Reconstruction of the old and installation of a new water supply system is one of the technological tasks during construction or overhaul. Do-it-yourself planning for the installation of plastic pipes for hot and cold water supply should be done after studying the principles of designing such systems and the technology of work processes.
It is necessary to understand the pipes used for water supply systems, laying rules, know the purpose of fittings and devices included in the system, be able to work with equipment for connecting elements.
Types of plastic pipes for water supply and fittings
The modern concept of plastic pipes is prefabricated. The number of types of plastic pipes with constantly improving technical characteristics is increasing as innovative production technologies and materials are created.
The line of plastic pipes produced by domestic and foreign manufacturers includes:
- Polyethylene (PE). Such products are used for cold water supply networks with low pressure (LPH) 2.5 atm, high pressure (HPV) 8 атм и расчётной температурой жидкости 0—40 градусов. Изготавливаются по ГОСТ 18599–2001 из ПЭ-80, ПЭ-100. Рекомендуются для прокладки водопровода в малоэтажных зданиях или при поэтажной зонированной разводке в квартирах. На маркировке обращайте внимание на значение SDR — прочностные характеристики полиэтиленовой трубы. Чем ниже это значение, тем стенки толще, изделия выдерживают большее давление. Сварка при монтаже водопровода производится стыковым методом для изделий диаметром >5 cm, wall thickness >5 mm, with the help of special electric couplings for smaller sizes.
- Polypropylene pipes (PP). Products are used for supplying cold drinking water in the plumbing system. Thermoplastic polymer is highly rigid, assembly is carried out only with the help of corner fittings. Connection — soldering iron (diffusion welding). Pipes are marked depending on the composition of the raw materials from which they are produced — PPH, PPR, PPB. Products withstand pressure 10 atm, design operating temperature 70–80 degrees. Pipes with a blue stripe are for cold water, a red stripe indicates the use of material for hot water supply, a yellow stripe indicates gas pipes, they are not used in water supply.
- Metal-plastic (metal-polymer). Products are used for laying cold and hot water supply, heating. The name itself — metal-plastic indicates that the structure of the pipe is a layered structure. The outer and inner layer is ordinary or cross-linked polyethylene, inside is an aluminum thin-walled pipe or mesh, the layers are bonded on an adhesive basis. Marking: PE-AL-PE (two layers of ordinary polyethylene + a layer of aluminum), PE-AL-PERT (thermo-strengthened polyethylene inside, normal outside, aluminum layer in the middle), PEX-AL-PEX (cross-linked polyethylene inside and outside). Products are used for pipelines with a design temperature of +90 degrees at a pressure of 10 MPa. They are mounted using compression fittings or on press fittings with a special manual hydraulic wrench.
- Polybutene (polybutylene). Pipes from materials related to innovative developments. They have improved characteristics, high elasticity. Marked “PB”. Assembly is carried out using fittings or a soldering iron.
Criteria for choosing plastic pipes for plumbing
The right choice of plastic pipes for plumbing is based on characteristics such as:
- design pressure in the network;
- required inner diameter based on fluid flow, head;
- calculated liquid temperature;
- physical-mechanical and ecological properties;
- availability of mounting tools (soldering iron, wrenches or manual press wrenches);
- the total cost of the plumbing project.
Advantages and disadvantages of plastic pipes
With the advent of plastic pipes, which have a number of undeniable advantages over metal ones, it causes their widespread use in plumbing, heating and sewer systems.
General advantages of any plastic products over metal ones:
- Chemical resistance to alkalis, surfactants, lack of reaction with oxygen dissolved in water allows the inner surface of products to remain unchanged, rust does not form.
- Layers of insoluble salts are not deposited inside the pipes, so the cross section of the passage hole remains constant, and cleaning is not required for the entire period of operation.
- Plastic pipes do not burst when the carrier freezes.
- Bacteria colonies do not form inside, drinking water remains clean.
- Light weight of the material, ease of installation of water supply systems.
- Guaranteed service life up to 50 years.
- Budgetary cost of products, components.
- The disadvantage is the limitation of application according to the calculated operating temperatures, pressure.
- Plastic is a combustible material and should not be used in fire protection systems.
Fittings and their application
Fittings — special parts of the water supply system, necessary for laying, connecting products, connecting to distribution plumbing fixtures, installing shutoff valves. The use of fittings allows you to connect plastic elements with metal ones, make any trace regardless of the configuration of the room, assemble a system of any complexity.
For each type, size of pipes, type of connection with plumbing fixtures from another material, the industry produces a complete set of required fittings. The table does not provide a complete list of fittings used in the installation of a water supply system, their purpose. A more complete list is available on the market.yandex website.
products of one
|From 5.4 rub.
Rotate 90 degrees.
There are taps
under 45 degrees.
|From 7.00 rub.
available for pipes
under 90 and 45
|From 13.0 rub.
|From 240 rub.
Under the cold
|From 90 rub.
|Applied in places
|From 56 rub.
double for wall mounting.
Drawing up a water supply scheme
The design of the reconstruction of an old or newly built cold and hot water pipeline should be based on the norms, requirements of SNiP 2.04.01–85 *.
Construction drawings, water supply schemes are axonometric projections of the route indicating the locations of sanitary appliances, shut-off and technological valves. The diagram indicates the dimensions of each section of the wiring, the necessary fittings for routing, the intersection of walls, ceilings.
Drawing up axonometric diagrams is carried out at the design stage of a building under construction. Correctly drawing up a project for hot and cold water supply is not an easy task. The best option is to contact the design organization.
When drawing up a diagram on your own, carefully study the regulatory documents, decide on the method of water supply, the number of consumption points, and the laying method.
This method provides for the sequential distribution of cold, hot water from central water supply risers if a water pipe is being installed in an apartment or from a boiler, pump in a private house.
With the tee method, the water pressure in the system drops, the pressure at each subsequent point of consumption decreases. Such a system requires calculation, it is used when there are not many water flow points (faucets, toilet bowl, bathroom, washing machine), the probability of simultaneous opening is not significant.
This method involves the installation of a distribution manifold at the system inlet. Each consumption point is connected to the collector individually.
With this parallel method of distributing pressure, the pressure of the liquid in the system remains constant, the number of connection of consumers is not limited. Even when the devices at the flow points are fully switched on.
Rules for laying water pipes
When drawing up a water supply scheme with plastic pipes, one should be guided by the provisions of SNiP 2.04.01–85 *:
- when laying a water pipe, hidden wiring should be provided;
- tracing along the bottom of the walls is allowed, while it should be carried out in closed boxes that protect pipes from accidental damage;
- with the collector method of supply, a beam distribution under the floor screed should be provided, while the thickness of the screed and coating should be sufficient for safe operation;
- in sanitary facilities (toilet, bathroom, shower room, tiled kitchen) concealed wiring is not allowed. It is possible to lay in boxes with access to the places of installation of shut-off valves, control devices;
- hidden wiring on columns, trusses is not allowed;
- seal the furrows in the walls with plaster on the grid or tiles;
- lay pipelines with a slope of 0.002;
- at the system inlets, provide for the installation of a check and shut-off valve, pressure regulators with a pressure gauge, a water meter assembly, and a meter;
- at the upper points of the system, provide devices for bleeding air, at the lower points — fluid drain devices;
- Install compensators (fittings) to compensate for linear expansion of the pipe when the temperature of the medium changes in long runs or where walls are limited. When laying through interfloor ceilings, design the installation of expansion joints from corners, which will allow you to maintain the linearity of the risers;
- with open wiring, communication elements are attached to the wall with clips or clamps in long sections, at corners of rotation, at the points of connection of devices;
- lay pipes with hot water higher than with cold water. For the latter, provide thermal insulation;
- in places where consumable plumbing fixtures or other devices are connected, install shut-off ball valves on American or spurs;
- according to the norms for the installation of galvanized pipes, it is allowed to replace them with non-galvanized pipes with appropriate justification;
- In order to restore the coating, paint the welding seams of galvanized pipes with a paint containing >94% zinc dust.
Tools and accessories
For the installation of a hot and cold water supply system, the required number of pipes, fittings, control and shut-off valves, plumbing fixtures, and other elements included in the plumbing system will be required for this. These data are taken from the scheme that was drawn up before the start of work.
Calculate how many pipes you need, what diameter, summing up the dimensions of individual sections of the wiring. See where the bends, tees and other fittings needed for routing are installed, count the number. The number of other elements of the system is also determined based on the drawn up scheme.
Buy materials with a safety factor of 1.15.
If there are difficulties with the calculations, contact the seller of the store where you are going to buy materials with your scheme. He will select the necessary components for the plumbing, answer questions about the application and installation procedure for each element.
In addition, you will need:
- building or laser level;
- pencil, ruler;
- rag with solvent;
- scissors for cutting pipes;
- perforator, screwdriver for mounting fasteners;
- a soldering iron or a wrench for connecting pipes, depending on the installation method (glue is needed for polyethylene and PVC pipes);
- grinder to disconnect from the riser and tap for threading when connected;
- gloves and work clothes.
Working with a soldering iron
When buying a soldering iron, choose a device from the middle price category. They have a high-quality Teflon coating of the heads, this guarantees a long-term preservation of the surface of the head when soldering plastic pipes (it will not stick when heated).
- Read the instructions. Pay special attention to the table with the recommended heating temperature of the head for the type of pipes selected and the heating time of the soldered elements depending on the wall thickness and diameter. Check that the head matches the diameter of the pipes to be soldered. Set the required operating temperature for heating the head with the regulator. Conduct an experimental connection of the pipe with the coupling.
- Turn on the soldering iron. The lights will turn red, which means the soldering iron is heating up. Take the coupling, measure the working depth of the entry. Set aside this distance from the end of the pipe to be welded, mark with a pencil, draw a line from above, and also make a mark on the coupling. Degrease the surface of the end of the pipe and inside the coupling with acetone.
- After the lights go out or turn green, connect the parts to be welded evenly and without much effort, hold the time recommended by the instructions. Remove the parts smoothly from the head, connect to each other to the depth mark and align the marks from above. This must be done quickly, but without much effort, to the entry depth mark. In this case, elements must not be rotated (rotation 5 degrees is allowed) or inserted at an angle. A uniform annular bead should form at the soldering site.
- Hold the elements in this position for 5–6 seconds. Inspect the connection — the correct alignment of the marks, maintaining the diameter of the internal through hole. If the result is satisfactory — good, if there are defects, repeat the soldering. Working with a soldering iron must be mastered well, the quality of the assembly of the system depends on it.
Stages of plumbing installation
Before starting work, agree on a temporary shutdown of the water supply, call a plumber for this time. Disconnect from the riser, cut the thread, put the plug.
Do not turn off the water supply yourself, the riser is the responsibility of the company servicing the house.
Drain the remaining water from the pipes, dismantle the components of the old plumbing. Disconnect the sewer, inspect. If necessary — dismantle the sewer, replace with a new one.
Clean the walls and floor of the room, prepare for installation work, nothing should interfere. Remember the sequence of pipes from bottom to top when tracing together: sewerage, cold water, hot.
Draw lines for laying pipes according to the diagram, install mounting clips. Do not forget about the slope of 0.002 cm per meter of the track. Prepare the necessary holes with sleeves in the walls.
Start the installation work with the nodes coming from the connection points of the plumbing equipment. Collect knots, strengthen to the walls.
Work on soldering polypropylene pipelines is allowed to be carried out at a temperature not lower than +2 degrees in the absence of wind. Plastic products should be heated or stored in a warm room. In the wind, at low temperatures, it is not recommended to work with a soldering iron, it is good to warm up the workpieces, it is impossible to obtain a high-quality connection.
Assemble the communications completely to the connection points to the risers. If possible, reduce the number of adhesions, do not get carried away with the use of unnecessary bends, tees. This will reduce the hydraulic resistance, increase the quality of the polypropylene pipeline as a whole.
If you have problems with soldering at the joints, use a second soldering iron, install a compensator, or move the joint to another place, making this section separately.
After the communications are assembled, the entire system is pressure tested by 1.2 of the calculated value, but not higher than the allowable for the products used. No pressure drop allowed. Floor screeding or grouting of concealed wiring channels is allowed only after a positive pressure test result.
Coordinate the connection of communications to the risers with the dispatcher of the management company.