What is the average flow rate? The standard sprinkler flow rates, in general, are from 4 gallons per minute (gpm) from a 5/32-inch nozzle at 30 pounds pressures to over 11 gpm from a 7/32-inch nozzle at 70 pounds pressures.
According to the National Fire Protection Association, the average water output of a residential fire sprinkler is between 13 to 15 gallons per minute, while the average flow from a fire hose is 95 to 200 gallons per minute, under high pressure.
Typical sprinkler flow rates may vary from 4 gallons per minute (gpm) from a 5/32-inch nozzle at 30 pounds pressure to over 11 gpm from a 7/32-inch nozzle at 70 pounds pressure. The nozzle size is usually stamped on the nozzle. Wheelmove systems typically have 3/16-inch nozzles.
Fixed spray heads apply 1.5 to 2 inches of water per hour in a fan-shaped spray. Rotors apply about 0.5 inches of water per hour in a single, rotating stream of water. Rotary nozzles apply approximately 0.4-0.6 inches per hour in multiple, rotating streams of water.
The answer is that it usually takes up to 30 minutes to get a half inch of water. Watering 3 times per week equals to an inch of water on a lawn. Plants can be watered 1 to 2 times a week in seasons where there is a higher chance of rainfall and less evaporation.
The average system uses approximately 15-16 gallons per minute, per station.
If your sprinkler output is 1½ inches per week, your sprinklers should run for only ⅓ hour or 20 minutes that week (½ divided by 1½). On a twice-weekly watering schedule, run your sprinklers 10 minutes each time.
To determine how long you need to water to get one inch, place a plastic container in your yard and set a timer. On average, it will take 30 minutes to get a half inch of water. So, 20 minutes, three times per week will give a lawn about an inch of water. This formula works best with healthy, well-cultivated soil.
The average usage of water in a residential sprinkler system is between 12 – 30 gallons per minute depending on the type and size of the sprinkler head.
Using Direct Measurement of Sprinkler Discharge Rate
Keep track of the time it takes to collect a known volume of water. Then, calculate the sprinkler discharge rate (gallons per minute). Example: If it takes 100 seconds to collect 2 gallons of water from a sprinkler head, the discharge rate is 1.2 gpms.
A typical sprinkler used for industrial manufacturing occupancies discharge about 75-150 litres/min (20-40 US gallons/min). However, a typical Early Suppression Fast Response (ESFR) sprinkler at a pressure of 50 psi (340 kPa) will discharge approximately 380 litres per minute (100 US gal/min).
How to Calculate Sprinkler Flow Requirements? The flow calculation is relatively simple, since design engineers only have to multiply the covered area and the flow density that was previously determined: Q (flow) = Coverage Area x Flow Density.
Most sprinkler systems use around 12 gallons of water per minute. If left unchecked, that could mean a lawn filled with standing water. A general rule of thumb is to water three days a week in the spring and summer and two days a week in the fall and winter.
Fire sprinkler systems release anywhere for 35 to 150 gallons of water per minute with the average about 60. A 1.75″ fire hose sprays 150 gallons of water per minute. One activated sprinkler head can send a torrent of water in a 12' diameter circle, enough to fill a bathtub in less than a minute.
Each zone with overspray can waste 1.6 to 8 gallons of water per minute. That's up to 5,760 gallons of water wasted per month per zone with a typical watering schedule!
For conventional sprayheads, precipitation rates typically range from 1.3 inches to 2 inches per hour. For gear drive rotors, precipitation rates typically range from 0.4 inch to 1 inch per hour. For rotary nozzles, precipitation rates typically range from 0.4 inch to 0.6 inch per hour.
“Be careful not to over-water. Most people think more water is better, but it's not.” Conversely, too frequent or very light watering can lead to fungus growth and a shallow root system that can't support the grass. Watering that soaks the soil more deeply encourages the roots to grow deeper and stronger.
Start by turning on the sprinklers for 15 minutes, then come check to see if you are noticing runoff. If water is running off, that means the soil needs time to absorb the water. Turn off the water for 40 minutes or even an hour to let the water soak in, then water for another 15 minutes or until you see runoff.
Sprinklers should be set to run for about 30 to 35 minutes at a time twice a week. Your goal is at least 1″ of water a week for your lawn.
Watering 101
Your lawn needs 1 to 1 ½ inches of water per week. A typical in-ground sprinkler system provides ½” of watering, per zone, in a half an hour. This would mean that you need to run each zone of your sprinkler system for 30 minutes, 3 times a week to sufficiently hydrate your lawn.
You should run your sprinkler system for as long as it takes to apply a half inch of water to your lawn. You will need to water for at least 10 minutes per week for most systems. Measure your sprinkler system's output to ensure you're not using too much water or underwatering.
Sprinklers generally cover up wider ground and spread out water at a slow yet steady pace, which makes all the soil moisturized evenly and soaked underground. A watering hose takes time to cover space and can clutter the soil if there's too much water.
In general, your lawn needs 2 to 3 cm of water per week, so a good average is to water about 2 times a week, or even 3 in the warmer months. You can then adjust the watering frequency according to the age of your lawn. For example, if your lawn is several years old, one watering per week is sufficient.
There is no sun, so solar radiation does not contribute to water evaporation. Estimates of water loss during night-time irrigation are approximately 15%, once again depending on humidity, wind speed, and temperature. The resident who applied 1 inch of water receives the benefit from 0.85 inches.