Fire, as well as the subsequent spread of smoke in the room, leads not only to large financial losses, but also to death. Most of us believe that in a 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 he alth.
Operation principle
The natural smoke exhaust system is based on the principle of air heat flow. It has several ways to control mechanisms: remote control of smoke hatches using infrared rays, control panels and special sensors, as well as manual buttons.
Natural ventilation systems can be used in all types of premises, you just need to choose the right scheme. SNiP (sanitary norms and rules) define all the necessary fire resistance indicators for each type of premises.
Depending on the purpose of the enterprise andits cross-country ability, various system combinations can be installed: separate electronically controlled windows for enterprises with a small crowd of people or special complex systems that meet more stringent fire safety requirements.
Design and calculation of smoke hatches
Smoke exhaust systems are designed in several stages.
First of all, you need to study all the technical documentation for the installation object.
The next step 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 a very important stage, because only after it you can choose the most suitable equipment for a given room. In the absence of ventilation shafts at the facility, specialists determine whether it is possible to conduct additional communications. If there is such an opportunity, you can start the calculation.
Smoke hatch functions
Hatches are designed to be used with:
- Natural uniform lighting. As you know, top lighting is twice as effective as side lighting. Since smoke hatches illuminate almost every square meter of the room, the savings in lighting costs are very significant. In addition, natural daylight increases efficiency and improves well-being, which is very important in office environments.indoors.
- Natural ventilation. Constant circulation of fresh air maintains a comfortable temperature in the room, which again can significantly save on the cost of artificial ventilation.
- Smoke removal. The removal of smoke in an emergency ensures the efficient use of escape routes and the efficient work of rescue services.
- Significant simplification of engineering systems. Smoke hatches in certain cases can eliminate the need for artificial air vents.
Smoke hatch control systems
Smoke hatches are controlled by specialized systems of three types: ventilation control system, smoke control system and mixed system.
Also, systems are divided depending on the type of mechanism control. They can be of three types: pneumatic, electric and pneumatic-electric.
Smoke hatches activate the control system automatically using special sensors that respond to an increase in air temperature or smoke in the room. However, at the request of the client, the smoke exhaust system can be additionally equipped with devices for remote and manual start, as well as start through the fire alarm system.
In addition, the sunroof control system can be equipped with special sensors and a weather station. In this case, with strong wind and precipitation, smoke hatches will closeautomatically.
Practical recommendations for installing smoke hatches
The main condition under which the installation of smoke hatches can be considered correct is their uniform location on the roof of the building. However, if materials of different burning intensity are located in the room, uneven placement of hatches is allowed.
When installing hatches, consider the angle of the roof: if it is less than 12 degrees, then the maximum distance from the edge of the roof 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 at least the sum of the long sides of two hatches (or their diagonals).
From a practical point of view, a large number of small hatches will cope with their task much more effectively than a small number of large ones. A roof slope of less than 12 degrees implies the mandatory installation of at least one hatch per 200 square meters. m, more than 12 degrees - per 400 sq. m.
Smoke hatches can be installed on roofs with different types of coating: membrane, reinforced concrete, etc. It is imperative to take into account the layouts and loads calculated at the design stage. The most common consequence of errors at this stage is hypothermia in the winter and overheating in the hot season.
Special requirements
When determining the number of smoke hatches in crowded places, their area must be equal to or greater than 3%floor area of this room.
The method for calculating the area of the theater smoke hatches is as follows: if the floor area of the stage is less than 150 sq. m, then smoke hatches should be at least 3% of it. If the surface area of the stage exceeds 150 sq. m, then the area of smoke hatches is calculated by the formula: A \u003d 0.5 √2F-100 (F is the surface area of the stage floor).
Thus, the article discusses in detail the types of smoke hatches and the issues of their installation.
