NFPA Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems (NFPA 25) Practice Exam

The correct answer highlights the distinct testing procedures between dry and wet sprinkler systems due to their differing operational principles. Dry systems are filled with pressurized air instead of water, and they release water only when the system is activated. This means that testing for dry systems involves checking air pressure levels and ensuring that the system can properly switch to a water supply when needed.

In contrast, wet systems are filled with water at all times, and their testing procedures revolve around ensuring that no obstructions are present in the water supply and that the water pressure is adequate. Therefore, the focus of testing dry systems on air pressure and water supply restoration is crucial for ensuring their reliability in an emergency.

Understanding these differences is important because it emphasizes the need for specific maintenance strategies tailored to the functionality of each type of system, ensuring that both can effectively protect against fire when activated.