When planning industrial buildings and public facilities, specialists try to solve many problems, one of the main ones is to ensure fire safety. If, however, a critical situation arises, then it is important even at the design stage of the building to ensure that the fire does not spread through the duct and the ventilation system. The most popular devices that are used for passive protection against fire are fire-retardant valves. They have an automatic drive, which entails the triggering of the mechanism if an emergency situation occurs.
Main types of fire retardant valves
Fire dampers are designed to prevent the spread of fire through ducts and ventilation. Inside their body is a flap, which acts as the main element. It is located on the transverse axis, which guarantees a smooth rotation. Considering the fire-retardant valves, you should consider the tasks that should be performed.
After reviewing the rules and the established standards, we can distinguish several types of valves, they are:
- normally open;
- normally closed;
- double acting valves;
- smoke removal valves.
In the first case we are talking about the device, which is constantly in the open state, and when a fire occurs, the valve closes, preventing the penetration of fire into other rooms. Fire retardant valves can also be normally closed. They are necessary for operation in the conditions of the smoke ventilation system. When a critical situation arises, the valve opens, and clean air begins to be sold to the premises.
Description of the valve double action and smoke removal devices
If a double-acting valve is in front of you, then it is installed in the ventilation system, as well as aerosol and powder fire extinguishing systems. When a fire occurs, the valve closes, and upon completion it opens and does not prevent removal of the effects of fire extinguishing and combustion products.
The design and principle of operation of the smoke valve can be compared with a normally closed device. The only difference is that the first is installed only in smoke removal systems. In standby mode, it is in the closed state, whereas when a fire occurs, the flaps open and the removal of combustion products begins.
Overview of valves with different bodies and dampers
Fire-retardant valves can be divided by the type of valve, they are multi-stage and conventional. The first are characterized by the fact that the flap has a smaller overhang of the hull, this is important if the installation is carried out in a narrow space. The valve can have its own version of the housing, in this case, special attention should be paid to units that have a rectangular or round shape. Here the role is played by the form of the channel.
The equipment may have one or two sections, which are separated by a heat insulating layer. This parameter is affected by the level of fire resistance required. You can find valves that have two or one flange, and the actuator can be located outside or inside the device.
Feedback on valves with different types of actuators
The drive of the fire-retarding valve is the main feature of such equipment after the function. Thus, the device can operate in offline mode, and is triggered after a signal from the automation. According to consumers, the most common today are the valves with manual actuator type. In this case, the connection is made from the operator's console. The valve can be rotated by one of several types of drive, among them should be highlighted:
- electric reverse;
- thermal lock or fusible insert.
Consumers like the valves to have an electric actuator or a combination of an electrical device and a thermal lock. Most often, buyers choose equipment with a thermo-closing device and an electric drive, because such units can have a return spring. As users emphasize, valves with an electromagnetic drive without a lock and a drive without a temperature sensor are safe. This is because the heat lock has recently been banned.
Electric Belimo Valve Specifications
Flame-retardant Belimo valves may have several versions, among others it should be highlighted:
- with normally open damper;
- with normally closed damper;
- valves that are not intended for installation in premises according to the requirements of fire and explosion hazards.
In the first case, the element can be installed in channels, mines and air conditioning systems of buildings of various purposes. The fire-retarding valve with electric drive and normally closed damper can be used in smoke-free ventilation conditions. If we are talking about a device with an electromagnetic drive, then an additional thermal lock of 72 ° C is supplied in combination. The device may be deprived of this element. If the cross section is round, the valve does not have a thermal lock.
When the device has a spring drive, the thermal lock can be set to 72 or 141 ° C. In this case, the design assumes the presence of a microswitch. Operation of such devices is carried out in areas where the temperature should be in the range from -30 to +40 ° C. By purchasing a motorized valve, you can count on a temperature range from -20 to +40 ° C. It is necessary to ensure the absence of exposure to precipitation, moisture and condensate on the valve.
The body of the product is made of galvanized steel sheet, the design of the rotary blade contains a fire-resistant material. Along the perimeter of the rotary blade there is a thermoactive seal that expands under the influence of elevated temperatures, ensuring high tightness. The valve is fire retardant, the price of which is 5200 rubles. can be picked up by you for fire resistance. They are limited to the following values: 60, 90, 120, 180 minutes.
The smoke protection and ventilation system should include a valve control cabinet, which can be serviced automatically, remotely or locally. Management of fire-retarding valves in this case involves the use of light-signal fittings with a response threshold, which eliminates interference from pickups with long supply lines. Additional functions can be implemented in the cabinet, among which should be highlighted: installation of buttons for testing the performance, control of valves in accordance with smoke zones, installation of a motorized valve that will be controlled by a valve.