D To remove combustion products inside the furnaces of heating appliances, chimneys for a gas boiler in a private house of different designs from different materials are used. The standards SP 7.13130 specify the requirements for cross-sections, height, location of chimneys, safe schemes for passing through structures made of combustible materials.
Chimney from a gas boiler on the facade of the house
Chimney requirements and installation rules
The combustion products have high temperatures, so the chimneys must fully comply with the standards of SP 7.13130. It is not allowed to use factory products that have not passed the certification of the Russian Federation.
The main provisions of the code of fire safety rules are:
- internal chimney section - 14 x 14 cm - 14 x 27 cm, depending on the thermal power of the boiler (3.5 - 7 kW, respectively) for concrete, brick, ceramic structures, the area of \u200b\u200bround or asbestos-cement pipes must correspond to these dimensions;
- height - 5 m minimum from the firebox to the deflector;
- chimney thickness - 6 cm for heat-resistant concrete, 12 cm for ceramic bricks, not standardized for asbestos cement, sandwich.
The height of the deflector (an umbrella structure that protects the pipe from rain, wind) relative to the ridge depends on the degree of remoteness of the chimney from it:
- 0.5 m higher within 1.5 m;
- flush with the ridge at a distance of 1.5 - 3 m;
- at the level of an imaginary line at an angle of 10 degrees relative to the horizontal drawn from the ridge to the pipe, at a distance of more than 3 m from it.
When the chimney is moved outside, bends are allowed within 1 m from the axis of the root pipe to the side at an angle of less than 30 degrees relative to the vertical. The cuttings should exceed the thickness of the ceilings with decorative ceiling linings by 7 cm with a uniform distribution of this size from the bottom / top.
The distances from the outer surfaces of the structures to the wooden elements of the load-bearing structures (battens, rafters, beams, crossbars) must be greater than the indicated dimensions, depending on the material of the chimney:
Attention! It is forbidden to combine chimneys with ventilation ducts without a special project. On the other hand, combustion products from two boilers can be launched into one pipe if necessary.
Chimney structures
When choosing a chimney or channel, you should focus on the best combination of construction budget, resource, maintainability. Depending on the materials used, chimneys for a gas boiler in a private house are fastened with clamps to the building envelope or rest on separate foundations.
In all vertical structures, a serious problem is the formation of condensate, which is released when hot gases come into contact with cold pipe walls. In coaxial modifications, which are more often located horizontally, this minus is absent. In addition, it is enough to give a slight inclination of the pipe to the ground, so that any condensate flows out of it without additional costs on its own.
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The installation of a chimney for a gas boiler in a private house is carried out according to the general scheme for asbestos-cement, sandwich, ceramic pipes. For coaxial aluminum, plastic pipes, the circuit is, in principle, not needed. In the manufacture of masonry from blocks, modules, bricks, standard stonework techniques are used.
Sandwich installation
Chimneys from two pipes of different diameters, inserted one into the other, with a heat insulator between them, are called sandwiches. The design allows you to reduce the outside temperature of the walls (increased fire safety), eliminate the formation of condensate (useful for increasing the resource).
A sandwich chimney of a wall-mounted gas boiler is mounted in a private house using two technologies:
- by condensate- the upper elbow is inserted into the socket of the lower one, when condensate drains in the annular space, its penetration into the channel, ignition is excluded;
- by smoke- the upper pipe is put on the lower one, preventing the penetration of combustion products into the room.
Attention! Gas boilers have gases with low temperatures at the exit from the combustion chamber. Therefore, the technology "by condensate" is used.
The chimney assembly technology looks like:
- installation of a gate valve on the outlet pipe of the boiler to adjust the cross section of the chimney channel;
- installation of pipes to overlap "by condensate";
- production of cutting from a steel box attached to the ceiling from below;
- passage of the chimney cutting, building up to the roof;
- fastening to the crate of the roof - a plate with a conical branch pipe located at the right angle to it, depending on the slope of the slopes;
- fixing the sandwich pipe of the chimney to the roof with a comfrey (conical collar of a complex profile), which decorates and seals the joint.
After that, it remains to install one of the elements on the mouth of the pipe:
- volper - a deflector for increasing traction with a flat cover;
- weather vane - deflector to improve traction of the original design;
- fungus - a cone nozzle to protect against precipitation.
These elements are made of stainless steel, fully consistent with the style of sandwich chimneys.
Stone and brickwork
Chimneys for a private house can be built into brickwork (only in a load-bearing inner wall) or made from blocks. Domestic manufacturers produce several types of chimney modules:
- concrete - used only together with ceramic pipes passing inside them, the outer surface is square, the inner is round;
- ceramics - pressed out in special forms, then fired in furnaces, have the design of an inner tube, an outer square thin-walled box, connected by stiffeners.
The Ukrainian company Schiedel produces chimney blocks from pumice of volcanic origin. The modules are called Isokern and are a budget option for individual developers. The material is much lighter than concrete, ceramics, the only drawback is the rough inner surface, the lack of Russian certificates. Regional fire safety services accept structures made of this material in 50% of cases.
Brick chimneys are built into the walls at the stage of erection of enclosing structures. For laying blocks, it is necessary to concrete a separate foundation. On the other hand, pipes can be placed in any convenient place, there are no problems with passage nodes, truss systems, ceilings.
Asbestos cement pipe
In aggressive advertising of sandwich chimney manufacturers, the main disadvantage of asbestos is the lack of environmental safety. In fact, only safe raw materials and technologies are used in domestic production. According to the reviews of masters who install all types of modern chimneys, an asbestos-cement pipe has the following advantages:
- is self-supporting - no need to attach to the walls;
- does not condense moisture - there are no leaks inside the combustion chamber;
- resistant to combustion products - the resource is higher than that of concrete, brick;
- cheaper than ceramics - the cost is much lower.
Installation of an asbestos-cement pipe is extremely simple:
- the first pipe is installed on the foundation, fastened with racks or a frame;
- the chimney is increased to the desired height, the pipes are connected by couplings;
- the top is covered with a deflector, a hatch is made below for installing a cleaning door.
The tie-in from the boiler is carried out with a steel elbow, which can be replaced if necessary.
Installation of a coaxial structure
Unlike other chimney modifications, a coaxial pipe can only be used for closed combustion chambers. (supercharging) is a mandatory operating condition of the system. The design of a coaxial chimney is similar to a sandwich, however, instead of insulation, there are jumpers between pipes of different diameters. The inner pipe is used to remove combustion products, the outdoor air necessary for burning natural gas is sucked into the annulus.
Unlike conventional chimneys, the pipe does not have to be pulled vertically through all floors. Instead, a 90-degree bend is put on the outlet pipe, the coaxial chimney is attached to it horizontally, goes out through the nearest wall, observing the fire safety distances:
- the maximum length of the horizontal part is 3 m;
- at least 0.2 m to the ceiling, floor, ground;
- more than 30 cm from the chimney axis to the wall surface;
- at least 60 cm from the mouth of the pipe to the opposite wall.
The coaxial structure can be brought vertically above the roof, horizontally through the wall, or connected to a smoke channel built into the brickwork of the wall.
