Which device is responsible for removing large solids that could obstruct water spray nozzles?

The strainer is the device specifically designed to remove large solids that could obstruct water spray nozzles. In a fire protection system, ensuring that the water supply remains unobstructed is crucial for effective operation. The strainer works by filtering out debris and larger particles, allowing clean water to flow through to the nozzles, which is paramount for maintaining the integrity and efficiency of the standpipe system.

While filters are also used in various systems to capture particles, they are typically more refined and can deal with smaller debris. Valves control the flow of water rather than filtering it, and backflow preventers are designed to prevent contaminated water from entering the clean water supply, rather than to remove solids.