Wearing out plumbing or laying a new pipeline in an apartment or private building requires certain knowledge and skills. The material you work with is also important. The plumbing system has a lot of nuances, one of which is the size of the pipes themselves. This parameter must be chosen carefully, since with small sizes, high pressure will constantly act in the network, and with large ones, the cost of the system will rise several times. There are certain calculations and tables that can significantly facilitate the work and achieve the desired result.
The influence of the internal diameter of the pipe on the throughput
A certain pipe diameter is capable of passing a strictly regulated amount of water. If this indicator is less than necessary, the pressure inside the pipe will increase, which will lead to breakdowns.
An important parameter is also the number of consumers, that is, the number of points through which water flows directly to residents. In a private house, this calculation is much easier to make than in an apartment building.
The main factors that influence throughput:
- Water pressure in the system. This parameter is the most important, since all calculations are made based on their pressure. Even with accurate information about all consumers, it is necessary to make a certain reserve. This will affect the cost of the system, but will save on fewer breakdowns in the future.
- The total number of changes in system direction. This parameter includes sharp turns, as well as joints at which pressure differences occur during operation. If the plumbing system does not allow changing the design, then the only the right decision there remains an increase in the internal diameter of the pipeline.
- The temperature of the environment in which the system will be operated. For example, for a hot water pipeline, pipes with thick walls and a large diameter will be required, otherwise frequent breakdowns may occur.
According to a large amount of technical literature, a pipe with a diameter of 25 mm passes no more than 30 liters of water per minute. To calculate the water supply system, special tables and reference books are used, which contain this information in detail.
Hydraulic calculation
The concept of hydraulic calculation implies determining the exact volume of liquid that can pass through the water supply system without causing harm to the system. To do this, the following factors should be taken into account:
- The material from which the pipes are made. Modern materials practically do not change their internal diameter even after a long period of time.
- Total length of pipes. This parameter also includes all bends and joints.
- Total number of consumers. When making hydraulic calculations, it should be taken into account that liquid will be consumed from all points.
- Pipe capacity. This factor is very important and shows how much pressure the system will withstand.
It is possible to carry out hydraulic calculations using tables. For example, the Shevelev table is suitable, which contains all the necessary information about pipes made from various materials.
IN modern construction prefer to use special programs that allow you to optimize the water supply network. They contain all the necessary data; the user just needs to select certain conditions, and the system will perform the hydraulic calculation independently. This method is relevant when laying water supply networks in apartment buildings, since this is where there are a large number of consumers.
Pipe material is an important component when calculating diameter
It is not enough to determine the internal diameter of the pipeline; you also need to be able to look into the future. Some materials from which pipes are made are susceptible to corrosion, contamination and the influence of harmful microorganisms. These factors will significantly affect throughput in the future.
Most often, plastic products are chosen, as this material is the least likely to change the internal diameter, even after a long period of use. Plastic does not corrode; pipe walls are made of of this material No harmful deposits are deposited, and accordingly the throughput does not change. Unfortunately, during sudden temperature changes, plastic is prone to changing linear dimensions.
Metal-plastic pipelines have all the positive aspects described above, but do not change their size during temperature changes. The diameter of this product does not change even after a long period of use.
Steel and cast iron pipes They are practically not used in modern construction, as they have a lot of negative qualities. These materials are prone to corrosion and are also heavy. With the advent of corrosion, various types of contaminants increasingly settle on the walls of pipes, which leads to pressure drops. Different pressures in the system cause malfunctions to occur. The only advantage of this material is that it does not change its structure even with frequent temperature changes.
How to calculate the diameter of a pipeline
To calculate the internal diameter of the pipeline, you will need data that can be gleaned from tables and technical literature. To carry out accurate calculations, attention and knowledge of the specifics of the operations being performed are required. At correct calculation the relationship between the pipeline and the fluid flowing through it will be optimal.
You should be aware that as the speed of the transported liquid increases, the internal diameter of the pipes may decrease. The cost of the system with this factor becomes lower. But you cannot be sure that the flow rate will be uniform. Therefore, the diameter of the pipeline must have a certain margin.
For water pipes circular cross-section, use the following formula:
Where Q is the water flow parameter, d is the diameter of the pipeline, and w is the flow rate. By transforming the formula, you can get it as follows:
The water flow rate is determined based on the number of consumers. More complex formulas in their structure have another important factor - the coefficient of hydraulic friction. Such formulas have a cumbersome structure and require more time for calculations, but the output is accurate numbers.
In modern construction, they prefer to use either the tabular method or resort to the help of computer programs. Digital devices provide the introduction of a large number of parameters, which allows for accurate calculations with minimal errors.
Calculation of pipe diameter for water supply in a private house
The water supply system in the private sector is smaller than in apartment buildings. But even here it is necessary to make calculations and select the most optimal values.
An important factor is the length of the pipeline, which may be too long, especially if the house is located far from the main network. The diameter of long pipes should be slightly higher so as not to create sudden pressure drops in the system.
It is also worth paying attention to the water pressure in this area. An undersized pipeline diameter, with excessive pressure, can lead to a breakdown of the system. With a small diameter and low pressure, the consumer will not receive a high-quality jet of liquid. This parameter is very important, since many owners of private houses have a farm and a certain area for irrigation.
Pipeline options for a private home:
- At total length pipeline up to 30 m, you should choose a pipe diameter of no more than 20 mm. This option will not create overspending, but will only provide additional savings.
- If the length of the pipes exceeds 30 m, then it is necessary to use a larger cross-section - from 25 to 32 mm. 32 mm is ideal for a private house with several floors and a large number of consumers.
- If the house is located directly next to the water supply system, then you can use pipes whose diameter does not exceed 10 mm. This parameter is sufficient for normal pressure in the system and no breakdowns.
You should be aware that inches are often used to indicate the internal diameter of a pipeline. 1 inch is equal to 2.54 cm, from this data the most suitable product should be selected. It is very problematic to choose products with external and internal threads that are produced according to foreign standards. The difference is in both the thread pitch and its length.
Sometimes the outer diameter of the pipe may be specified. To obtain the internal value, it is necessary to subtract the pipe wall thickness from the internal diameter.
Summing up
The diameter of the pipes is a very important parameter when laying water pipes. Inconsistency between values may result in system failure or malfunction. To avoid this, all calculations should be made accurately, without deviating from the values in the tables and strictly following the formulas.
Many modern construction companies not only lay the pipelines themselves, but also carry out a full calculation of the system. These professionals are armed with the latest software developments that not only simplify the design process, but also make the final result more accurate. But, if desired, you can calculate the diameter of the pipeline yourself, just follow the recommendations exactly.
Many of us have to deal with the need to replace water pipes. You can solve this issue yourself or with the help of a professional technician. When replacing a pipeline, it is important to understand what diameter of pipes for the water supply is optimal from a technical point of view. There is a wide variety of pipes on the market today, which vary in material quality, size and diameter. Our article will tell you what diameter products are suitable in this or that case.
Pipe dimensional characteristics
Modern water supply is a rather complex structure, important element which are the pipes. The most popular are metal-plastic, steel and copper pipes. The main physical characteristics that determine the size of water supply pipes are:
- Inner diameter is a single characteristic for units and pipes of a water supply system. The internal diameter must be the same for both the pipes being connected and the fittings connecting them.
- Nominal diameter is a nominal value, measured in millimeters, used when installing water pipes.
- Wall thickness.
- Pipe length.
It is important to choose the correct diameter plastic pipes for plumbing, otherwise you may experience constant noise and problems in the plumbing. This is due to flow turbulization, a process that occurs as a result of the use of small diameter pipes.
Relationship between characteristics
How does the length of the water pipe affect the diameter of the pipes?
The average flow speed in a standard water supply is 0.02 km/s. This indicator affects the selection of pipe diameter. How to calculate the diameter of a water pipe taking into account the length of this communication:
- If the length of the system is less than 30 meters, you should pay attention to pipes with a diameter of 25mm.
- If the length of the system is more than 30 meters, the use of pipes with a diameter of 32 mm is considered relevant.
- If the length of the system is less than 10 meters, pipes with a diameter of 20 mm are perfect.
The standard length of domestic water supply pipes is 4 meters. But in practice, pipes up to 14-15 meters long can be used.
When choosing long products, special attention should be paid to the quality of fittings, couplings and other connections. They will ensure reliable and durable operation of the water supply system.
Why does the diameter of the pipes determine the throughput of the water supply system?
The diameter of the pipe determines an important characteristic - the throughput of the water supply system. For example, pipes with a diameter of 25 mm can move up to 30 liters of water within a minute. For a 32 mm pipe, this figure increases to 50 liters.
It should be borne in mind that an ordinary faucet in the kitchen or bathroom can flow no more than 5 liters of water. Thus, the choice of pipe diameter directly depends on the consumption of water resources.
The more points of water consumption, the larger the diameter of the pipes should be. Pipes for hot and cold water supply can be selected of the same diameter, but the wall thickness of pipes for hot water should be an order of magnitude higher.
When deciding what diameter of water supply pipe you need, pay close attention to the following parameters:
- The length of the water pipe.
- Number of proposed joints.
- Number of turns.
- Water pressure in the system.
Complex technical calculations, used by professionals, make it possible to calculate the complex influence of these factors on plumbing system. However, for premises in apartment building their use is hardly advisable.
Standard solutions
By general rule For water supply, pipes with a diameter of 10 or 15 mm are chosen, while the diameter of the pipes for the riser should be 25 mm. When purchasing pipes of the specified diameter, be prepared for the fact that these products do not have pinpoint accuracy. That is, a 10 mm pipe can actually have a diameter of 10-12 mm.
Complex plumbing work requires the use of pipes of increased diameter. They are optimal for operating a system with numerous joints, turns and permanent changes in water pressure.
To summarize: when choosing the diameter of pipes for water supply, we pay attention to the following points:
- How more complex design water supply, the larger the diameter of the pipes.
- Hot water pipes require pipes with reinforced walls.
- The higher the water consumption rate, the larger the diameter of the pipes.
The installation of a water supply system through the eyes of a non-professional is not at all complicated: several pipes, tees and taps will do an excellent job of delivering water, and the most important thing to take care of is sealing the joints, and the diameter of the water supply pipes does not play a particularly important role in it.
In fact, everything is somewhat more complicated: you need to make a series of calculations, draw a project, and correctly place the components and fittings of the water pipeline. Of great importance is the correct selection, or rather even calculation of the diameter of the pipes, allowing this value to be brought into line with the volume of water supplied. You can read more than one complaint online that after altering the water supply system, the pressure dropped to a minimum, and in such conditions the functioning of household appliances becomes significantly more difficult, to the point of complete inability to perform their functions.
Factors influencing the diameter of a water pipe
There are several indicators based on which you can navigate and decide what diameter of pipe for the water supply to choose. These include the factors listed below.
Network water pressure
The lower this indicator, the larger the diameter of the supply pipe should be. If you choose it incorrectly, you will not be able to get more than a thin stream of water flowing from the tap. Fortunately, today you can connect to your home water supply pumping station and raise even the most hopeless pressure to the desired level.
Total length of water pipe
There are special formulas according to which you can calculate the drop in water pressure depending on the length of the water pipe. They allow you to select the size of pipes for the water supply to minimize the influence of this factor.
In general, the trend is this: the longer the length, and the more often there are joints and turns on it, the lower the pressure level, and, consequently, the larger the diameter of the water pipe should be.
This issue can be approached in a differentiated manner, gradually changing the size of the cross-section of the pipes as they move away from the input.
How to calculate the diameter of water pipes?
By selecting the diameter of the pipes, of course, you can try to properly equip the plumbing system, but it is better to use special formulas for this. Of course, not every home craftsman knows how to calculate the diameter of a water pipe, but installation specialists engineering systems have all the necessary knowledge. Therefore, if you want to do everything accurately and correctly, it is better to turn to professionals, if not for installation, then at least for calculations.
Also on many sites there are calculators for calculating hydraulic resistance and calculating the required indicators, but if your competence does not include measuring all the parameters required for substitution in the formula, you can either contact engineers or use ready-made tables that provide average data.
Recently, there is also special software for calculating pipe diameters. Real specialists do not use it, treating it condescendingly, but at an amateur or entry-level level such a program will be extremely useful.
Pipe diameter selection
Before starting the installation of a water supply system, you should decide what material the pipes will be made of. Both plastic and metal pipes, have their own advantages and disadvantages. Having determined the specifics of use, you can come to the right decision.
The choice of pipe material is also important because pipes made of different materials are differentiated by the difference between the internal and external diameters. So, the diameter of plastic pipes for water supply outside and in the inside has a slightly different difference than the same indicators for metal ones, and when making calculations, it is necessary to take this into account. The difference in diameters indicates the thickness and strength of the pipe walls, which can affect their operation.
Choosing diameter polypropylene pipes for water supply it is also necessary to take into account the difference between the outer and inner diameters, and also to provide for the possibility of high-quality and tight installation of all connections. Some difficulties may arise here, especially if the water supply system uses pipes with different cross-sectional sizes. All kinds of tees and adapters will come to the rescue, through which you can make all the joints at a professional level.
Selecting the diameter of pipes for a water supply system is an important procedure, and a serious approach is required here. Otherwise, you may end up with insufficient pressure in the system and poor quality water supply.