A typical fire sprinkler design requires 26 gpm, which is fine for 3/4-inch and 1-inch meters, but exceeds the maximum flow for 5/8-inch meters. One solution would be to use low-flow sprinkler heads to lower the system demand at or below 20 gpm.
The average system uses approximately 15-16 gallons per minute, per station. Here is an easy formula to help you calculate the approximate amount of water you are using each month.
NFPA 13D Chapter 10 requires hydraulic calculations flowing a maximum of 2 sprinklers — 26 gpm total for standard residential sprinklers.
The number of sprinklers needed is based on the size of each room; in residential systems the goal is to spray at least 0.05 gallons of water per minute per square foot of floor area. Coverage per head ranges from a low of 12 feet by 12 feet to a high of 20 feet by 20 feet.
They report that typical lawn sprinkler irrigation systems may require 12-gallons per minute (gpm) to operate properly. They indicate 10 gpm is the minimum for fire protection, with 20 gpm being preferred.
You can operate 2 or 3 sprinklers at one time with 'Y's and extra hoses, depending on your water pressure. To run more than one sprinkler off the same faucet, attach a 'Y' to your faucet and run a hose to each sprinkler.
Ordinary Hazard 1 and 2: Coverage area of 130 square feet per sprinkler head; 15-foot distance maximum between sprinklers. Extra Hazard 1 and 2: Coverage area of 90-130 square feet per sprinkler head, based on certain factors; 12-foot distance maximum between each sprinkler head.
➢ Fire sprinklers typically require only 7 pounds-per-square-inch (psi) to operate, which is less than the minimum required pressure for residential plumbing fixtures.
For spray heads, it is 30 psi, with an operating range of 15 to 30 psi. For drip lines, this is about 20 psi, with an operating range of 15 to 30 psi. Remember, flow rate and pressure are directly related to one another. If pressure is not well-controlled, irrigation efficiency will suffer.
CATEGORY 3
Large residential care homes, student accommodation, dormitories, hostels. Calculate for up to 2 or 4 sprinkler heads operating. Average 168-200 litres/minute. Storage for 30 minutes supply. Tank size 6m³ to 9m³
Generally, the larger a pipe is, the higher the water flow. The water pressure level always has to be taken into consideration, however. Even the biggest, smoothest pipes will not have effective water flow if the water pressure is low, because there is not enough strength to defeat the force of friction.
Open your main water valve.
Your house has a main water valve, usually located near the meter; the valve controls the flow of water into your home's pipes. Find the valve and check to see if it's completely open. Opening a half-shut valve is one of the quickest ways for increasing home water pressure.
The sprinkler pipe size from the water supply source to a sprinkler shall be not less than 3/4 of an inch (20 mm) in diameter.
The optimum operating pressure for most residential sprinkler heads is between 30 and 50 pounds per square inch (PSI). With correct water pressure, each head will perform the way they were designed, and the result will be even spray-patterns and efficient use of water.
For a fixed spray system, aim for 20-30 psi per sprinkler. On a rotor/pop-up system, shoot for 30-60 psi. Irrigation and drip systems require 20-40 psi.
NFPA 13R further lowers costs by permitting a potentially lower level of water discharge than NFPA 13, which may result in smaller pipe sizes. NFPA 13 also calls for a greater density and spacing for sprinklers, as well as attic requirements that can significantly drive cost.
Light Hazard (10-15 ft). Excluding heads in combustible concealed spaces, all sprinklers in this category have 15 feet (4.6 meters) of maximum allowable spacing between them. Ordinary Hazard (15 ft). All sprinklers in these environments have a 15-foot (4.6-meter) maximum.
If you choose to use PVC pipe for your irrigation laterals, make sure to use pipe that is at least 3/4" thick. 1/2" inch laterals clog very easily. If you choose to use fittings, most common PVC fitting types work fine.
If your home's water capacity was 10 GPM, you could place 3 heads per zone. Consult the Performance Charts on or inside the box your sprinkler head came in for your head's exact performance data, or locate the performance data in the Support area of this website.
Probably the most popular size is 1/2” Poly Tubing, since this is the most commonly used size for drip systems.
Most spray and rotator heads are designed to work their best at about 30 psi. When pressure is lower, the watering radius will be reduced, so you may need to place your heads closer together to get the coverage you need. Higher pressures – those above about 40 psi – will cause the head to mist or fog.
For many sprinklers, the recommended operating water pressure ranges between 30-40 pounds PSI. A pressure regulator ensures that water pressure consistently stays within this recommended PSI range, regardless of the water pressure before it reaches the sprinkler.