Not a single private house, in which there is a boiler or gas equipment, can do without a chimney channel. Technically, measures to organize a system for the extraction of combustion products may seem too troublesome and costly, but modern technologies have optimized the arrangement of furnaces and boilers. Instead of traditional masonry, you can use a galvanized pipe of the desired diameter to equip the chimney. It is easily attached and does not require special maintenance operations during operation.
Varieties of metal chimney designs
Three types of pipes are made on the basis of galvanized steel - simple single-circuit, double-circuit (sandwich pipes) and coaxial. In the first case, univalent steel is used without an insulating substrate. These are small-diameter designs that are suitable for different types of heating equipment - an almost universal solution, but with high heat losses and a low degree of strength. Is it possible to use a galvanized pipe with a single circuit for a chimney, if we are talking about a high-power boiler? Theoretically, this is possible, but due to the low throughput, the chances of smoke increase.
Sandwich pipes are favorably distinguished by the presence of an internal insulation and a large diameter, which expands the range of applications. At the same time, dual-circuit models are more expensive and have their own operational risks, which will be discussed below.
As for coaxial chimneys, their designs are just oriented to support high throughput by increasing the diameter, but without the inclusion of an insulating layer. Such pipes are advisable to use in rooms with impaired air circulation or with an absent forced ventilation system.
Basic selection options
When planning a chimney purchase , you should also focus on the following selection criteria:
- Sizes. The standard is a galvanized pipe of 120 mm. A chimney of this size serves most of the country houses and cottages, but it is still recommended to calculate the parameters based on the capacity of the heating equipment.
- Type of heating system. There are special models of pipes for stoves, boilers and fireplaces, and in different configurations. Often the differences between different sentences are expressed not by specific design characteristics, but by a complete set and additional functional elements.
- Layout configuration. The device of the roof of the house and the type of roofing also impose their requirements on the individual parameters of the choice of pipe - both in length and thickness, and in the type of insulation materials.
Calculation of the diameter of the chimney pipe
If the height is selected individually for the general characteristics of the house, taking into account the parameters of the attic space and the angle of the ramps, then the diameter of the pipe will depend on the heating unit. The volumes of produced burns depend on the performance of boilers and furnaces - accordingly, the design of the outlet channel is also selected for the power potential. So, for units with power up to 3500 W, it is desirable to install structures with a thickness of 80-100 mm. Size increases as you approach 5200 watts. For such boilers, standard galvanized pipes of 120 mm are recommended. Chimneys with a large diameter should be calculated taking into account the presence of auxiliary layers - both insulation and reinforcement.
Structures from 120 to 150 mm thick are distinguished by thick walls and a double-circuit configuration. That is, the technological layer of the insulator is also provided, which will not affect the throughput in any way. For example, in a galvanized pipe for a 150 mm chimney, a heater can occupy 15-20 mm. However, it is worth talking about thermal insulation materials separately.
The nuances of the use of thermal insulation in the chimney
The insulation layer is used only in double-circuit sandwich pipes. It should be noted right away that the presence of the insulator has practically no effect on the mass, but it increases the rigidity of the barrel. But another question arises regarding the use of a thermally insulated galvanized pipe for a chimney - can it be used taking into account fire safety requirements? Such limitations are justified, since heater ignitions due to contact with red-hot steel and exhaust gases often occur in potbelly stove-sandwich-pipe combinations. But this applies to cases of violations of the rules of the operation of the chimney and, in principle, the use of low-quality materials.
The main rule for those who want to insure themselves against such threats is to select a pipe with a heater designed for the temperature of the exhaust gases. For example, the normative regime reaches 180-200 ° C, and a heater based on crushed vermiculite withstands from -250 to 1150 ° C. But more often they use more familiar mineral and synthetic materials, basalt or ceramic wool. In this case, we can speak of a critical temperature of 600 ° C.
Possible pipe installation patterns
Before starting the preparatory and installation operations, you should at least sketch out a work plan with the definition of the installation of the pipe. Installation can be carried out according to two principles - “by smoke” and “by condensate”. What does it mean? In the first version, the system will provide for the presence of branch channels with tees for condensate drainage. In the second scheme, technological branches for the condensate are not needed due to its natural absence.
The choice of one of these configurations is important due to the fact that the design must be protected from excess moisture, harmful to both the insulator and the metal. By the way, the chimney pipe made of galvanized steel is the most protected from moisture, but protective coatings are not enough to completely protect the structure. In any case, ventilation circuits must be present in the pipe passage areas. Therefore, the optimal solution would be to combine segments with drainage channels for condensate and solid areas for the release of smoke. It is also not worthwhile to abuse tees and other technological waste channels, since they reduce the efficiency of the chimney as such.
Preparing for installation work
First of all, conditions are being prepared for the organization of the channel. A place should be prepared not only for the passage of the pipe, but also for its fastening with the arrangement of technological branches. Particular attention is paid to attic flooring and roofing. Holes of suitable diameter are formed in them and, if necessary, support joints are installed for rigid fixation of the barrel. At the edges of the created holes, the installation of an insulating coating is carried out. It is necessary to provide linings for holding and warming the galvanized pipe. For the chimney, attic elements are also mounted in the attic. This is especially true for double-circuit structures of large diameter. From the lateral holding points, you can grab the structure with soft-padded clamps. Means of sealing joints at pipe passage points are also thought out in advance. For this, flange plates or liquid silicone seals can be provided.
Assembly events
During installation, the assembly is carried out from the bottom point from the pipe of the heating equipment up. Pipe extension is carried out in segments by attaching each subsequent section to the previous one. Double-walled trunks can be expanded by integrating one branch pipe segment into another. Further, with the help of lock fasteners, the mounting unit is simply clamped on the principle of a clamp. In the case of installing a galvanized sandwich pipe for the chimney , the walls of the aisle between the ceilings should be filled in advance with non-combustible heat-resistant material. This operation will also increase the fire safety of the structure. Do not forget about the fastening of technological elements, among which there may be knees, tees, condensate collectors, etc. Additional fittings are usually fixed with complete hardware, brackets and clamps of a suitable format. Moreover, regardless of the type of joint connection, it is desirable that the support fixture is present for every 200 cm of the pipe.
Organization of the chimney exit
A very crucial stage of installation is the arrangement of the output part of the structure. To output the pipe outward, special equipment is used, which is placed around the roof opening and is attached to the coating, capturing the pipe. At this point, the main part of the chimney with a rigid support in the form of a so-called metal cup should be fixed from the attic. The final segment of the structure will leave from it through the hole in the roof. At the final stage, the arrangement of the outer part of the pipe is performed. At a minimum, a head or umbrella should be installed on the galvanized chimney pipe in order to protect the channel from rain and debris. It can be made independently of sheet metal, welded to the pipe.
Positive feedback on galvanized chimneys
A metal chimney is in high demand among private homeowners because of its functionality, ergonomics and ease of installation. At least, these advantages are visible against the background of the use of classic brickwork. Moreover, metal pipes are often used to modernize existing structures made of other materials. For example, you can extend the asbestos chimney with a galvanized pipe using special couplings and rubber rings. Another thing is that reviews of combined systems are no longer so positive due to a decrease in the strength of the chimney barrel.
You can compensate for the lack of rigidity with metal screeds or a reinforcing belt at the junction, but such inclusions will add load to the roof and roof structure, which is also not always permissible.
Negative reviews of galvanized chimneys
The main disadvantages of metal pipes used in the design of the chimney are associated with low structural reliability and the need for additional protection. Users of such structures in cold regions note the negative influence of cold bridges, which have to be regularly repaired, because the galvanized chimney pipe is loose under the influence of winds. Reliable fastenings do not always help in such cases due to the lack of strong structural supports that make it possible to keep the pipe in a stable position at a height of 100-150 cm above the roof.
Conclusion
The fashion for the use of modular chimneys fully fits into the principles of the modern organization of private home communications. As standard, the galvanized chimney pipe takes up little space, allows you to assemble structures of varying degrees of complexity, and at the same time regularly performs its basic tasks. But along with the individual nuances of maintenance in practice, one should also prepare for the serious costs of purchasing the main elements of the pipe. The cost is about 2-3 thousand rubles. for one segment, and there may be more than a dozen.