When planning industrial buildings and public facilities specialists try to solve many tasks, one of the main is to ensure fire safety. If, however, a critical situation arises, it is important even at the design stage of the building to take care that fire does not spread through the duct and the ventilation system. The most popular devices that are used for passive protection against fire are the fire-retardant valves. They have an automatic drive, which triggers the mechanism if an emergency situation occurs.
The main types of fire retardant valves
Fireproof valves are designed to prevent the spread of fire through the ducts and ventilation. Inside their body is a damper, which acts as the main element. It is located on the transverse axis, which ensures smooth rotation. Considering fire retardant valves, it is necessary to take into account the tasks that must be performed.
Having familiarized with the codes of rules and established norms, we can distinguish several types of valves, they can be:
- normally open;
- normally closed;
- double-acting valves;
- smoke exhaust valves.
In the first case we are talking about a device that is constantly in the open state, and when a fire occurs, the shutter closes, preventing the penetration of fire into other rooms. The fire retardant valves can also be normally closed. They are necessary for operation in a smoke-free ventilation system. When a critical situation arises, the valve opens, and clean air is introduced into the room.
Description of the double-acting valve and smoke removal device
If you have a double-acting valve, it is installed in the ventilation system, as well as aerosol and powder extinguishing systems. When a fire arises, the valve closes, and upon completion it opens and does not interfere with the removal of fire extinguishing effects and combustion products.
The design and operation of the smoke valve can be compared to a normally closed device. The only difference is that the first is installed only in the smoke exhaust system. In standby mode, it is in the closed state, whereas in the event of a fire, the flaps are opened and the removal of the combustion products begins.
Overview of valves with different housings and flaps
The fire-retardant valves can be classified as a damper, they are multistage and conventional. The first are characterized by the fact that the flap has a smaller outward movement beyond the boundaries of the hull, this is important if the installation is conducted in a narrow space. The valve may have its own version of the housing, in this case, special attention deserves units that have a rectangular or circular shape. Here the shape of the channel plays a role.
The equipment may have one or two sections, which are separated by a heat-insulating layer. This parameter is affected by the level of the desired fire resistance limit. It is possible to find valves that have two or one flanges, while the drive can be located outside or inside the device.
Reviews of valves with different types of drive
The drive of the fire retardant valve is the main feature of such equipment after a functional purpose. Thus, the device can operate in autonomous mode, but it works after a signal from the automation. According to consumers, the most common today are valves with a manual drive type. In this case, the connection is made from the operator's console. The flap can be rotated by one of several types of drive, among which are:
- reverse electric drive;
- thermal lock or fusible link.
Consumers like that valves can have an electric drive or a combination of an electrical device and a thermal lock. Most often, buyers choose equipment with a thermal closure device and an electric drive, because such units can have a return spring. As the users emphasize, valves with an electromagnetic drive without a lock and a drive without a temperature sensor are safe. This is due to the fact that the thermal lock has not been used for a while.
Characteristics of Belimo valves with electric drive
Belimo fire retarding valves can have several designs, among others:
- with a normally open flap;
- with a normally closed flap;
- valves, not intended for installation in rooms for fire and explosion hazard requirements.
In the first case, the element can be installed in canals, mines and air conditioning systems for buildings of different purposes. The fire-retardant valve with electric drive and normally closed flap can be used in smoke-free ventilation. If it is a device with an electromagnetic drive, then in addition a thermal lock of 72 ° C is supplied in combination. A device may be stripped of this element. If the section is round, then 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. The design assumes a microswitch. The operation of such devices is carried out in rooms where the temperature should be in the range from -30 to +40 ° C. Buying a valve with an electric drive, you can expect a range of temperatures ranging from -20 to +40 ° C. At the same time, it is necessary to ensure that there is no impact of atmospheric precipitation, moisture and condensate on the damper.
The body of the product is made of galvanized steel sheet, the design of the rotor blade contains a fire-resistant material. On the perimeter of the rotary blade is a thermoactive seal, which expands under the influence of elevated temperatures, ensuring high tightness. The valve is fire retardant, the price of which is 5200 rubles. can be matched by you in terms of 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 that can be serviced in an automatic, remote or local mode. The control of fire-retardant valves in this case assumes the use of light-signal fixtures with a threshold of operation, which excludes illumination from interference with extended power lines. In the cabinet, additional functions can be implemented, among them: installation of buttons for checking operation, control of valves in accordance with smoke zones, installation of a valve with electric drive, which will be controlled by a damper.