What are the Different Types of Fire Sprinkler Systems?

Wet pipe, dry pipe, pre-action, and deluge are four types of fire sprinkler systems. Each of these systems helps prevent flames from spreading and reduces fire damage. The main difference between these types of fire sprinkler systems is their applications and how they activate.

Wet Pipe Fire Sprinkler System

Wet pipe fire sprinkler’s pipes contain water and are the most common type of fire sprinkler system. Since water is present in the system, facilities must maintain a temperature of at least 40 degrees. This prevents the water in the pipes from freezing. The process to activate a wet pipe fire sprinkler is simple. When a fire sprinkler element reaches a designated temperature, it breaks and releases the water. Wet pipe fire sprinkler systems are found in office buildings, schools, and high-rise buildings with ordinary hazards.

Dry Pipe Fire Sprinkler System

Unlike wet pipe systems, dry pipe fire sprinklers are filled with nitrogen or pressurized air. The air pressure holds a dry pipe valve closed and prevents water from entering the system. When a fire sprinkler detects a sudden temperature increase it activates and the air pressure drops in the system. This causes the dry pipe valve to open and floods water into the dry pipe fire sprinkler system. Then the activated fire sprinkler discharges the water. Since dry pipe fire sprinklers contain no water, they’re ideal in areas subject to freezing temperatures. Unheated warehouses, parking garages, and attic spaces often utilize this type of fire protection system.

Pre-Action Fire Sprinkler System

Pre-action fire sprinkler systems contain pressurized air or nitrogen instead of water. Activating pre-action systems is a two-step process. First, a heat or smoke detector must detect a fire which then sends a signal to open the pre-action valve. This fills the system with water. Next, a fire sprinkler head must detect an increased temperature to indicate a fire. Once, the fire sprinkler opens water immediately pours onto the fire. Pre-action fire sprinklers two-step activation process helps prevent accidental system activations. This makes these types of fire sprinkler systems ideal for applications such as museums, server rooms, libraries, and data farms.

Deluge Fire Sprinkler System

High hazard facilities utilize deluge fire sprinkler systems since the open style sprinkler heads can discharge water quickly. Unlike the other types of fire sprinkler systems, these sprinkler heads always remain open and activate all at once. These systems also contain no water nor pressurized air. Once a heat or smoke detector detects smoke or heat, the deluge valve opens and sends water to all the fire sprinklers. This allows water to discharge from each sprinkler head. When highly combustible material catches on fire the flames can grow and spread immediately. That’s why facilities like aircraft hangars, industrial plants, and manufacturing companies need a fast-acting deluge fire sprinkler system.



There are four main types of fire sprinkler systems. Depending on the type of facility and the hazards present helps determine which type of fire sprinkler will provide the best protection. Even though these systems differ in the way they activate and whether their pipes contain water, pressurized air, or neither each prevents fires from spreading. For additional information about fire sprinklers and their response, contact Expert Fire Sprinkler today to learn more.