What is the function of a "backflow preventer" in sprinkler systems?

The function of a backflow preventer in sprinkler systems is to prevent contamination of the potable water supply. This device is critical for ensuring that water from the sprinkler system, which may be subjected to contaminants, cannot flow back into the clean, drinking water supply.

When water flows through the sprinkler system, especially in scenarios involving irrigation or firefighting applications, there is a risk that contaminants present in that water could flow back into the main water supply if the pressure fluctuates or if there is a system failure. The backflow preventer is designed to create a physical barrier that stops any backflow, thus safeguarding public health and maintaining the integrity of the potable water system.

The other options relate to functions that do not accurately reflect the primary purpose of a backflow preventer within the context of sprinkler systems. For instance, while increasing water flow, enhancing system pressure, or lowering installation costs may be relevant to the overall design and efficiency of a sprinkler system, they do not capture the crucial role of preventing contamination, which is the key function of a backflow preventer.