- Reinforced-plastic pipes
- Compression fittings
- Press fittings
- Welded fittings
- Push fittings
- Plastic pipes and fittings
- Steel pipes
- Steel pipe fittings
- Shut-off valves and filters
- Mesh filters
- Water supply hoses
This article will consider various types of water pipes, fittings, taps, filters and other elements, without which it is difficult to imagine a modern water supply system..
New materials and technologies that have appeared in plumbing over the past 15 years have revolutionized the industry. Craftsmen run the risk of being left idle, since modern pipes for water supply are installed easily, quickly and reliably. Anyone who knows how to work with their hands can assemble a water supply system from them. However, before that, it will be useful to study the properties of various materials, their purpose, as well as the advantages and disadvantages..
Reinforced-plastic pipe is a composite material consisting of five layers. The outer and inner sheaths are made of heat-resistant or cross-linked polyethylene, designated PERT or PEX respectively. At the center of the structure is a thin aluminum tube. The remaining two layers are a special adhesive compound that bonds plastic to metal..
Construction of metal-plastic pipes
Reinforced-plastic pipes are heat-resistant enough to be used in heating and hot water systems. Their operating temperature is 95 ° C, and their peak is 110 and 125 ° C for PEX and PERT, respectively. With proper installation and compliance with temperature parameters, metal-plastic can withstand a pressure of 10-14 bar. All performance characteristics are indicated in the marking, which is applied to each meter of the product. Service life depends on operating conditions and ranges from 35 to 50 years.
This type of pipe is very popular due to its low weight and ductility. These two factors make transportation and installation much easier than with other materials. Plasticity allows you to reduce the number of corner fittings when laying the water supply – to turn it, it is enough to bend the pipe with your hands. One meter of metal-plastic with a diameter of 16 mm weighs about 100 g, 20 mm – 150 g and 26 mm – 200 g. That is, an adult can lift a two-hundred-meter bay. In addition, a special tool is not needed to assemble such a water supply system; a set of keys is sufficient. Polyethylene is not susceptible to corrosion, rusty deposits do not form on its smooth surface, so that the pipe clearance does not decrease during the entire period of operation.
The main disadvantage of metal-plastic is low resistance to temperature extremes. Although its coefficient of linear expansion is much lower than that of unreinforced polymer pipes, delamination can occur with sharp temperature changes, which will significantly reduce the service life. The outer shell is sensitive to ultraviolet radiation, therefore the use of metal-plastic for the outer gasket is possible, but undesirable. Under the sun’s rays, the top layer loses its elasticity, becomes covered with cracks and gradually collapses. Concealed and underground laying is allowed only with the use of permanent joints or a single piece.
For metal-plastic, the most popular are compression-type fittings, in which the end of the pipe is fixed with a split ring (collet), which crimps it around the fitting. Tightening takes place using a special nut, and the tightness of the connection is ensured by rubber rings.
The main advantage of such fittings, which became the reason for their popularity, is their ease of installation. As already mentioned, this does not require special tools: to tighten the crimp nut, any wrench of the appropriate size will do. The connection is then detachable, although it is usually necessary to change the O-rings before reuse. There is also a relatively new version of the compression fitting – Eurocone – made in the American style. Its nipple and body are separate parts, which are connected with a crimp nut. This design makes it easier to dismantle metal-plastic systems and often avoids damage to seals..
The disadvantages of collet fittings are the relatively high cost, detachable connection and the fact that rather thin rubber rings are responsible for tightness. In conditions of temperature changes, they can lose elasticity and cease to cope with their task. For this reason, fittings of this type are not used for closed water pipelines. In addition, after the first year of operation, it is recommended to tighten the nuts, although the need for this is rather controversial. As a result of squeezing, the pipe and collet are deformed, due to which the strength and tightness of the connection after a few months is such that no leakage is observed, even if the nut is unscrewed.
The service life of compression fittings depends on the operating conditions and material quality. Low-quality products are characterized by thin nuts, which often burst when tightened. If there is nothing to compare – pay attention to the marking. It should be clear, and numbers and letters should not go beyond the edge. The inside of a good fitting is funnel-shaped, which reduces flow resistance and reduces the noise of flowing water. It is better to spend money and buy high quality pipes and fittings that will last for more than a dozen years than to fix leaks every now and then, suffer from unnecessary noise and eliminate the consequences of floods.
By design, a press fitting resembles a compression one, only instead of a nut and collet there is a thin stainless steel sleeve, which is used to crimp the pipe. It is impossible to disassemble such a connection without damaging the sleeve. Press fittings are more reliable than compression fittings, but less popular. The reason is that at almost equal cost, a special tool is required for their installation – a press. It is also desirable that the crimp profile is in accordance with the manufacturer’s recommendations. Under these conditions, a welded joint is more attractive, since the cost of the material is much less..
Welding technology, previously available only for polymer pipes, has recently been applied to metal-plastic. Special fittings are made of heat-resistant polyethylene and metal. They can only be used with a pert-al-pert pipe, and are not suitable for pex-al-pex. In appearance, the novelty is similar to the usual fittings for polypropylene pipes, and differs from them only in the presence of a brass or aluminum insert inside. Welding is carried out with a conventional apparatus, but with special nozzles. The one-piece connection guarantees no leaks, which at a relatively low price of fittings promises them a good future.
Until recently, assembling a plumbing without the use of tools seemed unrealistic. However, new technologies have made that possible. The installation process of push-fittings, or PUSH-FIT, is as follows: the calibrated pipe is inserted in one motion into the receiving sleeve so that its end appears in the inspection hole. Inside, it is rigidly fixed with a collet grip, and rubber rings seal the connection, making it tight. If necessary, the connection can be easily disassembled and reassembled.
Obviously, when using push fittings, there are enormous savings in labor time. Nevertheless, they are still used quite rarely, and their perspective is very vague. The required reliability of such a connection can be achieved only if all parts are manufactured and assembled with high precision, which implies considerable cost. The price of this product is much higher than the compression analogue, but for installation in hard-to-reach places push fittings can become indispensable.
Plastic pipes and fittings
The most common polymer used in plumbing is polypropylene. It is used to make pipes for sewerage, water supply, as well as socket and welded fittings. In terms of heat resistance, it is not inferior to PERT grade polyethylene and is significantly superior to PVC. Especially noteworthy is the relatively new modification of this material – polypropylene type 3 (PPRC), which exhibits high resistance to sudden temperature changes and does not emit harmful substances under the influence of an open flame..
Plastic pipes, regardless of material, are marked as follows:
- PN10 – only for cold water;
- PN20 – for cold and hot water (may have fiberglass reinforcement);
- PN25 – aluminum reinforcement for hot water supply and heating systems.
In addition, a blue longitudinal stripe is applied to products for cold water, and a red stripe for hot water.
The big advantage of plastic pipes is the ability to install them using diffusion welding. In this case, all abutting elements must be made of the same material. The connection is one-piece and absolutely sealed, which allows you to create hidden water supply systems. For PVC products, it is also allowed to use special adhesives.
The disadvantage of polymer pipes is the lack of plasticity. They are produced in 4 meter lengths, which creates certain difficulties during transportation and increases the amount of waste during assembly. Since the pipe cannot be bent, more fittings have to be used than for metal-plastic. Consequently, the terms of work also increase..
A few words about fittings. They are all-plastic and combined. The former are used to connect pipes to each other and are made of the same polymer as the pipe itself. The latter are needed to dock the plastic elements of the water supply system with metal ones, for which they have a stamped threaded insert.
In inter-house wiring, steel pipes are used less and less due to their short service life, time-consuming installation and high weight. Their main enemy – corrosion – appears after 5–7 years of operation. The inner surface begins to grow with rust, which leads to a decrease in throughput. In addition, due to the high thermal conductivity of steel, condensate forms on the surface of cold water systems, which triggers the corrosion process outside..
Stainless steel pipes are devoid of this drawback. But, despite the almost century-old service life, they are rarely used, mainly due to the high price. A cheaper alternative to stainless steel is galvanized steel. Pipes with a protective coating last longer than conventional pipes, and are not much more expensive.
The main advantage of steel pipes is their high strength, which allows them to withstand high pressures and external loads. In some cases, this makes them indispensable for laying underground and external systems. It is worth mentioning the coefficient of linear expansion, which is much lower for steel than for polymers and metal-plastic.
Steel pipe fittings
For permanent connection of steel pipes, threaded fittings of various nomenclature are used. In this case, sealing is achieved using various sealing materials. By means of threaded fittings, you can not only connect two straight sections of the water supply, but also make a turn, change to another diameter, branch, and also lengthen the pipe. To connect various devices and facilitate the dismantling of the system, squeegees and so-called American women are used.
In cases where it is not possible to cut or weld threads during repairs, it is allowed to use compression fittings – GEBO and saddles – as a temporary measure. Gebo consists of a body, a crimp nut, a collet, a gasket and a tapered sleeve. The pipe is fixed inside the body by a collet ring, and the tapered collar ensures tightness. Provided correct installation and good quality materials, the package is quite dense, but the tensile strength of the joint leaves much to be desired. So use gebo fittings with extreme caution..
The saddle is a two-piece split tee. One of them has a branch with an external or internal thread. The structure is fixed to the pipe with tightening bolts, like a clamp. Rubber gaskets are used for sealing.
Shut-off valves and filters
As the locking elements of the intra-apartment water supply wiring, coupling full-bore ball valves are usually used. They are arranged quite simply: inside the body there is a steel ball with a hole for the medium passage, which is a shutter. There are ring saddles on both sides of it, providing a tight overlap. They are usually made of fluoroplastic. For control there is a handle on a spindle connected to a ball.
This design has undeniable advantages over screw cranes. First, it is simplicity and reliability. PTFE saddles retain their elasticity and shape for a long time, and also show high abrasion resistance. The overlap remains airtight for decades, while the gaskets of screw valves require frequent replacement. The second advantage is excellent bandwidth. The hole in the ball and the lumen of the connected pipe are almost equal in diameter, so there are no local restrictions.
Ball valves are often available in combination with an American (straight and angle) or strainer. The first option is very popular because it simplifies installation and saves working time. The merits of the second combination are controversial. With the same advantages, it has one drawback: in the event of a malfunction of one device, the entire structure will have to be replaced. For plastic pipes, ball valves are produced from various polymers, which can be welded directly to the water supply system, without unnecessary fittings.
The combination of shut-off valves and filter appeared for a reason. The water quality in our hot water and cold water systems is extremely low. In addition to dissolved salts, it contains sand, rust and other solid impurities, which accelerate the wear of all parts of the pipeline and plumbing fixtures. Small particles quickly clog mixer spargers, while large particles can completely block the passage of a half-inch fitting, hose, or damage the water meter. Therefore, immediately after the shut-off device, it is recommended to install a coarse filter (sump).
Most often, conventional mesh mud collectors are used, due to their simplicity of design and low cost. As the name suggests, the filter element in them is a fine mesh made of stainless wire. The body can be either metal or plastic. Filters with a flush valve are also available for ease of maintenance. It allows you to easily and quickly clean the mesh from small particles of contamination, but if large pieces of rust get in, the mesh will still have to be removed and washed by hand.
Water supply hoses
Many plumbing fixtures are connected to the water supply using a flexible hose. For example, if you want to damp vibration or compensate for linear expansion. Therefore, the set of washing machines always includes hoses, and manufacturers of water heaters often put them on the hot water outlet in advance. Flexible pipes are also traditionally used to connect faucets and toilets..
Hoses are made from various materials: rubber, polymer, silicone and even steel (bellows hoses). For greater strength, they can be reinforced with a metal braid or fabric cord. Hose termination is available in two versions: nut-nut or nut-union. It is connected to the ferrules in much the same way as pipes with press fittings: the hose is put on a sleeve and crimped with a steel sleeve.
It is this connection that is the weak point of the product, since it has low tensile strength. A poor quality hose can be pulled out of the mount by high pressure or water hammer. Another disadvantage is a short service life, which is much shorter than that of any type of pipe.
The advantages of hoses are flexibility and ease of installation. The devices connected with their help can be moved without disconnecting from the water supply, albeit for a limited distance. This will be very useful if you need to move the washing machine or sink..