Chimneys From An Asbestos-cement Pipe, Including How To Choose, As Well As Features Of Installation And Operation

2024 Author: Bailey Albertson | [email protected]. Last modified: 2023-12-17 12:53

Chimneys from asbestos-cement pipes: when they are appropriate and safe

Asbestos-cement pipes are the cheapest base for a chimney, therefore they are most often used in private construction. But professionals say: they can be mounted only in rare cases and only with the right technology. Therefore, if you paid attention to this building material, you should make sure that it is suitable for your building.

Content

• 1 Chimneys from asbestos-cement pipe: characteristics

  • 1.1 Table: advantages and disadvantages of asbestos-cement pipes

    1.1.1 What do doctors say about the dangers of asbestos cement

• 2 How to choose a chimney from an asbestos-cement pipe

  2.1 Video: rules for calculating the height and diameter of the chimney

• 3 Installation of a chimney from an asbestos-cement pipe

  • 3.1 Video: do-it-yourself junction of the chimney pipe to the roof

  • 3.2 Do-it-yourself installation of chimneys from an asbestos-cement pipe

    • 3.2.1 Instructions for installing an asbestos-cement chimney in a finished building
    • 3.2.2 Video: Replacing an asbestos-cement chimney pipe
  • 3.3 How to insulate a chimney from an asbestos pipe

• 4 Features of the operation of chimneys from an asbestos-cement pipe

  • 4.1 Chemical cleaning of the chimney

  • 4.2 Mechanical chimney cleaning

    4.2.1 Rotary chimney cleaning method

• 5 Reviews: what users are saying

Chimneys from asbestos-cement pipes: characteristics

Asbestos-cement pipes are concrete products (85%), reinforced with asbestos fibers (15%). The latter are extracted from a natural mineral by crushing and fluffing. Pipes made of asbestos cement are hard and brittle (can be damaged during transportation), porous and prone to moisture accumulation. They are connected using couplings of the same material, while there is a need for careful sealing of the joints. The installation procedure for asbestos-cement products requires some skill and more time than the construction of a chimney from sandwich elements or a double metal pipe. But ordinary people justify most of the shortcomings by the low price of building materials.

Asbestos-cement pipes are inexpensive and are produced in large volumes

Experienced builders recommend using asbestos-cement pipes to remove smoke from barbecues and barbecues in open areas, as well as in summer kitchens and country houses, which are visited only from time to time. It is better not to install them in more solid structures for permanent residence.

Table: advantages and disadvantages of asbestos-cement pipes

Positive traits	Negative qualities
Low cost. On average, an asbestos-cement chimney is 3–5 times cheaper than analogues.	The tendency to accumulate on the inner walls of soot and soot due to the rough surface. They require frequent cleaning (from 1-2 times a year), but since inspection hatches are not installed in them, it is sometimes impossible to do this in a timely manner. These factors reduce the durability of the chimney.
Dielectric properties. This means that asbestos pipes do not build up a charge and do not need cathodic protection. If it is not provided for metal pipes, stray currents will quickly lead to electrochemical corrosion and reduce the life of the chimney.	Cases of spontaneous combustion of soot in asbestos-cement pipes occur several times more often than in chimneys made of other materials. This could potentially lead to structural failure and fire in the building. True, a sufficient amount of soot is produced only by furnaces, with which asbestos cement is not allowed to be used.
Ease of installation. Pipes are sawn and drilled without a professional tool, the butt end does not need additional processing or protection. Thanks to this, a chimney made of asbestos cement can be built independently.	The need for a strictly vertical installation, which often causes difficulties during installation and difficulties in choosing the optimal place for the pipe to pass through the ceilings and the roof.
Resistance to heating, which makes it possible to install these pipes in the chimney. They are used in combination with modern gas and pyrolysis boilers, as well as for the construction of distant fragments of the chimney from more intense heat sources.	Temperature resistance of asbestos is limited to +300 of C, so it can not be done from a chimney for the stove, fireplace or coal-fired boiler. They give off too much heat, which can cause the pipe to crack.
High moisture resistance, which allows the use of asbestos-cement pipes without waterproofing.	The need to install third-party materials. Due to the fact that the pipes quickly heat up from the gases escaping from the boiler, it is necessary to equip the cake with thermal insulation, which, in turn, needs waterproofing.
Excellent strength (including tearing from the inside) with a low weight, which is achieved due to the reinforcement of concrete with asbestos fibers.	Risk of destruction due to temperature. When cooled and heated, the pipe significantly changes its size. Therefore, if a brick contour is built around it without a proper gap, asbestos cement can burst.
Good weather resistance. In particular, the material resists rotting, fungi, low temperatures, and chemical attack.	Uninsulated asbestos pipe impairs traction and promotes the spread of condensate through nearby structures. In order not to spoil the characteristics of the heating system and the structure of the roof and walls, you will have to spend money on high-quality insulation.

What do doctors say about the dangers of asbestos cement

Medical contraindications are considered one of the main disadvantages of asbestos-cement pipes. It is believed that a chimney installed in a house made of this material can lead to cancer in the future. But doctors are not so unambiguous. Research has confirmed the danger of amphibole asbestos, so its use and extraction is completely prohibited.

Chrysolite asbestos is used for the production of pipes

Products made from safer chrysolite asbestos are on sale, which can only harm if inhaled in the form of dust. That is, it negatively affects only the workers of factories where pipes are made of mineral fiber and cement. And only because they regularly get the opportunity to inhale large quantities of chrysolite dust. But even if the artisans do not use personal protective equipment, the lungs independently (without procedures and preparations) remove half of the dust in 10 days. The remainder, when accumulated, can cause coughs, allergies, in the worst case - asthma, but not cancer.

When studying the harm of asbestos, first of all pay attention to the lungs

In the finished state, the products are completely safe, they can be carried with bare hands, cut and drilled without a respirator. When overheated, the material can emit a certain amount of reaction products, but exceeding the temperature regime with the correct use of asbestos-cement products occurs only in force majeure cases. In addition, the smoke, together with harmful substances, quickly leaves the chimney and is carried by the wind.

Therefore, doctors are sure that a properly installed chimney cannot cause disease.

How to choose a chimney from an asbestos-cement pipe

Since this building material belongs to the budget, you should not try to save even more and look for the cheapest asbestos-cement pipes. It is better to buy them in a reliable store that provides guarantees for the quality of products. Otherwise, there is a risk that cheap pipes will not even reach the installation site and will crack on the way.

Rusty deposits and dirt on the surface of asbestos-cement pipes are an indicator of improper storage and unsatisfactory quality

When buying a pipe, it is recommended:

• carefully inspect each product, make sure that there are no cracks and chips, loose lumps and uncharacteristic inclusions in the material;
• check (at least visually) the evenness of the pipe and the uniformity of the wall thickness;
• pick up an asbestos cord for sealing joints;
• make sure that the cross-section of the pipe exactly matches the diameter of the boiler pipe.

The range of asbestos-cement pipes will not limit your choice

Manufacturers offer asbestos-cement pipes with a diameter of 10 to 50 cm, so choosing the best option for your boiler is not difficult. To minimize the number of joints, it is worth purchasing a 5 m long pipe, but if it cannot be transported, you can take 3 m (this is the minimum permissible chimney length). It is recommended to purchase an adapter or a stainless steel gas outlet pipe directly for connection to the branch pipe, which can be tightly connected to both a metal branch pipe and an asbestos-cement flue duct.

Video: rules for calculating the height and diameter of the chimney

Installation of a chimney from an asbestos-cement pipe

It is possible to install an asbestos-cement chimney only when the heat source is a gas or pyrolysis boiler, and the building itself is not used for permanent residence. If you decide to equip a summer house or a bathhouse with such a chimney, be sure to follow the technology to ensure your own safety.

Experienced builders recommend:

• make the length of the pipe no less than 5 m (from the grate to the upper end of the chimney), but no more than 6 m (if you make it higher, the smoke will begin to return);
• place it at a distance of more than 1 m from the combustible elements of the roof;
• use a connector no more than 1 m long between the boiler nozzle and the asbestos-cement pipe;
• do not save on couplings; to ensure the tightness of the joints, they must be of high quality;
• sealing joints used for materials with a working temperature up to 1000 ^of C;
• when passing through ceilings, it is imperative to isolate the chimney from the construct with the help of non-combustible materials (the larger the diameter of the pipe, the thicker the layer of fluff is needed);
• it is imperative to construct the pipe insulation pie in the open air;
• remove it from a flat roof at least 0.5 m above the outer layer of the roof finish, and from a pitched roof - 1–1.5 m above the ridge;
• reinforce the pipe with guy wires or brackets if its height exceeds 1.5 m.

Video: do-it-yourself junction of the chimney pipe to the roof

Do-it-yourself installation of chimneys from an asbestos-cement pipe

The installation procedure for a chimney made of asbestos-cement pipes is slightly different depending on when it is installed.

The diameter of the umbrella can be adjusted to the size of the asbestos-cement pipe using a clamp

Required tools and materials:

• asbestos-cement pipes of the required length (on average 5–6 m);
• cap (umbrella) to protect the chimney from precipitation;
• couplings for connecting pipes to each other;
• bituminous sealant for insulating joints;
• asbestos cord for sealing joints;
• adapter element for connecting pipes and boiler nozzle;
• metal fastening clamps (one for each connection);
• cement, sand and reinforcement for the foundation;
• grinder for cutting materials;
• metal shears for cutting steel pipes;
• a drill with a mixing nozzle or concrete mixer for building a foundation;
• trowel, spatula, construction knife, plumb thread and other small hand tools.

Installation instructions for an asbestos-cement chimney during building construction:

1. Build a foundation to support the asbestos-cement pipe. Brick or concrete is suitable for this, but heat-resistant cement is best, since the base is located near the heat source. The higher the foundation, the colder gases will enter the asbestos-cement pipe, and the longer it will last. Make an inspection hatch in it for cleaning the chimney.

   

   Inspection hatches are made in the pipe using tees

2. Install a one-piece asbestos cement pipe on the foundation and fix it strictly vertically. The five-meter product is heavy, you will need 1-2 assistants.

   

   When installing an asbestos-cement pipe in the wall, it is especially important to control the correct location

3. Connect the pipe to the boiler nozzle through an adapter made of a more heat-resistant material (steel, tempered glass, ceramics).

   

   Corrugated stainless steel pipe is mounted on the boiler branch pipe and asbestos-cement pipe using sealant and clamps

4. Seal the joints with heat-resistant material and check for any inconspicuous gaps.

   

   Tests confirm that black tube sealant can withstand temperatures up to 1500 degrees

5. Install a rain cover on the top of the pipe.

   

   The original chimney cap will not only add uniqueness to the chimney, but also increase the draft

When constructing ceilings and a roof of a house, a thermal insulation belt will need to be organized around the pipe.

Installation instructions for an asbestos-cement chimney in a finished building

Sometimes you need to install a pipe in an already built building:

1. Make a foundation-support under the chimney according to the above rules.

   

   If the foundation continues upward and equips the pipe channel, the chimney will be much more stable.

2. Provide openings for the passage of pipes in the floors and roofs and protect the perimeter with a thick layer of non-combustible materials.

   

   It is much more difficult to make a hole in a concrete ceiling than in a wooden one, so carefully check the dimensions when working

3. Start assembling the chimney from the top down. Fix the first fragment of the asbestos-cement pipe to the roof structure through heat-insulated clamps with the socket down. Equip the perimeter waterproofing and return the decorative roofing to its place.

   

   When installing the pipe, carefully check the vertical position of the product.

4. Place a protective cap over the top of the pipe to prevent precipitation from entering the pipe. After this, installation can be continued even in the rain.

   

   You can choose an umbrella for the size of the pipe, or you can make it from tin, observing the indicated proportions

5. If you have purchased pipes without a socket, first put on a metal fastening clamp on the lower part of the pipe and assemble the chimney with them.

   

   A wide metal clamp will help to securely fasten the pipes, and the crate will not allow them to move

6. Take the next piece of asbestos-cement pipe and use a jack to press the thin end into the socket of the previous one. If the upper element is secured sufficiently securely, the lower one will fit snugly into it without visible gaps.

   

   The connection diagram of asbestos-cement pipes on sockets and clamps will help to do it right

7. Seal the joint thoroughly with asbestos cord and bitumen sealant.

   

   Asbestos cord is sold in reels and cuts

8. Repeat the operation until the pipes reach the level of the foundation. Install the chimney on the base. Add a pipe section of the desired length, if necessary.

   

   Asbestos-cement pipes are perfectly cut with a grinder

9. Connect the chimney to the boiler connection through the adapter.

   

   Steel pipe with 90 degree elbow is a good option for converting to a pipe hidden in the wall

At the end of the installation, according to any of the described methods, it is required to check the presence of traction. Light a chip in the boiler furnace and look at the position of the light. If done correctly, it should tilt towards the chimney.

Video: replacing an asbestos-cement chimney pipe

How to insulate a chimney from an asbestos pipe

Insulation of the asbestos-cement chimney is mandatory. For this, as a rule, mineral or stone wool is used. These materials give the chimney the heat capacity required for normal draft and at the same time are non-combustible, which reconciles asbestos cement with fire safety rules.

There are two ways to insulate the chimney:

1. During chimney installation. As soon as one fragment of the asbestos-cement product is installed in place, a stainless steel pipe of a larger diameter is put on it, and insulation is stuffed into the gap formed. This continues until the very end of the chimney. Since the mineral wool needs waterproofing, the joints of steel pipes must be sealed not only with clamps, but also with a heat-resistant sealant.

   

   Cotton pipes with metallized waterproofing will help insulate the asbestos-cement chimney reliably and quickly

2. After installing the chimney. The finished pipe is wrapped with a thick layer of rolled cotton wool. To prevent the insulation from slipping, it is fixed with metal clamps or just wire ties. The second layer is wrapped up with a moisture-proof membrane, if necessary, the joints are glued with tape. The decorative finish is the same stainless steel tube but cut vertically. The cut allows it to "hug" the asbestos-cement chimney together with the insulation. Each piece of steel pipe is also fixed with clamps and treated with a sealant.

   

   In a metal frame with slabs of cotton wool, you can hide two pipes at once and at the same time give the chimney a decorative look

Keep in mind that insulation of the chimney with foam of any kind, as well as other combustible heat insulators, is by no means permissible.

Features of the operation of chimneys from an asbestos-cement pipe

One of the main difficulties in using asbestos-cement pipes is the need for timely soot removal. Due to the fact that only one inspection hole is installed in such a chimney, cleaning the pipes is difficult, so first of all it is worth doing prevention.

Chimney chemical cleaning

Under the brands Hansa (Lithuania), Spalsadz (Poland), "Chimney sweep" (Russia) produce cleaning agents in the form of a powder (a mixture of copper chloride, phosphates, ammonium salts, etc.). When 1-2 measured spoons of the composition are poured onto burning wood, the chemicals react with slag and soot on the walls of the chimney. The catalyst converts pollutants into flammable gases and solids. The gaseous component leaves the chimney with smoke, the rest of the particles fall into the furnace and are cleaned out together with the ash. Manufacturers recommend using the product every 4-5 lights to keep the pipes clean. The effect of the drug is easy to notice by the emitted whitish smoke. A product with the same effect is also available in the form of a log impregnated with the necessary chemicals.

The action of the chemical chimney cleaner is very simple.

Users confirm that this method of cleaning and prevention is very effective and greatly simplifies life in the absence of inspection hatches in the chimney. But given that asbestos-cement pipes are sensitive to temperature rise, use the anti-soot powder with caution. If the manufacturer does not specify the dosage for such a chimney, it is better to start with half of the standard portion.

Mechanical chimney cleaning

Manual soot removal is carried out using round brushes and long-handled scrapers. It is best to select them with a diameter slightly larger than that of the pipe, and with a pile of metal wires. Since the inner surface of asbestos-cement chimneys is initially rough, and soot can sink deeply, cleaning with plastic brushes will not bring the desired result.

If the roof of the building is very high, there is a reason to entrust the cleaning to professionals

The brushes can be placed on rods or rods, but even the longest handles do not allow you to properly clean a 5-meter chimney. Therefore, they can only be used for partial cleaning of the pipe in the accessible area. But if a convenient inspection hatch is equipped, you can scrape out the chimney first from below and then from above.

A wire rope with a brush and weight can also be used to clean long pipes. Its end with a cleaning tip is lowered from above and, by gravity, sinks to the very foundation of the chimney. Since chimney ducts made of asbestos-cement pipes are always mounted strictly vertically, almost all the dirt can be removed in 1–2 passes.

Rotary chimney cleaning method

The rotary method is a type of mechanical cleaning. It is based on the same scraper brush on a long flexible rod, only the holder itself can be connected to a drill or a powerful screwdriver. The mechanism will provide such high brush speed that cannot be provided manually. Therefore, cleaning is performed much faster and better. Rotary cleaning kits such as TORNADO are not difficult to find on sale, but some craftsmen make similar devices on their own.

For rotary cleaning, you can make the device yourself

If cleaning the chimney is not difficult for you, the rest of the asbestos-cement pipes will not bring much trouble.

Reviews: what users say

Asbestos-cement pipes are, of course, not ideal for a chimney, but quite a worthy and inexpensive temporary analogue. If you are not yet ready to spend a lot on a country house or are not sure whether you will need a gas boiler in the future, you can safely mount just such a chimney. Subject to the above-described installation technology, asbestos-cement pipes will serve you long enough so that you have time to decide on the final version of the chimney.