FIXED FIRE EXTINGUISHING SYSTEMS FOR LAND USE

Automatic sprinkler systems, or sprinkler systems, are the most popular and well-known systems for intervening on a fire. 
The key feature of the sprinkler system is its fully automatic operation. The system consists of a supply unit, a control valve, and a network of piping, to which the sprinkler emitters are connected.
Sprinkler systems are simple and extremely safe: operation is automatic, and the bulb ensures that the system is triggered the moment a fire develops.
There are different types of sprinkler systems: systems can have a constantly pressurized distribution network of water (wet system) or air (dry system). Enclosed bulb or fuse sprinklers are then connected to the network.

Advantages and benefits of sprinkler systems:
Sprinkler systems have the ability to contain the fire, safeguard the structure, and provide effective cooling of the environment in which they intervene.
They are simple and safe, activate in automatic operation, and can be used in a variety of applications. The technical standards referenced in the design of sprinkler systems are NFPA13 and the recently published European standard EN12845.

A carbon dioxide (CO2) system quickly extinguishes any kind of fire in areas not occupied by personnel and allows all work operations to be restored in a very short time. It also leaves no residue in the environment after its use.
Applications include full saturation systems (for surface or deep fires), locally applied systems, or manually operated systems. 
CO2 gas systems are a valuable and reliable firefighting tool for a wide variety of applications. Its excellent extinguishing properties result in a decrease in oxygen concentration that hinders combustion, and it has a cooling effect.

Advantages and benefits of CO2 systems:
CO2 systems are characterized by the absence of odor and color. They are, in addition, electrically non-conductive. Carbon dioxide acts quickly and extinguishes the fire within seconds. 
The system, when properly designed and calculated, does not damage materials during extinguishment, does not corrode, and leaves no residue. It turns out to be a versatile system that can be used on a wide range of hazards, electronic equipment and high-voltage equipment, as well as flammable materials.
It is particularly suitable for total environment saturation types of installations or installations located on high-hazard or outdoor equipment. 
The system is designed with reference to the NFPA12 reference standard.

The IG 55 system is a total saturation extinguishing system that uses a mixture of Argon and Nitrogen, usually found in the atmosphere, in a 1:1 ratio.
The mixture acts on the fire by decreasing the concentration of oxygen in the protected area to a value that prevents combustion, without affecting the safety of the personnel present.
The system has no environmental impact. In fact, it does not appear to have any depletion effect on the ozone layer (ODP=0 and Gwp=0).

Advantages and benefits of inert gas systems:
The system is ideal for areas occupied by personnel. In fact, effectiveness in extinguishing fire is accompanied by efficiency in terms of personnel safety. 
These systems are usually used for the protection of archives, museums, libraries and any other rooms containing high-cost instruments, as well as in places predisposed to hazards caused by flammable and combustible or electrical gases.

The wide variety of cylinder capacities, ranging from 30 to 140 liters, pressurized at 200-300 bar, ensures the amount of gas needed to saturate any required volume.
The use of the 300-bar pressurized cylinders, with a similar diameter as the 200-bar cylinders, allows space and consequently costs to be minimized. The number of cylinders is reduced as well as the installation and maintenance time of the system.
Systems can be modular or centralized, suitable to meet any need, and the use of pneumatically actuated directional valves allows the gas discharge to be directed, offering flexibility to each system.

Cylinders are TPED-certified (Directive 99/36/EC), valves PED-certified (Directive 97/23/EC), and systems are designed in accordance with the main design standards.
The system is designed according to national and international ISO and NFPA standards.

The purpose of foam systems is to extinguish the fire with a mixture of water and foam of varying types and proportions depending on the fuel present, interposing itself between the fuel itself and the oxidizer (oxygen) thus extinguishing the flames by smothering.

These systems vary according to the volume ratio of the water-foam mixture before and after use. They can be of three types:
- Low-expansion: with expansion ratios as low as 1:20;
- Medium expansion: with expansion ratio up to 1:200;
- High-expansion: with expansion ratio up to 1:1,000. 

The foamers used change depending on the fuel present and the type of foam plant chosen. Operation of the system involves interconnection with a detection system, usually smoke or thermal detectors.

They are manually activated protection systems consisting of:
- UNI EN 671-2 standard wall hydrants;
- Above-ground column hydrants to UNI 9485 standard;
- Underground hydrants to standard UNI 9486;
- Hose reels to standard UNI EN 671-1;
- Delivery connections for fire engine VVF;
- Disconnection system.

Water supply is provided directly from the aqueduct or from water reserves connected to appropriately sized pumping units.
The pipe networks, preferably made closed loop, are perpetually under pressure and are for fire-fighting use only.

A fire detection system is a component of the fire alarm system that can detect and signal the presence of a fire within a building or infrastructure.
A smoke and fire detection device typically consists of electronic equipment that detects the presence of smoke, heat changes, or the start of a fire based on the physical phenomena associated with fire development.

This is a system that uses finely atomized water as the extinguishing agent.

Definition from the European reference standard UNI CEN/TS 14972:2008: 

water mist is a water spray for which Dv0.90, measured in a plane located 1 m from the nozzle nozzle, is less than 1000 µm.

What is Dv0.90? It is the value of the characteristic diameter such that 90% of the total volume of the spray is characterized by droplets having a diameter less than that value. Such a type of water spray is achieved by using special spray nozzles fed with high-pressure water.

With reference to the design pressure of the system, the European standard (UNI CEN/TS 14972:2008) provides for three types of systems:

1. Low-pressure systems (design pressure up to 12.5 bar);

2. Medium pressure systems (design pressure between 12.5 and 35 bar);

3. High-pressure systems (design pressure above 35 bar). 

Fire suppression actions that distinguish water mist:

- Thermal cooling action, brought about by the enormous absorption of the amount of heat;

- mechanical action of decreasing the concentration of comburent oxygen, originated by the large amount of quickly produced water vapor;

- attenuation action of heat power transmitted by radiation, determined by the high amount of fine particles and vapor dispersed in the air, which is followed by the combination of absorption and scattering phenomena.

Oxygen reduction plants are inertial fire prevention systems that artificially create a normobaric and hyposis environment in which the amount of combustion O2 is insufficient to trigger a fire.
How is it realized? diluting the oxygen contained in the air with nitrogen (Nytrogen System). This technology uses hypoxic air, with O2 concentration reduced to 15%.

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Advantages and benefits of oxygen reducing plants:
These plants are characterized by their reliability and simplicity. There is no need to install additional fire detection systems. The oxygen-reducing system contributes to the reduction of depletion of objects and has no aesthetic impact.