Ventilation in different shapes present in almost all buildings and premises. In most cases, it is arranged to fulfill certain goals, but sometimes it occurs spontaneously, due to natural factors. Why is it needed, what are the design principles, nuances and types of ventilation systems - let’s look at these issues in more detail.
The main purpose of ventilation is to organize air exchange. They are designed to supply the required amount of fresh air and remove contaminants along with exhaust air. The same thing is a consequence of poor ventilation.
Types of room ventilation depend primarily on the purpose of the objects themselves. According to this principle, systems are:
These types of ventilation systems serve slightly different roles. If systems for residential and public buildings are primarily designed to supply the required amount of oxygen along with outside air and remove human breath products, then industrial ventilation is often designed to remove harmful substances first of all, with compensation of the removed air with outside air.
In addition to the scope of application of the air ventilation system, it is also classified according to other parameters.
Types of ventilation in buildings are primarily divided according to the direction of movement. They come in supply and exhaust types. In general, the volume of supply and exhaust air should be equal. This ratio is called air balance. It is necessary to ensure that the removed amount of air is completely replaced by fresh air, otherwise a vacuum occurs or, on the contrary, increased pressure due to the large supply of outside air squeezes it out through cracks in windows and leaks in doors.
The placement of the supply and exhaust systems depends on the requirements for the premises. It is not necessary to have both supply and exhaust in every room or space. For example, types of ventilation in residential buildings They come with equipment placed in such a way that the exhaust is carried out in technical rooms (bath, toilet, kitchen), and the inflow is supplied to the living rooms. The movement of air from the supply units to the exhaust units passes through the cracks under the doors or through specially installed grilles in them.
In addition to the direction of movement, ventilation is classified into the following types:
Types of natural ventilation are primarily classified into supply and exhaust. In fact, there is only natural exhaust ventilation, which operates under the influence of the difference in pressure between atmospheric air and indoor air. And the influx occurs as an effect of replacing the removed air; it occurs as a result of rarefaction of the air in the room.
The natural ventilation scheme includes mainly vertical ventilation ducts in walls that must be of sufficient length for traction to occur. What systems are often used in residential multi-storey buildings or private cottages.
Types of ventilation for industrial premises also include natural systems in various combinations. Also in such buildings, aeration is widely used, which is essentially ventilation when installing window or ventilation openings on different sides of the building.
Previously mostly forced ventilation in natural systems, it occurred through leaks in windows and doors under the influence of exhaust hood, but with the spread of vacuum double-glazed windows and energy-efficient windows, such a mechanism practically disappeared. Because of this, the ventilation does not work correctly, there is not enough of it. To solve a problem in the absence centralized systems apply supply valves in or which allow a certain amount of air to be supplied to living rooms for people to breathe.
Artificial ventilation differs from natural ventilation in that mechanical devices are used to move air. These are electric fans of different types and devices. Fans are:
If the first two types are also typical for natural systems, supply and exhaust systems are a purely mechanical area. Their peculiarity is that the equipment for both branches is the same.
Mechanical systems include not only fans, but a large number of other equipment: filters, heaters (electric and water), heat pumps, valves, dampers, grilles. It is necessary to regulate air flow, purify and heat it.
Types of mechanical ventilation are also classified according to the layout of the system. This can be either a prefabricated system, when the fan and all other elements are selected separately and assembled on site, or monoblock, when all these elements are assembled at the factory into one housing (heat and sound insulated) and delivered to the site. The first type is cheaper and more flexible, but monoblock devices are more convenient to install. They do not require additional configuration. Most often they come with built-in automation.
Let's consider supply and exhaust systems separately. This is a relatively new type that is designed to improve the energy efficiency of equipment. The purpose of ventilation systems of this type is similar to supply and exhaust. The main difference is that all elements (primarily fans) are arranged in one device and are interconnected during operation.
There are two large groups of such systems:
Devices without recovery differ little from separate supply and exhaust systems, mainly by selecting fans to ensure the same air flow. Heat recovery devices - modern and efficient equipment, the peculiarity is that the arrangement of equipment for both branches in one housing allows reducing energy consumption.
Recovery is the return of heat from the exhaust air back into the room. When a conventional system operates, exhaust air is removed from the room, irretrievably carrying away heat. And the external air supplied to the room cold air V winter period requires constant heating. This leads to excessive consumption of energy resources for heating. Recuperation can partially solve this problem. Heat from the exhaust air is transferred to the supply air using recuperators.
Lamellar(cross, cross-flow), in which air moves in a special package of aluminum, paper or copper plates, where the supply and exhaust do not mix. The second name appeared because of the direction of air movement - they seem to intersect. They have an average efficiency of about 80%.
Rotary air handling units. They have a mounted rotor made of a material with good heat capacity, which rotates slowly along an axis located between the supply and exhaust branches. During rotation, part of the rotor is heated by the exhaust air. When rotating, the heated part of the rotor moves into the supply zone and transfers heat to the cold air passing there. Most efficient systems. In some cases it can exceed 90%.
Rarely, but systems are still used with heat pump. They use a compressor and heat exchangers, which are located in the supply and exhaust branches. The compressor pumps heat from the exhaust zone to the supply zone. They are most often used for swimming pools, as they allow for the removal of moisture.
With glycol recuperator. The design is similar to a heat pump, only the heat is transferred from the exhaust branch to the supply branch not by freon, but by a coolant - a mixture of glycol and water. Their efficiency is not very high (up to 50%) and in this indicator they are inferior to rotary and plate ones. Mainly used for large systems.
The efficiency of recovery depends on both the type of equipment and the operating characteristics. This parameter is also influenced by the temperature and humidity of the air in both the supply and exhaust systems. Most often it is in the range of 70-80%, but sometimes 40-50% already provides significant savings in energy resources.
The ventilation scheme in the house most often involves a plate heat exchanger, less often a rotary one. Heat pumps have found their way into ventilation systems for swimming pools. Types of industrial ventilation that use recovery include all sound systems.
Purpose local ventilation– maintenance of a specific area in the room. They are used to reduce the need for air and reduce the cost of the system. For example, exhaust hood above ordinary home kitchen hood is local ventilation. What types of ventilation are there? Local systems come in the following varieties:
The use of local systems allows reducing costs for equipment and air heating.
The general exchange system, unlike the local one, serves the entire volume of the room or building. For example, the types of ventilation in a private house are mostly general. They can be either mechanical or natural. In general exchange systems, it is important to properly distribute the air; for this you need to know the characteristics of the room and the location of the work areas.
The hood is most often installed in the upper zone, because warm, polluted air often rises to the ceiling where it is easier to remove. But in some systems the hood must be located near the floor. This applies to industries where heavy gases occur. In the same garage carbon monoxide falls to the floor.
Should also take into account the location, people's work places, beds and rest areas.
The considered purpose and classification of ventilation systems allow us to generally navigate this important utility network and choose the optimal equipment for your purposes.
A ventilation system is a set of special equipment for the constant or periodic removal of exhaust air from industrial, warehouse and residential premises. Until the beginning of the 19th century, there were no mathematical calculations for ventilation; the indoor microclimate was maintained only through natural ventilation of the premises using exhaust ventilation. This approach could not guarantee proper performance, was associated with large losses of thermal energy, and significantly complicated the process of air exchange at night and in winter.
The theoretical description of air movement in exhaust ventilation ducts was first made by M.V. Lomonosov, and V.H. Friebe created the theory of air exchange rates in heated rooms. At the same time, he took into account that the influx of fresh air and removal of exhaust air is done through leaks in the door and window openings, special engineering elements were not provided in those days.
Only several decades later, scientists proved that it was impossible to ensure effective ventilation only through natural ventilation; types of ventilation systems with forced supply and removal of air appeared. Depending on the location of the specific installation, operating conditions and required technical parameters, the general exchange system has several types.
Ventilation units perform the following tasks:
Installed ventilation systems can perform either only one of the assigned tasks or work in a complex manner. Depending on the engineering features, technological schemes and operating principles, ventilation systems come in several types.
Currently, there are several types of ventilation, differing in the installation method, installed equipment, operating principle and technical capabilities. Ventilation systems are distinguished by several technical parameters: the method of air flow circulation, service area and design features.
Air flows can have natural physical causes of movement indoors, mechanical stimuli, or a mixed type. Specific types ventilation is determined after engineering calculations made taking into account the technical specifications. The technical specifications for air exchange indicate the maximum number of individual factors and requirements.
Natural ventilation
With natural ventilation, air can move due to differences in the density of air flows. Indoor air, as a rule, has higher temperatures than outside. Warm air with a lower specific density rises up and is removed out through special channels or natural leaks, replaced by denser cold air. This type of ventilation has its positive and negative sides.
Due to such peculiarities of functioning, natural ventilation is currently enjoying little popularity; preference is given to mechanical exhaust. For new construction of various buildings, state standards require the installation of mechanically driven ventilation.
Mechanical ventilation The movement of air flows is ensured by axial or centrifugal fans, air moves through the channels. The technical parameters of the channels and fan are selected taking into account the requirements for the systems.
Mechanical System Features The movement of air flows is ensured mechanically, which allows you to create systems with precise given parameters. Depending on the method of air supply and removal mechanical types ventilation can have several varieties.
An electric fan forces air into the room, thereby increasing its pressure; to equalize the pressure values, the excess comes out naturally. The fan is mounted directly inside the ventilated room, in special technological rooms or outside. The final decision on the mechanical system is made after calculations have been performed, taking into account the technical parameters of the equipment and the location of the building. The supply system is not used for residential premises.
The fan is installed to forcefully remove contaminated air; fresh air is supplied through special ventilation ducts or through loosely closed window and door openings. Exhaust ventilation is most often installed above individual work areas, in closed cabinets in laboratories, and in food and pharmaceutical industries. In some cases, an exhaust system is the only way to ensure safe conditions labor.
Air is supplied and removed from the premises forcibly. One fan pumps air, and the second fan removes air from the premises. Air exchange is characterized by high intensity and can be adjusted for each parameter separately. A mechanical supply and exhaust system of this type is used for ventilation of heavily polluted rooms; it is rarely installed in residential buildings.
Local ventilation Local ventilation allows you to remove pollution only from the most contaminated areas; it may have special filters to prevent environmental pollution. According to the principle of operation, it is most often of the supply type. Local ventilation can serve one or more workplaces, work on each zone separately, or ventilate all at the same time. The power of the mechanical system is relatively small, but the specific parameters depend on the characteristics of the technological processes and the features of the building layout.
Local supply ventilation Local supply system It is rarely used due to the great difficulties in cleaning the exhaust air. Most often it is used only to lower the temperature of operating equipment; it is ineffective for cleaning the air from harmful substances. The supply air supply is used in large sales areas and warehouses. It is often installed in office and government buildings, where the local supply system is constantly functioning.
Local exhaust system Purpose – removal of harmful compounds from the air in small volume. It can have several options for air suction: from enclosed spaces or with special suspended air receivers. The latter are often installed above cooking stoves, electrolytic baths and other equipment with small linear dimensions.
Special types of ventilation systems There are several types of special purpose ventilation systems:
According to the type of air ducts, general-exchange ventilation systems can be ducted or ductless.
Ventilation system calculation parameters Calculation of the ventilation system - complex engineering work performed only by specialists with special technical education. During the execution of work, the following initial data are taken into account:
When calculating the ventilation system, the initial data (technical specifications) of the customer are taken into account. The customer must indicate the required air circulation in accordance with the existing operating conditions of the premises. Further calculations are performed according to the following scheme:
At the preliminary development stage project documentation agreed with the customer, changes are made if necessary.
Installation of ventilation systems can only be carried out by specialized companies licensed to perform this type of work. Regardless of the type and purpose, general ventilation consists of the following units and elements:
After installation, it is mandatory to check the functionality of the ventilation; the air exchange is measured both in the room as a whole and above each work area. Acceptance and delivery certificates are signed by members of the state commission in the presence of the customer and contractor. Records of periodic inspection, repair and maintenance of industrial ventilation systems are made in a special journal and signed by the responsible persons.
Ventilation is one of the main engineering systems modern buildings. If in residential buildings it is not yet as popular as the norms require, then in public and industrial buildings it is designed and installed almost everywhere.
Let's take a closer look at what types of ventilation there are, how these systems are classified and how they differ?
Modern ventilation systems come in different types and, depending on their purpose, are divided into several subgroups. This division is carried out according to several parameters: the direction of air movement, the method of bringing air masses into motion, the territory served.
Ventilation in the house
What kind of ventilation is there in rooms in the direction of air movement? According to this parameter, systems are divided into two large groups:
There is also ventilation and its classification according to the factor that sets the air in motion. According to this parameter they are divided into:
There is also a division of ventilation, the types of which vary depending on the service area. According to this principle, ventilation systems are divided into:
All types of ventilation systems considered can be used both separately and together in one building or even room.
Systems can also be classified as ducted or ductless, depending on whether they use ductwork or move air through openings in the walls or fans without pipes attached.
Let us examine in more detail all the types and subtypes of room ventilation systems, how they differ and what their tasks are.
As already mentioned, natural ventilation is one of the popular types of modern systems. This type of room ventilation means that the air is driven natural factors. More precisely, it is the pressure difference between the internal volume and the external atmosphere. For it to function, it is necessary that the pressure outside is slightly less than inside the room. If such a factor occurs, air begins to move through specially designed ventilation ducts.
Natural ventilation
A striking example of such ventilation is the installation of exhaust ducts in the walls of multi-storey and private houses. The main positive factor in using natural ventilation is its low cost. There is no need to use expensive equipment or organize an electrical connection. Air exchange occurs on its own. But you need to keep in mind that there are also negative sides to using such a system. First of all, this is a dependence on atmospheric parameters.
It is not always possible to obtain the necessary air flow through windows and doors; sometimes weather conditions prevent this. And that is why special devices are created - ventilation systems that provide a solution to such a problem. But huge variety practical conditions leads to the fact that these systems are divided into a number of types.
Such an important type of communications as ventilation is strictly regulated by regulations. The key requirements are contained in SNiP 41-01-2003. As the developers of the act themselves state, it regulates:
All these points must be ensured strictly, regardless of the specific format of ventilation and the range of tasks it solves. IN Lately More and more attention is being paid to improving mechanical ventilation and connecting it with air conditioning systems. The creators of SNiP relied on the provisions of GOST related to:
The standard requirement for air supplied to living rooms is to warm it up to at least 15 degrees Celsius in winter. IN public buildings and administrative facilities require a minimum of 12 degrees Celsius. And in production workshops it is not allowed to supply air whose temperature would be less than 5 degrees. The design specification may include lower air temperatures during the cold season. All pipelines are installed only in such a way that they can be easily repaired or replaced.
All openings for air receiving devices can be placed at a height of at least 1 m above a stable snow line. This parameter must be determined taking into account data from meteorological services that monitor weather conditions in a certain area. Where sandstorms occur, it is necessary to surround these chambers with devices that trap harmful particles. Air intake systems must be separate for each fire compartment. When calculating air requirements, the largest numbers are taken as a basis.
According to this parameter, natural and artificial types of ventilation are distinguished. Natural movement is ensured by:
The first option is best used where a lot of heat is generated. More often we're talking about about production workshops, the air of which contains small amounts of toxic gases and dust particles. Aeration will have to be abandoned if it requires sophisticated preparation of the incoming air, as well as in the case when its intake provokes the appearance of fog and condensation. Natural ventilation, which works using a pressure imbalance between two points, requires creating a difference in height of at least 3 m. It is advisable to install horizontal sectors of air ducts no longer than 300 cm, limiting the rate of air movement to 1 m per second.
The wind system works when parts of the building facing the wind are subject to increased pressure, and in the opposite place it is reduced. Naturally, air rushes from a denser area to places where there is rarefaction; In order for it to get inside, there must be openings in the fences. The faster the wind flow, the greater the pressure difference, and therefore the air will flow inside in a larger volume. Any of the described ventilation complexes is characterized by simplicity and the absence of the need for electric current. But since the driving forces are very unstable and the air pressure is quite small, it will not be possible to count on a successful solution to the entire range of problems.
The solution is to use special equipment that facilitates and accelerates the movement of air over significant distances. The increased capabilities of mechanized ventilation often result in significant costs for electrical energy. Air can be extracted from specific locations or added as needed without being affected by unstable environmental conditions. Another advantage is the possibility of full processing, including increasing humidity or removing contaminants. To eliminate problems, mixed ventilation is often used, which can operate in forced or natural mode.
This parameter allows you to select supply and exhaust complexes. The names already eloquently characterize their essence. Thanks to supply equipment it is possible to ensure the receipt of clean street air instead of removed mass. In certain cases, the incoming air is treated (purified, made more humid or heated). Exhaust systems are designed to remove the exhaust air.
In practice, systems of these two types are used simultaneously, trying to ensure a balance between air intake and its discharge to the outside. There are cases when only an exhaust or inflow is installed. In such situations, to exchange air with external environment the main structural openings of the room itself or adjacent parts of the building are used. Developers can provide for the influx and removal of the waste gas mixture for the entire facility as a whole. But sometimes they are placed only in certain areas.
There are such types of air exchange as local, general, emergency, fire and combined options. Any system that supplies portions of air to specific places or removes contaminated mass from individual problem areas falls into the category of local ventilation. Air showers are considered an option for local influx. Like their water counterparts, they direct the flow in a concentrated manner and increase its speed. Basically, such systems are needed to reduce the heating of the workplace and cool the people themselves who are at risk of heatstroke.
The so-called air oases have also become quite widespread. They are formed by separating certain parts of the room from the rest of its volume using mobile partitions. Each oasis must be supplied with a relatively cold (compared to the main mass) air flow. At industrial facilities where there are devices and machines that create high temperature, are often used air curtains. The undoubted advantage of local ventilation is that it is more economical than capital systems.
But the use of such complexes in all parts of buildings is not always appropriate. After all, this significantly complicates design and installation and requires careful coordination of separate ventilation segments with each other. Therefore, even in serious enterprises, the main role belongs to the general system. Local units are used only in those workplaces where there is a need for a special circulation mode. As for local hoods, they are needed to prevent pollution from local sources from leaking into the rest of the building.
Many options for localized removal systems have been developed:
Suction devices are subject to very strict requirements. So, we must try to cover all the space that is subject to clogging. If this is not possible, it is necessary to ensure that as much of the plant as possible is removed from the installation producing harmful substances. Further, suction must necessarily exclude interference with the full functioning of the enterprise as a whole and its individual employees.
To reduce energy consumption, it is necessary to direct harmful substances to the same place where they themselves would go. Not open, but semi-open suctions are preferred. Their advantage is that a much smaller volume of air is required to purify the atmosphere. Local hoods must be equipped at the input with devices that remove dust. Important: if the work process covers the entire room as a whole or involves the movement of people, a general ventilation system is needed.
A common exchange apparatus allows you to evenly extract air from the room or distribute it equally evenly.
The following main tasks are solved:
If, when collecting data for a project, it turns out that there is not enough heat in the room, the general ventilation supply should be equipped with mechanical accelerators and devices that warm the air. In this case, it is advisable to free the air mass from dust. After all, any heating equipment, with rare exceptions, only increases its quantity. And if dust particles fall into an open fire or on a heated surface, it may appear bad smell. Since in a number of industries the emissions contain high-density gases and dust, and the equipment itself produces almost no heat, in such cases floor or underground pipelines are installed.
But many industrial facilities operate in such a way that many different types of harmful substances appear. Moreover, they usually do not enter the room in the same way. IN similar situation it is necessary to combine local and general ventilation. Separately, these two systems will not cope, even if their design and installation are carried out impeccably.
It is useful to take a deeper look at the differences between natural and mechanized ventilation. In any case, first you need to calculate the intensity of air exchange, find out what the cross-section of the air channels should be. It is generally accepted that the natural type of ventilation is more comfortable for people. In addition, limiting the flow rate allows for almost no risk of drafts. And it is this factor that is the “initiator” for many respiratory diseases.
But the problem is that reducing the air speed requires (given the same volume) an increase in the size of the channel. This not only complicates the work and increases its cost. Often it is simply not possible to use pipelines of the required size. This creates technical or design difficulties. Therefore, it is not advisable to simply abandon mechanical devices.
The common thing between natural and mechanical air movement is that you need to think about its flow inside a house or large building. Typically, this goal is achieved by installing special grilles in the doors along the desired flow path. Professionals believe that the dirtiest place should be blown last. For a residential building, such a zone is a sanitary unit; it is preceded by a kitchen.
If the grill option is not an option, you can leave a gap from the bottom of the door to the floor. Its size must be uniform - at least 2 cm along the entire length, regardless of the type flooring and the purpose of the rooms connected by the opening. When there is no grille (gap), no investment in the ventilation system will be justified. If there is an exhaust hood in the bathroom, the increase in pressure will make it difficult to open the door. Important: when taking into account the natural flow of air, you need to take into account that part of it that makes its way through cracks and holes in external walls and in other structures.
If loose wooden windows are installed (and they still remain in many places), in an hour after 1 sq. m of their surface, up to 20 kg of air will pass inside. In private houses and apartments whose area does not exceed 150 square meters. m, this is often enough to satisfy hygienic needs. Especially when you consider that some of the inflow comes through loose joints on doors and even through walls. If the rooms are glazed with modern plastic ones, aluminum windows, they are much more airtight. But here it is necessary to introduce corrections for the intensity of ventilation and micro-ventilation in accordance with the manufacturer’s documentation.
Supply-type structures are mostly duct-type and consume a fairly significant amount of electricity. But it ensures a complete supply of air even to the most hard to reach places. Therefore, the costs of arranging such communications pay off in the shortest possible time. Since the speed of pumping air using mechanical systems is quite high, the influx must compensate for everything that the outlet took away. An exception is made only for places where there are toxic or foul-smelling substances.
At such points, less air is necessarily added than is removed from there. To compensate for the difference, pumping is used through windows or from areas where the atmosphere is cleaner. The basic components are:
There are situations when there is no need to heat the incoming air. In this case, it bypasses the heater and moves along a bypass route. During the design process, supply mechanical ventilation is installed mainly in clean or almost clean rooms. Ejectors or conventional fans can be used to pump air. The choice between them in a particular case is made for engineering reasons.
General exchange exhaust - in the process of calculating such systems, the goal is to find the configuration, which would allow, after replacing the displaced air, to reduce the concentration of harmful substances to the MPC level or less. The use of systems with extended air ducts is allowed. When total length such a pipeline is more than 30-40 m, it is right to fear excessive pressure losses. They can be compensated by replacing axial fans with centrifugal ones, which drive air more powerfully. In some cases, elements that provide aeration come to the aid of the general exchange exhaust system.
The supply and exhaust option stands out compared to the already mentioned excellent performance. There are two ways to create a supply and exhaust system.
In the first scheme, the air is mixed like this:
To place the fans, choose a position under the ceiling or on it itself. But there is another solution, which involves pushing out the exhaust air with a flowing mass. Here you will need fans with low rotation speed, and they are placed at the bottom. An exhaust pipe is mounted on the external wall, which is connected to the exhaust valves using special channels. Valves and channels are located on top.
When the fan operates, new portions of air are sucked in from outside. The part of it that is already in the room manages to warm up. At the same time, it becomes lighter, rises to the ceiling, where it is mechanically pushed through the valve. It is not difficult to understand why this design works best in homes with high ceilings. In order not to provoke a pressure difference, the pulling and suction elements must be very well balanced, otherwise their work will be poorly coordinated.
Important point: the formation of areas with high pressure helps prevent bad odors from kitchens and bathrooms from entering adjacent rooms. In these places, the influx should be more active than the air suction. In most regions of Russia, the addition is appropriate supply and exhaust ventilation heat recovery means. These devices alone reduce the total heat loss during the removal of air masses by almost ¼. In essence, recovery is provided by heat exchangers in which street air absorbs part of the heat from the leaving mass without mixing with it.
The next logical step is to equip the recuperator units with devices that increase air humidity and additional filters. But the problem is that not all specialists can install even simple devices. Moreover, it will not be possible to create ventilation with your own hands, which uses a heat exchanger with additional options. They also complicate calculations and subsequent maintenance. So before making a final decision, you need to weigh all these circumstances.
If it is necessary to dismantle broken ventilation and then restore it, you need to approach the matter very seriously. First you need to find out what type of box is installed in a particular room. The decisive test, which accurately identifies serious faults, is carried out by yourself, without the involvement of experts. You just need to see whether the light deviates towards the air channel or not.
Restoration work begins with the dismantling of ceilings and walls. It is very important to select exactly those materials that meet the standard requirements. Most often, gypsum slabs and foam concrete-based blocks are used. You cannot narrow the ventilation duct too much so as not to have to do the work from scratch. The convenience of individual materials does not justify their use for ventilation.
Fire ventilation plays a special role. Smoke removal is especially important in areas actively used by people and along escape routes. First, an evacuation plan is drawn up, and only then, in accordance with it, a ventilation scheme for pumping out smoke is prepared. The corresponding systems must be made separate from other devices. It is imperative to install smoke ducts:
Recently, amendments have been made to the federal regulatory framework requiring the installation of smoke ducts in underground parking lots, public garages and warehouses. Smoke removal structures must ensure:
It is often practiced to pump air under high pressure. This is ensured by the use of special fans. Depending on the specific conditions, harmful substances can be drawn out either naturally or mechanically. But almost always they use special mechanics in order to speed up work as much as possible and increase efficiency. Most often, checking the quality of installation of fire ventilation systems is combined with a fire drill.
The channels through which the air flows are divided into:
The rectangular type of duct is practical, but the air inside forms vortices. If you use a rounded ventilated channel, the flow will begin to slide freely. This can only be achieved if the surface is sufficiently smooth. As for the joining method, it determines the financial and time costs, and at the same time the quality of the seams created. If you need to stretch round pipe, apply a bandage.
For the production of pipes the following is used:
The decisive factors when choosing between these options are their thermal and mechanical resistance. The scope of application is determined by the rigidity of the structure. The pressure is considered low if it does not exceed 0.9 kPa. Pressure over 2 kPa is declared high. Intermediate indicators belong to the average category.
The differences between ventilation in these cases are associated not only with the fact that there are few harmful reagents in the houses. The difference is due to the fact that the volume of pumped air is very different. IN industrial buildings ventilation should ensure the cleaning of the internal atmosphere from:
Until relatively recently, loose areas in the room and even on the balcony were used for ventilation. wooden frames. But modern ventilation systems, although they can successfully replace them with full glazing, work well only if high-quality insulation. First of all, it is necessary to insulate the structure from the outside to reduce the formation of condensation. The most common type of ventilation in this area is supply and exhaust valves, which:
The arrangement of ventilation ducts in the wall also has its own characteristics. warm attic. Roof aerators direct the supply air mass in the eaves area. Most people choose soffits with special openings installed in the lower part of the eaves. Perforated structures, allowing fresh breezes to pass through, block the passage of insects. Thanks to soffits, it is possible to create an impeccable appearance and guarantee functionality.
Cold attics are ventilated mainly with means that they create independently. For this purpose, air is passed through:
Ductless ventilation devices do not give good results in all cases. Not every apartment can be ventilated in this way. But garages and utility rooms are fine. If the building is divided into a number of zones that differ in their parameters, only duct complexes will have to be used. Important: a ductless configuration is quite compatible, like a ducted one, with mechanical and natural encouragement of air flow.
The natural ductless method of ventilation is, in principle, uncontrollable and does not allow control of the process. In addition, it leads to significant heat consumption. Mechanical inflow without the use of channels involves the use of either special fans or air conditioners. In terms of execution, these are similar to the already described oases and curtains. Because of high power necessary devices that drive the flow, it is necessary to install devices that dampen the sound.
Indispensable parts of the ventilation system include exhaust and air inlet openings. Their size is determined individually, taking into account the need for inflow and discharge. Both gratings and pipelines are selected according to the size of the holes. To hold open areas (hanging without solid support), special brackets are used that press the channel to the wall or ceiling. The role of adapters is to connect pipes of different sections to each other, to form turns and intersections.
Controllers and control panels are used mainly in cottages and other serious facilities. Additionally the following can be used:
Ventilation- this is a set of measures and devices that provide controlled air exchange in industrial premises. Ventilation is designed to provide sanitary (1) and technical (2) purposes.
(1) consists of maintaining an indoor air environment that complies with SNIP, GOST and general sanitary standards.
(2) Consists of ensuring a certain cleanliness, temperature, humidity and air speed in the room, based on the characteristics of the technological process
Types of natural ventilation:
Organized - through special openings and structures.
Disorganized - due to structural leaks.
Wind pressure, thermal pressure
TO merits Natural ventilation has low operating and capital costs.
Flaws natural ventilation: not used in rooms where there is a release of substances, does not carry out cleaning before release into the atmosphere.
Advantages of artificial ventilation over natural:
Possibility of supplying and removing air in any room
Possibility of supplying air with any temperature, humidity and mobility
Possibility of uniform operation all year round
Possibility of local suction devices
Possibility of cleaning the air removed from the room
Ventilation system is a set of devices for processing, transporting, supplying and removing air. Ventilation happens : Natural, Mechanical, Mixed.
Natural ventilation systems - simple devices, but their operation depends on unstable factors: temperature and air pressure, wind direction and speed. With natural ventilation, it is impossible to heat, cool, humidify, dry or purify the incoming air.
In the event of a disruption in the technological process or the operation of any equipment and the release of a large amount of harmful or explosive substances into the air, emergency ventilation is usually provided - general exhaust ventilation, not compensated by an appropriate air flow, creating rarefied air during its operation and preventing harmful substances from entering other rooms.
Mechanical ventilation- air is moved by fans.
Mechanical ventilation systems are divided into:
1) Flow-through (pump air)
2) Exhaust (remove air)
3) Combined
Based on the nature of room coverage, ventilation can be divided into:
1) General exchange. Provides air exchange throughout the entire room and serves to dilute emitted pollutants with a fresh air flow.
2) Local. It is used to remove air contaminants directly at the point of origin and prevents the penetration of harmful substances into the entire room.
3) Combined systems. Used when there is a significant release of harmful substances into the air.
Advantages mechanical ventilation: pre-treatment of air is carried out, the possibility of supplying and extracting air at any point in the room, the possibility of air purification. Flaws: high operating and capital costs.
When designing, the requirements of SNiP 2.04.05-91 “Heating, ventilation and air conditioning” and GOST 12.4.021-75 SSBT Ventilation systems are taken into account. General requirements.
General ventilation is: supply, exhaust and supply and exhaust.
Local ventilation is: supply and exhaust.
Supply ventilation diagram
1 – air intake device; 2 – air duct; 3 – filter; 4 – heater; 5 – fan; 6 – supply nozzles.
Forced ventilation is used in industries with significant heat generation and low intensity of release of harmful substances, provided that the incoming fresh air ensures the dilution of harmful substances to an acceptable concentration.
Exhaust ventilation diagram
1 – Exhaust nozzles; 2 – fan; 3 – Cleaning device; 4 – Deflector.
Local exhaust ventilation is used to remove harmful substances directly at the site of their formation. It is more economical and efficient.
General exhaust ventilation can be used:
In the presence of minor leaks of harmful gases and vapors from closed equipment where it is impossible to equip local suction systems
Excess moisture and heat
Removing dust.
Types of local exhaust ventilation:
Completely closed enclosures covering sources of harmful substances.
Receivers that conceal sources of harmful substances, but have working windows for maintenance
Receptacles that partially conceal sources of harmful emissions from the production environment
Open air intakes, which are suction outlets of one design or another, close to the source of harmful substances.
