What is the role of an alarm valve in a fire sprinkler system?

The role of an alarm valve in a fire sprinkler system is to detect flow and sound an alarm during a fire or a system malfunction. When a fire occurs, the sprinkler heads activate, allowing water to flow through the pipes. The alarm valve is designed to monitor this flow. When water starts flowing due to a sprinkler activation, the alarm valve sends a signal to the fire alarm system, causing it to alert occupants and emergency services. This function is critical for fire safety, as it helps to ensure that any fire is promptly detected and addressed.

The other options describe different components or actions within a fire sprinkler system. For instance, while an automatic shut-off system is essential in some scenarios, it does not represent the primary function of the alarm valve. Regulating water pressure is typically managed by pressure regulators or pumps within the system and is not the function of the alarm valve. Preventing the system from freezing is usually addressed through insulation or heating mechanisms rather than the alarm valve, which focuses specifically on flow detection and alarm signaling.