Features of water pipes made of metal. Types of products, their pros and cons, existing sizes, selection rules and pricing.
Metal pipes for water supply are products that serve as carriers of hot or cold water. Despite the emergence of new modern materials for the transportation of liquids, they remain in high demand today. Our article will tell you about their features, the choice.
Types and classification of metal pipes
In the photo, metal water-gas pipes
One of the materials used to make metal pressure pipes for plumbing is high quality carbon steel. It is durable, copes with temperature extremes and has a very low coefficient of thermal expansion.
According to the method of production, steel products are subdivided as follows:
- Galvanized pipes … These include the category of zinc-finished products. Such a protective layer increases their anti-corrosion resistance and allows them to be used not only for supplying water, but also for heating.
- Seamless pipes … They belong to the pipe-rolling assortment of hot-deformed products; they do not have a longitudinal weld seam.
- Electrowelded pipes … The material is made from low-alloy sheet or carbon steel. Products are used for the installation of heating systems and building structures.
- Water-gas pressure (VGP) pipes … Their characteristics are determined by the ratio of diameters determined by the wall thickness.
The greatest demand among the above products is for VGP pipes, which are produced in accordance with GOST 3262-75, and electric-welded pipes (GOST-10704-91). Copper, brass and stainless steel pipes are less commonly used due to their high cost.
The thickness of the walls of the water pipes determines their classification and conventionally divides them into light, ordinary and reinforced. Moreover, their diameter is of decisive importance. For example, with an internal section of 25 mm and a wall thickness of 4 mm, the pipe will be considered reinforced. With the same wall thickness, a product with a diameter of 100 mm will be classified as light.
Conventional steel pipes
used in the absence of special requirements for withstanding high pressure with a water supply system or for the total weight of the material.
Reinforced steel pipes
for a water supply system they have not only a significant weight, price, but are also worse amenable to gas welding. Their processing is a rather laborious task.
Lightweight thin-walled pipes
used to be used to transport gas and were connected by welding. Their use for plumbing is undesirable, since they can rust faster, and the thread on them, due to its fragility, can break off after a couple of years.
Advantages of metal pipes for water supply and their disadvantages
The main advantage of such pipes is their strength. Where the pipeline is subjected to high mechanical stress, such products are indispensable. Steel pipes can be installed under the floor or when pressurized fluid is required.
Other important advantages of the material include:
- Low thermal expansion … This is a useful property of metal pipes, as they are often embedded in screed or plaster. If the thermal expansion is high, this action can cause cracks on the surface of the structure.
- Acceptable cost … Steel pipes, although they do not belong to the category of cheap products, are quite affordable for the client. It is important that almost always their remains are in any household of a private house.
- Wide range of fittings … Any tees, bends or corners can always be found in a specialized store, which cannot be said about fittings for plastic pipes.
Any of the building materials has its drawbacks. When it comes to steel pipes, many of these drawbacks can be solved. The negative qualities of products include the following:
- Poor oxidation stability … Cold water pipes rust most often. This is due to the formation of condensation on them when combined with warm indoor or outdoor air. You can protect the product from such a misfortune with an external primer, painting or thermal insulation.
- Reducing the working section … Over time, metal pipes inside are overgrown with deposits and rust. The throughput of such products is significantly reduced. Helps to solve the problem of restoring the inner diameter of steel pipes of the water supply system periodic flushing of the system with special compounds or replacing its defective part with new pipes.
- Heavy weight … It is felt in the process of mass delivery of products to objects, and does not particularly affect installation.
- High labor intensity of installation of a steel water supply system … An experienced specialist and equipment are required for a high-quality welding of pipes. If this is not the case, the pipeline can be assembled using threaded connections. But making them will require a lot of physical effort and a special tool.
Technical characteristics of metal pipes for water supply
When designing, the following typical sizes of round bars are distinguished:
- Conditional pass (Dy) … In fact, it denotes the inner diameter of metal pipes for plumbing, rounded up to the nearest standard value. Standard pipes are manufactured with Dy 15, 20 and 32 mm
- Outside diameter … It characterizes the volume of the product, taking into account the thickness of its wall.
- Pipe length … The sizes of standard pieces of water pipes are 4-12 m.
When measuring round metal pipes, designations in inches and millimeters are used. In the metric system, the millimeter is considered a stable value. Inches show reference and reference measurement options.
For connection to each other on metal pipes, thread is cut with dimensions: 1/2 "with Dy = 15 mm, 3/4" with Dy = 20 mm and 1 "with Dy = 25 mm. Hence the names - half-inch, inch and 3/4 inch pipes.
The diameter of the pipe, the thickness of its wall, the material of manufacture, the number of GOST or TU must be the marking of the product. Sometimes the marking contains information about the length of the pipe, delivery batch number, production date and other useful information.
Important! Inches can be converted to millimeters, taking into account that 1 inch is 2.54 cm. This will help determine the millimeter value of the diameter of a metal pipe for a water supply, if it is specified in the imperial measurement system. Rounding up should be done.
How to choose the right metal pipes for plumbing?
Water pipes are chosen based on their characteristics and operating conditions. The maximum operating pressure data and the operating temperature they can withstand are taken into account. The necessary parameters must comply with the standards adopted by law and be documented in regulatory enactments.
Plumbing is a piping that delivers water to the equipment that consumes it. Plastic pipes and fittings cannot be used by any network. The operating conditions for these products can vary significantly. Therefore, during installation, plastic is installed in channels and shafts to avoid the risk of damage. There are no restrictions in application in relation to water pipes made of non-ferrous metals and steel. They can work under pressure, serve to transport any water.
For lines of each type and size, the value of the limiting pressure in the network that the pipes can withstand has been determined. It is desirable that it exceed the maximum possible value of the network pressure. For example, the pressure of a centralized water supply system at home can fluctuate from 2.5 to 7.5 bar, and its standard value is 4 bar. Sometimes the highest values can be 10 bar. To keep the water supply intact, it is tested at a pressure of 12 bar.
The choice of the diameter of the metal pipe for the water supply must be done taking into account the following factors:
- Water pressure … With a low pressure, the diameter of the water supply must be larger. A too thin pipe will not increase the pressure, but will only give out a stream of water.
- Plumbing length … With an increase in its length, the pressure in the network decreases. Consequently, large diameter pipes will have to be used.
- Number of pipeline turns … Each of them reduces blood pressure.
If you buy a metal pipe of a significant diameter for the water supply, you can increase the amount of water supplied to the house. In addition to factors depending on the properties of the pipeline, when selecting the diameter of the pipes, the water temperature and the characteristics of the pumping equipment are taken into account. An accurate determination of the diameter can be performed using special formulas, but the main rule when choosing a pipe is not to save on its diameter.
A narrow pipeline has a lot of hydraulic losses. In the future, they will need to be compensated for with a more efficient pump and an increase in the amount of electricity that will be needed to operate such equipment. This will lead to additional costs.
Most often, the common pipeline laid before entering a house or apartment has Dy = 32 mm, and pipes with Dy of 15-20 mm are used for wiring. The inlet pipe is always made of steel. The wiring can be performed with polymer pipes, if the operating conditions of the system allow it.
Prices of metal pipes for plumbing
The price of metal pipes in Russia starts from 30 rubles per 1 m
| Metal pipes | Price, rub / m |
| Galvanized | 120-880 |
| Seamless | 400-790 |
| Electrowelded | 30-100 |
| Water-gas pressure | 73-620 |
The price of metal pipes in Ukraine is at least 14 hryvnia per 1 m
| Metal pipes | Price, UAH / m |
| Galvanized | 55-400 |
| Seamless | 186-360 |
| Electrowelded | 14-47 |
| Water-gas pressure | 34-290 |
To the factors influencing the formation of the cost of 1 running meter. pipes include:
- Preparation method … Steel pipe can be produced by seamless, welded or other method. An electrowelded product is cheaper than a seamless one. This is due to the complexity of the production technology.
- Manufacturing material … Metal pipes are made from various alloys. The result can be stainless steel, structural or otherwise. The type of metal and the content of impurities present in it are taken into account. The most expensive are copper, brass and aluminum products. Their steel counterparts are cheaper.
- Geometric characteristics … They affect the cost of products in the following way. Using mathematical formulas, first calculate the volume of metal in 1 r.m. products. Then, to calculate the weight, the resulting value is multiplied by a number that characterizes the density of the material. Weight determines the cost per meter of pipe, not its length.
- Product sales region … The cost of the goods includes the distance to the manufacturing company, since the pipe products are large and require costs in the process of delivery to the consumer.
- State … The pipes in the warehouse can be new, recently from the factory, used, substandard or low-grade. Their price is determined by compliance with GOST and condition. Naturally, new pipes will be more expensive.
- Factory processing … To improve performance, finished pipes can be further processed by grinding, galvanizing or polishing at the factory. All this allows you to make the appearance of products more presentable and expand their scope of use, even if the prices of metal pipes for water supply do not depend on it.
Real reviews of metal pipes for water supply
In the photo, the process of installing copper pipes for water supply
During construction and renovation, many want to save money and therefore buy cheaper building and finishing materials. But in some cases, this is strongly discouraged. It's about the quality of the water pipes. Selecting such materials, it is worth minimizing the risk of a system breakthrough as much as possible, which brings a lot of losses due to flooding of premises. The wide selection baffles many, and people go looking for comments on plastic pipes and reviews of metal pipes on the Internet.
We suggest reading a few comments from experts and ordinary people:
Maxim, 37 years old
I build turnkey houses. Of course, plastic is used in budget options, but really well-thought-out projects will always have metal. Ideally, copper pipes that will last almost forever. But if the price tag bites, then just steel ones will show themselves from a very good side. How many times have I already come across the fact that plastic pipes are short-lived. Many people complain about them. And metal ones serve faithfully.
Inna, 46 years old
After the plastic pipe on the radiator burst, I have only metal pipes throughout the apartment. Better yet, in 20 years I will completely replace them with new ones, but I will be sure that neither my apartment nor the apartment of the neighbors below will suffer from water anymore. Renovation of a flooded apartment is a pretty penny. So why not protect yourself from risk and unpleasant emotions?
Review of metal pipes Vasily, 21 years old
After my parents bought me an apartment, they set a condition - earn money for repairs yourself. Therefore, when spending money, I wanted it to be really reliable. I consulted with experts in the store, read a lot of reviews. And in the end I spent on metal pipes, which I do not regret a single drop. Yes, more expensive, but more reliable. How long I spent on the Internet in various forums - everyone agrees on this opinion.
Sergey, 55 years old
I have been working as a plumber in the housing office for more than 30 years, and I can tell you there is nothing better than metal pipes. The pipes installed in the USSR many years ago still serve people today. Yes, metal turns out to be more expensive than newfangled plastic, but if you do it for yourself and for years, then nothing has been invented better than it. I'm tired of going out on calls with burst plastic pipes, by the look of which you can't tell whether it will burst tomorrow or in a year.
How to connect metal pipes - watch the video:
Despite the fact that the popularity of plastic plumbing is increasing every year, steel pipes are still the most reliable. This fact is confirmed by their long-term operation in any conditions.
