If fresh air in the room can be provided with ventilation, then ventilation is required to exhaust the exhaust gas. Residential and industrial buildings are not complete without ventilation ducts. In houses with stove and boiler heating, chimney channels are also required, since the volume of exhaust air here is much higher. You can arrange the ventilation yourself: laying brick ventilation ducts or a pipe structure is not so complicated.
The need for arrangement of smoke and ventilation ducts
Full-fledged ventilation is air circulation, during which enough fresh air enters the room and exhaust masses are removed.
In modern homes, it is becoming increasingly complex. This is due to the equipment of the apartments with plastic windows. Sealed structures reduce heat loss and protect against noise, but inhibit microcirculation. As a result, natural exhaust does not cope with air exchange. The house has to be equipped with additional ventilation ducts or forced ventilation.
For stove or boiler heating, separate chimney channels are needed that serve only the heating unit. It takes 10 cubic meters of oxygen to burn 1 cubic meter of natural gas. It is impossible to take such a mass of air from the room. The supply of oxygen and the removal of combustion products provide chimneys.
Requirements and Norms
A number of documents regulate the construction of ventilation and chimney channels: SNiP “Heating, ventilation and air conditioning”, SNiP “Gas supply”, “Safety rules in the gas industry” and many others.
Based on these documents, a building ventilation project is being developed. Calculations are made taking into account the amount of necessary air exchange. For a living room, 3 cubic meters of air per 1 hour per 1 square meter is enough. m square. For bathrooms, this value is much higher - up to 25 cubic meters. For the kitchen, at least 60 cubic meters are required. m. per hour, and if the gas stove is working - 100. Cooking in the kitchen with metal-plastic windows is possible only if there is a hood, since it is very difficult to arrange such powerful natural ventilation.
Requirements for ventilation ducts:
- The smaller the horizontal parts, the more efficient the ventilation. If compulsory settles in, horizontal fragments can be quite long, turns are allowed.
- A circular section is more effective than a rectangular one. It is preferable to use pipes with a minimum diameter of 120 mm.
- Ventilation openings should be placed at a distance of no more than 10 cm from the ceiling.
- The minimum length of ventilation ducts made of heat-resistant brick is 12.5 cm - half the usual brick.
- The height of the shaft head depends on the distance to the ridge.
Chimney channels impose additional requirements. The combustion temperature of the fuel is very different. In addition, firewood, coal, even gas often do not completely burn out, with the release of aggressive acid residues. This is taken into account when choosing.
- The chimney duct must be absolutely hermetic and not in contact with the air of the room through which it passes.
- The design should be strictly vertical.
- The chimney material must withstand the combustion temperature of the fuel and the action of aggressive substances.
Ventilation and chimney ducts need to be cleaned periodically, when developing the project this requirement is taken into account.
Technical features of channel laying
The construction of the channels is carried out in accordance with the rules of SNiP:
- The construction of air ducts of any type without an approved project is strictly prohibited.
- Masonry of both smoke and ventilation ducts is prohibited. They are equipped separately.
- It is recommended to mount the ventilation duct parallel to the chimney. Combustion products heat the air in the ventilation duct, which improves traction.
- Masonry depends on the thickness of the wall. With a value of 380 mm, the masonry is single-row, with a thickness of 640 mm - double-row.
The dimensions and nature of the masonry depend on the power of the heating system, the area of the room, the purpose of the building. This is important when building a brick channel: after all, its parameters depend on the parameters of the brick.
System Design Options
Ventilation ducts in a private house made of brick can have a different device. Choose a design taking into account the characteristics of the rooms and one common feature for the hood. Together with the exhaust air, heat is also removed. To prevent cooling, a brick ladder will be included in the ventilation system. It creates a barrier and prevents premature removal of heated air: after a delay, the air stream manages to partially transfer heat to the room.
Findings from the premises
This design is used to equip complex ventilation. In the upper part of the building, all channels are combined into a common shaft and led out through the roof, like a chimney. Its height and diameter depend on the volume of the premises and the distance to the roof ridge.
Wall pipe
The air duct is arranged right in the inner wall. Mount ventilation ducts, and even more so chimney wall pipes in the outer walls is allowed only in exceptional cases. The wall is in contact with the cold outside air. In this case, the exhaust gas, passing through the duct, cools faster and does not warm the room properly. For the same reason, condensate quickly forms inside the chimney or ventilation duct. This reduces traction and accelerates wear, since acid anhydrides are deposited on the walls of the mine. The wall pipe in the outer wall must be additionally insulated.
A separate chimney is installed for each furnace. In exceptional cases, equip 1 chimney for 2 furnaces. The ventilation duct is mounted for every 2 chimneys.
The chimney riser ends on the upper floor and turns into a regular chimney. The height of the chimney and the head of the ventilation duct depends on the outlet.
Root pipe
It is usually equipped in wooden buildings. They build a brick chimney on their own foundation, and the latter does not adjoin the foundation of the building. The wall thickness is equal to half a brick.
The root tube can be connected to two foci. For this, flip sleeves are installed.
Nozzle pipe
It is built directly on the stove. Experts recommend placing a brick chimney not directly on the neck of the furnace, but laying on it a preliminary plate of reinforced concrete with holes. This device allows you to further repair the furnace without dismantling the chimney.
Materials for smoke and ventilation ducts
The air ducts are under considerable pressure. Hot air comes out through the mine. When in contact with cold outside air, the gas inside cools quickly. Since its humidity is much higher, condensate is deposited on the walls of the channel. In this case, the difference between the temperature inside the ventilation duct or chimney and the temperature outside becomes even greater.
Under-exhausted combustion products, acid anhydrides and oxides are removed with the exhaust gas. When condensate appears, they turn into acids and destroy the material of the walls. So the latter must be resistant to temperature and the action of acids.
Brick
Brick Ventschacht - a traditional solution. Ventilation and chimney ducts of any kind are constructed from building stone. When arranging, the following rules are followed:
- Not every brick is resistant to temperature. For chimney channels, only full-bodied ceramic is taken. Silicate and hollow temperature does not withstand and is unstable to the action of acids.
- The shaft section is rectangular, which reduces traction. It is necessary to accurately calculate the height of the pipe.
- The inner surface of the duct is carefully leveled. The smoother the surface, the less soot, soot, sulfur oxide is deposited on it.
- Tightness is a prerequisite. This is also true for ventilation, since with cracks, bumps, good traction can not be achieved.
The laying of brick ventilation ducts and chimneys is paid at high prices compared with the construction of a partition.
Prefabricated single-loop galvanized and steel systems
With high ceilings, removal by wall pipes is not possible. It is also almost impossible to draw up an effective general ventilation scheme if the building is intended for rental, as each owner has his own needs. In this case, single-circuit systems are mounted.
The design is assembled from metal pipes and elbows. Airtight connection - to the lock or screw connections. There are pipes of round and square cross-section. The former are taken for a chimney, the latter for ventilation, where the traction does not matter.
There are several limitations:
- The smoke channel can include only 1 elbow - when leaving the furnace or boiler.
- The pipe is very hot. It can be laid in a brick or stone wall, but not in a wooden one. If the pipe is not hidden, it is thermally insulated to prevent fire.
- Galvanized steel should not be taken for the chimney: the alloy actively interacts with acids and will quickly fail. The best option is stainless steel.
The life of a single-circuit system is small - up to 15 years. However, replacing pipes is very easy.
Bypass systems
Option for the chimney. The system includes 2 steel pipes - for supplying air and for exhausting combustion products. Pipes are isolated from each other and from external air by mineral wool. The system is fireproof and lasts much longer. Thanks to thermal insulation, condensate forms in smaller quantities.
Asbestos-cement pipes
Not very resistant to temperature, but insensitive to the action of chemically aggressive substances. The cost is low. Suitable for the construction of ventilation ducts and chimneys for devices with low temperature output.
Asbestos-cement pipes are inconvenient: installation of corners or transitions is impossible, the material is fragile, it is difficult to work with it.
Sand cement pipes
Such mines are built from a special type of building blocks. Their form is traditional - 20 * 20 * 40 cm, but include 1.2 or 3 channels. Dimensions can be large. Blocks are used in the construction of wall ventilation. They are not suitable for the chimney, as they are rarely of high enough quality and do not always provide tightness.
Prefabricated Ceramic Systems
They consist of a round ceramic pipe, thermal insulation made of mineral wool and a concrete cover. Such blocks are easy to install, serve a very long time and are very hopeful. The downside is the high cost.
Ceramic systems are used in the construction of chimneys, such ventilation is too expensive. If desired, the blocks can be mounted in the wall and hide the chimney.
Corrugations
Corrugated steel pipes allow you to build complex exhaust systems where you can not do without turns and transitions. Often they are used as hoses and for connecting wall chimneys to boilers. A corrugated pipe is not suitable for smoke removal: a lot of soot and soot is deposited on such a wall, the pipe quickly fails.
Polymer pipes
They have limited use. Plastic does not differ in high heat resistance, therefore they are used for drawing and for chimney flue from boilers for liquid fuel or gas: here the comparatively low temperature of fuel combustion.
Plastic pipes are used to modify an old brick chimney. Enter into the channel as a sleeve.
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- Ceramic pipes
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- Corrugated stainless steel
Installation of smoke and ventilation ducts
Chimneys and ventilation ducts in masonry work only under one condition - sufficient draft. It arises due to the difference between air pressure at different heights. In a one-story house, it is quite small, but this is enough to ensure that more rarefied heated air is drawn out.
To provide traction, the following requirements are met:
- The ventilation and chimney go to the roof and reach a certain height. The value depends on the distance between the exit and the ridge. If the distance is less than 1.5 m, the pipe should be 50 cm above the ridge, if from 1.5 to 3 m, it should be at the same level with the ridge. If the distance is more than 3 m, the height is calculated: the line from the ridge to the head of the pipe below the horizon by 10 degrees. If there is a parapet on the roof, a higher structure is located nearby, the height of the pipe is increased.
- Ventilation ducts can be combined. Chimneys are combined only in exceptional cases - during the construction of a stove with a fireplace.
- If the chimney channels are not placed in the wall, they are insulated along the entire length. Any conclusions at the points of transition through the roof are insulated. Use asbestos or safer mineral wool.
It is recommended to waterproof the pipe between the roof and the otter. If this is not done, the whole wall gets wet.
Algorithm for masonry flue and ventilation ducts
Installation of air ducts is carried out according to a previously created project. In order not to make a mistake when laying the channel in the wall, a template is preliminarily created: a wooden board 250 * 14 * 2.5 cm on which the channel scheme in the wall is marked out. Thanks to the workpiece, it is easier to construct a straight, even stroke.
Duct construction scheme:
- The template is used from 1 row of masonry. The board is laid so that the end face adjoins the wall from the inside, and chalk outlines for the channels. The template is used constantly to prevent shifts.
- The walls of the channel are laid out in 1 brick. If the cross section is large, you can strengthen the ventilation by laying a brick across the channel.
- The bricks are laid back to back, the excess solution from the clay is immediately removed. Perform a mop treatment: thoroughly rub the seams and align. A single-row dressing is used near the ventilation duct. Perform it at the expense of halves and three-quarter.
- If necessary, do the channel tap. An angle of at least 60 degrees from the horizon. Spread the tap of the brick, hewn at the required angle. In this case, the dimensions of the main channel and the outlet remain the same.
During construction, it is important to keep clean. Holes are laid with newspapers. After removal, check the cleanliness of the shaft with a ball.
