Smoke extraction hatches: types, functions, installation
Fire, and also following itthe spread of smoke in the room leads not only to large financial losses, but also to the death of people. Most of us believe that in case of fire the main danger comes from exposure to high temperatures, but sad statistics prove that exposure to harmful substances and combustion products is no less dangerous to health.
Operating principle
The natural smoke exhaust system is based onprinciple of air heat flow. It has several ways to control the mechanisms: remote control of smoke flashes via infrared rays, control panels and special sensors, as well as manual buttons.
Natural ventilation systemscan be used in all types of rooms, you only need to select the necessary scheme. SNiP (sanitary norms and regulations) determine all necessary fire resistance indicators for each type of premises.
Depending on the purpose of the enterprise and itspatency can be installed various combinations of the system: separate windows with electronic control for enterprises with a small number of people or special complex systems that meet more serious fire safety requirements.
Design and calculation of smoke flues
The design of smoke removal systems is carried out in several stages.
First of all, it is necessary to study all the technical documentation for the installation site.
The next stage involves the inspection of existing ventilation shafts (if any) and their detailed analysis. And only after that you can proceed directly to the calculations.
Inspection of the design object is very importantstage, because only after it you can choose the most suitable equipment for this room. In the absence of ventilation shafts at the facility, specialists determine whether there is the possibility of additional communications. If there is such a possibility, you can start the calculation.
Functions of smoke hatches
Hatches are designed to be used to:
- Natural uniform lighting. As you know, the top lighting is twice as effective as the side lighting. Since the smoke flaps cover almost every square meter of the room, the saving in lighting costs is very significant. In addition, natural daylight increases efficiency and improves well-being, which is very important in office buildings.
- Natural ventilation. Constant circulation of fresh air ensures the maintenance of a comfortable temperature in the room, which again allows to save considerably the costs of artificial ventilation.
- Smoke removal. Smoke extraction in an emergency situation ensures effective use of evacuation routes and effective operation of rescue services.
- Significant simplification of engineering systems. Hatches smoke in certain cases are able to eliminate the need for artificial air vent.
Smoke control systems
Management of smoke flue hatches is carried out with the help of specialized systems of three types: a ventilation control system, a smoke control system and a mixed system.
Also, the systems are subdivided depending on the type of control of the mechanism. They can be of three types: pneumatic, electrical and pneumatic-electric.
Smoke extraction hoods activate the control systemautomatically with the help of special sensors that respond to a rise in air temperature or smoke in the room. However, at the customer's request, the smoke exhaust system can be additionally equipped with remote and manual start-up devices, as well as triggering through a fire alarm system.
In addition, the ventilation management systemhatches can be equipped with special sensors and a weather station. In this case, with strong wind and precipitation, the smoke flaps will be closed automatically.
Practical recommendations for installing smoke flaps
The main condition under which the installation of hatchessmoke removal can be considered correct - this is their uniform location on the roof of the building. However, if materials of different combustion intensity are located in the room, uneven placement of hatches is allowed.
When installing hatches, take into account the inclination angleroof: if it is less than 12 degrees, the maximum distance from the roof edge to the hatches is 10 meters, if it is more than 12 meters - the distance increases to 20 meters.
The distance between hatches must be at least 20 meters and not less than the sum of the long sides of the two hatches (or their diagonals).
From a practical point of view it is much more effectivewith its task will cope with a large number of small hatches, rather than a small number of large ones. The roof slope of less than 12 degrees implies the mandatory installation of at least one hatch of 200 square meters. m, more than 12 degrees - by 400 square meters. m.
Smoke can be installed onroofs with different types of coating: membrane, reinforced concrete, etc. It is absolutely necessary to take into account the layouts and loads calculated at the design stage. The most frequent consequence of errors at this stage is the supercooling of the room in winter and overheating during the hot season.
Special requirements
When determining the number of smoke flue hatches in places of mass congestion, their area should equal or be more than 3% of the floor area of this room.
Method for calculating the area of smoke fluesThe theater is the following: if the floor area of the stage is less than 150 square meters. m, the smoke flue hatches should be at least 3% of it. If the surface area of the scene exceeds 150 square meters. m, the area of smoke flue hatches is calculated according to the formula: A = 0.5 √2F-100 (F is the surface area of the floor of the stage).
Thus, the article details the types of smoke flue hatches and the issues of their installation.
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