Basic requirements for materials
The material that can be used for thermal insulation work must meet the following requirements:
- Have low thermal conductivity. This is a basic requirement, choosing a product with a low coefficient will effectively protect the pipeline from freezing and save money.
- It is good to tolerate the effects of chemical and organic substances contained in the soil, to have biological resistance to various types of microorganisms and bacteria.
- Have a long service life without losing their physical characteristics.
- The insulation should not be afraid of exposure to moisture, absorb and pass water, its physical parameters should not change in the aquatic environment.
- The impact of high and low temperatures, as well as their differences, should not destroy the insulator and affect its physical properties.
Beginning of work
Any work on laying pipes begins with a preliminary drawing up of a scheme
It is important to include the following points:
- The main characteristics of the existing soil: friability, softness, and so on;
- The total area of the site;
- Source of water intake;
- pumping system;
- Hydraulic accumulator.
What do you need to purchase?
The first and most important thing you need to buy at the store is water pipes. It is better if they are made from low-density polyethylene
It is also necessary to pay attention that the products are suitable for organizing a water supply system for transporting drinking water.
Why polyethylene? Products made from it have a lot of advantages: resistance to corrosion, high pressure, low temperatures, strength, plasticity, ease of installation, low price of fittings. You should not buy too cheap products, as they can cause a lot of problems during operation, which will lead to additional waste. However, you can purchase products from other materials. It all depends on the requirements and preferences of the owner of the house.
How to determine the depth of the gasket?
The depth to which it is necessary to lay the water supply is determined by SNIP (a document that serves to determine the optimal technical aspects when installing various communications). SNIP standards indicate that pipes should be laid to a depth of at least 1.6 meters. This item directly depends on the depth of soil freezing.
The average depth of soil freezing is 1.4 meters. It is clear where the figure of 1.6 meters came from, because if you lay the water supply above this level, it will freeze, and its further operation will be impossible. But the depth of soil freezing still varies, because there are areas with different temperature climates.
If you do not want to use average values, we recommend that you contact your nearest construction organization for advice regarding specific soil freezing indicators in this area.
But in any case, you will not lose anything if you lay the water supply according to the standard. Regardless of the area (unless, of course, your dacha is located in remote Siberia), at a depth of 1.6 meters, a positive temperature remains even in the harsh winter season. And this means that the plumbing will delight you with its uninterrupted operation.
What should be remembered when laying water pipes in the ground?
Often, owners of cottages or private houses are faced with the problem of the impossibility of laying the pipeline to the desired level due to the structure of the soil. This difficulty is relatively easy to solve. The trench breaks as deep as possible, to the level that the soil allows. Then water pipes are laid.However, thermal insulation must first be arranged. It is required to install a heating cable throughout the entire length of the plumbing system, which will make it possible for its uninterrupted operation in winter.
Of course, it is still better to lay pipes in a trench dug at the right level. The heating cable, its installation - all this is expensive, expensive in terms of time, and can cause some inconvenience. However, if a trench with the required parameters does not work out, then a measure with a cable is required when laying an autonomous water supply system.
After laying the plumbing system in the country or in the area adjacent to a private house, before filling the water supply with earth, you need to check whether everything is done correctly. For this, a test run of water is carried out. Just turn on the water and wait until it passes through the entire plumbing. At the same time, carefully observe the entire path of the liquid
It is important for you to check whether there are leaks in the water pipes, whether the nodes are tight
A small addition: Even if your private house or cottage is located in the south, you still should not significantly violate the norm for the depth of laying the system in the ground, equal to 1.6 meters. Otherwise, if the water supply was laid too close to the surface, it may be deformed due to various kinds of mechanical influences. If it is laid too far from the surface, the water supply may burst, unable to withstand the high pressure.
Methods for laying an electrical cable
The technical features of laying HDPE pipes depend on the location of the cable and its operating conditions. This also affects the list of equipment used and the necessary components.
Installation in enclosing structures
Inside the premises, electrical wiring using HDPE pipes is laid as follows:
- outline the location of the cable;
- fix the pipe, and it can be attached to the floor with metal brackets, and to the ceiling or walls - with special holders with a latch;
- pull the cable so that it is located freely, without tension;
- the structure on the floor is poured with a concrete screed, and in the wall or ceiling it is covered with plaster or other materials, depending on the diameter of the protective case.
Cable laying using HDPE pipes on the floor
HDPE pipe allows:
- reduce the length of the wiring;
- carry out repair work and cable hauling without damaging the surface of ceilings and walls.
When installing communications indoors, it is possible to use various connecting parts to fix individual sections of the protective casing: bends, couplings and other components. However, corrugated elements are most often in demand for turns at the points where the pipe enters the floor slab or the transition from the floor to the wall. In this case, the HDPE pipe for electrical wiring must be bent at an angle of 90⁰, and this is impossible without crushing and deforming the material.
According to current regulations, for the installation of hidden electrical wiring, which is located inside floors or walls made of non-combustible materials, it is allowed to use smooth or corrugated HDPE pipes.
Laying in the ground with digging a trench
This technology is in demand when laying communications in suburban areas. Before starting work, you should inspect the cable and check the integrity of the sheath. If it is damaged, the protective function of HDPE pipes will be useless.
Then, during the laying process, the following operations are performed:
- make markings and dig a trench of the required depth;
- a HDPE pipe is placed in it with or without a broach of the desired diameter;
- pull the cable and lay it in such a way that it is located without tension;
- the pipe is first covered with a layer of sand 10 cm thick, and then with soil by about 15 cm.
To quickly locate the cable, you can lay a special signal tape over it.
Cable laying using HDPE pipes in the ground
When using HDPE pipes for laying power networks in the ground, it is desirable to exclude the use of couplings and other connecting elements, since this makes it difficult to ensure sealing. However, when the cable is brought into the building, fittings are simply necessary.
For laying the cable in a straight section, use solid pieces with a cross section of at least 4 mm. If the section is too long, then an elastic metal wire or a special nylon broach should be used to tighten the electrical wiring. They are first launched into the pipe, and then the tied cable is tightened.
Trenchless laying
Trenchless technology is used for laying electric cable, which is located in hard-to-reach places. Most often, it is in demand by public utilities, as it is carried out with the involvement of complex equipment and special equipment.
Horizontal drilling method
The essence of the method lies in horizontal directional drilling, which allows you to lay underground communications without disturbing the surface layer of the soil. First, they study the composition of the soil and obtain permission to carry out earthworks. Then the cable is laid in the HDPE pipe, which includes the following steps:
- Drilling a pilot well. The puncture of the soil is carried out using a drill head, which has a bevel in the front and built-in radiation. When it enters the ground through special holes, a solution is supplied that fills the well. It reduces the risk of collapse and cools the heated tool.
- Well expansion. It is performed by a rimmer that replaces the drill head.
- Laying HDPE pipes with cable inside. They are pulled into the well using a drilling rig.
Cable laying by horizontal drilling
The main disadvantage of horizontal directional drilling of soil is the complexity of its implementation, therefore, for such work, they conclude an agreement with an organization that specializes in such activities and has the necessary equipment.
Horizontal drilling rig
Laying a cable using HDPE pipes allows you to ensure its reliable protection for a long period of time, you just need to follow the technology for installing power lines and other communications.
Laying HDPE pipes for communication cable
One of the requirements of regulatory documents for laying underground communication lines is the requirement to lay a communication cable in 32T. The outer of this brand is 32 mm, the inner - 25 mm. They must be laid in trenches in advance. Polyethylene pipe allows you to stretch a significant length of the cable and reduce the number of cable joints. During operation, it will protect the communication cable from damage if preparatory work is carried out to lay the cable for a new communication line, when laying a massive cable not in pipes, during repair work and excavation of a previously laid cable.
The outer diameter of a polyethylene pipe for underground communication lines is 32 mm, the inner diameter is 25 mm.
A polyethylene pipe wound into a coil is installed on a movable vestibule and immediately unwound to the maximum possible span length. In this case, they must be taken into account, which will be performed in each transit well available on this span. The length of the cuts is considered as the sum of the distance between the channels plus 400-450 mm. As a result, its length should be such that trimming is minimal in the last well. If it is impossible to stretch the entire length of the span, it is measured with a tape measure, and then the polyethylene pipe is cut off in accessible places. In wells where there is a change in the direction of the route (corner wells), it must end in each of them.
The pipe is equipped with a tip and pushed through the entire length of the span. If there are transit wells inside the span, then the cablemen help to push it into the next well.If she hit an obstacle somewhere with her tip, and her further advancement turned out to be impossible, then the cablemen should, by joint efforts, turning the pipe clockwise, try to continue its movement along the span.
After the pipe has been stretched along the span, it is cut at a distance of 200-250 mm from the channels and metal plates (anti-thefts) are installed on the protruding parts with recesses equal to its outer radius. The plates are bolted together so that they do not move along the pipe. These stops should prevent them from moving when the cable is pulled through them.
In order to save HDPE pipes, it is allowed to join small-sized residues for the purpose of their use on spans whose length does not exceed 70-80 m. Their joints are connected using a metal cuff 150 mm long and 1.5-2.0 mm thick. On the inner side of the pipes, before joining, chamfers are removed at an angle of 30 °. On both sides of the cuff next to it, one belt (in two layers) of savilen is applied to the pipes or a layer of GIPC-14-13 glue is applied. A heat-shrinkable pipe 250 mm long is installed over the belts. In wells, they are protected from debris entering them by wrapping the joints with layers of plastic adhesive tape.
High-quality laying of water supply in the ground - low cost per meter of work
If you live outside the city, plumbing in the house is a necessary thing. What kind of comfort can we talk about if you need to go outside every time to wash your hands or dishes? And if it can be winter outside, and you don’t want to leave a cozy room? That is why laying water pipes in the ground is the solution. Pipes under a sufficient layer of soil provide uninterrupted water supply to the house all year round and make life comfortable. The Chisto Honestly company has been successfully providing services for laying water pipes in the ground at affordable prices for many years.
Polypropylene pipes.
Polypropylene pipes and fittings
Polypropylene pipes are easy to install and operate. Polypropylene pipes are excellent technical characteristics and a long service life: polypropylene pipes are able to maintain their characteristics for 50 years. In comparison with steel pipes, the main advantage of polypropylene pipes in water supply systems is their resistance to oxidation. Polypropylene pipes are light, during their installation there is no need for threading, the use of sealing materials and sealants is minimized
They do not need to be welded (in the traditional sense, like metal) and periodically painted, which is also important because it affects the cost of maintenance. Plastic pipes are easy to install, connected using standard fittings. Fittings also make it possible to connect polypropylene pipes of various diameters to each other by welding warm sockets
The seam cools down in a minimum time, which allows you to continue the installation work almost continuously.
To date, six types of polypropylene pipes and fittings are produced:
- pipes PN10, PN20;
- pipes PN20, PN25 reinforced with aluminium;
- fibre-reinforced pipes PN16, PN20;
- fittings for connecting pipes, both among themselves and between metal shut-off valves and pipelines, with transitions to flange and threaded connections
Pipes are produced in the following sizes indicated in millimeters: 20, 25, 32, 40, 50, 63, 75.
Strengths:
- Low cost.
- Clips for wall mounting.
- The ability to cover the entire wiring with plaster - due to the lack of necessary maintenance work.
Flaws:
- A special tool is required - an electric welding machine equipped with nozzles of the required size for polyfusion welding, creating a high-quality homogeneous seam.
- A rather complicated procedure for preparing for welding.
- It is not possible to repair the marriage without removing the defective parts and re-assembling the removed structure.
Taking into account the results of the above analysis and the possibility of subsequent modernization of the water supply system, I chose metal-plastic pipes for it. When installing the water supply, I used compression fittings, since their installation, although responsible, is not difficult, and even a beginner can do it with his own hands.
Of the tools you will need:
- knife for cutting plastic pipes;
- calibrator for correcting edge deformation after trimming;
- roulette;
- spanners;
- construction knife.
To understand how the fittings are mounted, let's look at one of them in disassembled form.
Disassembled compression fitting
The range of compression fittings is shown in the following figure.
Compression fittings
Installation of each fragment of the water supply system provides for the following sequence of actions:
- Measure the required length of pipe with a tape measure.
- With a knife for cutting plastic pipes, cut off the desired piece, if you notice burrs on the edge, process it and calibrate if necessary.
- Select the desired fitting and remove the nut and clamping ring from it, which you put on the pipe.
- Slide the pipe onto the fitting nipple and align it with the fitting run.
- Put the clamping ring back in place and tighten the nut, first by hand and then with a wrench, but do not overdo it. You can strip a thread or destroy a fitting. Such a fitting will have to be thrown out.
Fitting installation
Repeat this sequence of actions for each joint. Use clips to fasten pipes to the wall.
Fastening pipes with clips
As an example, I cite the connection to the water supply of a shower mixer and a sink.
Connecting the sink to the water supply
Shower faucet water connection
Laying your own plumbing
The biggest difficulty, after you have received permission from the relevant organizations to connect to the central cold water supply network, may arise if the pipeline needs to be laid under a sidewalk or roadway. Here, without horizontal drilling, and with a large distance that needs to be drilled, one cannot do without special equipment. In any case, it is necessary to take into account the physical properties of the soil and the scheme by which the water supply will be laid. The characteristics of the soil must be known, since the choice of material for the water supply system depends on this, and the scheme is necessary in order to know the number of inputs (outputs) and branches.
Scheme of trenchless laying of HDPE pipes using a drilling machine
The most suitable are HDPE pipes of the PN10 brand. These are special pipes for laying drinking water. They, of course, do not rust, withstand pressure up to 10 atmospheres, that is, approximately 1 MPa, bend easily, do not burst when frozen and do not lose strength after defrosting. When purchasing, do not be tempted by the cheapness of PN6 pipes, they are, of course, cheaper, but there will definitely be problems with them during operation and, perhaps, all the work done will be in vain.
The trench for laying the pipeline should be dug to a depth that is greater than the freezing depth of the soil, by about 20 cm. Data on the freezing depth can be obtained from any construction organization that performs work year-round. In any case, the depth of occurrence should not be less than 1.6 m. If the soil does not allow digging a trench to the required depth, then the pipes must be insulated.
Sewer pipe laying technology
Pipes are laid so that the socket is in the direction of the slope.
- Pipes are laid so that the socket is in the direction of the slope. Further work consists in checking the cleanliness of the inner surface. Before joining, the inside of the socket and the outer surface of the next pipe must be thoroughly cleaned of dirt and lubricated with a special lubricant that is usually supplied with the pipes.Only silicone grease is allowed. No oils can be used.
- Before applying lubricant, the pipe is inserted into the socket until it stops and a mark is made on the outer surface. After applying the lubricant, it should enter the socket to the level of the mark.
- For the device of turns from the sewer outlet in the foundation, bends with angles of rotation of 15, 30 and 45 degrees are used. Every 15 m of the length of the pipeline, in case of its cleaning, it is necessary to install revisions.
The use of HDPE pipes in the process of installing electrical wiring
To protect electrical cables, either corrugated or smooth HDPE pipes are used. Such pipes are chosen because, firstly, they are elastic and flexible, and secondly, they do not conduct electricity.
When installing wiring using pipes, you can choose either a hidden location in the walls, or place them on the surface. In addition, pipes are also used in cases where electrical wiring needs to be laid in the ground. The tightness of the connections will be important in the last version of the arrangement of electrical wiring, as well as if the electrical cable is laid in rooms with high humidity or outdoors.
To make the connection tight, you can weld HDPE pipes end-to-end, or use couplings. It is also possible to apply hot casing of the pipe directly in the socket.
In the latter case, the pipe must be heated and then inserted into the socket with little effort. Partial deformation of the material inside the socket will fill all the irregularities, which ultimately will ensure tightness.
Water supply from HDPE pipes
To perform work with HDPE pipes indoors, several methods are used to connect pipes. The choice of one of them depends on what the level of pressure in the water supply will be and whether there is an appropriate welding tool to do the necessary work.
Most often, water pipes from HDPE pipes are connected using compression fittings., which are used to join pipes with a diameter of not more than 110 millimeters. In practice, it is more convenient to connect pipes in this way, the diameter of which does not exceed 32 millimeters. This is quite enough for water networks.
The principle of connecting HDPE pipes differs little from the installation of metal-plastic pipes. The only difference is the use of a rubber seal rather than a split ring.
The work algorithm will be as follows:
- first you need to cut the end of the pipe at an angle of ninety degrees. To do this, you must use a pipe cutter;
- after that, you need to prepare a union nut and a rubber ring to seal the connection and put them on the pipe;
- then the pipe is installed in the fitting, and the nut is screwed onto the thread.
This installation method is very simple and allows you to create a collapsible connection, which, if necessary, can be quickly repaired by cutting it out of the pipe and replacing it with a new one. The disadvantage of this method is that the water supply system will completely depend on how high-quality the sealant was chosen. The connection will leak if the rubber is short-lived and of poor quality.
The second method involves the use of fittings that are used in diffuse welding. The same method is also used when it comes to the installation of polypropylene pipes.
To connect HDPE pipes in this way, the fitting is heated from the inside, and the pipe is heated from the outside. For this, a special soldering iron is used. After that, the pipe must be inserted into the fitting. The connection will be ready within a couple of seconds.
When using this method, keep in mind that such a connection cannot be disassembled. But if the installation is done correctly, then the pipes will not need to be repaired for a very long time. If the pipes leaked, then a soldering iron would be required again to restore their tightness.
As a rule, poor-quality pipe connections occur due to irregularities and burrs remaining on their surface. Therefore, before installation, it is required to free the outer surface of the pipe from the chamfer and check if there are any defects left on it.
In order to connect HDPE pipes with a large diameter, it is used butt welding method.
To connect pipes in this way, you must first center them. An electric heater is placed between their end part, which is removed after the ends of the pipes begin to melt. Then the pipes are joined, and the connection is considered ready after the polyethylene has cooled down.
Compared to a solid pipe, such a connection has a strength of 80 to 90 percent. This method is used when it comes to connecting pipes with a wall thickness of five millimeters. But often home craftsmen connect pipes of smaller diameter in a similar way, heating them on a gas stove. The result is not a very neat seam, but practice has proven that such pipelines have been operating uninterruptedly for years.
One of the most expensive and at the same time simple ways is electrofusion connection. To do this, use the same fitting that is needed for welding. The only difference is that the socket or fitting is compatible with the soldering iron. A special spiral is installed in the plastic. Power is supplied to it to heat the material.
How and why pipes are bent
Pipe bending technology is based on the properties of the polymer to take any shape under the influence of high temperatures.
It is also necessary to bend the pipe to give the desired bend shape when installing the pipeline, which can have a different configuration, so as not to use additional connecting parts, you can simply give the pipe the desired shape using its technical properties.
This is achieved with the help of special heating equipment in the form of a molding machine, a building hair dryer or a gas burner:
The principle of operation of the molding machine is to use a special frame made of wood board, in which the pipe is fixed, placed in a silicone shell created by the machine. Under heating, the pipe takes the form of a frame. It is cooled for 10 minutes and then removed and left to cool completely.
Distinctive features of HDPE pipes
This immediately changed the performance of HDPE pipes. And their main difference from ordinary polyethylene pipes is that they begin to melt 20 ° C higher, and this greatly expanded the scope of this type, for example, they can be used in hot water systems at any water temperature.
Scheme of an extrusion line for the production of plastic pipes: 1 - loading device; 2 - extruder; 3 - forming head; 4 - calibrating sleeve; 5 - water vacuum baths (vacuum calibrators); b - thickness gauge; 7 - water cooling baths; 8 - counting and marking device; 9 - pulling device; 10 - cutting device; 11 - receiving device; 12 - winding device.
These pipes are elastic, and it is easy to give them a complex shape, that is, they “work” well both in tension and in compression, because when bent, one side of it, without collapsing, experiences a tensile load, and the opposite compressive load. They also have good impact strength and can withstand significant impact loads when in the ground, which is why they are called high-strength. In winter conditions with HDPE pipes it is possible to work outdoors even in northern regions.
HDPE pipes cannot be used to transport liquids and gases with which they can enter into a chemical reaction. Subject to this condition, the service life of HDPE pipes without loss of their inherent properties, even in the ground, is 50 years.
They are designed for internal pressure, which has the following range of values: 0.5 0.63 0.8 1.0 1.25 and 1.6 MPa; you can pick up pipes of almost any diameter in the range from 16 to 1200 mm and a length of 5 to 12 m with a multiplicity of 0.25 m.
HDPE pipes are much cheaper than steel and, especially, copper pipes. They can reasonably be considered the material of the future.
