The ventilation includes ducts with a set of fasteners through which the exhaust air circulates. The exhaust pipe in the kitchen is connected to the dome, where fat is drawn, fumes from boiling, carbon dioxide. The design delays combustion products, prevents them from spreading to other premises of the housing and accumulate in the form of soot on the walls and ceiling.
The importance of kitchen exhaust pipes and applications
The pipeline is installed as part of a flow or circulation ventilation system. The first scheme is used in the kitchen, which completely removes dirty streams and does not reuse them after partial processing. For high-quality air purification, only openings in the channel riser are not enough, therefore ventilation pipes for gas extracts are used.
Advantages and disadvantages
The advantages include the fact that the pipe connects the dome hood with the entrance of the ventilation shaft and unpleasant odors in the air do not go to other rooms of the apartment. The walls of the collector are made of strong and durable material that resists high temperatures and the action of chemicals.
The disadvantage is the bulkiness and the need to seal with decorative panels, so as not to spoil the interior. Poor installation leads to increased noise from the fan. Pipelines require external and internal cleaning.
Difference from ventilation
A cooker hood differs from natural airing in that it removes contaminated air in a forced way and is independent of atmospheric and weather conditions. The pipe under the hood to the kitchen is not similar to general exchange ventilation in that the design removes the spent masses from a separate place, and does not provide general air exchange in all rooms.
The hood is not allowed to be installed in the kitchen if there is a geyser or a boiler with an open firebox in this room. Using the hood may cause the draft in the chimney to tip over if forced draft is not provided.
The main types of ducts and their characteristics
The regularity of cleaning the pipeline and its appearance depends on the material of manufacture. On the inner surface of the channel regularly aggressive substances in the composition of the air, which destroy the walls. The high temperature of the exhaust gases, steam and condensate also have a negative effect.
Plastic
PVC duct is a rigid pipe having a round or rectangular cross-sectional shape. The dimensions of the plastic pipe for the kitchen hood are determined by the calculation method according to the formulas, depending on the number of burners, the distance to the shaft.
Positive aspects of the use of plastic pipes:
- a smooth surface inside and out facilitates the cleaning of soot and grease;
- when the turbine is working, vibration noise is damped;
- combined with most finishing materials;
- Durable elements resist condensation and the action of heated steam.
The disadvantages include the need to purchase additional adapters and rotary elements.
On sale there are pipes made of polyvinyl chloride, polyurethane, polyethylene.
Corrugated aluminum
This type of pipe is made of semi-rigid aluminum fabric, which is compressed in the form of an accordion. The collector can be stretched to the required size due to this wall design.
Advantages of aluminum corrugation:
- Elements are installed simply, connectors and adapters are not used, because the pipe bends at an angle, the boxes are connected with clamps, cut with scissors;
- easy to disassemble and reassemble;
- soft bends of the pipeline do not create an additional obstacle to the air flow;
- Do not burn and do not melt.
The disadvantage of a corrugated pipe is the presence of folds on the inner surface, in which soot and grease are collected. After stretching, the element cannot be returned to its previous length. The pipeline has a less aesthetic appearance than PVC.
Metal
Before the appearance of plastic collectors, pipes for kitchen hoods were made of galvanized steel or stainless steel. Products are used now, but are placed in industrial premises or public institutions. Boxes are lightweight, durable and resistant to thermal effects. Sometimes, the surface is powder coated.
The thickness of the walls of the collector depends on the size of the cross section and is prescribed in SNiP. The segments are joined by flange connections or adapters of various shapes are used. Rectangular ducts are easily embedded in the design of a false ceiling.
By degree of flexibility for hoods
Flexible options include corrugated piping. If the ventilation shaft is located near the hearth, there is no need for a complex structure. Otherwise, there are stationary branches, tees or corner elements for the plastic line.
Sometimes the main line for connecting the cooker hood and ventilation riser is made of a mixed design. Instead of hard corners, flexible sections made of polyurethane or corrugated aluminum are placed so as not to add value to the pipeline.
Selection tips
The diameter of the exhaust fitting is the size that is taken into account when installing the pipe in the hole of the mine channel. Depending on this, a section of the box is selected. The dimensions of the pipe depend on the shape of the duct, internal resistance, duct material.
The dimensions of the ventilation pipeline are calculated by specialists, you can apply the formulas yourself, but it is difficult to take into account all the existing nuances.
Dimensions and Cross Section
Ideally, the outlet to the shaft should have the same cross-sectional area as the similar pipe size. Incorrect diameter negatively affects the quality of work. Narrowing the line leads to an increase in internal pressure, resulting in increased noise and vibration.
If the exhaust pipe has a large diameter, the pressure rate decreases, the output of the combustion products is less effective. Upflows are not completely captured and partly transferred to the atmosphere of the room.
Diameter and shape
Round ducts are less resistant than square and rectangular ducts, therefore they are used more often. In rectangular boxes, a certain obstacle to the flow in the form of angular cavities is created.
For round pipes, a diameter of 80 - 100 mm is used, the running dimensions of rectangular collectors are 100 x 50 or 150 x 80 mm. The hood's efficiency is reduced if a large number of turns are used, so it is better to install the stove near the opening of the channel shaft.
Mounting the exhaust pipe in the kitchen
When laying, the trajectory of the highway and its length, which is not recommended to be made more than three meters, are taken into account. The hood and duct are not placed in front of the ventilation hole in the ceiling or wall. Each extra meter of length, as well as rotation at an angle of 90 °, reduces efficiency by 5 - 10%.
Do not bend the pipeline at an acute angle, because this will lead to the operation of the hood in overload mode.The exhaust pipe overlaps the opening of the ventilation shaft, so you need to take care of the organization of natural ventilation of the entire kitchen space.
Pipe Outlet Options
The highway from the hood to the entrance to the ventilation riser does not always fit organically into the interior of the kitchen, so decorative masking is used. Most often, not only the pipe, but also the dome itself hides in an artificial box. For his device, you need a frame made of metal profiled elements, which is sheathed with the appropriate finish.
In the second version, pipes from the hood are placed even before the walls and ceiling are finished, therefore they are closed with plastic, wood panels or drywall at the same time as other surfaces and look like a whole. The disadvantage is that such structures cannot be cleaned without dismantling the finish.
Single entry
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 total air from the room. Sometimes you can slightly expand the size of the hole, if the design allows.
The hood hood sucks the spent mass only in a certain place above the gas stove. Even the large power of the equipment does not allow to remove air from remote areas of the kitchen. Room ventilation with an exhaust hood is not standardized in the relevant documents.
A double grille is placed on the ventilation hole, where the pipe is discharged and a check valve is placed or another fan is mounted. Electricity is connected so that it is possible to switch between the two air intake openings.
With two inputs
This option is rarely the case in the standard kitchens of a multi-storey building. The wall provides two ventilation ducts (in addition to the bathroom), which are not connected to each other. If they are discharged into one riser, during operation of the hood, the phenomenon of reverse traction occurs.
The problem is solved if, when the dome is turned on, open the window in the kitchen so that the volume of air taken in matches the incoming air and there is no vacuum. The second option is to install a check valve in the hole of the second channel, which will only work on the output of air flows.
To the street
Often, due to the small size, it is not possible to make two functioning channels in one ventilation outlet for separate gas extraction and removal of the total mass of air. There is an option to remove the pipe from the hood through the wall to the street, and provide the shaft hole with a standard ventilation grill.
Usually the vertical fence in the multi-apartment sector has a thickness of two and a half bricks (510 mm), therefore, specialists with the appropriate drilling tools are invited to work. The exit from the wall is closed on the outside with a grill so that the birds do not penetrate. A check valve is installed to prevent the cold from drawing in when the hood is not working.
