A wet fire sprinkler system is the most common type of fire sprinkler system used in buildings. It is called "wet" because water is constantly present in the pipes, ready to be discharged when a sprinkler head activates. Here's how a wet fire sprinkler system typically works:

1. Water Supply: The system is connected to a reliable water source, such as a municipal water supply or an on-site water storage tank. The water is pressurized and maintained at a sufficient pressure level to ensure effective operation.

2. Control Valve: The system includes a control valve that regulates the water flow. The valve is typically kept open to allow water to flow through the pipes at all times. It may be electronically or mechanically controlled.

3. Sprinkler Heads: Sprinkler heads are strategically placed throughout the building. Each sprinkler head is equipped with a heat-sensitive element, such as a glass bulb or a fusible link.

4. Heat Detection: When a fire occurs, the heat from the flames raises the temperature in the vicinity of the sprinkler head. Once the temperature reaches the activation threshold of the heat-sensitive element, it activates and releases the water.

5. Water Discharge: When the sprinkler head activates, it opens a valve within the head, allowing water to flow out. The water is discharged directly onto the fire or in a specific spray pattern, covering the designated area.

6. Fire Suppression: As water discharges from the activated sprinkler head, it helps control or extinguish the fire. The water absorbs heat, cools the surrounding area, and helps prevent the fire from spreading further.

7. Alarm System: Many wet fire sprinkler systems are interconnected with fire alarm systems. When a sprinkler head activates, it can trigger an alarm to alert occupants and emergency responders.

8. Restoration and Reset: After a fire incident, the sprinkler system needs to be restored and reset. The water supply is shut off, and the system is inspected, damaged sprinkler heads are replaced, and any necessary repairs or maintenance are performed.

It's essential to ensure that wet fire sprinkler systems are installed, inspected, and maintained by qualified professionals who are knowledgeable about local regulations and fire protection standards. Regular inspections and maintenance are crucial to ensure the system's reliability and effectiveness in case of a fire.