Automatic fire detection and extinguishing systems

Automatic fire detection system is designed to detect fire in its earliest stages. Alarms are reported to Fire Department via monitored phoneline.

Automatic fire detection system are divided into:

  • conventional systems
  • addressable systems

In conventional systems fire alarms are monitored by zones. Usually there can be up to 20 detectors in single zone, thereby source cannot be detected with an accuracy of a detector. Because of this conventional systems are generally used in smaller buildings.

An addressable system enables to trace the location of alarm to individual detector. Addressable systems provide more possibilities of integration with other ventilation, elevators, escalators, sprinkler system, smoke exhaust systems etc. in cases of fire. The central unit is equipped with time delay function, allowing personnel to verify reason of fire alarm and cancel false alarms prior to engaging evacuation. Addressable systems are suitable in high-rises, large office buildings, hotels, schools etc.

Both systems use detectors working of same principals. The main detector types are:

  • optical smoke detecors that alarm of detecting visual smoke
  • fixed temperatue detectors that alarm when temperature rises above 56°C or 90°C. Temperature detectors are used in premises where use of smoke detectors is not possible
  • temperature rise detectors that alarm on rapid rise of temperature. Temperature rise detectors are used in premises  where there is smoke and/or permanent elevated temperature.

Special detectors are used in cases of explosive (EX) environment, for gas and flame detection. Line detectors and „air probe“ detectors are designed for special purposes

Each fire alarm system has push buttons, installed next to evacuation routes, alarm bells and sirens inform occupants of fire. In larger sites pre-recorded evacuation messages are replayed through public address system (link to PA text).

All fire detection systems must be designed in accordance to local Fire Safety laws and regulations. We recommend to consult with and approve Your system design with local Fire Department specialists prior to construction.

One cannot totally eliminate possibility of fire as a result of electrical short-circuit of servers and other high-tech equipment. Gas extinguishing systems are used to eliminate fire in such situations. Benefits of gas extinguishing are fast elimination of fire without residual extinguishing materials

 Gas extinguishing systems consist of gas cylinders, gas piping with nozzles and fire detectors connected to extinguishing panel.

Main types of extinguishing gases:

  • Inert gases where the extinguishing principle is to reduce oxygen in the room to put out fire. Inert gases are perfect for larger rooms and cost-efficient. The downside is the large number of cylinders, sometimes requiring separate room. One must also consider investment for pressure hatches and piping to exhaust the excess pressure from the rooms as up to 50% of room volume is filled with gas. Most common inert gases are Argon, Argonite, IG-55.
  • Chemical gases which extiguishes fire through heat absorbing reaction by eliminating one of three components of fire (fuel, oxygen, heat). Chemical gases are mainly used with computers, electrical installations, telecom, museum archives, aviation, shipping, flammable materials’ storages etc. Investments for chemical gases extinguishing systems are are less when used in smaller rooms. In order to engage extinguishing process, only 7-9% of room volume must be filled. Most chemical gases do not produce remarkable pressure, thus eliminating need for pressure hatches. Most common chemical gases are FM-200, FE-13 and HFC-227

If You consider investing into gas extinguishing system, always consult with competent and properly trained systems’ expert. Design and commissioning of properly functioning gas extinguishing system requires thorough knowledge about implementation of extiguishing solutions. Expert can also assist in finding the most suitable and cost-efficient solution for each case. To prepare a project and quotation, the following data is required:

  • Exact measures of the room, indicating false ceilings and raised floors;
  • Number of ventilation ducts
  • Presence of air conditoning
 

References