Which factor listed can reduce the calculated sprinkler water supply due to the presence of a backflow preventer and area demand?

Which factor listed can reduce the calculated sprinkler water supply due to the presence of a backflow preventer and area demand?

• A. Installation of a backflow preventer
• B. Increased demand in area
• C. Partially closed valves
• D. Deterioration of water supply

Answer: (A)

The factor is the installation of a backflow preventer. In sprinkler hydraulics, a backflow preventer adds hydraulic losses in the water supply line. That extra head loss reduces the pressure and flow that can actually reach the sprinkler system, so the calculated sprinkler water supply is lower when a backflow preventer is present. Area demand affects how much water you need, but it’s the backflow device itself that diminishes how much water is available to meet that demand. Partially closed valves or deterioration of the water supply can reduce flow for other reasons, but they don’t specifically illustrate the reduction caused by the backflow preventer in combination with area demand.

The factor is the installation of a backflow preventer. In sprinkler hydraulics, a backflow preventer adds hydraulic losses in the water supply line. That extra head loss reduces the pressure and flow that can actually reach the sprinkler system, so the calculated sprinkler water supply is lower when a backflow preventer is present. Area demand affects how much water you need, but it’s the backflow device itself that diminishes how much water is available to meet that demand. Partially closed valves or deterioration of the water supply can reduce flow for other reasons, but they don’t specifically illustrate the reduction caused by the backflow preventer in combination with area demand.