Water-based fire protection systems

The fire-fighting system is designed to serve hoses and monitors strategically placed in the area to be protected, with pumps 

of specific minimum capacities that should be able to simultaneously serve all the different water-based fire protection systems present.

The hoses are made of non-perishable material and have standard lengths ranging from 15 to 25 m. At the end, they are equipped with a nozzle featuring a shut-off valve and a mechanism to produce both a solid stream and a spray. Monitors are nozzles placed on fixed pedestals and can be operated manually or remotely through hydraulic systems.

Water for fire extinguishment must be immediately available and supplied without interruption by the automatic start-up of fire pumps. For this reason, pressure vessels equipped with booster pumps are commonly used, along with a water tank for refilling. This ensures the working pressure at the ends of the system when it is fully or partially on standby. As known, a decrease in pressure within the circuit triggers the pressure vessel's operation, followed by the main feeding pumps.

The number of main pumps is determined by regulations, and the pumps can be shared with other systems. Additionally, when they are located in the same area, an emergency pump must be present.

The fire protection circuits consist of a single main horizontal ring manifold, which consists of two parallel manifolds connected by cross-sectional sections. Branches extend from each manifold to reach the various fixed points (hydrants and monitors). At each branch and at the crossover points between the two manifolds, shut-off valves are installed to isolate any damaged branches.

A sprinkler is an automatic valve with thermal operation that, upon opening, distributes water in a fragmented manner for the purpose of fire extinguishment over a specific area. It consists of a body with a sealed discharge orifice, which is assembled with a metal gasket held in place by a welded articulated system (fusible sprinkler) or a glass bulb (bulb sprinkler), and a threaded connection for attachment to the water supply piping.

The release of water, or the activation of the system, is triggered by the breaking of the ampoule or the closure fuse when a certain temperature is reached within the environment. The operating temperature of the system typically ranges from 55 to 343°C. Different temperature settings are identified on the sprinkler heads using color-coded markings.

In the event of a fire, the rise in temperature at the ceiling level of the space causes the sprinklers located above the affected area to gradually reach their predetermined activation temperature, resulting in the breaking of the thermosensitive elements within the sprinklers. This leads to the release of fragmented water onto the fire area for the duration specified by the system designer. Sprinklers operate independently of each other and only activate in the area affected by the fire. After the fire, the activated sprinklers need to be replaced in order to restore the functionality of the system.

Deluge systems simultaneously discharge the extinguishing agent over the entire protected area with the purpose of:

• Fire suppression;
• Protection against fire exposure;
• Prevention of fire and explosion.

The system consists of a network of typically empty pipelines, on which open-type nozzles are installed to deliver a predetermined quantity of water to the protected space or individual equipment. Additionally, the system includes a control panel that governs the water supply to the pipelines, and a control system typically comprising a combination of fire detectors or a manual control. This type of system is primarily used for cooling processes or external tank systems. It can also be applied to protect specific equipment. The flow rates delivered by the system range from 2 to 20 liters per minute per square meter, depending on the type of protection required