Fire Sprinkler Systems: What You Need to Know

Automatic fire sprinkler systems offer the highest degree of fire protection for a building, providing an immediate response that can significantly reduce the development and spread of fire and safeguard lives and property. In a study conducted by the NFPA, data collected between 2017 and 2021 in the United States show that fire sprinklers reduced average property loss by 55% and death and injury rates by 90% and 32%, respectively.

Fire Sprinkler Systems Control Fires

Automatic fire sprinklers have been shown to be highly effective in reducing the impact of fires and the most cost-effective fire safety measure to satisfy building regulations. The same NFPA study showed that sprinklers operated in 92% of fires in which they were present and controlled 97% of fires in which they operated.

Once installed, an active fire sprinkler system improves the overall fire safety standards of a building. In the event of a fire, sprinkler systems assist in controlling or suppressing the spread of fire throughout the building by limiting its development at the source, using water as a firefighter to put out the flames and absorb heat. The water spray from the sprinklers ultimately reduces:

• The rate of burning and quantity of smoke produced, subsequently increasing the available safe evacuation time.
• The fire intensity and duration, which in turn reduces the severity of fire exposure to structural and fire-separating elements.
• The chances of a fire spreading beyond the area of origin or flashover occurring.

Types of Sprinkler Systems

Four basic types of sprinkler systems can be used for the majority of applications in buildings.

Wet pipe system. Wet pipe sprinkler systems consist of a piping network filled with water under pressure. Automatic sprinklers have heat-responsive elements (e.g., heat bulbs or fusible links) that activate at a specific temperature. In the event of a fire, heat will activate the sprinkler, breaking the heat bulb or fusible link, which allows water to discharge from the sprinkler over an assigned floor area (i.e., area of protection). A wet pipe sprinkler system is the simplest and most commonly used system in various building types and applications.

Dry pipe system. Dry pipe systems are similar to wet pipe systems. However, as the name suggests, no water is held in the piping network. The piping network contains air or nitrogen to keep the special dry pipe valve closed and hold back the water.

Dry pipe systems are provided with automatic sprinklers with heat-responsive elements. When activated, the pressure in the dry pipe system drops as air escapes from the sprinkler, causing the dry valve to be operated by water flow. Water then enters the piping network and discharges from the sprinklers over the assigned area of protection. A dry pipe system is used in applications where the water in the piping would be subject to freezing.

Deluge system. A deluge system consists of a piping network connected to open sprinklers, meaning the sprinklers are not provided with heat-responsive elements. Water is held behind a special deluge valve activated by a separate fire detection system. Upon activation, water flows through the pipe and discharges simultaneously from all sprinklers connected to the deluge valve. Deluge systems protect against rapidly spreading, high-heat-release fires (e.g., tunnels, airport hangars).

Pre-action system. A pre-action system consists of a piping network charged with air or inert gas under pressure, which makes the system airtight while a special pre-action valve holds back the water. Automatic fire sprinklers are used in the pre-action sprinkler system, and an independent detection system is also installed in the same area as the sprinklers.

Similar to the deluge system, the detection system activates the pre-action valve to admit water into the piping network. Since the pre-action sprinkler system is provided with automatic sprinklers with heat-responsive elements, water is only discharged from the sprinklers when activated by heat from the fire.

Pre-action systems could also be arranged so that the pre-action valve is activated when both the detection system and automatic sprinklers are initiated (via receiving an alarm from the detection system and a monitored low-pressure alarm from sprinkler operation). Pre-action sprinkler systems are generally used in applications where accidental water discharge is a concern (e.g., data centres, computer rooms).

Testing Sprinkler Systems

Sprinkler systems are an essential part of a building’s fire protection system and must be correctly designed, commissioned and maintained to not only meet industry standards but also limit property damage and protect life. Rigorous testing of automatic fire sprinkler systems is essential to satisfy building regulations, ensuring sprinkler systems can provide sufficient time for occupant evacuation and fire services intervention.

Completing comprehensive testing of automatic fire sprinklers through an active fire testing program is one of the best ways of demonstrating a commitment to duty of care and the ongoing maintenance of fire suppression systems. Using our extensive expertise and customised automatic fire sprinkler testing program, Jensen Hughes can help ensure systems maintain high operational quality and reliability while meeting stringent safety regulations. Explore our range of independent fire testing and assessment services.