The occurrence of a fire in a multi-storey building is always an extremely dangerous incident, because of which hundreds and even thousands of people can lose their lives. Indeed, with large areas of fire and high smoke of a tall building, it is very difficult to extinguish a fire. In addition, if a large number of people are in the room, serious problems with evacuation and, as a result, a large number of human casualties can arise. For the above reasons, the smoke exhaust system is one of the most important communications in modern high-rise buildings. This system copes with its task due to the fact that it contains fire-retardant valves. We will talk about how they are arranged, what their types are, and what their principle of action is, in this article.
How the smoke exhaust system works
Smoke removal is due to specially mounted system channels, which are located in the middle of the ventilation structure. The smoke removal process consists of several stages. The first is the weathering of the smoky stream. And the second is pumping clean air into the middle of the building. Thanks to this, safe and fast evacuation of people during a fire becomes possible. Fire retardant valves help to cope with this task. We will discuss them further.
What are fire retardant valves
The fire-retardant “bug” valve is a metal box made of high alloy or galvanized metal, equipped with a special sensor and mechanism. It is installed in ducts and openings that cross fire walls and walls. The fire retardant valve actuator is located in close proximity. These valves are able to prevent the spread of fires through ventilation systems. They have high fire resistance.
Types of fire retardant valves
Fire retardant valves are divided into several types. Among them, valves of normally open type (NO) and normally closed (NC) can be distinguished.
Normally open valves are designed for installation on ducts. They are constantly in the open state. As soon as a fire signal arrives , the valve closes automatically. Thus, a smokescreen is installed, and the fire can no longer freely spread through the ventilation channels. After the fire has been completely extinguished, the fire-retardant valves will open and fresh air will begin to flow into the room. Thus, the room is ventilated after the elimination of the source of fire.
Normally closed fire retardant valves are installed directly in the ventilation lines. Their task is to prevent the spread of smoke. Every day they are in a closed state and open only by a signal from a fire station. Such valves are designed to vent smoke from a burning room.
Installation of fire retardant valves is always done exclusively by specialists. Incorrect connection can lead to the failure of the entire system.
Purpose of valves for delaying fire
Fire retardant valves can be used for different needs, so they have slightly different designs. According to the type of execution, three main ones can be distinguished.
1. Industrial valves are the most common type. They are installed in residential premises, shops, offices, shopping centers and in enterprises that do not have an increased risk of explosions.
2. Explosion-proof valves are distinguished by their ability to withstand explosions. They are distinguished by the presence of "non-sparking pairs of materials." Such valves are intended for installation in those rooms where explosive mixtures of all groups and categories are available. They also differ from other types by the presence of an additional flameproof enclosure of the valve actuator. They are not equipped with electromagnets and thermo-closing devices that have a duplicate effect.
3. Valves intended for use in nuclear power plants. They have a number of differences in their structure. In everyday life and industry they are not used.
Flame Retardant Valves
The fire-retardant "bug" valve is completed with the following components:
- an electric drive in which a return spring is built-in;
- electric drive type "closed / open";
- an electromagnet having a return spring;
- an electromagnet with a return spring having a fusible insert (oriented to a temperature of 72 ° C).
How to control fire retardant valves
Fire control valves are typically controlled in two ways.
The first is manual mode. In this case, the command by which the valve closes or, on the contrary, opens, is sent from the fire department. This type is good in that it does not require complex and expensive automatic equipment. But in terms of security, it is noticeably inferior to the following.
The second type is automatic mode. This method eliminates the impact of the human factor, and therefore is considered more reliable. The valve starts only by a signal that comes from the automatic control system.
The importance of fire fighting systems
The presence of high-quality and properly installed fire-retardant valves in the room is a mandatory requirement for the fire safety system of any civil or industrial facility. It is also a guarantee of people's safety. Fire retardant valves are just one of the components of the whole fire extinguishing system, which must be equipped and installed in accordance with all norms and requirements for fire safety in rooms.
In addition to a competent and high-quality installation, the system should undergo regular technical inspections. According to their results, all breakdowns should be immediately eliminated. After all, human lives depend on this.