How to choose an air duct for hood
The most optimal design that provides the output of wet air, a variety of fumes and smells from the room, is an exhaust ventilation system of a forced type. This option is very often used in apartment buildings.
The exhaust output can be connected to the general system of channels or release it immediately to the street, if such manipulations allow you to do walls in the kitchen. The hood consists of two main parts: the fan and duct.
On the second it is worth stopping in more detail. There are many different types that differ from each other in material used for manufacture, sizes and other technical parameters. As a result, it is worth considering the answers to the question “How to choose an air duct for hoods“.
What is the difference between the hood from ventilation
According to generally accepted sanitary standards in our state, each dwelling should be equipped with a ventilation system. Special channels are placed inside the walls, in places where unpleasant factors for human life are most common. Smells, humidity, water, etc.D All this is in large quantities in the kitchen and in the bathrooms, respectively, the ventilation ducts are located there.
The main difference between the hood and the general ventilation system is that the first provides forced ventilation, thereby improving the process of natural air circulation. Hood is a mechanical device that can be turned off and turned off as necessary.
Pipe output options
The highway from the hood to the entrance to the ventilation riser does not always organically fit into the interior of the kitchen, so decorative masking is used. Most often, not only the pipe is hidden in the artificial box, but also the dome itself. For its device, you will need a frame of metal profiled elements, which is sheathed with the corresponding finish.
In the second version of the pipe from the hoods, they are placed even before the walls and ceiling, therefore are closed with plastic, wooden panels or drywall simultaneously with other surfaces and look like a whole. The disadvantage is that such designs cannot be cleaned without dismantling the finish.
With one entrance
In the presence of one channel, it is divided for hoods and general ventilation
If the kitchen has only one ventilation hole leading to the wall shaft, you need to divide it for the pipe from the hood and remove the common air from the room. Sometimes you can slightly expand the size of the hole, if the design allows.
The dome of the hood sucks the spent masses only in a certain place above the gas stove. Even the high power of the equipment does not allow air to remove air from remote sections of the kitchen. Ventilation of the room using an exhaust umbrella is not normalized in the relevant documents.
A double grate is placed on the ventilation hole, where the pipe is displayed and the check valve is placed or another fan is mounted. Electricity is connected so that there is the possibility of switching between two air fence holes.
With two inputs
Several ventilation ducts are equipped in a private house
This option is rare in standard kitchens of a multi.storey building. The wall provides for two ventilation ducts (in addition to the bathroom), which are not connected to each other. If they are displayed in one riser, during the operation of the hood there is a reverse traction phenomenon.
The problem is solved if during the inclusion of the dome to open the window in the kitchen so that the volume of the air taken corresponds to the incoming and there is no vacuum. The second option is the installation in the opening of the second check valve channel, which will only work on the output of air flows.
Often, due to small sizes, it is not possible to make two functioning channels in one ventilation output for separate gases stretching and removing the total mass of air. There is an option to remove the pipe from the hood through the wall to the street, and supply the mine opening with a standard grate for ventilation.
Typically, a vertical fence in an apartment sector has a thickness of two and a half brick (510 mm), therefore, specialists with the corresponding drill tools are invited to work. The exit from the wall is closed from the outside with a grill so that the birds do not penetrate. A check valve is put to prevent the cold, when the hood does not work.
Flexible and hard products
There are many different types of ducts for hoods in the kitchen. For example, all products can be classified according to the materials from which they are made. The final cost of products, as well as its operational characteristics, directly depends on this quality. However, this is far from the only factor by which the air supply is divided.
All types of structures are divided into 2 types:
- Flexible. can be placed at different angles. If necessary, it is permissible to compress or stretch them (of course, within a reasonable one). However, it should be borne in mind that the weakly elongated duct is much better resisting air flows. This helps to reduce the effectiveness of the ventilation system as a whole. Similar designs are often made from aluminum. The main disadvantage is that experts do not advise making a corrugated fabric more than 3 m long. This is due to the fact that each extra meter will reduce the performance of the system by 10%.
- Strong constructions are characterized by simplicity of assembly. In addition, the inner surface of such products is smooth and even. The price of these models is much higher, but their positive properties justify the cost.
Description and installation of built.in hood in a kitchen cabinet
Material. Speaking of a metal duct, most often they mean aluminum corrugation. This flexible pipe is also plastic, but due to the cheapness, the aluminum. It is made of multi.layer foil, folded by accordion. Inside has a frame. rings made of steel wire.
Diameter. In the cross section of the corrugation, only round. The greatest demand are the following diameters: 100, 120, 125, 150 mm.
Resistance. At least at the time of installation, the corrugation is stretched, the grooves still delay the air a little. It moves faster on the smooth surface.
Exploitation. Working temperature. 300 and above. Corrosion rod corrosion, but requires periodic cleaning. Fat sticks on the ribbed inner surface, soot.
Noise level. Air “clings” to the rings inside the pipe. This makes her vibrate, creating a noise. Therefore, the metal duct works louder than a plastic.
Assembly. Installation passes very quickly: it is simply stretched over long distances. A flexible sleeve is able to lengthen 4.5 times. Turning the duct in any direction is easy, which means that M-shaped adapters do not need. Corrugation “adapts” to any configuration of furniture and ledges on the walls.
Appearance. A flexible metal duct is not as beautiful as a plastic.
Options for the output of the duct
With two inputs
Not a very common option. When there are two separate openings in the wall in the exhaust channel-everything. They take the pipe into one, and the other remains for natural ventilation. However, during the operation of an exhaust umbrella, a nuisance may occur. reverse traction. Wonderful ventilation suddenly begins to work in the opposite direction, filling the kitchen with unpleasant odors. Consider why it happens and what to do.
If there is no hood in the house, but there is only a ventilation duct, the air should still change. This is how natural ventilation works. Warm air in the room is less dense than cold air on the street. Less dense. it means light. He rises and goes into the ventilation shaft.
Fresh air should come from the cracks in the windows and doors to the kitchen. When designing houses, it was assumed that this is how ventilation would be carried out. Today, almost everyone has sealed plastic windows and doors with seals that violate the principles of ventilation. Ideally, if double.glazed windows do not provide an air flow, the situation should be corrected by supply valves. They are installed in a plastic window or wall next to them.
If you install a kitchen hood, the situation will be complicated. Modern hoods are very powerful. During their work, all the air from a small kitchen climbs very quickly. Suppose she “took” 1000 cubic meters of air in an hour. Tightly closed windows do not let air out of the street. Then the ventilation begins to serve a spent, unpleasantly smelling air to the kitchen.
In order to prevent reverse traction, when turning on the hood, open the windows or install the check valve in the second ventilation hole. When turning it off, the valve will be closed without letting the dirty air into the kitchen.
With one entrance
Most often, the kitchen wall has only one window in ventilation. Above was told about the features of different pipes for hoods to the kitchen. This implied this particular, the most common option.
Kitchen hood installation #diy #shorts
If the ventilation hole is one, in no case should you completely close it with an air duct. Many people think: since there is a kitchen hood, it means that ventilation goes through high quality. In fact, an exhaust umbrella is not mentioned in regulatory documents. Ventilation ventilations, on the contrary, are required when designing buildings. If the hood with its duct blocks the entrance to the ventilation shaft, then ventilation in the kitchen is impossible.
No matter how powerful there is an exhaust umbrella, it is not able to absorb air, which is far away, for example, under the ceiling or near the opposite wall. Remove the air mass at a distance of a larger in the input. Thus, it “works” only with air over the stove. The rest should go through the exhaust channel.
The optimal solution is to install a special lattice on the ventilation hole. It differs from the usual one in that it consists of two parts: holes for the air duct and grate for natural ventilation. In addition, you need a check valve.
Unfortunately, the size of the entrance to the ventilation shaft is often modest: 130 x 130 mm. If you give most of the holes under the duct, there will be very little space for natural ventilation. Therefore, the ideal option is to remove the extract of the hoods out into the street, and leave the window into the ventilation in the ventilator with a regular grille.
Cannot cope with this work on your own. you need to invite specialists. They make a hole in the wall with diamond drill, install a pipe and a protective deflector. This device, which enhances traction and protects the duct from precipitation, the formation of ice crust. The deflector also has a valve that closes and does not let in cold air.
Pipe decoration methods from hood
Often, when installing an air channel for the hood, a decision is made to decorate the duct so as not to violate the overall interior in the kitchen.
There are several ways for this:
- Gypsum cardboard box. Here, the crate is installed around the channel, then plasterboard slabs are attached to it. In the future, the box is deprived of the overall interior. This method well eliminates the problem of aesthetics, but it is inconvenient if you need to open the pipe for any reason.
- The housing is plastic. Specialized boxes are sold in stores for decorating a corrugated duct. Such a decor is the simplest analogue of a drywall box.
- Installation above the stretch ceiling. When such a decision is made, the air channel is mounted from the hood up and hides among the ceiling structures. Part of the duct from the hood to the ceiling is covered with a facing plate or remains undisguised, at the discretion of the owner. The disadvantage of this option is that the pipe can only be carried out before the repair. That is, after tensioning the ceilings, hiding the duct with this method will be impossible. As well as in the case of the preventive repair of the channel, first you will have to disassemble the hinged ceiling.
- Installation of a single kit. In this case, you need to order or make with your own hands a hinged cabinet for the size of the hood to the ceiling. It will hide in it and a device for the removal of carbon monoxide and the duct. The disadvantage of such a decor is that the place is hidden for all sorts of kitchen accessories.
- A canopy on the cabinet. The previous method is used here, only in the budget version. The hinged cabinet is made or ordered not to the ceiling, then a decorative panel is installed on it for the overall interior in the kitchen. This method hides a pipe going up from the hood to the opening of the ventilation well.
- Installation of the duct next to the wall above the hinged kitchen set. In this case, usually the cabinets are hung quite high, and then the channel above them will not be visible.
- Painting. This method is the cheapest and simple option, for which you just need to paint the pipe in the tone of the interior.
Installation of the duct from the hood in the kitchen
After the hood is hanged at a certain height (70 or 80 cm, depending on the stove), the air duct desired in diameter has been purchased, it is necessary to install it correctly. Installation of a plastic and corrugated duct in the kitchen can be done with your own hands.
Consider step by step the entire algorithm of actions:
Step out the path of installing the pipe, and find out the distance of any straight section. Keep in mind the laying of horizontal elements above the cabinets. If it is decided to communicate with a corrugated pipe, then you need to find out its entire length.
Step to put the duct on the pipe of the exhaust device, for this, preliminarily enter the end of the pipe through the technological hole in the hood case. If the corrugation is carried out, then the pipe is pulled together by a clamp.
A step prepared along a certain length of the segments from plastic pipes, combine with the help of couplings and discharge.
Step mount a special grille with a nozzle in the opening of the ventilation canal, for which they need to be pre.purchased in the store.
Step connect the pipe to the pipe, check the reliability of the connected network, as well as accuracy in the horizontal and vertical plane. With a horizontal, it is desirable to observe a small slope towards the hood.
The step is to make the final assembly if the pipes are collected without cuffs: to disconnect the elements of the pipes, smear their ends with a silicone sealant and collect again.
The step of the air duct, walking horizontally along the wall, must be fixed with special clamps at a distance of 1 m, and in the corrugation after 0.5 meters. This is done in order to avoid sagging.
Step check the traction. To do this, put a pot of water on the stove with an open lid, turn on the hood. After boiling, all evaporation should go up.
In the case when an extract with a powerful fan is mounted in the kitchen, and the valve is not provided in it, reverse traction from the ventilation well may occur. This applies to hoods with a performance of more than 650-750 m³ per hour. To prevent this from happening, you need to install the check valve on the horizontal section in the air duct in front of the ventilation well. If the duct is installed in a private house, then such a device crashes outside.
In the ventilation system, ducts are an integral part, and they also need a preventive examination. During operation, sealing may be disturbed or reduced due to adhesive deposits. Therefore, it is necessary to monitor the technical condition. And then there will be no trouble in the kitchen due to extraneous smells, which means that there will always be a comfortable atmosphere.
Some features of the installation of corrugated tube
Installation of corrugated pipe in the kitchen does not require special skills. All work can be done independently. However, in order for the system to function for a long time and efficiently, when installing, you need to take into account several important points.
Best Ventilation Hoods for Professional Ranges for 2022
- If it was not possible to pick up the diameter of the corrugation for the hood, the product with a large size connects through a special adapter is used. For a kitchen hood, this will be only a plus: with an increase in size, the air flow rate decreases, which means that the noise will decrease.
- Before installing the corrugation on the ventilation hole, a special site is installed with a lattice, flange and check valve. It is used in order not to completely overlap the hood of the pipe. The grate serves for natural ventilation, the flange for forced. Then the air in the kitchen will be constantly updated regardless of whether forced traction works or not.
- If the kitchen has a second ventilation hole, you can connect the pipe to the flange without a grille.
To fix the corrugation, special mounts are used. metal or plastic clamps. Do not plant a pipe on glue or sealant, this will create unnecessary problems if it is necessary to disassemble the duct for cleaning.
- Each turn at an acute angle reduces the performance of the system by 10 %. The installation of the hood should be made in maximum proximity to the ventilation hole.
- Before installing the corrugation, it is advisable to clean the ventilation in the apartment. You also need to check the presence of traction. For this, a sheet of paper is applied to the hole. If he holds himself, without the help of hands, then there is a craving.
Attention! Reverse traction can significantly reduce the effectiveness of the entire system as a whole.
- It is important to choose the optimal performance of the hood for the kitchen. It is easy to check it using an anemometer, which is installed at the base of the pipe.
- The pipe and the exhaust device must match the size and cross.section. Otherwise, you will have to use an adapter.
Is it always possible to install hood?
It is prohibited to connect the duct tightly to the duct. On the way to the exit, the air should overcome obstacles from an oily grid, motor and turbine. In addition, the air fence is not under the ceiling, as it should be, but from the level of the hood. All this makes ventilation ineffective, especially in the summer, when the thrust is weak. In addition, a complete blocking of total ventilation can lead to the accumulation of natural gas in case of a malfunction of gas equipment and cause an explosion.
Therefore, air ducts for hoods are mounted in special ventilation grilles with a check valve. There is a hole for the duct in such a grate on top, and from below there are slots for ventilation. When the exhaust is turned off, the air passes freely through the holes and the duct. During the operation of the device, the valve does not allow the designed air to return to the kitchen. The check valve can be in the form:
It must be installed vertically at an angle of 2 degrees. In this case, the valve opens under the influence of its own severity, although it does not protect 100 % of the reverse entry of dust.
It rarely happens that there is no ventilation shaft in the house, there is no entrance hole in the right room. Or in old houses, natural ventilation is greatly disturbed, and the stretched air from the kitchen enters the neighbors. For such cases, recirculation hoods are suitable. The principle of their work: they take air out of the kitchen, pass it through filters (coal, fat) and return back. The disadvantage of such a system is the need to constantly change filters. It turns out expensive and uncomfortable. In addition, such hoods do not solve the problem of high humidity in the room.
Types of air ducts for hoods. Advantages and disadvantages
The duct to the hood can be attached flexible or stiff. The most popular models are made of plastic and aluminum. The choice of the buyer also depends on the financial capabilities and the general style of the kitchen.
Plastic air ducts for hoods
They have a neat appearance, fit into almost any interior of the kitchen. Even surfaces are less contaminated and easier to clean, do not rust. Less noise is created when air passes through the pipe. Since this is a hard product, a more accurate calculation of the size is required. When installing a duct made of plastic for a kitchen hood, it is necessary to use adapters and connecting elements. Turns are more sharp than that of flexible products. Costs more.
Plastic is not as resistant to high temperatures as metal. If necessary, it can be covered with moisture resistant and heat.resistant paint to the tone of kitchen furniture. There are:
- Round. in this case, no adapter is needed to join the hood;
- Rectangular air ducts. It is convenient to carry them along the wall above the kitchen furniture. You can collect the design of any trajectory. One of the options of rectangular are flat ducts that occupy very little space and are almost invisible.
Possible transitions from round products to rectangular and vice versa.
Corrugation is made of different materials: aluminum, steel, plastic. The most common is the corrugation of aluminum. This metal is light, withstands high temperatures. The corrugation should be installed in the most stretched state. Then there will be less resistance to the passing air, below the noise level. True, stretching, it can no longer be squeezed back. It is easily deformed, so accuracy is needed when installing it.
The duct made of aluminum is a flexible design, it is simply installed, it costs cheaper. Installation is carried out using clamps: it joins the hood for the umbrella flange, to the ventilation pipe behind bars with a check valve. The joints are treated with sealant (silicone) or strengthened with aluminum tape. You can not use superclly.
The appearance is not very attractive, so the corrugation is often masked. Special finished boxes of polyvinyl chloride, aluminum, stainless steel or wood are installed on top. The choice depends on the interior of the kitchen. Some ducts are immediately sold complete with casings. Make a design from drywall. It is putty, primed and painted in the desired color. Simultaneously install local lighting. Built.in air ducts are carried out inside the kitchen cabinet. If the installation of the exhaust system is carried out at the repair stage in the kitchen, you can hide it behind the stretch ceiling.
Disadvantages of such an air duct: above the noise level, soot, dirt, butter are delayed in the folds of the corrugation. Aluminum is characterized by good thermal conductivity, so sometimes condensate can accumulate in the kitchen.
Steel air ducts are smooth, durable, not deformed and resistant to high temperatures. They are inexpensive. There are galvanized options and stainless steel ducts. Of the shortcomings, it is necessary to note a large weight of the structure, which requires reliable fixation to the walls, special means are needed to seal. During the operation of the exhaust system, a lot of noise is created.
Calculation of the diameter of the duct
The diameter of the air duct must match the input diameter into the ventilation shaft. If the cross.sectional area of the duct is less than the ventilation duct, the efficiency of the extract is reduced.
Ventilation passages in buildings have a diameter of 14 cm, there are square, 13 13 cm in size or rectangular 10 15 cm. Their throughput is about 300. 400 cubic meters per hour. It makes no sense to put a more powerful hood, the effect of overturning traction may occur.
When choosing flexible products, it is recommended to make no more than 3 turns along the course. Also, you can not put several turns in a row without areas for acceleration of air. The total length of the duct per hood for the kitchen should not exceed 3 m. Otherwise, the resistance will greatly increase when passing air, and the efficiency of the entire system decline.
The instructions for the hood, as a rule, indicate the technical requirements for the duct, including the recommended diameter. Most hoods have an output diameter of 125 mm, less often. 100 mm. You can not make the diameter of the duct is much smaller than the diameter of the output pipe on the hood. This will lead to significant vibration and noise. The most common diameters 125, 150, 160, 200 mm.
The following parameters are suitable for rectangular ducts:
- Dimensions 110 55 mm are required for hoods with a power of up to 300 cubic meters per hour,
- 120 60 mm at a power of more than 350 cubic meters per hour,
- 204 60 mm for devices with a capacity of up to 1000 cubic meters per hour.
Types of air ducts according to the material of manufacture
Air ducts are made from various different materials. To do this, use:
- stainless, black or galvanized steel;
- aluminum foil on a spiral frame;
- Polymeric materials. plastic, structural heat.insulating plates based on polyisocyanurate (PIR);
- Textile materials.
Metal ducts are used most often, t.to. are universality, and most importantly, construction and design organizations are used to them, t.to. There are a large number of companies on the market offering ventilation equipment of this type. Steel ventilation pipes are indispensable if the ventilation system is operated in high pressure and temperatures.
Galled steel ducts are allowed to be used almost everywhere: in any climatic conditions and for any type of ventilation. The only restriction is that they cannot be used to transport aggressive gas-air mixtures. The protective layer of zinc on the inner and outer surface of the duct protects it from corrosion, and even in damaged places when interacting with oxygen, a protective film is formed.
Such ducts are made of cold.rolled galvanized sheet steel thick from 0.5 to 1.4 mm. They can be operated in conditions of relative humidity of air that does not contain impurities, up to 80% and at a temperature of not more than 80ºС.
Black steel ducts are the most rigid, heat and fireproof, but more prone to corrosion and therefore are used less often than from galvanized and stainless steel. Used in industry.
A duct made of stainless steel of the round section EVG L 1250/0.8
Stainless steel air ducts are universality and can be used to ventilation of almost any gases and under any conditions. They withstand high temperatures and are very durable, so in industries they more often install ventilation made of stainless steel. But stainless steel is very expensive.
So, steel ducts have the following advantages:
- They are durable, reliable and durable;
- Smooth inner surface provides them with good aerodynamics;
- Dirt, dust and soot almost do not accumulate on smooth walls;
- They are able to withstand high pressure and temperature (up to 500ºC);
- Stainless steel ducts can be used at objects with increased sanitary requirements, t.to. almost do not collect dirt;
- used in conditions of exposure to aggressive media.
They also have disadvantages. this is the bulky structure, as well as the fact that steel ducts laid through cold rooms, such as attic, require insulation. If it is not provided, then condensate will constantly collect the surface of the pipe, which can lead to corrosion and premature destruction of the structure.
The corrugated duct of aluminum belongs to the class of flexible ducts and has a number of advantages. It bends perfectly, it can even be tied to the knot, while the duct will retain its qualities. And thanks to the corrugations, such an air duct perfectly withstands linear stretching. In addition, aluminum corrugated ducts have slight weight, strength and high elasticity, which facilitates their installation. They are resistant to high temperatures. Corporal ducts are used in extensive ventilation systems. where the use of hard is difficult.
The obvious disadvantages of corrugated air ducts from aluminum include high aerodynamic resistance and, as a result, noise during ventilation, as well as a significant level of pressure loss due to a corrugated surface. In addition, they are subject to increased surface contamination during operation.
Why are air ducts needed and where they are used?
Air ducts are an obligatory element of any ventilation or air conditioning system. Their main task is the regulation and direction of air flows in the room.
The air ducts are used in the installation of any vendes and air conditioners: household, commercial, industrial. They are also bought to connect a kitchen hood, because it also removes contaminated air.
Galled peolets is used for mounting air ducts. With its help, these elements can be securely fixed on the wall or ceiling.
Design features and dimensions
Remember that when purchasing air ducts from PVC, you need to stock up on adapters that will be needed to connect a plastic pipe and hood. Also, adapters are used for bends of the duct and connecting to a common ventilation. If a corrugated product is used for hoods, then on adapters for bending the pipe you can save.
Important! PVC pipe length should not exceed 3 meters. Otherwise, the performance of the hood will fall with each additional meter.
Any bend also negatively affects the functionality of the hood. When installing an air duct in the kitchen, try to avoid angles of 90 degrees. This will overload the hood, which will significantly reduce the service life of the product.
It is allowed to make no more than 3 knees and bends.
The diameter of the plastic pipe is selected according to the cross.section of the ventilation hole. The dimensions of rectangular and square kitchen ducts from PVC are standard. The following values are more often used: 110 × 55, 120 × 60 and 204 × 60 mm. The dimensions of round plastic pipes vary from 110 to 150 mm in diameter.
You can purchase these products in almost every construction store. It is worth noting that the price of flexible ducts is slightly higher than for flat PVC channels.
The most practical and convenient pipes in installation are corrugated. They are cut into pieces of the desired size and are connected to the elements of the hood and the ventilation shaft in the kitchen. It is recommended to replace the standard ventilation lattice with a special. with a mounted connecting nozzle. Squiring clamps are used as fasteners. For greater reliability, the joints are treated with sealant.
note! Corrugated pipes are installed in the most stretched position. This approach provides nominal throughput of kitchen ventilation.
Smooth PVC air ducts are mounted according to the same scheme. The pipe is cut with a hacksaw for metal into pieces of the desired size and attached to the elements of the hood with adapters. The pipe should delve into the pipe by about 50 millimeters. The mounting places are treated with silicone.
Advice! The installation of the hood is performed taking into account the direction of air movement. Otherwise, the service life of the product from the PVC will significantly decrease.
If you have installed a powerful hood, the reverse traction effect may appear. In other words, in the kitchen there will be aromas from the overall ventilation shaft. This applies to powerful models whose performance is about 600-700 cubic meters of air per hour. To avoid such a phenomenon, it is recommended to install a check valve. These devices can be made in two versions:
The valve must be installed vertically, otherwise it will work under its own weight.
You can do it differently: take the hood directly to the street. To do this, a hole of the desired diameter is made in the wall of the house. You should know that before the start of such work it is necessary to obtain permission in the housing and communal services and BTI.
To avoid such difficulties, it is recommended to consult the seller about the power of the hood and correlate these parameters with the area of the kitchen room. For the needs of an average family living in a typical high.rise building, a low.power hood is enough.
Why measure air speed
For ventilation and air conditioning systems, one of the most important factors is the state of supplied air. That is, its characteristics.
The main parameters of the air flow include:
- air temperature;
- air humidity;
- consumption of the amount of air;
- flow rate;
- pressure in the duct;
- other factors (pollution, dusting).
SNiPs and GOSTs describe normalized indicators for each of the parameters. Depending on the project, the value of these indicators may change within the framework of permissible norms.
The speed in the air duct is not strictly regulated by regulatory documents, but in the directories of the designers you can find the recommended value of this parameter. Find out how to calculate the speed in the duct, and get acquainted with its acceptable values, you can read this article.
For example, for civilian buildings, the recommended speed of air movement through the main ventilation channels lies in the range of 5-6 m/s. A correctly executed aerodynamic calculation will solve the problem of air supply with the required speed.
But in order to constantly observe this speed mode, it is necessary to control the speed of air movement from time to time. Why? After some time, air ducts, ventilation ducts are contaminated, the equipment can fail, the joints of the ducts are depressurized. Also, measurements must be carried out with planned checks, cleaning, repairs, in general, when servicing ventilation. In addition, they also measure the speed of flue gases and others.
Recommended air exchange speed standards
During the preparation of the project, the building performs the calculation of each individual site. In production, this is a workshop, in residential buildings. apartments, in a private house. poetry blocks or individual rooms. Before installing the ventilation system, it is known what the routes and dimensions of the main highways, what geometry the ventilation ducts are needed, what size of the pipes is optimal.
Do not be surprised at the overall dimensions of the ducts in catering establishments or other institutions. they are designed to withdraw a large amount of air used
Calculations related to the movement of air flows inside residential and industrial buildings are classified as the most complex, so experienced qualified specialists are required to engage in them.
The recommended air speed in the ducts is indicated in the SNiP. regulatory state documentation, and when designing or passing objects, they are guided precisely on it.
The table indicates the parameters that should be adhere to when the ventilation system is arranged. The numbers indicate the speed of movement of air masses to the places of installation of channels and gratings in generally accepted units. m/s
It is believed that indoors should not exceed an indicator of 0.3 m/s.
Exceptions are temporary technical circumstances (for example, repair work, installation of construction equipment, etc.), during which the parameters can exceed the standards by a maximum of 30 %.
In large in volume of rooms (garages, production workshops, warehouses, hangars) often, instead of one ventilation system, two.
The load is divided in half, therefore, the air speed is selected so that it provides 50 % of the total calculated volume of air movement (the removal of polluted or the supply of clean).
If force majeure occurs, there is a need to sharply change the air speed or complete suspension of the ventilation system.
For example, according to fire safety requirements, the speed of the air is reduced to a minimum in order to prevent the distribution of fire and smoke in neighboring rooms during fire.
For this purpose, cutters and valves are mounted in air ducts and in transition areas.