Sprinkler fire extinguishing systems are used to detect and extinguish fires in the early stages. When a fire occurs, the hot gas rises and accumulates under the ceiling, destroying the heads of the sprinklers.

When a certain temperature is reached, the discharge port is broken, and the sprinkler displaces water in different forms, depending on the type of sprinkler, over the affected area.

1. 1.      Mixed sprinkler systems

Mixed sprinkler systems incorporate either a mixed control and signaling valve or a mixed system consisting of a water-water control and signaling valve and a water-air filled valve. During the winter months, the facility downstream of the mixed control and signaling valve or water-air valve is filled with air or inert gas under pressure, and upstream the installation is filled with pressurized water. During the rest of the year the installation works as a sprinkler system in the water-water system. The pipes of mixed sprinkler systems are made of galvanized steel pipes.

1. 2.      Installations with sprinklers in pre-treatment systems

Pre-sprinkler fire extinguishing systems may be type A, type B or multiple pre-operation systems.

A-type sprinkler systems are water-air systems where control and signaling valves are operated by an automatic fire detection and signaling system, rather than triggering sprinklers. Inert air / gas pressure in pre-sprinkler systems should always be supervised. To activate the emergency pre-control valve, a quick start-up valve must also be provided. Type A pre-installation must be installed in areas where significant damage may occur in the event of an accidental discharge of water.

Type B sprinkler systems are installations in the water-air system where the control and signaling valves are activated either by an automatic fire detection and signaling system or sprinkler triggering. Independent of the detector response, a pressure shock in the circuit causes the control and signaling valve to open. The fire detection system shall be installed in all places and compartments protected by the sprinkler system with pre-conditioning and shall comply with the requirements of the other specific technical regulations regarding the fire safety of the constructions and installations.

Sprinkler-type extinguishing systems with at least two pre-conditioning installations must be made after the fire hazards assessment, to determine whether multiple pre-treatment installations can be operated at the same time. If this is appropriate, the following should be considered:

- the volume of water sources should be increased by the volume of pre-emptive installations;

- the time between triggering multiple pre-empowered installations and discharging water to the furthest water sprinkler shall not exceed 60 s.

The fire detection system shall be installed in all places and compartments protected by the pre-action sprinkler system and shall comply with the relevant parts of the European standard EN 54 or equivalent regulations.

1. 3.      Sprinkler systems in water-water system

Water-sprinkler systems must be installed only if an ambient temperature of at least 4 ° C is ensured and not exceeding 95 ° C. Only water-to-water installations should be used for interconnected and closed systems. Frost-exposed parts of the installation can be protected by introducing solutions based on glycerin or propylene glycol into pipelines so that by mixing with water a lower freezing point is obtained. These installations must be equipped with a retaining flap to prevent contamination of the water supply.

1. 4.      Installations with sprinklers in water-air system

Installations with sprinklers in the water-air system are normally loaded with air or inert gas, under pressure, downstream of the control and signaling valve and with water upstream. Installations with water / air sprinklers must only be made in a branched configuration. Air-to-air sprinkler systems should only be installed where there is a risk of frost or the ambient temperature exceeds 70 ° C.

The technical equipment of buildings, fire compartments and rooms, with automatic fire sprinkler systems, shall be provided at:

a) Closed buildings of categories of exceptional and special importance (A and B), classified according to the legislation in force, with a thermal load density higher than 420 MJ / m2;

b) high and very high buildings regardless of the destination;

c) set and closed filming platforms, television studios and landscaped scenes, with areas larger than 150 m2, their enclosures and workshops;

d) rooms in underground civil buildings in which the load density exceeds 840 Mj / m²;

(e) buildings, fire compartments intended for commerce and commercial spaces with an area of ​​1500 square meters or more or with a thermal load density exceeding 840 Mj / m2;

f) production and / or storage buildings with high and very high fire risk with an area of ​​more than 600 m2;

g) warehouses with stacks, under the conditions of SR EN 12845;

i) P1, P2, P3 and P4 underground car parks defined according to the provisions of the specific technical regulation, as well as the above-ground enclosures with more than 3 levels and more than 100 cars.

(j) buildings and administrative or cultural fire compartments with a built-up area of ​​more than 1250 m2 and a thermal load density of more than 840 Mj / m².

 Investors may also build such installations in other situations, depending on the danger and / or risk of fire, location, fire contribution, building value and protected property, etc.

 No sprinkler automatic sprinkler systems should be built in cases where extinguishing fire should be made by using other substances: gas, powder, foam, aerosols, steam etc.