Dimensions of asbestos cement pipes and their application

Currently, all sizes of asbestos-cement pipes - 100-500 mm in diameter are constantly in demand in civil and industrial construction - for transporting liquids or as elements of various structures. All of them are classified according to State Standards - pressure in accordance with GOST 539-80 and pressureless in accordance with GOST 1839-80, therefore, this determines their range in a particular construction niche.

Chrysotile cement has both positive and negative sides in front of plastic and steel, which is what will be discussed, and you can also see the video in this article confirming the written facts.

What they are and what they are used for

Tables

Note. Asbestos cement pipes also have a second name - chrysotile cement, which is essentially the same. Therefore, if you meet one or the other definition, then we are talking about the same product. Below you will see the technical characteristics of asbestos-cement pipes and the basics of their installation.

Table of sections of pressure chrysotile cement pipes and couplings

Table of sections of non-pressure chrysotile cement pipes and couplings

Theoretical mass of chrysotile cement pipes per meter

Advantages and disadvantages

• Asbestos cement or chrysotile cement is the same concrete that is reinforced with fibers and it turns out to be several orders of magnitude cheaper than plastic (HDPE or LDPE), cast iron or steel, which can be used for similar purposes, and the price always plays an important role in the design. The minimum service life for pipes of low and high pressure ranges from 25 to 50 years.
• It is very important that the asbestos-cement pipe of 150 mm or any other diameter does not conduct electric current, has a very low thermal conductivity (0.8 kcal / m · h · deg) and is not susceptible to corrosion, and this is the main drawback of similar products made of iron and steel.
• The coefficient of temperature elongation of asbestos cement is 12 times less than that of steel, therefore, there is no need to install expensive expansion joints for underground or surface laying. When transporting cold liquids on the surface of chrysotile cement there is no condensation.
• Any asbestos-cement pipe - 200 mm or with a different cross-section, when transporting hot water will have a slight expansion, but such deformation is perfectly compensated by sealing rubber rings on the coupling for pipes. It is noteworthy that the contact of asbestos cement with a liquid (especially hot) makes it even stronger, because this is the natural course of things for concrete.
• For such pipelines, the instruction does not provide for prophylactic cleaning of microorganisms. (moss, algae), as they are not formed there throughout the entire life cycle. Chrysotile cement is resistant to acid and alkaline medium.

Mounting methods

Laying the trunk into the trench is not done on the ground, but on a sand cushion - this allows you to evenly distribute the load over the entire area, and if it is a small diameter (100 mm asbestos-cement pipe weighs from 7.8 to 10.4 kg), then the workers without special efforts to lower it with their own hands.

But, in cases where the section is larger, then an automobile crane may be required for this, for example, a 500 mm BT12 type 3 asbestos cement pipe weighs more than 173 kg - installation will be possible without special equipment, but rather complicated. Before laying, as well as directly into the trench, all pipes and couplings are mandatory checked for integrity and / or leak tightness. If required by design appointment.

The installation of the road to the bottom of the trench is necessarily carried out under a slope - for a diameter of up to 200 mm it is 20-30 mm (asbestos-cement pipe 100 mm should have a slope of 20 mm / 1m), but for a cross section of 200 mm or more the slope will be 30-40 mm . And this applies not only to sewage systems, but also to conduit pipes - this ensures the flow of condensate or any liquid that has entered it.

Compound

Note. Pipes of this type are classified by pressure and purpose: a) for water supply: VT6, VT9, VT12, VT15; b) for heat pipelines: TT3, TT6, TT9, TT12, TT16.

Classification

When installing high-pressure asbestos-cement pipelines, couplings of similar material are used for docking, which are activated according to the self-sealing principle.

In cases where the working pressure is 9-15 kgf / cm², The instruction assumes the use of a two- or four-groove coupling (for 2 or 4 sealing rubber rings). If the pressure will exceed 16 kgf / cm², in this case, use couplings with wider grooves, where the sealing rings are also wider.

Installation, as already noted, can be done either underground or on top, but the latter method severely limits the design possibilities. The fact is that, according to the safety regulations, crossing the highway with the railway, tram line, residential sector, etc., is prohibited, or allowed, but under certain limited conditions.

But below the level of the soil, due to the technical characteristics, asbestos cement feels excellent and, moreover, there are no such restrictions as compared to the outer gasket.

Conclusion

There are situations when the installation is made instead of the old line after the last dismantling and the old pipeline is sometimes laid in the tray. In such cases, the tray is not dismantled, because the dimensions of the asbestos-cement pipe 150 mm (or other diameter) remain the same as that of steel or cast iron, so there is no point in removing the tray and filling the sand cushion.