The real life of a galvanized water pipe. Service life of steel pipes
Without pipes, it is impossible to imagine the life of not only an individual house or enterprise, but also entire regions and cities. Pipes are used to move cold and hot water, to create heating mains, sewage systems, and for many other purposes. Not only their service life depends on the quality of pipes, but also the ecology of both a separate section and the country as a whole.
The length of networks (in a single-pipe dimension) in Russia is impressive - it is more than 1 million km! At the same time, about 30% (!) of pipelines are so worn out that they need urgent replacement and repair.
Let's take a closer look various types pipelines (water supply, heat supply, sewerage), their condition and problems arising from their deterioration and poor quality.
Water supply pipelines
The total length of water supply networks is more than half a million km, and about 30% of them need to be replaced and repaired. What threaten the old steel pipelines overgrown with rust?
Firstly: with leaky pipelines, it is impossible to ensure the supply of water from its intake to the tap without reducing the quality. Water pollution during its transportation occurs both by corrosion products and as a result of groundwater infiltration through leaks. Polluted water impairs health and affects the life expectancy of every Russian at the genetic level.
Secondly: the overgrowth of the inner surface of pipelines leads to an increase in the energy required for pumping. The inner surfaces of about 80% of water pipes have deposits that throughput in comparison with the design, it is reduced by 2-2.5 and even 3 times! According to the calculations of the Academy of Public Utilities, the overgrowth of the inner surface of pipes leads to an increase in the cost of 1 m 3 of water up to 50%, and the cost of electricity for the production and sale of 1 m 3 of water is 30% higher than the average European level.
Thirdly, through the holes formed in the old rusted pipelines, water enters the soil, causing an increase in the level of groundwater, which in turn contributes to corrosion damage to the outer surface of the pipeline. It is obvious that the increase in the level of groundwater due to leaks from pipelines threatens the safety of engineering communications and buildings.
Fourthly, the loss of water during its transportation through leaky pipelines, amounting to tens of percent, leads to the fact that the consumer is forced to pay for water that he does not receive. Russia annually takes about 80 billion m 3 of water from open and underground sources for municipal, industrial and agricultural needs. If we take losses in the amount of 30% of the volume of water supplied to the network (25 billion m 3), and the cost of 1 m 3 of water at the level of 30 rubles, then the cost of annually lost water will be 225 billion rubles.
District heating pipelines
Hot water is supplied through these pipelines for heating and hot water supply systems.
Of the approximately one-third of a million km of heat supply networks (in single-pipe measurement), approximately one-sixth are in need of replacement and repair. Obviously, in heating mains, in addition to the problems described in the story about pipelines for water supply (overgrowth and leaks), another important component is added - heat losses during the transportation of hot water from a heat source to its consumer.
The following, truly depressing, figures speak of the deterioration of modern heating networks:
- in a number of regions there are up to 400 accidents per 100 km of networks,
- more than 70 million tons of standard fuel are lost due to leaks in the networks without use, the total cost of which (at the cost of 1 ton of fuel equivalent is 2100 rubles) is 147 billion rubles.
- According to the Association of Producers and Consumers of Industrial Polymer Insulated Pipelines, about 300,000 accidents occur annually in heating networks in the country. With an average cost of eliminating one accident of 30 thousand rubles. annual costs may amount to 9 billion rubles.
- the durability of heat networks is 1.5-2 times lower than abroad, and does not exceed 12-15 years.
It is worth noting that the quality of heating mains is most relevant for Russia, because. we have the highest level of district heating (up to 80%).
The predominant way of laying heating networks in Russian Federation is a laying in impassable channels with mineral wool insulation (80%). Channelless laying, made from prefabricated structures using insulation from armored concrete and bitumen-containing masses (bitumen perlite, bitumen vermiculite, bitumen expanded clay), makes up 10% of the total length of heating networks.
Due to the moistening of the materials used during operation, the heat-shielding properties of heat-insulating structures are sharply reduced, which leads to heat losses that are 2-3 times higher than the normative ones.
The total heat loss in district heating systems is about 20% of the supplied heat, which is 2 times higher than in the advanced countries of Western Europe.
Water disposal (sewerage) pipelines
More than 150,000 km of pipelines are used for wastewater disposal, of which more than 30% need to be replaced and repaired. Worn out and old systems are depressurized, which creates the risk of contamination of water bodies. Besides, sewer networks often laid next to water pipes, and given that there are leaks in both, sewage or contaminated soil is sucked in and enters through aquifers into water pipes. Worn out underground pipelines are one of the main causes of intestinal infectious diseases, which have long been forgotten in developed countries!
We reviewed the current deplorable situation. Question: "Who is to blame?" we will leave it for other authors and other publications, and here we will try to answer another eternal question:
What to do?
One of the main problems is that about 70% of the existing engineering networks in Russia consist of steel pipes.
The main advantage of steel pipes is their strength. This is important when moving high-pressure media through pipelines. At the same time, in the housing and communal sector, the strength qualities of steel pipes are used by no more than 30%. Thus, the main advantage of steel pipelines turns out to be practically unnecessary, and the disadvantages (corrosion, and as a result, through damage, loss of pumped liquid, groundwater suction, the quality of transported water deteriorates, overgrowth of the inner surface and reduction in the internal section, and as a result, an increase in energy expended by pumping water, etc.) take a lot of money.
In recent years, throughout the civilized world, steel pipes have been replaced by pipes made of polymeric materials. This is not at all strange, because they are not subject to corrosion, and their service life is many times greater than the "life expectancy" of steel. This is clearly seen in Table 1.
Table 1. Normative service life of pipeline networks
Growth rates of a share of plastic pipes in the developed countries are characteristic. In Europe, approximately 40,000 km of plastic pipes are used per year. Their share in the systems of internal pipeline networks during new construction in industrialized countries is 20-40%, and in the most economically prosperous - even more (in Switzerland - 69.3%, in Finland - 50.8%, in Germany - 46, 2%). In the Netherlands, the share of plastic pipelines in water supply systems exceeds 40%. Currently, in England, 99% of newly built water pipelines are made of polyethylene. Already in 1997, 1.9 billion m of such pipes were used in Western, Eastern and Central Europe. It is assumed that the annual increase in the use of plastic pipes will be 6-8%.
I would like to dispel the typical misconception that plastic pipes are more expensive than steel pipes. Real calculations show that even in construction they are cheaper than steel pipes. According to the Moscow Research and Design Institute of Typology and Experimental Design (MNIITEP), the use of pipes made of polymer materials can reduce the cost of the sanitary section of a residential building by 23.5%, secondary school by 21.4%, children preschool by 21.9%.
In the field of creating modern heating mains, the most relevant is the use of pipes in thermal insulation made of polyurethane foam and in a waterproof shell made of polyethylene or galvanized steel. Such pipelines can significantly reduce heat losses during its transportation, and also solve the problem of protecting the outer surface of steel pipes from corrosion.
To exclude the possibility of formation of internal corrosion of pipelines, the most optimal is an industrially manufactured design of a heat pipeline using pipes made of polymeric materials that are not subject to corrosion and overgrowth of the inner surface with various deposits.
In particular, for hot water and heating systems, it is permissible to use pipes made of a random copolymer of propylene with ethylene (random copolymer - PPR-80), having a thermal insulation layer of polyurethane foam (PPU) and a waterproof coating (shell). With channelless laying of such pipes in the ground, the hydroprotective shell is made of polyethylene pipe, at channel or open - from galvanized steel. Another promising corrosion-resistant material for heat supply pipelines is cross-linked polyethylene, which is widely used in world practice for internal sanitary pipelines for hot water supply and heating.
Summarizing, we can say that the problem of replacing old worn-out pipelines is indeed very large and serious, but it can be solved using new materials and technologies.
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Moreover, they are still installed in most apartments. Steel pipes are characterized by low cost, while the cost of their installation is high. But even in this case, this option is much more economical than, for example,.
Branch pipe clamp allows you to connect to an existing pipeline without cutting it or inserting a tee
It is also important to note that for heating systems it is preferable to use pipes made of black steel, and for water supply it is better to choose from galvanized steel. The main disadvantage of steel pipes is corrosion. It is completely impossible to prevent it. It can only be slowed down if a zinc coating is used in the production of pipes (inside and outside).
When purchasing pipes for metal communications, pay attention to the method of their manufacture (this affects the period of their use). They can be either electric-welded and used for plumbing, heating systems and gas pipelines, or seamless. The fact is that with an equal inner diameter, it is lower than, for example, that of copper or polymer. The reason lies in the inner surface, which is rough in them and, accordingly, causes turbulence in the fluid flow, thus making it difficult to move.
Features of pipeline communications made of steel
Installation of heating pipes when connecting shut-off / control valves or steel pipelines using a flange connection, where 1 is a steel pipe; 3 - steel flange according to GOST 12820-80 with a groove of inner diameter (2); 4 - shoulder sleeve; 5 - gasket; 6 and 7 - fasteners; 8 - a socket welded into a socket to a pipeline made of polymeric material and a shoulder sleeve.
Steel pipes easily withstand hydraulic loads, and this does not affect the durability and, accordingly, does not shorten their service life. They have good thermal conductivity and low coefficient expansion of the material with temperature changes allows you to hide in the wall. They are also great for creating radiant forms of water heating.
Nevertheless, the disadvantages of metal steel communications are no less than the advantages. Of course, they are heavy and bulky, which makes them not so easy to use. Installation of pipes is not possible without gas welding, which significantly increases its cost. On average, steel pipes in real life serve more than 20 years.
They are operated in terrible conditions underground or in multi-storey buildings as various utility lines at a coolant temperature that is close to the boiling state and an internal pressure of more than 6 atm. And with water hammer, it reaches up to 12-15 atmospheres. It is under such conditions that they are actually used, in a mode in which no metal-plastic or plastic pipe Couldn't even last 15 minutes. This is the main advantage of metal pipes.
In an ordinary urban high-rise building, steel pipes serve while being in open form or plastered in brick walls. In conditions under which the internal is 6-7 atm., And the water temperature reaches 90 degrees, only pipes made of steel can work.
Due to their mechanical strength and low coefficient of thermal expansion, in the water supply and heat supply system in urban multi-storey buildings, varieties of metal pipes currently have no competitors. But no one wants to work with such pipes, since they are straight (sometimes up to 12 meters), heavy and difficult to transport. When working with them, the most unpleasant thing is that they are mounted by gas welding.
A few more benefits
It is worth mentioning the life of steel pipes in Stalin-era houses, where they are used in the heating system during temperature regime not exceeding 50-60 degrees. Heating systems that are equipped cast iron radiators, can easily last more than a century. Although they can’t even, they serve. There are cases when such heating systems were built at the end of the 19th century and functioned perfectly until the mid-80s of the 20th century.
It is worth noting another good property of steel. It is difficult to overestimate it - this is the lowest coefficient of thermal expansion among other pipes. So, for example, for copper it is 2 times more, and for plastic - 15-20 times. In simple terms, this is the stability of their sizes.
So, no other pipes can be hidden in walls or floors, as they increase or decrease in size when the temperature changes (this is especially important if heating is considered). And this already leads to a violation of the integrity of the coating in which they are mounted. Therefore, when using non-metallic pipes, such compensating structures are used, such as, for example, soft thermal insulation.
A steel pipe, like many metal pipes, is best suited for the construction of radiant (not to be confused with radiant) water heating systems. If we talk about the shortcomings, then the most important one can be recorded a high level of corrosion, as well as damage different nature. All steel pipes used in heating rust very quickly and become clogged with various deposits. the best way protection is the use of galvanizing technology and the laying of pipes of a larger diameter.
Perhaps the only and main drawback of using galvanizing is the impossibility of using antifreeze in this system, on which the operation depends, that is, the service time. If we consider it in more detail, then the zinc coating increases the resistance to corrosion, from which their service may deteriorate. This contributes to the fact that the term of "life" and service of metal structures is extended by about several years.
Useful information about steel communications
There are several methods for galvanizing steel pipes: diffusion and hot. The hot-dip galvanizing method is a process where everything at a temperature of 450 degrees is immersed directly in liquid zinc. This is a very labor intensive process.
Diffusion coating is a process where the pipe is coated directly with zinc atoms at a temperature of 400 degrees. During this, zinc atoms penetrate into the intercrystalline lattice of the heating pipe and form a fairly strong bond. Such a coating is carried out in special powder containers. That is why the galvanized steel pipe receives the necessary electrochemical protection. While other options for metal structures behave differently when galvanized, so they get a completely different result.
Installation of steel heating systems usually occurs in two ways: by welding and by twisting threaded threads. The most common option is for heating, which occurs when using self-shielded wire. Its diameter ranges from 0.8 to 1.2 mm. In some cases, it is also possible to use electrodes, the diameter of which can reach up to 3 mm.
But non-galvanized pipes are welded mainly with an overlap. If there is, of course, a diameter of 25 mm. At enterprises, end-to-end pipe connections of this diameter are sometimes used. The main difficulties are the welding of metal heating pipes, which are under pressure, because they are almost always close to the walls of the building. During installation heating system special requirements are also imposed on the weld, the outer surface of which must be evenly welded without any cuts, cracks or sagging.
Steel pipes have a good 50-year history of use, significant advantages and look quite good against the background of new ones. modern technologies. But still, the use of metal pipes slightly lost its relevance when polymer pipes began to be actively used in heating systems.
The quality of living in a country or apartment building largely depends on what water pipes were installed in it. In this article, we will look at several types and characteristics of pipes for domestic plumbing.
Modern pipe manufacturers use a variety of structural materials in the manufacture of their products. However, at present, only plastic or metal pipes.
Metal pipes for water pipes
The first metal water pipes appeared in the homes of wealthy citizens 3 centuries ago. Since then, the metal sewerage system has hardly undergone any changes.
In modern houses and apartments, you can see sewer pipes made of the following types of metals:
- High-carbon, structural, unalloyed steel without corrosion protection, otherwise called "black".
- Copper of a high level of purification with a minimum amount of impurities of antimony, lead and arsenic (less than 0.001 percent).
- High-carbon, structural steel with a zinc-based anti-corrosion coating, otherwise called galvanized steel.
- Steel alloyed with chromium, or "stainless steel".
Plastic water pipes
Sewer pipes made of polymers appeared in apartments only at the turn of the 20th and 21st centuries. It was at this time that an industrial method for the polymerization of organic substances was created, with the help of which the following types of structural polymers were created:
- Polyethylene is the purest type of plastic, suitable for the construction of drinking water conduits.
- Polypropylene is a plastic with high heat resistance and high ring stiffness.
- PVC is a material with excellent structural rigidity and an excellent ratio between wall thickness and product diameter, guaranteeing a high level of throughput.
In addition to the above types sewer pipes, now there are water systems made of metal-plastic, which are a structural material, which includes layers of metal (aluminum foil) and plastics (polypropylene, polyethylene).
The properties of fittings and water pipes depend on a number of factors, including the parameters of the transported medium, the characteristics of the external environment, and more. Undoubtedly, the structural materials of the pipes have the greatest influence on the properties of the pipeline system. After all, the ability of pipelines to resist internal and external influences depends only on them.
In this article, we will consider the characteristics of all materials used for the production of pipes and touch on their positive and negative qualities.
Characteristics of metal structures
Metal pipes can be steel, copper, galvanized and stainless.
Despite the difference between these types of metal, they all have a common set of advantages, including:
- High level of heat resistance. Steel and copper pipes are able to work in hot and cold pipelines. In addition, these metals can withstand a very high temperature load compared to polymer products (up to 300 degrees Celsius). Therefore, pipes made of such materials can be used not only for drinking and technical water conduits, but also for the home heating system.
- High level of ring stiffness. Metal water pipes can withstand short-term loads of 250 MPa, which is much higher than that of plastic elements. This suggests that the throughput of metal structures is an order of magnitude better than that of similar products made of polymers.
- Excellent maintainability. Any metal pipe can be repaired without completely dismantling the plumbing system. Copper pipes are repaired by soldering, and steel pipes by welding.
There is only one common drawback with metal water pipes - they all have a large mass. Steel and copper structures in general weigh up to 10 times more than those made of plastic. In addition, the installation of steel systems will cost more time and money than the installation of polymer pipes. Water pipelines made of steel are mounted either on not the most reliable threaded connections or a very reliable weld. Copper pipes are installed using compression couplings or by soldering.
Copper pipes differ from their metal "brothers" in that they almost do not corrode, due to which they serve for an incredibly long time. In the absence of serious breakdowns, a copper plumbing system can last several centuries. However, this metal is quite expensive and pipes from it are several times more expensive than steel pipes.
Properties of steel pipes
The exact characteristics of steel water pipes depend on what type of steel it was made from. For example, non-galvanized water pipes are distinguished by their cheap construction and the wide distribution of this substance, but on the other hand, their service life is rather low.
Steel pipes coated with a galvanized layer are devoid of this disadvantage, however, they are much less suitable for repair and have several restrictions on the type of installation; they can only be assembled on a thread.
"Stainless steel" has almost no flaws. It is relatively inexpensive and easy to repair.
But here, too, there is a downside. It consists in the incredibly time-consuming process of installing stainless steel plumbing. This is due to a number of difficulties during the welding of such pipes. Therefore, you will have to spend a lot of money on the services of a specialist welder.
Characteristics of polymer pipes
Having studied the variety of different designs made of these materials, it is easy to understand that such pipelines have a lot of advantages, including the following qualities:
- Complete independence from the pumped substances. Plastic pipes not only do not change their properties under the influence of a liquid passing through them, but also do not affect them. chemical composition, which is especially important in the construction of drinking conduits.
- Good level of ring stiffness. A pipeline made of polymeric materials can withstand a pressure of 5 MPa. Of course, this is not much compared to systems made of copper and steel, but in most cases the pressure in domestic water pipes does not exceed half of this indicator, so the ring stiffness of polymer pipelines will be quite enough even to provide water to an apartment building.
- Long service life. With proper installation and careful use, a polymer pipe can last 100 years, which is several times higher than that of a non-galvanized steel pipe.
- Very simple installation process, most of the operations can be performed without the help of specialists.
The negative properties of polymeric materials, common to all types, include:
- High level of flammability. During a fire, plastic pipes not only burn, but also emit into environment mass of toxic substances.
- Poor structural rigidity. Polymer pipes cannot resist either transverse or longitudinal deformations.
- Susceptibility to mechanical damage. The pipe can be damaged by any sharp or heavy object.
Properties of polypropylene products
Water pipes and fittings made of polypropylene have the following set of advantages:
- Endurance high temperature transported substance (up to 95 degrees Celsius), so polypropylene pipes can be used not only to transfer cold, but also hot water.
- Very low cost. This applies both to the pipes themselves and to their installation. Polypropylene water supply will cost the buyer cheaper than all others.
The disadvantages of this material include the difficult process of installing collapsible connections in pressure systems. The method of installing pipes made of polypropylene is based either on gluing joints or on soldering. To equip a collapsible assembly, you can use a special fitting, in which, in addition to the polypropylene body, there is also a metal fitting.
Properties of polyethylene structures
The main advantage of a polyethylene pipe is a high level of plasticity. Only these pipes can freeze over their entire length in winter and thaw in summer without losing their tightness.
The high plasticity index ensures good seismic stability of the system.
Polyethylene water pipes are not afraid of any movement or tremors in the ground.
The disadvantages of this material include low heat resistance, a polyethylene pipe can only pump cold water, the temperature of which does not exceed 40 degrees Celsius.
Features of PVC pipes
Polyvinyl chloride products are almost never used for pumping water. This material is quite fragile and is mainly used in sewerage systems. However, this material can often be found in the drainage systems of fire extinguishing systems, because it is the most heat-resistant type of polymer and can withstand temperatures up to 400 degrees Celsius.
Metal-plastic pipes
In terms of their positive and negative characteristics, these products are similar to conventional polymer products. For example, the service life of a metal-plastic system does not exceed 80 years, as well as a polypropylene water pipe. Installation of these tubes is also easy because they are mounted on special fittings.
This material, which is a symbiosis of plastic and metal, differs from ordinary polymer pipes in a slightly different installation technology. In addition, metal-plastic pipes are produced only in certain sizes, and their diameter does not exceed 63 millimeters.
Features of the assortment of pipes for water supply
The assortment of metal pipes is determined by special regulatory documents. According to the same principle, standards have been established for the production of pipes from polymers. GOST describes all geometric parameters. According to it, the minimum diameter of a steel pipe is 6 millimeters, and the maximum is 150 millimeters. For copper pipes, this figure varies from 6 to 267 millimeters, and the wall thickness can vary from 0.5 to 3 millimeters.
Polypropylene and polyethylene water pipes can be produced in 34 standard sizes. The smallest size of a polymer pipe is 1 centimeter, and the largest is 160 centimeters. For plumbing systems, it is optimal to use pipes with a cross-sectional diameter of up to 16 centimeters, that is, a total of 15 standard sizes. Metal-plastic pipes are produced in 11 variants from 14 to 110 millimeters.
At the same time, fittings for pipes are produced with a diameter of no more than 63 millimeters, so the actual assortment of metal-plastic pipes is limited to 8 standard sizes.
How long do metal pipes serve for water supply? Today we have to rummage in search of an answer to this question in normative documentation and find out what reduces the resource of pipelines. Let's get started.
Announce the entire list
To begin with, let's remember what types of metal pipes are used in cold and hot water supply systems.
In fact, there are currently only four of them:
- Black steel (water and gas pipes GOST 3262-75);
- Galvanized steel, produced according to the same standard;
- Copper;
- Corrugated stainless.
It is curious: a few decades ago, cold water supply lines were massively laid with cast-iron pipes. However, now they have been almost completely replaced by pressure polyethylene ones.
black steel
Steel rusts. Especially quickly it rusts with prolonged contact with water. That is why the resource of steel risers and liners laid down in the regulatory documents, frankly, is not striking in duration.
Standard service life
The main document establishing the normative service life of engineering communications in a residential building is VSN (departmental building codes) number 58-88, adopted in 1988. They regulate the terms of maintenance, reconstruction and repair of buildings.
Appendix No. 3 to the document contains the following figures:
Destructive factors
What factors limit the service life of VGP pipes without anti-corrosion coating:
Image | Description |
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Corrosion. Pipe rusting is accelerated by a broken outer layer of paint, frequent water supply shutdowns (in this case, the unpainted inner surface of the pipe is in contact with air with high humidity) and poor ventilation in the bathroom (read - consistently high humidity). The first fistulas appear on longitudinal welds (VGP pipes GOST 3262 - electric welded), on threads where the thickness of the pipe walls is minimal, and in ceilings where the surface of the pipes is not ventilated and (in the case of cold water risers) is continuously wetted by condensate falling on them. |
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Overgrowing of pipes with deposits (primarily lime salts) and rust. The overgrowth rate is directly proportional to the hardness of the water in the region: where it erodes sedimentary rocks on the way to the consumer, the gap in the water supply decreases much faster. The narrowing of the clearance leads to a drop in water pressure on plumbing fixtures connected to the water supply. |
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Pipeline diameter. The larger the internal section of the pipe, the longer it maintains an acceptable throughput. |
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Wall thickness. According to GOST 3262, ordinary, reinforced and lightweight pipes are produced. It is clear that those reinforced before the appearance of the first through fistulas will last longer. |
Note: a steel line that has become overgrown with deposits can often be cleaned with a steel cable or string. Even more effective destruction of deposits is provided by chemical washing of the water supply system: an alkaline or acidic environment dissolves lime and iron oxides.
Real life
In the memory of the author, the minimum period of trouble-free service of the cold steel water supply system in the new building was only 10 years. The house was built and rented shortly before the collapse of the Soviet Union, in conditions of austerity on building materials and the actual inoperability of Soviet norms and standards. Lightweight VGP pipes, purchased for reasons of economy, quickly and massively began to leak on welded joints and threads.
By the way: despite the same standard service life indicated for black steel pipes in cold water and hot water systems, pipes on cold water break down much faster. They rust intensively due to the condensate that falls on their surface during the hot season and rapidly overgrow with deposits due to the lack of lime and rust-dissolving additives in drinking water.
The oldest engineering systems made of black steel have been serving for more than half a century.
In addition to the large thickness of the walls of pipes, their longevity is facilitated by:
- Low humidity level;
- Lack of condensate on cold water pipes;
- Periodic painting of risers and eyeliners;
- Low content of mineral salts in water.
Cink Steel
Due to the anti-corrosion coating, galvanized steel should be more durable than black steel. How much?
Standard service life
We can find data about him in the same VSN 58-88:
Destructive factors
How and why can a galvanized metal pipe for water supply fail?
During his work as a plumber, the author observed the only scenario for the appearance of fistulas on a galvanized water pipe: they appeared on a welded joint. Strictly speaking, it is impossible to weld galvanized pipes from the word “absolutely”: in the area of \u200b\u200bthe seam, the zinc burns out completely. You see, it evaporates already at 900 degrees, and steel melts at 1400-1500.
As a result, the owner of a galvanized water pipe, mounted on welded joints, receives a line from a corrosion-resistant (albeit in some places) material, but at twice the price.
How to properly mount galvanizing with your own hands to ensure the maximum resource of the water supply?
Here is the instruction that plumbing equipment installers used in the 50-60s of the last century:
- All connections are made only and exclusively on threads (cut by hand or on a screw-cutting lathe) using cast iron threaded fittings;
- The joints are sealed with sanitary flax impregnated with minium lead winding.
Do galvanized pipes overgrow in water supply? Deposits and rust do not linger on their walls, however, the formation of a plug impermeable to water is still possible under certain circumstances. It happens like this:
- Debris accumulates in the water supply (usually cold) - sand, scale from welding and rust flakes. A blockage is formed if the water supply taps always open only partially, and the speed of the water flow does not allow it to carry debris into the mixer and further into the sewer;
- Over time, the accumulation of debris is cemented with lime and iron oxides, gradually turning into a material with the strength of stone.
Real life
The author of the article must repent to the reader: he cannot name either the minimum or the maximum service life of galvanizing in water supply. The fact is that he has never met a galvanized pipe that needs to be replaced due to natural wear.
Liners and risers that were opened after 50-70 years of operation were invariably in perfect condition and did not differ from new ones in any way.
Copper
The next metal on our list is copper.
How long can these metal pipes for hot water supply last? Any normative documents There are no specific terms of service that establish. Manufacturers promise a vague "50+" years.
In practice though:
- The oldest copper plumbing has been in service for over a century and is still in perfect condition;
- Copper does not degrade over time, is not subject to corrosion and is only afraid of significant mechanical stress: the metal is very ductile, and the pipe walls are only about a millimeter thick.
Destructive factors
As they say in the hero city of Odessa, “there are still them”:
- The service life of a copper water pipe may be reduced if, instead of soldering, press fittings with rubber o-rings are used during its installation. For 20-30 years, rubber loses its elasticity (primarily at hot water) and is capable of leaking;
- Banal erosion can lead to the destruction of the walls of copper pipes. At a high flow rate, sand and other suspensions rapidly destroy soft metal;
Note: the problem is solved by installing coarse filters and limiting the water flow rate to 2 m / s.
- A water hammer and freezing of water in it can theoretically break a copper plumbing. However, the water hammer must be really extreme (the breaking pressure for copper pipes is 200 - 240 atmospheres), and the defrosting must be repeated at least 5-6 times: the ductility of copper allows it to withstand a slight change in diameter or length without destruction.
Corrugated Stainless Pipe
How long will the corrugated stainless steel on the water supply?
According to one of the leading manufacturers, Lavita - indefinitely. Lavita expressly specifies an unlimited service life for its products.
However: silicone seals in press fittings will still have to be changed after 30 years. This work is not difficult: the fitting is disassembled to replace the seal with a pair of adjustable wrenches in 30-60 seconds.
What real term stainless steel services for water supply, so far it is impossible to say simply because of the limited time of its operation.
Destructive factors
The only thing that can cause damage to a stainless water pipe is a rough mechanical impact. Thin (only 0.3 mm) walls are easily crushed with a strong impact.
But you can not be afraid of the notorious water hammers and defrosting:
- The combination of tensile strength of 210 atmospheres (according to Lavita) in combination with the corrugation of the walls, which act as a damper, will allow the water supply to withstand any short-term pressure surge;
- When water freezes, corrugation will allow the pipe to lengthen and accommodate the volume of ice that has increased during crystallization without breaking.
Conclusion
We hope that we have succeeded in satisfying the curiosity of the reader. To learn more about how long pipes for water supply - metal and plastic - can last, the video in this article will help you. Good luck!