction loss and reduce pressure and flow at the sprinkler heads.
- Filters and screens – Dirty filters create blockages that restrict flow.
- Sprinkler spacing – Closer spacing causes interference between spray patterns which can limit flow.
Checking for leaks, damaged pipes, and clogged nozzles can help maximize sprinkler flow rates. Consulting an irrigation specialist is recommended when flow rates are much lower than expected.
Conclusion
The flow rate specification of Rain Bird sprinklers provides guidance for selecting the right sprinklers and designing an efficient irrigation system. Adjustable flow rate models allow further customization of the sprinkler output to the environment and landscape plants being watered. Performing periodic catch can tests ensures the sprinklers are operating at their expected flow rate and applying the proper amount of water.