Construction Of Fire Protection Systems

Fire Suppression Systems with Water or Foam

WATER SYSTEMS FOR FIRE SUPPRESSION

Description

The liquid type fire suppression / extinguishing systems, use water as a means of extinguishing, which is diffused directly onto the fire, through a fixed network of pipes. Four types of water-based systems are available. The risk assessment of the space under design and the fire categories to be suppressed, determine the type of system you need.

Wet type systems under pressure

This is the majority of the systems installed today. The fire protection system consists of a fixed network of pipes with water under pressure, supplied by a reliable source, such as the water supply networks of cities, fire pumping stations, etc. Heat-sensitive automatic sprinklers, distributed according to design standards, are used to detect the fire. When the fire occurs, the detection device i.e. the ampoule with the eutectic liquid (located on the head of the sprinkler) is activated, allowing the free flow of water. During operation, sprinklers discharge water over a specific area, in order to limit the spread or extinguish the fire. As the water starts flowing through the pipe network, the flow switch is activated, which in turn activates the alarm, so that we are immediately informed that the system is working. Through heat, only sprinklers located directly above or next to the source of fire are activated (regardless of their quantity), minimizing collateral water damage. Since the piping system is usually under pressure with water, the temperature of the piping system should be maintained above 4°C, in order to exclude the risk of blockage of pipes or mechanical damage due to frost.

Typical areas for installing automatic system with sprinklers

  • Warehouse areas
  • Electromechanical spaces (without the presence of electricity)
  • Car parks

Dual energy systems (Preaction system)

These systems require an independent detection system used in conjunction with a fixed network of tubes with sprinkler for their operation. The detection system can be hydraulic, pneumatic or electrical and may be activated by smoke detectors, heat detectors, flame detectors, beam detectors, aspiration systems or even manual e.g. with an activation button. Detection systems are usually activated before sprinklers and trigger an alarm. Preaction systems are usually supervised with compressed air. The purpose of supervision is to monitor the integrity of the system. In case of a sprinkler or pipe failure, the air pressure within the pipes will decrease and an alarm is triggered. An alarm is triggered also in case of insufficient supply of air to the network.

There are several kinds of Preaction systems.

  1. Non-Interlock

An automatic water flow control valve on the water supply branch of the sprinklers (deluge valve) is activated, either by the operation of a sprinkler or by the activation of the detection system. The water is then channeled into the pipes and flows from the open sprinkler (if opened).

  1. Single-Interlock

The fire detection system activates the automatic water flow control valve to the water supply branch of the sprinklers (deluge valve), allowing water to enter the piping network. However, if the sprinklers are not activated, the water remains in the network, until their activation temperature is reached and they open, distributing the water over the specific area, to limit the spread or extinguish the fire. At the same time, by activating a sprinkler, a signal is sent to the control panel, which informs about the loss of air pressure in the network.

  1. Double-Interlock

In order for water to flow into the pipe network, the command to the deluge valve is required to come from both the fire detection system and the loss of air pressure through the pipe network (due to the operation of a sprinkler). Only then, the fire extinguishing is activated.

Typical areas for installing an automatic dual-energy system (Preaction system)

  • Data Rooms
  • Control Rooms
  • Areas with sensitive equipment
  • Places where water could damage the equipment under protection

Deluge type system

Deluge-type systems are used in high-risk areas where there may be a rapid outbreak/spread of fire. In these areas it is more appropriate to install total sprawling systems with sprinklers or water mist. The Deluge-type system consists of a fire detection system (usually consisting of heat detectors), the piping network with open type sprinklers (without e.g. ampoule) and an automatic water flow control valve to the water supply branch of the sprinklers (deluge valve). When the fire detection system is activated, the deluge valve is opened and the water flows directly and with pressure into the network and is diffused by all sprinklers, on the fire. This system has the disadvantage that in case of false alarm, damage can be caused, since the sprinklers are of the open type.

Typical areas for installing Deluge automatic system

  • Transformers
  • Spaces with the presence of electricity (LPXT, tables, etc.)
  • Boilers

Dry type systems without water under pressure

A system with sprinklers, dry type, without water under pressure, like the other systems mentioned above, is an automatic fire extinguishing system with sprinklers, that operates with compressed air or nitrogen, within the piping network, instead of water under pressure. In the event of a fire, the sprinkler operates, the pressurized air escapes and the control valve opens (when the pressure falls below a predetermined safety limit), allowing the flow of water. At the same time, an alarm is also sent to the control center. The system is recommended when the network of pipes is subjected to an environment with frost temperatures.

Typical areas for installing dry-type systems

  • Installations or areas subject to frost (concerns areas with temperatures below 4°C
FIRE DETECTION SYSTEMS, DETECTION OF EXPLOSIVE GASES AND CO IN PARKING STATIONS / CARGO STATIONS / WAREHOUSES

Fire Detection Systems

A fire detection/alarm system consists of a number of devices that work together to supply information in a timely manner, through optical and audio devices, when smoke, fire, carbon monoxide or other emergencies, such as explosive gases, occur.

Fire detection can be activated automatically by smoke and/or heat detectors or can also be activated through the use of fire alarm triggers, such as buttons. The audible and visual alarm is usually transmitted either by sounder beacon or by separate audible and visual means. Sometimes a notification is heard from a loudspeaker, followed by an evacuation voice message that warns people inside the building, for example, not to use the elevator.

After deciding the purpose and type of fire detection to be installed - usually with reference to the minimum levels of protection set by the standards, legislation, insurance services and / or other authorities - the designer sets up the correct placement of the elements that will constitute the fire detection system as a whole. Materials and devices specially manufactured for these purposes are selected through standardized installation methods during the design. EN 54 is the standard that is obligatorily applied to the design and manufacture of such products in the European Union.

Explosive gas detection systems

In everyday life, the term "gas leak" refers to a leak of natural gas or other explosive gas from a pipeline or other storage device, in a place where the gas should not be. Since flammable gases can explode when there is a flame or spark, with dangerous consequences, we install systems for detecting these gases. In addition to causing fire and explosion hazards, a leak can be harmful to vegetation, including large trees, and can release powerful greenhouse gases into the atmosphere.

Carbon Monoxide (CO) detection systems in parking areas (garages) / Loading and unloading areas / Warehouses

Vehicle exhaust gases are an important source of carbon monoxide production, a toxic gas often referred to as a silent killer. In all enclosed spaces, where carbon monoxide can be a danger to life, it is mandatory to have a ventilation system, so that there is a minimum number of air changes in the area, per hour. This is achieved by using ventilation fans, which often work continuously, to ensure that the risk is minimized. The areas most at risk for the gas concentration of Carbon Monoxide (CO) are enclosed parking spaces, loading and unloading areas, internal combustion engine maintenance areas and warehouses. In addition, areas where internal combustion engines, boilers, etc. are installed, are particularly dangerous.

AEROSOL FIRE SUPPRESSION / FIRE SUPPRESSION WITH 3MTM NOVECTM, CO2 ETC.

Automatic extinguishing systems control and extinguish fires, without human presence. The most common extinguishing materials for the application of automatic extinguishing systems are aerosol generators and extinguishing gases such as 3M™ Novec™ 1230 Fire Protection Fluid, CO2 and many more, and there are special standards for each one. When fires are extinguished at the beginning, the damage is minimal. A statistic survey found out that "93% of all fire deaths occur at the moment when the fire has moved beyond the early stages".

Systems differ because of their multiple applications. In general, however, automatic extinguishing systems fall into two categories: Prefabricated and not.

  • Extinguishing systems, according to the requirements of the specific area and / or application are most often used for larger installations. Such systems, for example, are installed on ships or boats, vehicles, Server, Data & Control rooms, E/M spaces, electrical installations, panels, warehouses, archive rooms, galleries, production lines, etc.
  • The prefabricated systems concern the installation of standardized products, which have been prescribed for a specific use, without the need to carry out an application design. The most common types are the dry powder systems (automatic roof fire extinguishers), with applications in areas such as household boiler rooms, fuel tanks, carpentry, etc.

Therefore, by definition, an automatic extinguishing system can work without human intervention. The extinguishing system consists of two main parts, the prompt detection system and the extinguishing agent. Detection is achieved by mechanical or electrical means. Mechanical detection uses flexible connectors or heat-sensitive cables or pipes. This type of detectors are designed to detect a specific temperature and activate a command (e.g. automation relay, shutter restraint mechanism, detonator, etc.). Electrically activated fire detection uses detectors suitable for detecting e.g. temperature, smoke, flame or air suction and analysis systems, usually connected to a fire detection/extinguishing panel that controls whether or not the extinguishing is activated. Some times the possibility of remote control and operation is required, while local manual activation is always possible. The extinguishing material is usually stored in a container or containers (bottles or generators) that release the material when they receive the command from the fire detection/extinguishing system. In the case of gases, the extinguishing material is released through high pressure piping (SCH40) and ends up in the air, through specially designed nozzles. The type of nozzle used depends on the application, the material, etc. Unlike the extinguishing gases and liquids, the aerosol generators are placed on the ceiling, without pipes and are released directly.

SPOT FIRE SUPPRESSION FOR RESTAURANTS WITH WET CHEMICALS OR DRY POWDER

The risk of a fire is proving to be a very common and serious enemy for the modern catering business. A fire in a kitchen is generally due to the ignition/combustion of cooking oil. However, cooking oil and fats are burned at a relatively high temperature and therefore once a fire has occurred it is difficult to extinguish. Adding to this, open flames, hot cooking surfaces and a high-fat environment help the kitchen fire to spread quickly, further threatening the business and its staff; In order to protect modern kitchens from such dangers, we install KITCHEN FIRE EXTINGUISHING SYSTEMS. These systems are developed and designed according to European standards and/or the NFPA and their use is  mandatory for all commercial kitchens in hotels, institutes, restaurants, schools etc.

System design:

The Restaurant’s Local Application/Extinguishing system is designed to provide fire protection to ventilation hoppers and cooking hobs and/or appliances.

The basic system consists of a container with a liquid chemical element (Wet Chemical) or dry powder, temperature sensors, heat detection cable, control panel, nozzles, piping, etc.

The system provides automatic activation with the possibility of manual activation through a remote station or manual traction button.

The system, if necessary, can also deactivate other devices when activated, for example gas supply, ventilation, etc.

Additional equipment, such as remote manual traction station, mechanical and electrical gas valves, pressure switches, electrical switches and accessories such as alarms, warning lights, etc. can be integrated into the system.

As the fire is detected, the Control Panel activates the container with the extinguishing material, which through a properly constructed network of pipes and special nozzles, diffuses directly onto the fire to extinguish it.

Form of interest

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