Water supply - critical communications for drinking and industrial needs of people fighting fires. Water quality and operating conditions largely depend on the components of the system. Water pipes - the main element for conveying fluid from the source network to the consumer. In many types of products for sale, differing material characteristics and cost. Installation of each of them involves the use of certain technologies.
Types of water pipes and basic requirements
Water is supplied for different purposes:
- drinking, cooking;
- for irrigation;
- fire fighting;
- hot water supply;
- providing production and technological cycle.
pipe is used for internal or external water network:
- welded steel according to GOST 10704;
- copper water and gas GOST 52318;
- Polyethylene pressure according to GOST 18599;
- Pressure Thermoplastic according to GOST 52134;
- multilayer of metal and polymers in accordance with GOST 53630;
- asbestos cement according to GOST 539-73;
- cast iron according to GOST 21053.
Standards normalized inner and an outer pipe diameter, wall thickness, weight per meter, strength, composition and properties of materials. Design should be resistant to the constant pressure, to maintain the working temperature of the medium. On the inner and outer surfaces is not permitted damage, deformation, a crack or a sink.
Outdoor paving plumbing underground, internal network in a building along or inside the walls, under baseboards or under the floor.
The highest demands on the quality of pipes for drinking water at home. Hazardous substances can penetrate into the liquid and harm human health. Thus a surplus of copper leads to the disease liver cirrhosis and increased concentration of iron - the deposition of toxic compounds in human organs.
Main characteristics - an outer (OD) nominal or conditional (DN or DN) diameters, wall thickness. Products diameter 5-102 mm are classified as small-size, 103-427 - average, above - bolshemernye.
Water supply networks rely on a specific indicator of pressure:
- up to 12 atm - low pressure;
- 12-25 - average;
- over 25 - high.
The apartments or private houses pipes must withstand the pressure of not less than 2 atm. The pressure in the internal fire water higher - up to 10 atm.
To transfer the cold water pipe is used to limit temperature resistance up to + 46 °. Transporting a high-temperature environment is carried out "hot" pipelines.
On the question of which is better to use a pipe for water, can be answered by considering all the options, weighing the merits or demerits of each.
Steel water pipes
Steel profiles - a traditional material for the manufacture of outdoor and indoor plumbing. They have a mechanical strength and durability, perceive multiple load from pressure surges in the network or temperature.
Profiles made of carbon steel by rolling (cold or hot) welding or folding. The sheet is cut into strips, aligned, welded along a straight line or a spiral line. Pipes were tested for strength and flattening elevated hydraulic pressure.
The need for large steel pipes. Over 10% of all the discharged metal consumed in the production of these products.
Steel pipes used:
- for laying of water or gas pipes;
- in industrial and civil construction;
- when laying highways;
- in the production of ships, aircraft, motor vehicles;
- in the metallurgical industry.
The Housing construction is used for the organization of external and internal water supply, heating systems. For external lining products are used to cross-section of 150 mm. When selecting a pipe diameter of the cold water pipe in a private home should be guided by the length of the communication:
- 10 m - 20 mm;
- 30 m - 25 mm;
- more than 30 m - 32 mm.
System collected by welding or by fitting. Screwing produce a variety of components.
The main disadvantage of steel communications - instability to galvanic corrosion.
Aggressive action of moisture or soil transported fluid gradually destroys the metal, resulting in the formation of holes in the walls through pitting or ulcers.
Standard life water supply - a riser or liner - steel pipes does not exceed 15 years. In fact perhaps the action of destructive factors, shortening the duration of operation. For example, cold water contributes to a faster corrosion than hot. The formation of condensation on the pipe surface is accelerated due to the temperature difference, resulting in the destruction of metal.
To avoid contact with water and oxygen, effects of stray currents material surface is coated with a protective layer of zinc or polymers. The external networks used sacrificial cathodic protection.
galvanized pipe
Longer service life from galvanized profiles. This is due to the fact that the coating interferes with the interaction with moisture of steel, and the passage of water less deposits formed on the smooth internal walls.
In the system itself practically no scale or rust pieces leading to the formation of irregularities in the lumen. This increases the capacity galvanized water pipe, so the home system is sufficient to use a 20 mm diameter outlets.
Standards define the duration of the water supply service of the galvanizing in 30 years. In reality, this term above - up to 50-70 years.
Galvanized conducted in three ways:
- Plated - applying a protective layer on a product placed into the electrolyte by electrolysis;
- hot galvanizing - coating secured to the surface at parts immersed in a molten metal;
- cold galvanizing - a protective composition is sprayed or applied by staining;
- diffuse - Treatment of zinc vapor occurs at elevated pressure and temperature.
Most quality protection is formed in the latter case.
The diameters of the steel galvanized pipes according assortment 6-150 mm (nominal diameter). Outside section products - 10,2-165 mm. The length of the profiles 4-12 m. The wall thickness varies from 1.8 to 5.5 mm. The mass structures coated steel black exceeds 3%.
Assembling is carried out preferably threaded plumbing connections with fittings. When using welding damaged protective layer. Subsequently, these places form centers of corrosion. Thus defeats the purpose devices of the system of galvanizing, as the durability is reduced to simple indicators black pipes.
To prevent damage to the coating when welding is used for spraying the area of the weld zinc composition, special flux or rutile electrodes.
stainless
Pipes from alloy corrosion-resistant steel durable, not exposed to the damaging action of water. They can last up to 400 years. oxidation products do not accumulate on the wall, do not fall in household plumbing. Increasingly, products made of stainless steel replace conventional carbon steel despite the higher price of the material and the complexity of the installation.
Constructions of stainless steel meet the sanitary and hygienic standards, are well tolerated hammering, resistant to the critical temperature. Stainless steel may damage the water with excess chlorine content and thus is recommended disinfection thoroughly flush the system.
Stainless steel pipes used in various fields:
- water, heat and gas supply;
- fire fighting;
- device channels for air conditioning;
- installation of "warm floor";
- for the protection of electrical power cables.
Water was collected by means of press fittings made of stainless steel also, welding a tungsten electrode in inert atmosphere. In an industrial environment use laser welding.
There is a growing water supply device from the flexible corrugated pipes. Their advantages - the possibility of installation in tight spaces, installation of long-distance lines, resistance to dynamic or vibration loads.
Brass
Water pipes made of copper is much more common in Europe than in our country. They are time-tested and deserve attention in connection with long-term trouble-free operation.
Advantages of copper tube:
- corrosion resistance - copper insensitive to chlorine, dilute acids or alkalis;
- resistance to temperature changes in the range -100 ° C... + 250 ° C, pressure fluctuations;
- the walls are not formed growths not settle bacteria, since the copper ions are harmful for them;
- with regular maintenance service life exceeding 50 years.
Copper pipes for plumbing in an apartment are further processed - annealed. It gives softness and elasticity of the products, they are easy to bend and cut. Such communication is very decorative. No additional protective coloring compositions.
The disadvantages include:
- higher compared to steel price counterparts;
- only for jointing copper fittings may be used as the metal forms a galvanic couple with steel, facilitating its destruction;
- assembly of the system is carried out with special equipment, which increases the cost of installation.
Tubes connect the high-temperature soldering or by fittings which are to be combined. soft metal cutting is not allowed.
Plastic pipes
The revolution in the chemical industry was marked by the emergence of new materials in construction. Of thermoplastic or thermosetting polymer produced various kinds of water pipes:
- polyethylene PE;
- PVC PVC;
- PP polypropylene;
- Polyamide PA;
- polybutylene PB;
- fiberglass;
- fiberglass;
- epoxy or polyester.
Diameter polyethylene pressure profiles - 16-1600 mm. The wall thickness is calculated on the perception of the operating pressure of 4-20 bar. Products with a cross section up to 40 mm are used for domestic water supply, 160 - for risers or sewage. Large-employed in the manufacturing sector.
Polyethylene pipes are marked for densities - from 63 to 100 (kg / m³). Less dense materials mechanically unstable. Of them are made pressure-free design - outside shower, irrigation, sewage sludge. PE 80 is stronger, they are used for cold pipe device inside the house. For supplying hot water and heating applied PE 100.
Polyethylene pipes are mounted via compression fittings or thermistor, by butt welding.
Polyvinylchloride tubes paving external water. They gray manufactured in lengths of 1, 2, 3 and 6 m nominal diameter products -. 90-500 mm. Designed for pressure of 6-16 bar. Mount them without joints or welding. At one end of the socket is formed with an annular seal, which is inserted into another part of the round profile. The compound is completely sealed, withstands regulatory burden.
Advantages of polymer pipes:
- resistance to chemical and electrical corrosion, corrosive environments;
- harmlessness, absence of harmful emissions in the transported liquid;
- smooth inner surface, which is not delayed pollution;
- low thermal conductivity, reducing energy losses and condensation;
- light weight and flexibility, making it easier transportation and installation;
- bad acoustic permeability, reducing noise when water passes.
During the reconstruction of the system is easy to change, cutting communications and connecting the new branch with the help of the fitting. The apparatus of pipelines cheaper than plastic pipes of steel by 30-40%.
Disadvantages of products, common to all plastics:
- instability to ultraviolet;
- high coefficient of linear thermal expansion;
- brittleness at low temperature;
- most of them do not burn, but sustain combustion, thus emit harmful substances;
- limit the operating pressure and temperature.
Most heat resistant pipe of crosslinked polyethylene PEX, which is produced at high pressure. Used for hot and cold water. It withstands temperatures up to + 95 ° and pressure to 20 atm.
metallopolimernye
Plastic tube produced by extrusion, coating the frame of mesh, wire or foil polymer melt.
Plastic materials are combined advantages of metallic and polymeric types of tubes for heating or plumbing:
- corrosion resistance, chemical resistance;
- low thermal expansion;
- durability;
- easy installation with detachable, crimping or press-fitting;
- operating temperature range to 95 ° - 110 ° and the pressure to 10 bar, withstand repeated freezing;
- life of up to 30 years.
Metal-plastic retains its shape during bending, it does not emit harmful compounds in water.
Disadvantages of aqueducts metallopolymers:
- smaller than that of steel pipes, the mechanical strength;
- not applicable at a pressure above 10 bar and a temperature of from 110 °;
- some species susceptible to fatigue failure.
A set of positive qualities make this material promising for widespread use in various areas of construction.
hydraulic calculation
To determine the most cost-effective cross-section of the aqueduct, conduct hydraulic calculation. Condition must be satisfied to ensure the required water flow rate, retention pressure and minimum pressure losses. Taking into account:
- the estimated direction of water flow;
- consumption according to water consumption norms;
- characteristics of water fittings and the number of points;
- overcrowding rate housing;
- pressure loss due to friction along the entire length of the tube.
According to the results of calculation are selected based on the diameter water pipes of the sizes of the table and product mix.
To determine the pressure loss using Sheveleva table or online programs.
Tables for the hydraulic calculation of steel, cast iron, asbestos cement, plastic and glass water pipes contained ready indicators depending on the diameter, material, length of the line pressure online. The loss is determined at each site and summed. From the obtained value determines the desired flow rate and pump power.
Water supply system - a complex engineering communication. It is important to choose a pipe with regard to their technical, perform installation correctly.