During technological progress, ventilation plays an important role, the design of which is carried out simultaneously with the preparation of the construction project of any building. We have long moved away from building houses made of wood and natural building materials, which normally let air through, while at the same time retaining heat. At the moment, they are massively used in plastic and polystyrene foam, which have poor air permeability and emit harmful substances such as formaldehyde. All these chemical building materials are used not only in industrial buildings, but also in the repair of residential premises. In order to save the situation a little, such a thing as "ventilation" appeared. And it's not just a tube that supplies fresh air. Therefore, ventilation design is a big science. A well-designed project makes it possible to breathe freely even near a hot machine at the factory.
Description of design
Necessarydraw up a technical task. This is the initial document for the design of ventilation or other technical object. It indicates the required air parameters in ventilated buildings, air exchange organization, types of heat carriers. During the preparation of such tasks, the following data are required: the purpose of the building, the characteristics of building materials and coatings, doors, windows, sections of rooms and floor plans. The technological process and operating mode are taken into account for production premises.
Ventilation calculation
First - the parameters of the indoor and outdoor climates are calculated in accordance with regulations (SNiP 23-01-99 "Construction climatology" and SNiP 41-01-2003 "Heating, ventilation and air conditioning").
Second - the required heat exchange is determined based on regulations and the volume of air consumed per person per hour, taking into account heat gains.
Third - when considering the characteristics of the room, the types of necessary ventilation are determined: general exchange or local, supply and exhaust or exhaust, natural, mechanical or mixed.
In conclusion, the selection of equipment is made according to technical and economic criteria.
Ventilation design involves calculating the distribution of air in different ways: displacement or mixing, supply and removal of air from the bottom-top, types of supply air jets, designing the number and types of air diffusers.
Air pipe network calculations are also carried out: sound pressureair during the outlet of the distributors, configuration, cross-section of air ducts, pressure losses in the network.
Then a graphical diagram is drawn up that displays a description of the adopted ventilation system project: plan, characteristics and location of technological units, description of the materials and equipment used.
Types of ventilation
Ventilation design for an industrial building includes different types of ventilation: simple systems for office space, systems of medium and high complexity for large workshops in production.
Natural ventilation is air exchange due to pressure difference, air rarefaction and the use of wind power, without the use of special equipment and energy costs.
Forced - this is an air exchange, which is carried out by technical devices: air conditioners, fans, etc.
Varieties of forced ventilation systems
By purpose, forced ventilation systems are divided into the following types:
- Forced ventilation. It works due to the fan, which supplies fresh air to the room, and due to the valve in the off state, the air cannot move through the fan in either direction. The outflow occurs naturally, due to pressure through the cracks in the windows and during the opening of the doors.
- Exhaust ventilation. It is produced using a fan that removes exhaust air from the room, while its inflow occurs due to leaks inwindows and doors.
Design of supply and exhaust ventilation is a drawing that shows the movement of air in the exhaust system. In this case, air supply and exhaust occur simultaneously with the help of special technological devices. This process is carried out by two types of air exchange. The first is a method of mixing air, when air from the room is mixed with clean air, and removed through exhaust valves. The second is the displacement method, when fresh air is supplied from below, and exhaust air is discharged from above in a natural direction.
More complex types of ventilation and their applications
In addition to the natural and most simple forced types, there are also more complex ones. They are used when designing industrial ventilation. For example, in factories where a large heat release occurs during the production process, an "air shower" is used, when a stream of cooled air is supplied at high speed precisely to the places of heat release. Another type of ventilation is an "oasis". At the same time, cooled air is supplied to the fenced area of the room and then distributed in the room. In production, where there is a large release of gas, dust, release of explosive substances, the services that design industrial ventilation require the use of very complex types of ventilation, such as aspiration (this is the suction of polluted air). Exhaust systems used in production can be both general exchange (aspiration) and local (onboard suction, exhaustumbrellas). In order to comply with safety regulations and protect the external environment, the norms that are included in the design of industrial building ventilation provide for the use of additional systems: air shields and curtains built into the ventilation system, anti-dust filters and those that are used from chemical impurities in the smoke.
Computerized ventilation design
Designing ventilation is a very complex and painstaking work. It requires a lot of knowledge in this area. In order to facilitate the work of specialists, a program for the design of ventilation was created. And at the moment there are already quite a lot of such applications, both for large organizations and for not very experienced users. For example, Vent-Calkona works on the basis of Altschul's formulas and allows for hydraulic calculation of the air duct. There are plenty of similar programs on the information market, such as CADvent, AutoCAD, Ventmaster, etc., with which you can easily create projects in 3D, 2D graphics, drawings and many other calculations.
Residential ventilation
Ventilation of a residential building with natural air exchange is designed according to generally accepted standards and prescribed in regulatory enactments. If this is described in simple words, then everything looks like this: through leaks in the windows and through open doors or when ventilating through the window, clean air enters, and through the ventilation outletsthe mine is deduced spent. But due to the fact that now almost all houses have plastic windows, the natural inflow is disturbed. We have to design forced ventilation. One option is to install an infiltration supply valve, which is placed on the wall or behind the heating radiator. In this case, fresh air will come in already heated, which is very convenient in winter. Its removal in the house is also sometimes blocked by the fact that the ventilation outlet shaft is not located in every room, but mainly in the bathroom, toilet, kitchen and corridor. Therefore, for unhindered air circulation in an apartment or in a private house, supply grilles are installed in the doors. If the natural ventilation of a residential building does not cope well enough, a mechanical forced system is installed. For this, special fans are mounted in the outlet shaft. Such devices are of different types. They are mounted on the wall at the entrance to the shaft or behind the ceiling and mounted in the duct pipe. These fans are called hidden fans.
Ventilation system design codes
In any building, both industrial and private, a ventilation system should be installed, but there are not always enough financial resources to hire specialists for such an important and responsible job. Therefore, sometimes you have to calculate and install such structures yourself. In order for you not to make gross errors in the calculation, we give an example of how the calculation is done anddesign of ventilation in a private house. All systems differ from one another in performance, therefore, according to accepted standards, it should have the following readings:
- for residential premises - 3 m³ per hour per 1 m²;
- for sanitary facilities - 50 m³ per hour per 1 m²;
- for separate bathrooms - 25 m³ per hour per 1 m²;
- for living rooms there must be an air supply.
Types of air ducts and installation of ventilation
During the installation of ventilation, air ducts, fasteners, filters and fittings are used. The main instruction is ventilation design and installation. Everything is produced according to this project, where a specific type of air ducts is indicated. Rigid structures are rectangular and round. Round ducts have the least air resistance, rectangular ducts have a little more, and flexible and semi-flexible ducts have the greatest air resistance due to the fact that they are corrugated. Therefore, the main highway passes through the data provided, which are included in the ventilation design, and the installation is carried out using rigid structures, and flexible ones are used as connectors. All air ducts must be insulated with mineral wool to prevent condensation.
