Any work related to gas pipelines and gas equipment is very responsible and dangerous. Therefore, increased demands are placed not only on specialists performing installation and maintenance. gas equipment, but also to the materials from which the equipment itself is made. The most important part of the city gas supply system, along with distribution stations, are the gas pipeline pipes themselves. The service life and trouble-free operation of the city’s gas infrastructure depend on their quality.
Pipes for gas pipelines
The metal pipes that make up the bulk of the entire gas supply network are susceptible to corrosion and rust. Costs for anti-corrosion preparation metal pipes before installation are very high, the maintenance of such a gas pipeline and its annual maintenance are no less expensive.
Modern plastic pipes made specifically for gas pipelines are a new step towards the durability and safety of gas pipelines. Plastic is not subject to corrosion and is neutral to aggressive environmental conditions. In addition, plastic pipes are cheaper to produce and weigh less, which makes transportation and installation easier. The inner surface of a plastic gas pipeline is smooth and without roughness, so the friction of the gas flowing through the pipe is minimal, which reduces transportation costs.
Ordinary plastic water pipes are not suitable for installing a gas main. Gas pipes are made of polyethylene grades PE80 and PE100; a yellow marking strip is applied along the entire length of the pipe, indicating the purpose. The range of pipe diameters ranges from 40 mm to 315 mm. The officially declared service life is 50 years.
Areas of use
Gas pipelines intended for urban needs are divided into three types:
- Low pressure gas pipelines up to 0.005 MPa, residential buildings and small enterprises are connected to them;
- Medium pressure gas pipelines from 0.005 to 0.3 MPa, they are designed to supply small boiler houses, city baths, and medium-sized enterprises;
- High-pressure gas pipelines of the 2nd category from 0.3 to 0.6 MPa supply large factories, thermal power plants and thermal power plants with natural gas.
In all types of such gas pipelines, it is possible to install plastic pipes to replace metal ones.
However, plastic gas pipes still have a number of restrictions on their use. Thus, the air temperature in the area where plastic pipes are used should not fall below -45°C (although a decrease in the impact strength of the pipe occurs only at -70°C), and the seismicity of the area should not exceed 6 points. The biggest disadvantage is the inability to use plastic gas pipes for the home. Only underground installation of such gas pipelines outside buildings is allowed. In apartment buildings residential buildings And production premises Gas pipelines are only allowed to be laid through metal pipes. Also, any air installation of a gas pipeline is made of thick-walled metal pipes.
However, in private homes it is still allowed to use metal-plastic pipes made of cross-linked polyethylene. They contain a gas-tight aluminum insert inside, and the pipes themselves can be bent, avoiding the use of fittings, reducing the risk of gas leaks. However, a bendable pipe is a hose, and corrugated stainless steel hoses have been used for connecting geysers and stoves for a very long time.
Insertion into a plastic gas pipeline
Tapping into a plastic gas pipe is faster and easier than tapping into a metal one. When inserting, conventional electric arc welding is not used, and therefore fire safety during work is increased. Special fittings called saddles are used. The saddle has 2 terminals to which a specialized welding machine and heats up the spiral installed inside the fitting.
The saddle is placed over the pipe and welded to it, eliminating the possibility of gas leakage. With a cutter installed in the saddle plastic gas pipeline cuts through and opens gas access to the saddle outlet. The cut part of the pipe rises along with the cutter and does not enter the gas pipeline. The insert is ready! The longest operation in the tapping process is cooling the saddle after heating to form a high-quality weld over the entire adjacent area.
Chimneys and hoods
Plastic pipes are also manufactured for use as exhaust systems for low temperature boilers and conventional gas stoves. Plastic pipes are smooth-walled, which significantly reduces the resistance of the extracted air, which means that the noise of such a hood will be close to zero. External side This type of pipe is easy to clean, unlike corrugated ones exhaust pipes, hidden in boxes, and will not accumulate dust and grease in the kitchen.
The plastic chimney is ideal for condensing and pyrolysis boilers, as well as any furnaces with an outlet gas temperature not exceeding 120°C.
At this temperature, metal chimneys quickly rust and fail due to insufficient draft and high concentration of alkaline steam in the exhaust, while brick chimneys are not always possible to install. The plastic pipe is neutral to alkalis and water, and the temperature does not exceed the operating range for this type of plastic. In addition, a chimney made of plastic pipes is easy to install, and it is connected with ordinary couplings.
Plastic chimney pipes gas boiler will last much longer than metal ones. Since the chimney is not exposed to critical temperatures, it can be closed in a decorative box that fits beautifully into the interior of the house. Materials for the manufacture of decorative boxes are selected non-flammable in order to increase fire safety.
The disadvantage of such a pipeline is its novelty - the necessary components are still difficult to find in stores.
Contrary to popular belief, a product such as PVC pipelines can be effectively used not only for laying water supply or sewerage systems, but also for supplying energy. A gas pipeline mounted from PVC components has many significant advantages, which will be discussed below.
What are the positive features of gas communications based on plastic pipes?
- The service life of the structure under discussion significantly exceeds that of a metal structure.
- Products of this type do not conduct electricity, which plays an extremely important role in many situations.
- Due to the low weight of polyvinyl chloride structures, the construction of various objects using them is carried out quite quickly.
- Construction of any communications using the pipes in question in domestic and industrial conditions– this is an optimization of the estimate; the use of the same amount of metal parts will cost much more.
For more in-depth study characteristics, it is best to familiarize yourself with the article devoted to this issue on our website - Temperatures, pressure, what they consist of and more.
How are communications laid on a private plot?
How to choose good parts for a gas pipeline?
Looking for an answer to the question “which plastic pipes are better for gas?” It is worth proceeding from the pressure under which the system will be operated. The gas transmission structure may fall into one of the following categories:
- Category No. 1. This section includes systems operating under high pressure and made exclusively of steel.
- Group No. 2. Intracity transportation systems. The optimal pressure for the operation of such systems is 0.3 - 0.6 MPa; the use of thick-walled plastic parts is permissible for their creation.
- List No. 3. Gas pressure – from 0.005 – 0.3 MPa. Such systems are used to transfer gas from a distributor to a certain number of high-rise buildings, due to which the gas appears in the consumer’s apartment. Application polymer parts is considered acceptable; it is possible to carry gas through plastic pipes.
- The last subgroup is all kinds of connections inside apartments. The pressure here is minimal and the use of the products in question is considered acceptable.
Based on such data, we can say that the answer to the question “is it possible to use PVC to lay a gas pipeline” largely depends on what the current technical, climatic and geophysical operating conditions of the structure are. But the answer to the question of whether gas corrodes plastic pipes was given quite a long time ago and is negative - gas does not interact with PVC. Learn more about the abbreviation and meaning.
PVC pipe for gas - connection with a plastic pipe and basic tolerances
Which plastic pipes are best for gas? Is it possible to use PVC for gas wiring in a private house or apartment. Pros and cons of such systems.
Gas plastic pipes
When wondering how best to supply gas to a private home or install it in the yard, take care to choose modern pipes.
Previously, they were made of metal, but with the development of progressive technologies, a safe gas main is laid from pipes made of inexpensive, reliable material.
Special plastic pipes for transporting flammable gases are used in industrial production, public utilities and household services by private individuals. Characteristic feature external design protrudes black with a longitudinal bright yellow stripe which prevents products from being confused with similar products that have a different purpose.
Advantages of gas plastic pipes
- long service life;
- wear resistance;
- light weight;
- easy installation:
- economical consumption of installation materials, because the products are produced in long sections or multi-meter coils;
- welding speed;
- reusability;
- easy disposal;
- safety of use (material is non-toxic);
Plastic pipes are gradually replacing steel and cast iron products that are used to lay gas pipelines. Metal products are used mainly at industrial facilities and in old public utilities, as well as when laying large gas transmission systems that transport cubic meters of raw materials amounting to thousands.
Benefits for small flue structures, which characterize polymers:
- the ability to last longer without losing its qualities;
- nonconductivity electric current;
- corrosion resistance;
- easy to assemble without using complex equipment;
- resistance to aggressive environments;
- water and soundproof;
- compliance with international safety standards;
- high permeability, thanks to the smooth internal surface, does not allow solid particles trapped in the system to settle;
- environmental friendliness, guaranteeing the integrity of the environment and human health;
- low weight speeds up installation;
- low cost compared to products made of metal;
- the possibility of quick replacement, which is important for the urgent restoration of supply to residential buildings and industrial facilities;
Capable of transporting liquids and gases over the required distances without unnecessary losses. Therefore, they are successfully used in production and public utilities. Aesthetic appearance and sound insulation make polymers suitable for urban environments or crowded areas.
Types of gas plastic pipes
It is important to consider the properties of the material:
- polyvinyl chloride (PVC)
- polyethylene;
- metal-polymer products;
- polypropylene;
Polyvinyl chloride- a common material that is valued for its affordable cost and ease of installation of indoor systems. The disadvantage is that during chemical decomposition, polyvinyl chloride releases a toxic substance - chlorethylene.
Therefore, the use of this material is only permissible for laying highways in open areas underground.
Polyethylene- This is a profitable option for cold transportation of gases and liquids in private households or in production. Affordability contributes to the widespread use of polyethylene pipes among the population.
It is worth taking care of their insulation. When used without insulation, the strength and solidity of the product is quickly lost, and the likelihood of leaks increases.
Metal-polymer differ in that the polyethylene layer is located in reliable insulation. Resistant to unfavorable factors from the outside, including mechanical damage. They are an order of magnitude more expensive than pipes made from other materials, however, they are very reliable in operation.
They can be easily given the desired shape, which makes installation and installation of equipment easier. Metal-plastic products bend without effort, taking the desired position. They are connected to each other using crimped or pressed fittings.
Polypropylene Designed for gas transportation in open areas. Low chemical activity prevents it from deforming and changing its quality characteristics. Polypropylene does not need additional insulation, as it is resistant to ultraviolet radiation and temperature fluctuations.
It is considered a gas-permeable material, so it cannot be used for wiring inside buildings.
Flexibility contributes to their hidden gasket, which protects against the negative effects of ultraviolet radiation, excessive thermal expansion and preserves the integrity of the products. To prevent leakage, avoid unnecessary connections by using multi-meter rolls of flexible polymer pipes.
Numerous joints increase the cost of laying the highway and lengthen the operation. It is important to use the same type of materials during installation. This approach helps avoid the appearance of cracks and other mechanical damage, which arise due to the heterogeneity of the structure.
Special tools and technologies that are used for welding plastic pipes significantly speed up the creation of a gas pipeline.
Three methods of welding polymer products:
- electrofusion welding carried out by melting the plastic due to the thermal effect of electric current on the fitting. It's economical and effective method, however, to use it in remote places you need to have a mobile source of electricity;
- socket welding used for joining polymer products into sewer systems and eyeliners;
- butt welding using a special soldering iron is the most used option for creating a reliable connection of polymer products.
Metal-plastic pipes, which have a low coefficient of thermal expansion, deserve special attention. This makes them ideal for hidden wiring inside the walls of buildings or for private gas installations in a summer kitchen, outbuilding or guest house.
Installation of metal-plastic is carried out exclusively with press fittings, tightly crimped special tools. It is important to remember that installation must be carried out by qualified workers who are familiar with safety precautions, material characteristics and work features.
Special shut-off valves are used to shut off the gas supply. Their operation is carried out using a key or manually. Shut-off valves do not require additional sealing, since the precisely fitted parts are tightly connected to each other.
IN basements the system must be open, and installation must be carried out with a mandatory gap between the pipes and the walls. The passages in the walls and ceilings are covered with special additional protection.
The hood is installed on load-bearing walls or partitions that are made of non-combustible materials. To prevent the appearance of outside condensation walls - the room is insulated.
Installation of devices without connection to chimney ducts is carried out where there are about five square meters of free space for each burner. A small water heater requires at least six meters, and a bathroom heater is placed on an area of approximately ten square meters.
If in the room where it is installed kitchen stove or a water heating system, there is no space necessary to ensure full air access, then a ventilation outlet must be built on top.
Considering the fact that gas furnaces, heating appliances and water heating devices use oxygen-saturated air for combustion, it is important to ensure its free access to the room using ventilation. For this purpose, a narrow gap is created between the door to the kitchen or other room and the floor surface.
All devices must be equipped with taps to shut off gas flows. Installation of heating devices and gas ovens It is advisable to carry out with the hood on or ventilation running. During installation, the tightness of the pipes is compromised, so upon completion of the gas supply system, it is necessary to check their integrity.
It is important to take into account some features of the materials and the area where the work is planned. Polymers are susceptible to exposure to chlorine, heat and ultraviolet radiation. When heated, they release hydrochloric acid, which causes chemical burns on contact.
Therefore, plastic products are insulated special materials, and gas pipelines in open areas are located underground. The laying of underground lines must be carried out with insulation. It is prohibited to place pipelines in concrete structures and poorly ventilated adits, since the accumulation of gas due to a leak can cause a strong explosion.
For hidden installation, it is necessary to take into account the coefficient of thermal expansion of polymers, leaving for this free place and equipping pipes with soft thermal insulation. It is recommended to use polyethylene pipes for wiring in residential, work, industrial and other premises. This material, like its analogues, is marked with a yellow longitudinal stripe.
When choosing plastic pipes for creating gas wiring, you must pay attention to the quality of workmanship and the manufacturer. Manufacturers who care about their reputation guarantee a long service life of products and provide the opportunity to exchange defective products or return them with monetary compensation.
When making a purchase, the accompanying papers must be stamped and signed by the seller, and a warranty card must be included with the purchase.
Plastic pipe for gas: properties and features of use
Plastic pipe for gas - relatively the new kind equipment. It is increasingly used for supplying and transporting fuel material on the site of a private home or in commercial buildings. This equipment has many advantages, but before using it on your site, you should familiarize yourself with certain features of the product and installation instructions.
Plastic pipes for gas have many advantages over metal ones, but they are only allowed to be laid underground
A high-quality gas pipeline for a private home: what does it consist of?
Gasification in a private cottage is complex and labor-intensive process. It requires maximum precision, accuracy and professionalism. If you need to build or repair gas communications, it is better to seek the help of specialists. It is very important to follow all safety precautions and ensure that the structure and its installation/repair comply with all fire safety requirements.
The gasification scheme in the house includes the following elements:
- gas holder – a special tank for storing gas;
- fuel supply pipes;
- gas boiler, water heater, gas stove, fireplace or other consumer appliances.
When arranging this system, it is important right choice gas pipes. It depends on what working volumes of the gas pipeline you are counting on, what type, soil condition and corrosion activity in the area, as well as how much you are counting on.
Helpful advice! It is better to use the services of specialists to determine what material the gas pipeline elements should be made of - metal or plastic. For this there are certain requirements to gasification and state standards.
Gas supply to the house must be carried out in compliance with safety measures, and the choice of pipes plays an important role here
Advantages of plastic
IN Lately Gas communication equipment made of plastic is very popular. The material itself was invented relatively not so long ago, and in the field of construction and repair work they began to use it even later. However, now it is in demand, as it has advantages compared to its metal counterparts.
Firstly, pipes made from it are not subject to corrosion, which is the main weak point iron products. Plastic pipes for gas pipelines do not require additional protection and insulation also because they do not conduct current and are resistant to negative influence environment, various organic and chemical aggressive substances. In addition, they do not require cathodic protection.
Secondly, the plastic gas pipe functions successfully even with frequent changes temperature regime, but not in extreme conditions.
In addition, such a pipe is very durable and strong, which is ensured by the uniform structure and performance characteristics of the material itself. The warranty period reaches 50 years.
Gas pipes made of plastic are convenient and easy to install, they are easy to transport to the work site
Another advantage is their versatility. Due to their plasticity, pipes can be used in the construction of gas pipelines of the most complex design and in the most hard to reach places, unfavorable natural conditions.
Features when compared with steel analogues
In addition to the advantages, any product has certain disadvantages, and plastic pipes for gas pipelines are no exception. Before installing them, please note that installation of such structures is impossible:
- Ground and above ground. Plastic pipes for gas are designed for underground communications located inside the ground.
- In areas of increased seismic activity. This applies to areas where the activity level reaches 6 points.
- Within the city in gas zones high blood pressure(in gas pipelines of categories 1 and 2).
- In enclosed spaces, residential, commercial and industrial buildings, collectors. Here it is customary to use mainly steel structures.
- A plastic gas pipe is inferior to a metal pipe in terms of strength characteristics.
If you compare plastic pipes for gas pipelines and steel communications, you can notice some significant differences:
- Price. Since steel pipes require additional electrical insulation and protective layers, installation and maintenance take more time and money. And the prices for steel are slightly higher than for plastic products.
- Weight and transportation. Steel equipment weighs much more, making it difficult to transport. In addition, polyethylene products are transported in coils, which makes them more compact.
- Versatility. If everything is simple with a plastic gas pipe in a private house, then steel products must be used strictly taking into account temperature, landscape conditions, and operational parameters. Depending on this, the required thickness and design features are selected.
- Installation. A steel pipeline is somewhat more difficult to install than a plastic one.
Despite all the advantages of plastic gas pipes, their use in high-pressure gas pipelines is prohibited
When choosing the right material, be sure to take into account the above differences and features.
Types of plastic pipes
Depending on the material, plastic pipes are different types. Each variety has its own characteristics and specifics, which must be taken into account when laying communications.
The first type is low and high pressure polyethylene pipes. There are two brands of such pipes, visually distinguished by a colored stripe. Gas ones are marked in yellow. This type The equipment is distinguished by its affordable price, light weight, and elasticity. This option is also suitable for installing communication systems for cold water supply and sewerage.
The second type is polyvinyl chloride pipes. This is a more stable design, but its use in water supply systems is not recommended, since when interacting with certain substances it releases the toxin chlorethylene. But for sewerage they are quite suitable as a replacement for cast iron pipes.
A safer option is polypropylene. It is practically inactive when interacting with chemicals. This gives it the same advantage that metal-polymer pipes have - versatility. That is, it can be used in different types of communication systems, including gas supply.
The most common type of gas pipes made of polymers are products made of low-density polyethylene
Pros and cons when comparing metal-plastic and polyethylene pipes
Transporting small-diameter plastic or polyethylene pipes is equally easy. They are produced in coils of 50-500 m and weigh 2-4 times less than their steel counterparts.
Butt welding of gas plastic pipes is also cheaper than in the case of steel ones. This does not require additional Supplies. And the process itself is much simpler and faster. You can use thermistor couplings, which will also simplify the installation procedure. Such a pipeline can be laid by pulling. And it will serve for a long time, without requiring frequent intervention and repair, also thanks to the smooth and elastic inner surface. Thick-walled polyethylene pipes can be used for gas pipelines of the third and sometimes even second category.
However, there are some differences between these types of material:
- at extremely low temperatures, gas polyethylene pipes lose their operational capabilities and possible breakdown;
- PVC pipe is more durable and safer in terms of reaction with chemicals;
- polyethylene is not resistant to the negative effects of ultraviolet rays, so you need to install a plastic gas pipe underground, and not in an open space or in a lit room. Otherwise, it may lead to a decrease in service life and negative consequences. But for PVC pipes this limitation is not relevant;
- Polyethylene pipes can only be laid outdoors in the soil to protect equipment from mechanical damage, while metal-plastic pipes are more durable.
A metal-plastic pipe has greater strength than HDPE, and it can be used where it is not possible to install a hidden pipeline
What to consider during installation
Before you begin installation work, make sure whether plastic pipes for gas can be used on your site. To do this, you should pay attention to some points.
A gas pipeline made of polymer pipes can only be laid hidden method. Polyvinyl chloride has a low expansion rate, so feel free to install pipes in concrete or specially equipped adits. However, not too tightly, but better with the use of insulating soft material so as not to damage the pipe.
Helpful advice! Remember that the fewer fittings, various connecting and butting elements, and accessories you use, the more stable the pressure will be. This means that energy costs for fuel transportation are also reduced.
Use pressed or crimp fittings to connect pipes. Draw up a diagram in advance according to which the plastic gas pipeline will be built. Make sure that it is approved by the relevant authorities. It’s better not to try to do the work yourself, but turn to specialists for help. Remember that equipment for supplying and transporting gas is a dangerous thing and improper installation or maintenance can result in tragic consequences for you and your loved ones.
Methods for connecting elements of communication systems
The plastic pipeline should be installed underground or in another environment (hidden method). Pipes are connected mainly by welding.
Welding of plastic pipes is carried out using a special welding machine, its type depends on the chosen welding method
There are three main welding methods:
- Electrofusion. A plastic gas pipe melts under the influence of current and is connected to another using a fitting. This technique is used for polypropylene and polyethylene gas communications.
- Stykova. This method is used to connect all types of plastic pipes with a diameter of 5 to 16 millimeters.
- Socket This is a type of welding primarily intended for the repair and installation of sewer and water supply systems. They connect pipes with a diameter of 15 to 90 millimeters.
As for plastic pipes for gas in a private house made of polyvinyl chloride, they are connected to each other using glue. Do not be skeptical about this type of fastening, since modern technologies make it possible to produce durable adhesive that provides a strong connection for several decades. This method is more convenient and does not require special equipment, special conditions to carry out the soldering process.
How to weld pipes correctly
In order to correctly and reliably connect the elements of gas communications to each other, strictly follow the instructions for butt welding a plastic pipe. This method allows you to quickly connect system elements. Thanks to it, even large pipes with a diameter of 50 to 120 millimeters can be processed without much difficulty.
To do this you will need a special welding machine. Exist different types such equipment:
- with hydraulic drive;
- with electric drive;
- on program control.
Which one to choose depends on what amount you are expecting, what working conditions are provided and what matters, of course, is the volume of work.
If you have purchased the necessary equipment, you can proceed directly to work.
- First we install the ends of the parts into the welding machine. Make sure that the fixation is good and even;
- then place the heating element between the ends of the pipes being connected. Wait until the first burr forms - that is, when the polyethylene begins to melt;
- Remove the hot plate and press the ends together with the necessary force. After finishing the process, give the pipe time to cool.
Helpful advice! Do not try to cool a plastic pipe by force using water. The temperature should drop to ambient levels naturally.
Plastic pipes for gas are modern material, which has a lot of advantages. But gas pipelines have their own specifics, so these pipes are not allowed to be used in all sections of the gas pipeline. Therefore, it is worth consulting with specialists before making a decision about installing or upgrading the system.
Plastic pipe for gas: properties and features of use
Plastic pipe for gas. Types, application features and characteristics of plastic gas pipes. Basic safety requirements for installation and operation of a gas pipeline.
If you intend to keep up with the times in everything, then it’s time to think about modern plumbing. If it seems to you that your old cast iron pipes, firstly, “don’t bother you”, and secondly, are still quite modern, then you are a little mistaken.
IN European countries They have long moved away from metal pipes. In our country, the transition to new technologies has not yet been carried out everywhere, but all this is available via inexpensive price. Why don't you find out more about the modern approach to gas pipelines? What kind of plastic pipes exist, and why are they good?
What types of plastic pipes are there?
The low thermal conductivity of polypropylene prevents condensation from forming, which means that transporting gases or liquids through such pipes does not damage the substance being transferred. Pipes can also be manufactured to any length and diameter, so they are suitable for operations of any size.
Advantages of using it in laying a gas pipeline
Plastic pipes have found their place in the construction of gas pipelines, having many advantages:
- Plastic pipes are ready to last much longer than metal ones.
- They do not interact with the soil and do not conduct current, which allows them to be cathodic exposed.
- In terms of weight, gas pipes consisting of polyethylene are several times lighter than metal ones, so the construction of gas pipelines proceeds faster.
- The prices for such pipes are lower, so the construction of gas pipes from polyethylene is much more profitable.
- Replacing plastic gas pipes is faster due to the availability and ease of installation of new ones. And this is another plus, since if cast iron pipes fail, tens and hundreds of people can be left without gas for weeks.
Gas polyethylene pipes have low pressure (hereinafter referred to as HDPE). They are capable of transporting water and gas over any distance. HDPE pipes transport natural gas from the main line to your apartment. They are also used for the construction of underground gas pipelines, through which flammable gases flow. This is, on the one hand, transportation of fuel, and on the other hand, raw materials.
Can be used in both household and industrial sectors. Nowadays, low-density polyethylene pipes occupy approximately 90 percent of all gas pipeline systems. It is worth noting that when gas is supplied through a pipe, the sound is isolated. Plastic pipes for gas pipelines have an aesthetic appearance.
Installation features
The installation of plastic pipes has its own secrets. Flexibility and high suitability for concealed installation make work easier. However, when installing, it is worth considering their low strength, thermal expansion and sensitivity to ultraviolet radiation.
The fewer connections your system has, the stronger and cheaper your system will be. Gas pipes made of polyethylene must be installed in special conditions in which there are no external influences. To increase the maintenance-free life, you should plan a network of gas pipes of the same material. Otherwise, various cracks and gaps will form at the joints.
In order not to damage the material, the elements should be connected by welding. Pipes that are not resistant to sunlight should be installed in dark areas to ensure their longevity. However, it is possible to determine how long gas pipes will last at the installation stage, since if any material is made from low-quality raw materials or is already damaged, then problems will begin to arise when assembling the system.
Welding: little tricks
Special equipment was invented for this. There are three welding methods: electrofusion welding, butt welding and socket welding.
- Electrofusion welding uses a method of melting plastic by thermal action current and connection to the fitting. This welding is used on sections of gas pipeline connections. Socket welding is often used to connect polyethylene and polypropylene gas pipes.
- Socket welding is used for connections in sewer systems. It is also suitable for bathroom renovations of pipes with a diameter of 15 to 90 mm.
- Butt welding is used for almost any plastic gas pipes with a diameter range from 5 to 16 cm. Gas pipes eliminate the need for labor-intensive cutting work and in most cases eliminate welding work.
When choosing the nature of installation and the technology by which the system will be installed, it is necessary to study the characteristics of the polymer and the connection conditions favorable for it. For example, polyethylene pipes, regardless of the location of assembly, are connected to each other by connecting fittings. This method is the most durable only for this type of pipe.
For polypropylene pipes An unusual welding method is used in which the air is heated to approximately 270 degrees. With this method there is no usual solder. PVC pipes are held on with glue, because all other types of installation are unsuitable for this type of polymer. You shouldn’t have a bad attitude towards such fasteners, since modern glue capable of ensuring the operation of pipes for several decades.
How to choose the right method
If you decide to start installing plastic pipes, it is better not to resort to the welding method, as it is demanding in terms of conditions. This means that it may be of poor quality at home. In this case, it is better to choose metal-plastic pipes.
Pipes such as polyethylene or HDPE are not suitable for home installation, as they have high conditions, practically impossible to implement at home.
Metal-plastic can be given any shape, which makes the work easier for the installer. These pipes bend easily and are secured with crimp or pressed fittings. The latter are more expensive, but their reliability is highly appreciated by experts.
The total cost of installation is made up not only of the cost of the material of the pipes used, but also of the quantity and quality of fasteners, and the number of connections. It happens that in one store pipes are more expensive, but fittings and other connecting things are cheaper, in other stores it’s the opposite. Also don't forget about shaped products, which will also have to be spent on.
It is worth remembering that plastic pipes are currently supplied to the market in huge quantities, so there is always plenty to choose from.
Do plastic pipes have any disadvantages?
Now let's talk about the disadvantages of plastic pipes. Unfortunately, plastic pipes are unstable when used in chlorinated water. Where water with high concentrations of chlorine is used, it is subjected to various resistance tests.
Also, with certain heat or light exposure, plastic pipes begin to release toxic substances. For example, PVC, when heated, releases hydrochloric acid, which, instantly evaporating, causes various severe burns. Also due to favorable conditions on interior walls Bacteria are formed that can penetrate through pipes into kitchens and other human habitats.
You should be careful when buying cheap gas pipes, because not all of them can ensure the safety of your home. You should immediately set the maximum temperature value that your pipeline can definitely withstand without various changes in its composition.
The disadvantages of modern plastic pipes limit their scope of application, but in the gas sector there are fewer problems with such pipes. This is explained by the chemically low-active gases flowing through the pipes and certain properties of gas pipes, which make it possible to build gas pipelines that are ready to last for decades. Gas pipes will serve you for a long time if they are in your home in conditions isolated from light and heat.
The domestic gas pipeline is installed naturally inside the building and premises. Its main task is to transmit gas through a flow meter to all equipment that requires gas supply (from the stove to the fireplace and convector).
The pipeline consists of parts:
- pipes and hoses;
- fittings (in other words, connecting elements).
To the pipeline components state of aggregation The energy carrier and its physical capabilities require a number of tasks:
- Seal gas connections and pipes. A gas leak can only lead to the most unpleasant consequences.
- The gas pipeline and its components must be endowed with high strength to withstand pressure from 1.5 -2.5 MPa. But the gas pipeline itself has only 0.3 MPa of pressure inside. Thus, the fitting, joint and pipe must be prepared for high pressure in a short time.
- The pipe itself must be created using a corrosion-resistant material and contain anti-corrosion components. But there is no need to protect its internal part from corrosion, since natural gas does not oxidize such structures.
Important! The entire process of connecting gas to a stove, boiler, convector, etc. should only be done with the help of professionals. But Special attention It is recommended to take it to places close to the point of consumption, as part of safety, check the strength several times.
All gas pipes need to be assessed and systematized, and fittings also come in different types depending on the diameter and the material being made, so we provide a list of product types.
Gas pipes and fittings made of steel
It is not for nothing that products made of steel are so often used in the construction of gas pipelines, as they are extremely durable and reliable. And when installing a domestic gas pipeline, you can use both welded pipes and seamless rolled products, regardless of the hot-rolled and cold-rolled manufacturing method.
Concerning internal diameter gas pipes, then it is no more than ½ inch. The gaseous medium is not viscous, and all corner joints and cut-ins in it are joined at an angle of 90 degrees.
The fittings are designed for threaded and welded installation. Welding installation involves the creation of a circumferential seam, which, due to gas soldering, is applied to the cutting of the joint between the pipe and the connecting element.
Not all welders are allowed to perform this type of welding, but only specialists who have the skills to work with high pressure in the system.
Only this installation is able to handle joints, cut-ins and corner connections on long sections of the gas pipeline. But fittings and connecting elements of specific consumption devices are only detachable.
As for detachable installation, it occurs in the following sequence:
- Cutting a drive to which a lock nut and a fitting with a thread inside are attached.
- The joint is reinforced with polymer tape and again with a lock nut.
Threaded connecting elements for gas pipelines are mounted in the same sequence, attaching them to the threaded outlet of the gas consumption device.
Important! When the entire gas pipeline system is ready, it is painted yellow. To determine the color in production, they put a mark on the color that needs to be used. But you can also leave it in the same place and paint them any other color.
Gas pipes and fittings made of polymer
All kinds of parts and components for a polymer gas pipeline are very easy to cut and can withstand high pressure. They are seamless and installation requires a regular soldering iron and connecting elements.
Distinctive qualities are corrosion resistance, strength for underground gas pipelines and reliability for main lines with medium and high pressure.
Polymer metal fittings and rubber hoses
Used in a gas pipeline chain to connect to consumer appliances. Naturally, a pipe is supplied to a certain distance, but a rubber hose is connected to the device itself and the fitting through a valve.
The gas hose is sold complete with prepared connecting elements (with internal and external threads). Based on this, the installation of the hose occurs extremely quickly and accurately.
During installation, it is necessary to use FUM polymer tape to screw the connecting element into the valve. And after this, the fitting is put on the fitting of the consumption device, also with a polymer tape.
If it happens that the connecting elements you have chosen are not suitable for gas hoses, then adapters (sleeve and fitting) with two types of threads can correct this problem. You just have to understand that all kinds of adapters reduce the strength of the structure itself and gas leaks may occur.
Metal fittings and metal-plastic gas pipes
Used for the construction of water pipelines and domestic heating systems. These pipes are also used to create household gas pipelines. The pressure they can withstand is about 4.5 MPa, which allows them to be mounted using both threaded and compression fittings. It is advisable to use crimp connecting elements, since they are able to maintain the tightness of the entire structure during the entire period of its use. Because threaded fittings can unwind over time and become a big threat to gas leaks and emergency condition the whole house.
Their defining quality is the non-corrosiveness and flexibility of the heat pipe itself. There is no need for corner fittings since it is so flexible that it can be turned in any direction and at any angle.
Good luck in creating your gas pipeline!
When installing autonomous gasification for a private home, it is necessary to ensure compliance with fire safety standards and current SNiP. The current requirements stipulate many important nuances. The standards, in particular, indicate: what gas supply pipes can be used, features around and inside the house installation, etc.
Polyethylene pipes for gas supply
PE pipes used in gas supply systems have earned a good reputation due to their ease of installation, long term operation, as well as full compliance with GOST. Unlike metal analogues, laying polyethylene pipes is much faster and does not require the use of gas-electric welding equipment.Provided proper installation, the service life of the product is at least 90-100 years. Polyethylene is not afraid of exposure to carbon dioxide, aggressive environments, and can withstand high pressure.
Where is PE pipe used for gas supply?
PE pipes are used to lay gas supply pipelines underground. According to existing standards, they are already connected to a residential building using polyethylene.A huge advantage of PE is the ability to create threadless connections by welding, which is a mandatory requirement during installation. Polyethylene can also be used when laying gas pipelines inside a building.
Pipe of the following categories is produced for the gas pipeline:
- Class - the material is manufactured in two classes marked PE 80 and PE 100.
- Size ratio– standard sizes SDR 17.6 and SDR 11 are used, the nominal diameter is 20-400 mm.
- Color – the pipe is black. PE 80 have yellow, PE 100 blue insert stripes.
The characteristics of PE pipes and their properties make the use of polyethylene optimal when laying a gas supply pipeline, both for private and industrial gasification.
How to weld PE pipe correctly
The welding technology of PE pipes fully complies with the requirements of SNiP. After installation, the pipeline is completely free of threaded connections, which ensures maximum tightness and no leaks.Welding is carried out in several ways:
- Electrofusion welding– the coupling provides the most durable connection, capable of withstanding pressure up to 16 atm. Welding is performed using heating elements, embedded in a coupling placed on the pipe. Electrical voltage is supplied to the fitting.
- Butt welding - the edges of the pipe are heated with a special soldering iron to a state of viscosity sufficient to fasten the parts together. Fittings for polyethylene pipes.
When constructing gas supply systems for autonomous gasification of a country or cottage village, electrofusion welding is used, which is a more expensive but reliable installation method. For individual gasification, it is allowed to use butt welding.
Advantages and disadvantages of PE pipes
The choice of using polyethylene pipes for gas supply is easy to justify thanks to a large number advantages and almost complete absence of disadvantages. As positive aspects can be distinguished:- Features of the use of PE pipes depending on their purpose. Products are manufactured taking into account various needs and operating conditions. There is a pipe specially designed for use in water supply and sewerage systems.
HDPE pipes are designed for gas supply. The material of the pipeline sleeve is able to withstand pressure and aggressive effects of various chemicals and other substances. - Resistance to mechanical stress. Above-ground and underground installation of gas supply network pipelines using PE 80 and PE 100 is allowed, even under conditions of seismological activity. The pipe loses strength only when the building deforms or shrinks by more than 7%.
The legislation of Japan (a country with a high level of earthquakes) allows the use of PE pipelines when conducting communications. - High pipe capacity - the inner side of the pipeline is completely devoid of roughness and is absolutely smooth. To supply gaseous mixtures there is no need to create additional pressure in the system.
The positive effect of the lack of roughness of polyethylene pipes is obvious when comparing PE products with metal. Bandwidth the first ones are 25-30% higher. Over time, no build-up appears on the inside, so the conductivity coefficient does not change. - Simple installation technology and low cost of polyethylene pipes. Modern pipelines and fittings of gas supply systems speed up the connection process due to the absence of the need to use complex equipment. Self-installation is allowed.
The cost of PE products is significantly lower than that of copper or steel pipes. Simplicity of installation is also achieved by the fact that the product bends easily during installation.
- Susceptibility to heating – the maximum temperature of the pipe at which deformation occurs 70-80°C.
- The influence of ultraviolet radiation - one of the disadvantages of PE pipes is that when exposed to direct sun rays on the surface of the pipeline, rapid “aging” of the material occurs. Therefore, if PE pipes are laid in a building or above the ground, the surface is stabilized by covering it with a carbon black-based polymer.
Metal-plastic pipes for gas supply
To carry out gasification of a private house, metal-plastic pipes PEX-B-AL-PEX-B are used. The sleeve of the product is protected polymer composition. The pipe is used for installation inside buildings, including using the hidden installation method.Installation of fittings, adapters and joints are carried out using crimping. Press fittings provide sufficient sealing. The pipe can be laid through residential premises.
Scope of application of metal-polymer pipes
Polymer-coated metal pipes are mainly used for laying pipelines inside residential premises and connecting household heating appliances and gas sources. A set of fittings allows you to connect to pipes made of other materials (PE, steel, etc.).Polymer-metal pipes are made from the following materials:
- The outer and inner layers are made of PEX-b polyethylene.
- Adhesive layer – connects plastic and aluminum
- The middle layer - the core is made of aluminum, welded using TIG welding.
Manufactured standard sizes and basic parameters of pipes are made in such a way as to ensure the most convenient installation. The consumer is offered pipes of 16, 20, 26, 32mm sizes. The material is supplied in coils of 50, 75, 100 m.
Pros and cons of metal-polymer pipes
Multilayer metal-polymer pipes have a number of advantages over analogues:- Easy installation - the crimping mechanism allows you to quickly install a gas pipeline without the involvement of specialists and expensive equipment.
- Cost-effective - the pipe bends well, which allows you to get by with a minimum number of fittings when laying a gas supply system.
- Possibility of running the pipe indoors. Good appearance and good sealing of the product makes possible installation even in living rooms.
The following can be identified as disadvantages:
- Limited prospects for use metal-plastic pipes– polymer products are intended for installation inside a building.
- Low heating temperature – the product remains sealed at temperatures from -15 to +40°C.
Steel pipes for gas supply
Steel products are manufactured in strict accordance with GOST 380 88 for pipes. The requirements stipulate that for underground communications the wall thickness should not be less than 3 mm, aboveground 2 mm. Pipeline units made of seamless steel pipes must have mandatory certification. The documents indicate:- Steel grade.
- Production method.
- Batch number.
- Mark on passing QC.
Laying gas supply pipelines from seamless steel pipes is a long and painstaking process. The joints are connected using electric arc or gas electric welding. Quality control of welded joints is mandatory. Simultaneously with pipe laying, insulation and laying work is carried out.
The main disadvantages of steel pipes are: the complex installation process, the high cost of the material and the need for welding, which significantly increases installation time.
Copper pipes for gasification
Lately it has become possible use copper pipes in gas pipelines of low and medium pressure. The standards regarding the use of non-ferrous metals when installing a gas supply system are stipulated in, as well as.Alloys are not allowed. The material is made of pure copper. For this reason, pipes made of non-ferrous metals are quite an expensive “pleasure”, and therefore are not widely used.
How to calculate pipe diameter
The choice of diameter of internal gasification pipes depends on several factors:- Gas speed and pressure.
- The length of the pipeline, starting from the gas tank and ending with the connection to the point of gas consumption.
- Minimum system pressure.
Requirements for laying gas supply pipes
Fire safety equipment, SNiP and Federal Law regulate safe minimum distances to the gas pipeline when performing autonomous gasification of a private house. Additionally, the following factors are taken into account:- The presence or absence of stray currents.
- Hydraulic calculation (presence of groundwater).
- Building density.
- Soil activity.
Near-house gas pipe installation
There are two ways to lay communications: aboveground and underground. The first is often used for industrial facilities. The rules for above-ground pipeline installation require:- Make electrical protection at the intersection of power supply systems.
- The height of the pipe in a crowded place is at least 2.2 m, above the roadway 5 m.
- Provided there is a complete absence of people and vehicles, fastening the pipeline is allowed on low supports from 0.35 m.
- Gas pipes must be located at least 3 m from the road.
- The depth of pipes is calculated depending on the freezing point, but not less than 0.8 m.
- Requirements for polyethylene pipes for laying gas supply systems are specified in SP 62.13330. Maximum length laying of the gas pipeline is no more than 50 m.
- Distribution to gas consumption points is carried out along the external walls of the building. The rules for laying polyethylene pipes for gas supply provide for the possibility of exclusively underground installation systems. If overhead wiring is required, seamless steel pipes should be selected.
- The standard distance of the low-pressure gas supply pipeline to the building wall is at least 10 cm. It is prohibited to place the pipe close to the wall. Entry into the room is carried out using a sleeve.
Installation of autonomous gasification of a facility is a complex technological undertaking that requires compliance with SNiP and PB, as well as technical regulations for laying pipes. It is almost impossible to complete all the work independently and without violations.
In-house gas pipe laying
The internal gas pipeline is carried out taking into account the following requirements:- For installation, a steel or metal-polymer pipe is used.
- Installation required additional components: pressure stabilizers, thermal shut-off valves, gas alarm.
- The length of the pipes to be laid is no more than 3 m. B multi-storey building The distribution is carried out along the external walls, directly to each source of gas consumption.
- At the intersection of electrical wiring with gas supply pipes, contact between them is made impossible. If necessary, the wiring is laid in a metal pipe.