During the design of the pipeline, the selection of pipe sizes is carried out on the basis of a hydraulic calculation, which determines the internal diameter of the pipes to pass the required amount of gas with allowable pressure losses or, on the contrary, pressure losses when transporting the required amount of gas through a log house of a previously specified diameter. The resistance that appears to the movement of gas in the pipeline is summed up from local resistances and linear friction resistances: friction resistances play their role throughout the entire length of the pipeline, and local resistances are created only at the point of change in the direction and speed of gas movement (tees, corners, etc. ). A detailed hydraulic calculation of gas pipelines is carried out according to the formulas given in SP 42-101-2003, it also takes into account the gas movement mode and the hydraulic resistance coefficients of the gas pipeline.
***
You can also use Online calculations, calculation of the diameter of the gas pipeline and its dimensions. Here is an abridged version.
***
To calculate the internal diameter of a gas pipeline, you can use the formula:
DP= (626AQ0/ρ0 ΔPsp)1/m1
DP is the design diameter. Q0 is the calculated gas flow rate (m3/h). ΔPr - specific pressure loss (PA/m)
The internal diameter of the gas pipeline is taken from the standard internal diameters of the pipelines: the nearest smaller one is for polyethylene gas pipelines and the next larger one is for steel ones.
In low-pressure gas pipelines, the calculated total gas pressure losses are taken to be no more than 1.80 * 10 (in the third degree) PA, in internal gas pipelines and inlet gas pipelines - 0.60 * 10 (in the third degree) PA.
In order to calculate the pressure drop, it is necessary to determine such a parameter as the Reynolds number, which depends on the nature of the gas movement. It is also necessary to determine the "λ" - coefficient of hydraulic friction. The Reynolds number is a dimensionless ratio that reflects the mode in which a gas or liquid moves: turbulent and laminar.
There is the so-called critical Reynolds number, which is equal to 2320. If the Reynolds number is less than the critical value, then the regime is laminar, if more, then turbulent.
The Reynolds number, as a criterion for the transition from laminar to turbulent and vice versa, is relevant for pressure flows. If we consider the transition to free flow, then here the transition zone between the turbulent and laminar regime increases, therefore, it is not particularly necessary to use the Reynolds number as a criterion.
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Today, gas is the cheapest and most accessible type of fuel. This is especially noticeable when compared with electricity. Therefore, recently the owners of country houses are interested in how to calculate the diameter of the gas pipeline and what to look for during installation.
After all, the paths leading to the house of explosive fuel should be laid with extreme caution and comply with all standards.
The main reason is cheapness and convenience. The difficult economic situation in the country is forcing the owners of private houses to look for the most affordable option for heating the building. Therefore, it is not at all surprising that over time, the owners of cottages come to the conclusion that it is necessary to gasify the building.
Yes, of course, you can heat your home with electricity. But such a solution is quite expensive, especially if you need to heat several hundred square meters.
Yes, and the vagaries of nature in the form of a strong wind or a hurricane can break the cables and you will have to sit for who knows how long without heating, food and hot water.
Modern gas pipelines are laid using durable and high-quality pipes and parts. Therefore, natural disasters are unlikely to harm such a structure.
Another alternative to gas is the old and proven way - to warm yourself with a fireplace or stove. The main disadvantage of this solution is that storing firewood or coal will lead to dirt.
In addition, it will be necessary to allocate additional square meters for their storage. Therefore, blue fuel will hold a leading position for more than one year.
The main types of gas pipelines
There are three types of highways. The first is a low-pressure gas pipeline. For such a system, the maximum allowable pressure is 5 kPa. Most often this type is laid in small settlements. It is also used for gas supply to medical institutions, residential buildings, children's and public buildings.
For the second variety - the medium pressure line - the fuel flow can be supplied with a force of up to 0.3 MPa. The scope of this type is limited to providing gas to quarterly and regional regulatory stations.
As for the high pressure line, it is designed to supply fuel to large industrial enterprises. For owners of private houses, such a decision is irrelevant. Indeed, gas is supplied to the cottage using a pipe, the pressure in which does not exceed 5 kPa.
Laying the highway is a complex and time-consuming process. To protect yourself and your home from gas leakage, you must use high-quality fittings and follow the recommendations of specialists
Norms and standards for laying pipes
Gas is supplied to residential buildings through inputs coming from distributing fuel stations. As a rule, they are installed on the basement floor and then laid along the stairwells.
The pipe that is connected to the residential building must be manufactured by the seamless method, and its wall thickness is at least 3.5 mm.
When supplying the main to a private house, it should be located at least 15 cm from the water pipes and the heating network. In the case of telephone or electric cables, this value increases to half a meter.
The gas pipeline is predominantly made of steel. Therefore, to prevent corrosion of the pipe, it is covered with a special insulating material. Due to this, the structure does not come into contact with wet ground.
Laying a gas pipeline in any living room is strictly prohibited. It should be placed in a separate well-ventilated area
Mounting methods and their features
The gas pipeline can be laid in various ways. It is underground, ground or underwater installation. In buildings, the laying of the network can be carried out hidden or open.
Each variety has its own advantages and disadvantages. Therefore, before giving preference to any of the varieties, it is necessary to understand in detail all its features.
Advantages and disadvantages of the underground method
More recently, when installing a gas pipeline, the underground method was mainly used. In this case, the pipes are laid in pre-dug trenches. Moreover, their depth must exactly correspond to the value specified in the project.
Today, this solution is used less and less. The drop in demand is due to the high cost of this kind of gasket. In addition, digging holes where pipes will be laid will take quite a lot of time.
Currently, engineers prefer the trenchless method. Its peculiarity lies in the use of equipment that can perform horizontal directional drilling.
Thanks to this, the cost of laying is reduced threefold, and the time required to organize the highway is reduced by at least two times.
Horizontal directional drilling avoids the dismantling of the roadbed. In addition, the well will be able to go around any obstacle without any problems, for example, an already laid pipeline.
The underground method with the help of HDD equipment eliminates the need to restore green spaces. Therefore, this kind of solution can be called as environmentally friendly as possible.
Installation by this method is the drilling of a pilot well, which is further expanded to the required dimensions. Further, the walls are strengthened with a special solution.
To protect the pipeline from underground water flows and excessive mechanical stress, it is placed in a protective case. The final step is to pull the pipes through the well.
External organization of the gas pipeline
The external method is used most often. In this case, the gas pipeline, as a rule, stretches through the yard of the cottage. In this case, the structure must be protected from unauthorized persons. For this purpose, the pipes are located at a considerable height.
Particular attention should be paid to fixation. Fastenings must be as strong and reliable as possible to minimize the risk of falling and, as a result, damage to the gas pipe.
Only experienced and qualified specialists should be engaged in the assembly of the structure. In this case, the installation must be carried out in accordance with the building regulations and technical documentation.
Ground and overground laying
Compared to the underground installation method, the ground installation will cost almost half as much. But in this case, special attention must be paid to protecting the structure from environmental influences and mechanical damage.
For example, the pipe must be insulated so that atmospheric precipitation does not fall on it and temperature changes are not noticeable. Moreover, the type of protection is selected depending on the climatic conditions of the region.
To prevent unauthorized connection to the highway, you need to take care of security. Indeed, due to the fact that the pipe lies on special supports on the ground, third parties can easily access it. Therefore, unlike underground laying, such a solution is less reliable.
An overland gas pipeline will be an ideal solution for well-guarded private houses and cottages. Especially if it is impossible to lay pipes underground due to a rather dense network of utilities
What is the best way to install a gas pipeline?
It is necessary to give preference to one or another solution depending on the climate of the region where the work will be carried out, building density and soil characteristics. Accordingly, there is simply no single answer.
To determine which installation method is best to choose, consider the following recommendations:
- When the soil on the site is characterized by rather high corrosive properties, then the most correct solution would be to install the gas pipeline by the ground method.
- If the pipeline is laid across the road, then the combined option is economically viable. That is, in the area of \u200b\u200bthe auto-canvas, the pipe should be located underground, and on the territory of the cottage - on the surface.
- In the case of laying the pipeline through neighboring sections, it is recommended to choose the ground (open) method.
- When high-voltage power lines are present at the site where the installation is planned, then a hidden installation of the main line would be a reasonable solution.
The laying method directly affects the material from which the pipeline should be made. The question related to which reinforcement to use in a particular case will be discussed further.
What documents will be needed?
Before proceeding directly to the installation, you will have to start collecting the necessary papers. To do this as soon as possible, you must immediately prepare a passport, as well as documentation that confirms the ownership of the site and the house located on it.
The next step is to submit an application to the relevant service. It expresses a desire to gasify the house. Employees will issue a form that lists all the technical conditions.
The document issued by the gas service is filled in by the specialist involved in the drafting of the project. Choose a qualified designer. After all, the result of work and the safety of residents depend on his competence.
According to the project, the gas network is being installed. Sometimes pipes are laid through the sections of neighbors. In this case, you must ask them for written permission to carry out such work.
In addition to the papers listed above, you will also need to obtain the following documents:
- the act of commissioning gas-powered equipment;
- agreement on the preparation of technical documentation and work;
- permission to supply natural gas and pay for this service;
- document on the installation of equipment and gasification of the house.
A chimney inspection will also be required. After that, the experts will issue the appropriate act. The last document - permission to gasify a private house - is issued by a local architectural and planning company.
How to calculate the diameter of a gas pipeline?
When drawing up a project, special attention is paid to the diameter of the pipe. The designer will do this using complex formulas or a program.
In order not to bother yourself with a variety of formulas, a good choice would be to use one of the specialized programs. The benefit of such software on the Internet is full.
Using the calculators is as easy as shelling pears - you just need to fill in the fields with the relevant information.
To determine the optimal diameter of the gas pipeline, you can use the table. To obtain the required value, you only need to select the required amount of fuel consumption
Selection of pipes and fasteners
Since the pipeline with blue fuel is an object of increased danger, all fittings used must have the necessary quality certificates. Otherwise, the commission conducting the final check will not allow the house with such pipes to be gasified.
The nuances of choosing a material
Pipe material is selected depending on the pipeline laying method. Products made of polyethylene and steel are in the greatest demand. The main advantage of the latter variety is its versatility.
After all, steel pipes can be used for both underground and outdoor installations. But such a solution will cost more.
The polymer pipeline can only be used for concealed installation. This is due to the fact that under the influence of the sun the material decomposes and quickly loses its properties.
As for the fasteners, for installation you will need corners, couplings, tees, crosses, plugs and adapters. As a rule, they are made of cast iron, steel or polyethylene.
Also, do not hesitate to install the counter. After all, it will significantly reduce costs.
Advantages of polyethylene pipes
First of all, such fittings do not rust over time. Therefore, it allows you to save on maintenance and repair of the pipeline. Thanks to a special production technology, polyethylene products have an absolutely smooth inner surface. As a result, the fuel flow rate is not slowed down in any way.
One of the main advantages of polymer pipes is their safety. No stray currents will appear in them, due to which gas can explode. So in the case of underground laying, there is no need to use a special expensive case.
If we compare the weight of a steel pipe and a polymer one, then the latter type is as much as 7 times lighter. This property makes it possible to significantly reduce the cost of construction, because it is not necessary to involve equipment with an increased carrying capacity.
A polyethylene pipeline, subject to all standards, will last at least half a century. And over time, its performance will not deteriorate in any way.
Pipes made of polyethylene, due to their flexibility, have earned the respect of specialists. Due to this, installation by horizontal directional drilling will not cause any difficulties or problems.
This solution is especially relevant when the well has an uneven shape or any obstacles were found during its creation.
When should you stop using polymer?
In some cases, polyethylene products will be a poor choice. The limiting conditions include the situation when the soil temperature in the winter season can drop below -15 degrees.
Plastic pipelines should be abandoned in regions where there is a risk of an earthquake with a magnitude of more than 7 on the Richter scale
The use of polymer reinforcement is also prohibited in the following situations:
- liquefied hydrocarbon will be supplied through the pipeline;
- an open mounting method was chosen;
- if the gas pipeline passes over any obstacles (railway or highway).
After all the necessary products have been purchased, and the documents have been collected, you can deal with the features of laying a highway with blue fuel.
The procedure for laying a gas pipeline
Despite the fact that the installation of pipes should be carried out exclusively by professionals with the necessary qualifications, each owner of a private house should familiarize himself in detail with the procedure for carrying out the work. This will avoid trouble and the appearance of unplanned financial expenses.
Installation of the riser and preparation of the premises
If a private house is gasified in order to organize heating, then you need to take care of the arrangement of the premises. The room with all the equipment should be separate and fairly well ventilated. After all, natural gas is not only explosive, but also toxic to the human body.
The boiler room must have a window. This will provide the opportunity to ventilate the room at any time, which will avoid fuel vapor poisoning.
As for the dimensions, the ceiling height in the room should be at least 2.2 m. For a kitchen where a stove with two burners will be installed, an area of 8 m 2 will be enough, and for a four-burner model - 15 m 2.
If equipment with a capacity of more than 30 kW is used to heat the house, then the boiler room should be moved outside the house and be a separate building.
Gas is supplied to the cottage using a special inlet, which is a hole above the foundation. It is equipped with a special case through which the pipe passes. One end is connected to the riser, and the other is part of the internal gas supply system.
The riser is mounted exactly vertically and the structure must be at least 15 cm away from the wall. The reinforcement can be fixed using special hooks.
Subtleties of laying pipes
During the installation of the pipeline in the wall, all its parts must be passed through the sleeves. In this case, the entire structure must be covered with oil paint.
The free space present between the pipe and the sleeve is filled with tarred tow and bitumen.
It is necessary to ensure that during the installation of the pipeline, as few threaded and welded connections as possible are used. This approach will make the whole structure as reliable as possible. Accordingly, for this it is necessary to select pipes of maximum length
Each of the nodes is assembled at the bottom, and at a height only fasteners of pre-preparatory components are carried out. If the diameter of the pipes does not exceed 4 cm, then they can be fixed with clamps or hooks. For all others, it is recommended to use brackets or hangers.
Welding, assembly and acceptance rules
All components of the pipeline are interconnected by welding. In this case, the seam must be of high quality and reliable. To achieve this, you must first level the end of the pipe and strip about 1 cm on each side of it.
As for the assembly of threaded connections, for this you need to use a special technique. First, the joint is processed with whitewash. The next step is to wind long-staple flax or a special tape. Only then can the threaded connection be tightened.
As soon as the masters finish the work, a commission should come to the house and check the quality of the installation. Moreover, without fail, the owner is given a detailed briefing on the rules for using the gas pipeline. Employees will also tell you how to properly use equipment that consumes blue fuel.
Conclusions and useful video on the topic
All about gasification of a private house:
The main stages of installation:
Laying a gas pipeline to a private house is a laborious and responsible process. After all, the safety of residents directly depends on the quality of the work. Therefore, it is better to entrust the execution of calculations and the installation itself to highly qualified and experienced employees.
This characteristic depends on several factors. First of all, this is the diameter of the pipe, as well as the type of liquid, and other indicators.
For hydraulic calculation of the pipeline, you can use the pipeline hydraulic calculation calculator.
When calculating any systems based on the circulation of fluid through pipes, it becomes necessary to accurately determine pipe capacity. This is a metric value that characterizes the amount of fluid flowing through pipes in a certain period of time. This indicator is directly related to the material from which the pipes are made.
If we take, for example, plastic pipes, then they differ in almost the same throughput throughout the entire period of operation. Plastic, unlike metal, is not prone to corrosion, so a gradual increase in deposits is not observed in it.
As for metal pipes, their throughput decreases year after year. Due to the appearance of rust, material detachment occurs inside the pipes. This leads to surface roughness and the formation of even more deposits. This process occurs especially quickly in pipes with hot water.
The following is a table of approximate values \u200b\u200bwhich was created to facilitate the determination of the throughput of pipes for intra-apartment wiring. This table does not take into account the reduction in throughput due to the appearance of sediment buildup inside the pipe.
Pipe capacity table for liquids, gas, steam.
|
Liquid type |
Speed (m/s) |
|
City water supply |
|
|
Water pipeline |
|
|
Central heating water |
|
|
Water pressure system in the pipeline line |
|
|
hydraulic fluid |
up to 12m/s |
|
Oil pipeline line |
|
|
Oil in the pressure system of the pipeline line |
|
|
Steam in the heating system |
|
|
Steam central pipeline system |
|
|
Steam in a high temperature heating system |
|
|
Air and gas in the central piping system |
Most often, ordinary water is used as a coolant. The rate of decrease in throughput in pipes depends on its quality. The higher the quality of the coolant, the longer the pipeline made of any material (steel, cast iron, copper or plastic) will last.
Calculation of pipe throughput.
For accurate and professional calculations, you must use the following indicators:
- The material from which pipes and other elements of the system are made;
- Pipeline length
- Number of water consumption points (for water supply system)
The most popular calculation methods:
1. Formula. A rather complicated formula, which is understandable only to professionals, takes into account several values at once. The main parameters that are taken into account are the material of the pipes (surface roughness) and their slope.
2. Table. This is an easier way by which anyone can determine the throughput of the pipeline. An example is the engineering table of F. Shevelev, by which you can find out the throughput based on the pipe material.
3. Computer program. One of these programs can be easily found and downloaded on the Internet. It is designed specifically to determine the throughput for pipes of any circuit. In order to find out the value, it is necessary to enter the initial data into the program, such as material, pipe length, coolant quality, etc.
It should be said that the latter method, although it is the most accurate, is not suitable for calculating simple household systems. It is quite complex and requires knowledge of the values of a variety of indicators. To calculate a simple system in a private house, it is better to use tables.
An example of calculating the throughput of the pipeline.
The length of the pipeline is an important indicator in calculating the throughput. The length of the main line has a significant impact on the throughput performance. The more distance the water travels, the less pressure it creates in the pipes, which means that the flow rate decreases.
Here are some examples. Based on tables developed by engineers for these purposes.
Pipe capacity:
- 0.182 t/h at 15 mm diameter
- 0.65 t/h with pipe diameter 25 mm
- 4 t/h at 50 mm diameter
As can be seen from the examples above, a larger diameter increases the flow rate. If the diameter is increased by 2 times, then the throughput will also increase. This dependence must be taken into account when installing any liquid system, whether it be water supply, sewerage or heat supply. This is especially true for heating systems, since in most cases they are closed, and the heat supply in the building depends on the uniform circulation of the liquid.
Laying a pipeline is not very difficult, but rather troublesome. One of the most difficult problems in this case is the calculation of the throughput of the pipe, which directly affects the efficiency and performance of the structure. In this article, we will talk about how the throughput of a pipe is calculated.
Throughput is one of the most important indicators of any pipe. Despite this, this indicator is rarely indicated in the marking of the pipe, and there is little sense in this, because the throughput depends not only on the dimensions of the product, but also on the design of the pipeline. That is why this indicator has to be calculated independently.
Methods for calculating the throughput of the pipeline
- External diameter. This indicator is expressed in the distance from one side of the outer wall to the other side. In calculations, this parameter has the designation Day. The outside diameter of the pipes is always shown on the label.
- Nominal diameter. This value is defined as the diameter of the internal section, which is rounded to whole numbers. When calculating, the value of the conditional passage is displayed as Du.
Calculation of pipe patency can be carried out according to one of the methods, which must be chosen depending on the specific conditions for laying the pipeline:
- Physical calculations. In this case, the pipe capacity formula is used, which allows taking into account each design indicator. The choice of formula is influenced by the type and purpose of the pipeline - for example, sewer systems have their own set of formulas, as well as for other types of structures.
- Tabular Calculations. You can choose the optimal cross-country ability using a table with approximate values, which is most often used for arranging wiring in an apartment. The values indicated in the table are rather blurry, but this does not prevent them from being used in calculations. The only drawback of the tabular method is that it calculates the capacity of the pipe depending on the diameter, but does not take into account changes in the latter due to deposits, so for lines prone to build-up, this calculation will not be the best choice. To get accurate results, you can use the Shevelev table, which takes into account almost all factors affecting pipes. Such a table is great for the installation of highways on separate land plots.
- Calculation using programs. Many companies specializing in laying pipelines use computer programs in their activities that allow them to accurately calculate not only the throughput of pipes, but also a lot of other indicators. For independent calculations, you can use online calculators, which, although they have a slightly larger error, are available for free. A good option for a large shareware program is TAScope, and in the domestic space the most popular is Hydrosystem, which also takes into account the nuances of installing pipelines depending on the region.
Calculation of the throughput capacity of gas pipelines
The design of a gas pipeline requires sufficiently high accuracy - the gas has a very high compression ratio, due to which leaks are possible even through microcracks, not to mention serious breaks. That is why the correct calculation of the throughput of the pipe through which the gas will be transported is very important.
If we are talking about gas transportation, then the throughput of pipelines, depending on the diameter, will be calculated according to the following formula:
- Qmax = 0.67 DN2 * p,
Where p is the value of the working pressure in the pipeline, to which 0.10 MPa is added;
Du - the value of the conditional passage of the pipe.
The above formula for calculating the throughput of a pipe by diameter allows you to create a system that will work in a domestic environment.
In industrial construction and when performing professional calculations, a different type of formula is used:
- Qmax \u003d 196.386 Du2 * p / z * T,
Where z is the compression ratio of the transported medium;
T is the temperature of the transported gas (K).
To avoid problems, when calculating the pipeline, professionals also have to take into account the climatic conditions in the region where it will pass. If the outer diameter of the pipe is less than the pressure of the gas in the system, then the pipeline is very likely to be damaged during operation, resulting in the loss of the transported substance and an increased risk of explosion in the weakened pipe section.
If necessary, it is possible to determine the permeability of a gas pipe using a table that describes the relationship between the most common pipe diameters and the working pressure level in them. By and large, the tables have the same drawback that the throughput of the pipeline calculated by the diameter has, namely, the inability to take into account the impact of external factors.
Calculation of the capacity of sewer pipes
When designing a sewer system, it is imperative to calculate the throughput of the pipeline, which directly depends on its type (sewer systems are pressure and non-pressure). Hydraulic laws are used to carry out calculations. The calculations themselves can be carried out both using formulas and using the corresponding tables.
For the hydraulic calculation of the sewer system, the following indicators are required:
- Pipe diameter - Du;
- The average speed of movement of substances - v;
- The value of the hydraulic slope - I;
- Degree of filling – h/DN.
As a rule, only the last two parameters are calculated during calculations - the rest after that can be determined without any problems. The amount of hydraulic slope is usually equal to the slope of the ground, which will allow the flow of water to move at the speed necessary for the system to self-clean.
The speed and maximum filling level of domestic sewage are determined by the table, which can be written as follows:
- 150-250 mm - h / DN is 0.6, and the speed is 0.7 m / s.
- Diameter 300-400 mm - h / DN is 0.7, speed - 0.8 m / s.
- Diameter 450-500 mm - h / DN is 0.75, speed - 0.9 m / s.
- Diameter 600-800 mm - h / DN is 0.75, speed - 1 m / s.
- Diameter 900+ mm - h / DN is 0.8, speed - 1.15 m / s.
For a product with a small cross section, there are normative indicators for the minimum slope of the pipeline:
- With a diameter of 150 mm, the slope should not be less than 0.008 mm;
- With a diameter of 200 mm, the slope should not be less than 0.007 mm.
The following formula is used to calculate the volume of wastewater:
- q = a*v,
Where a is the free area of the flow;
v is the speed of effluent transportation.
The rate of transport of a substance can be determined using the following formula:
- v=C√R*i,
where R is the value of the hydraulic radius,
C is the wetting coefficient;
i - the degree of slope of the structure.
From the previous formula, the following can be deduced, which will allow you to determine the value of the hydraulic slope:
- i=v2/C2*R.
To calculate the wetting coefficient, a formula of the following form is used:
- С=(1/n)*R1/6,
Where n is a coefficient that takes into account the degree of roughness, which varies from 0.012 to 0.015 (depending on the pipe material).
The R value is usually equated to the usual radius, but this is only relevant if the pipe is completely filled.
For other situations, a simple formula is used:
- R=A/P
Where A is the cross-sectional area of the water flow,
P is the length of the inner part of the pipe that is in direct contact with the liquid.
Tabular calculation of sewer pipes
It is also possible to determine the patency of the pipes of the sewer system using tables, and the calculations will directly depend on the type of system:
- Non-pressure sewerage. To calculate non-pressure sewer systems, tables are used that contain all the necessary indicators. Knowing the diameter of the pipes to be installed, you can select all other parameters depending on it and substitute them into the formula (read also: ""). In addition, the table indicates the volume of liquid passing through the pipe, which always coincides with the pipeline's permeability. If necessary, you can use the Lukin tables, which indicate the throughput of all pipes with a diameter in the range from 50 to 2000 mm.
- Pressure sewer. It is somewhat easier to determine the throughput in this type of system using tables - it is enough to know the maximum degree of filling of the pipeline and the average speed of liquid transportation. See also: "".
The throughput table of polypropylene pipes allows you to find out all the parameters necessary for arranging the system.
Calculation of the capacity of the water supply
Water pipes in private construction are used most often. In any case, the water supply system has a serious load, so the calculation of the throughput of the pipeline is mandatory, because it allows you to create the most comfortable operating conditions for the future structure.
To determine the patency of water pipes, you can use their diameter (read also: ""). Of course, this indicator is not the basis for calculating the patency, but its influence cannot be ruled out. The increase in the inner diameter of the pipe is directly proportional to its permeability - that is, a thick pipe almost does not impede the movement of water and is less susceptible to the accumulation of various deposits.
However, there are other indicators that also need to be taken into account. For example, a very important factor is the coefficient of friction of the liquid on the inside of the pipe (different materials have their own values). It is also worth considering the length of the entire pipeline and the pressure difference at the beginning of the system and at the outlet. An important parameter is the number of different adapters present in the design of the water supply system.
The throughput of polypropylene water pipes can be calculated depending on several parameters using the tabular method. One of them is a calculation in which the main indicator is the temperature of the water. As the temperature rises, the liquid expands in the system, so friction increases. To determine the patency of the pipeline, you need to use the appropriate table. There is also a table that allows you to determine the patency in the pipes depending on the water pressure.
The most accurate calculation of water according to the throughput of the pipe is made possible by the Shevelev tables. In addition to accuracy and a large number of standard values, these tables contain formulas that allow you to calculate any system. This material fully describes all situations related to hydraulic calculations, therefore, most professionals in this field most often use the Shevelev tables.
The main parameters taken into account in these tables are:
- External and internal diameters;
- Pipeline wall thickness;
- The period of operation of the system;
- The total length of the highway;
- Functional purpose of the system.
Conclusion
Pipe capacity calculation can be done in different ways. The choice of the optimal calculation method depends on a large number of factors - from the size of the pipes to the purpose and type of system. In each case, there are more and less accurate calculation options, so both a professional specializing in laying pipelines and an owner who decides to independently lay a highway at home will be able to find the right one.
Throughput is an important parameter for any pipes, canals and other heirs of the Roman aqueduct. However, the throughput is not always indicated on the pipe packaging (or on the product itself). In addition, it also depends on the pipeline scheme how much liquid the pipe passes through the section. How to correctly calculate the throughput of pipelines?
Methods for calculating the throughput of pipelines
There are several methods for calculating this parameter, each of which is suitable for a particular case. Some notations that are important in determining the throughput of a pipe:
Outer diameter - the physical size of the pipe section from one edge of the outer wall to the other. In calculations, it is designated as Dn or Dn. This parameter is indicated in the marking.
Nominal diameter is the approximate value of the diameter of the internal section of the pipe, rounded up to a whole number. In calculations, it is designated as Du or Du.
Physical methods for calculating the throughput of pipes
Pipe throughput values are determined by special formulas. For each type of product - for gas, water supply, sewerage - the methods of calculation are different.
Tabular calculation methods
There is a table of approximate values \u200b\u200bcreated to facilitate the determination of the throughput of pipes for intra-apartment wiring. In most cases, high precision is not required, so the values can be applied without complex calculations. But this table does not take into account the decrease in throughput due to the appearance of sedimentary growths inside the pipe, which is typical for old highways.
| Liquid type | Speed (m/s) |
| City water supply | 0,60-1,50 |
| Water pipeline | 1,50-3,00 |
| Central heating water | 2,00-3,00 |
| Water pressure system in the pipeline line | 0,75-1,50 |
| hydraulic fluid | up to 12m/s |
| Oil pipeline line | 3,00-7,5 |
| Oil in the pressure system of the pipeline line | 0,75-1,25 |
| Steam in the heating system | 20,0-30,00 |
| Steam central pipeline system | 30,0-50,0 |
| Steam in a high temperature heating system | 50,0-70,00 |
| Air and gas in the central piping system | 20,0-75,00 |
There is an exact capacity calculation table, called the Shevelev table, which takes into account the pipe material and many other factors. These tables are rarely used when laying water pipes around the apartment, but in a private house with several non-standard risers they can come in handy.
Calculation using programs
At the disposal of modern plumbing firms there are special computer programs for calculating the throughput of pipes, as well as many other similar parameters. In addition, online calculators have been developed that, although less accurate, are free and do not require installation on a PC. One of the stationary programs "TAScope" is a creation of Western engineers, which is shareware. Large companies use "Hydrosystem" - this is a domestic program that calculates pipes according to criteria that affect their operation in the regions of the Russian Federation. In addition to hydraulic calculation, it allows you to calculate other parameters of pipelines. The average price is 150,000 rubles.
How to calculate the throughput of a gas pipe
Gas is one of the most difficult materials to transport, in particular because it tends to compress and therefore can flow through the smallest gaps in pipes. Special requirements are imposed on the calculation of the throughput of gas pipes (as well as on the design of the gas system as a whole).
The formula for calculating the throughput of a gas pipe
The maximum capacity of gas pipelines is determined by the formula:
Qmax = 0.67 DN2 * p
where p is equal to the working pressure in the gas pipeline system + 0.10 MPa or the absolute pressure of the gas;
Du - conditional passage of the pipe.
There is a complex formula for calculating the throughput of a gas pipe. When carrying out preliminary calculations, as well as when calculating a domestic gas pipeline, it is usually not used.
Qmax = 196.386 Du2 * p/z*T
where z is the compressibility factor;
T is the temperature of the transported gas, K;
According to this formula, the direct dependence of the temperature of the transported medium on pressure is determined. The higher the T value, the more the gas expands and presses against the walls. Therefore, when calculating large highways, engineers take into account possible weather conditions in the area where the pipeline passes. If the nominal value of the DN pipe is less than the gas pressure generated at high temperatures in summer (for example, at + 38 ... + 45 degrees Celsius), then the line is likely to be damaged. This entails the leakage of valuable raw materials, and creates the possibility of an explosion of the pipe section.
Table of capacities of gas pipes depending on pressure
There is a table for calculating the throughput of a gas pipeline for commonly used diameters and nominal working pressure of pipes. Engineering calculations will be required to determine the characteristics of a gas pipeline of non-standard dimensions and pressure. Also, the pressure, speed of movement and volume of gas is affected by the temperature of the outside air.
The maximum velocity (W) of the gas in the table is 25 m/s and z (compressibility factor) is 1. The temperature (T) is 20 degrees Celsius or 293 Kelvin.
| Pwork(MPa) | Throughput capacity of the pipeline (m? / h), with wgas \u003d 25m / s; z \u003d 1; T \u003d 20? C = 293? K | |||||||
|---|---|---|---|---|---|---|---|---|
| DN 50 | DN 80 | DN 100 | DN 150 | DN 200 | DN 300 | DN 400 | DN 500 | |
| 0,3 | 670 | 1715 | 2680 | 6030 | 10720 | 24120 | 42880 | 67000 |
| 0,6 | 1170 | 3000 | 4690 | 10550 | 18760 | 42210 | 75040 | 117000 |
| 1,2 | 2175 | 5570 | 8710 | 19595 | 34840 | 78390 | 139360 | 217500 |
| 1,6 | 2845 | 7290 | 11390 | 25625 | 45560 | 102510 | 182240 | 284500 |
| 2,5 | 4355 | 11145 | 17420 | 39195 | 69680 | 156780 | 278720 | 435500 |
| 3,5 | 6030 | 15435 | 24120 | 54270 | 96480 | 217080 | 385920 | 603000 |
| 5,5 | 9380 | 24010 | 37520 | 84420 | 150080 | 337680 | 600320 | 938000 |
| 7,5 | 12730 | 32585 | 50920 | 114570 | 203680 | 458280 | 814720 | 1273000 |
| 10,0 | 16915 | 43305 | 67670 | 152255 | 270680 | 609030 | 108720 | 1691500 |
Capacity of the sewer pipe
The capacity of the sewer pipe is an important parameter that depends on the type of pipeline (pressure or non-pressure). The calculation formula is based on the laws of hydraulics. In addition to the laborious calculation, tables are used to determine the capacity of the sewer.
For the hydraulic calculation of sewerage, it is required to determine the unknowns:
- pipeline diameter Du;
- average flow velocity v;
- hydraulic slope l;
- degree of filling h / Du (in calculations, they are repelled from the hydraulic radius, which is associated with this value).
In practice, they are limited to calculating the value of l or h / d, since the remaining parameters are easy to calculate. The hydraulic slope in preliminary calculations is considered to be equal to the slope of the earth's surface, at which the movement of wastewater will not be lower than the self-cleaning speed. The speed values as well as the maximum h/Dn values for domestic networks can be found in Table 3.
Yulia Petrichenko, expert
In addition, there is a normalized value for the minimum slope for pipes with a small diameter: 150 mm
(i=0.008) and 200 (i=0.007) mm.
The formula for the volumetric flow rate of a liquid looks like this:
where a is the free area of the flow,
v is the flow velocity, m/s.
The speed is calculated by the formula:
where R is the hydraulic radius;
C is the wetting coefficient;
From this we can derive the formula for the hydraulic slope:
According to it, this parameter is determined if calculation is necessary.
where n is the roughness factor, ranging from 0.012 to 0.015 depending on the pipe material.
The hydraulic radius is considered equal to the usual radius, but only when the pipe is completely filled. In other cases, use the formula:
where A is the area of the transverse fluid flow,
P is the wetted perimeter, or the transverse length of the inner surface of the pipe that touches the liquid.
Capacity tables for non-pressure sewer pipes
The table takes into account all the parameters used to perform the hydraulic calculation. The data is selected according to the value of the pipe diameter and substituted into the formula. Here, the volumetric flow rate q of the liquid passing through the pipe section has already been calculated, which can be taken as the throughput of the pipeline.
In addition, there are more detailed Lukin tables containing ready-made throughput values for pipes of different diameters from 50 to 2000 mm.
Capacity tables for pressurized sewer systems
In the capacity tables for sewer pressure pipes, the values depend on the maximum degree of filling and the estimated average flow rate of the waste water.
| Diameter, mm | Filling | Acceptable (optimal slope) | The speed of movement of waste water in the pipe, m / s | Consumption, l / s |
| 100 | 0,6 | 0,02 | 0,94 | 4,6 |
| 125 | 0,6 | 0,016 | 0,97 | 7,5 |
| 150 | 0,6 | 0,013 | 1,00 | 11,1 |
| 200 | 0,6 | 0,01 | 1,05 | 20,7 |
| 250 | 0,6 | 0,008 | 1,09 | 33,6 |
| 300 | 0,7 | 0,0067 | 1,18 | 62,1 |
| 350 | 0,7 | 0,0057 | 1,21 | 86,7 |
| 400 | 0,7 | 0,0050 | 1,23 | 115,9 |
| 450 | 0,7 | 0,0044 | 1,26 | 149,4 |
| 500 | 0,7 | 0,0040 | 1,28 | 187,9 |
| 600 | 0,7 | 0,0033 | 1,32 | 278,6 |
| 800 | 0,7 | 0,0025 | 1,38 | 520,0 |
| 1000 | 0,7 | 0,0020 | 1,43 | 842,0 |
| 1200 | 0,7 | 0,00176 | 1,48 | 1250,0 |
Capacity of the water pipe
Water pipes in the house are used most often. And since they are subjected to a large load, the calculation of the throughput of the water main becomes an important condition for reliable operation.
Passability of the pipe depending on the diameter
Diameter is not the most important parameter when calculating pipe patency, but it also affects its value. The larger the inner diameter of the pipe, the higher the permeability, as well as the lower the chance of blockages and plugs. However, in addition to the diameter, it is necessary to take into account the coefficient of friction of water on the pipe walls (table value for each material), the length of the line and the difference in fluid pressure at the inlet and outlet. In addition, the number of bends and fittings in the pipeline will greatly affect the patency.
Table of pipe capacity by coolant temperature
The higher the temperature in the pipe, the lower its capacity, as the water expands and thus creates additional friction. For plumbing, this is not important, but in heating systems it is a key parameter.
There is a table for calculations of heat and coolant.
| Pipe diameter, mm | Bandwidth | |||
|---|---|---|---|---|
| By warmth | By coolant | |||
| Water | Steam | Water | Steam | |
| Gcal/h | t/h | |||
| 15 | 0,011 | 0,005 | 0,182 | 0,009 |
| 25 | 0,039 | 0,018 | 0,650 | 0,033 |
| 38 | 0,11 | 0,05 | 1,82 | 0,091 |
| 50 | 0,24 | 0,11 | 4,00 | 0,20 |
| 75 | 0,72 | 0,33 | 12,0 | 0,60 |
| 100 | 1,51 | 0,69 | 25,0 | 1,25 |
| 125 | 2,70 | 1,24 | 45,0 | 2,25 |
| 150 | 4,36 | 2,00 | 72,8 | 3,64 |
| 200 | 9,23 | 4,24 | 154 | 7,70 |
| 250 | 16,6 | 7,60 | 276 | 13,8 |
| 300 | 26,6 | 12,2 | 444 | 22,2 |
| 350 | 40,3 | 18,5 | 672 | 33,6 |
| 400 | 56,5 | 26,0 | 940 | 47,0 |
| 450 | 68,3 | 36,0 | 1310 | 65,5 |
| 500 | 103 | 47,4 | 1730 | 86,5 |
| 600 | 167 | 76,5 | 2780 | 139 |
| 700 | 250 | 115 | 4160 | 208 |
| 800 | 354 | 162 | 5900 | 295 |
| 900 | 633 | 291 | 10500 | 525 |
| 1000 | 1020 | 470 | 17100 | 855 |
Pipe capacity table depending on the coolant pressure
There is a table describing the throughput of pipes depending on the pressure.
| Consumption | Bandwidth | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| DN pipe | 15 mm | 20 mm | 25 mm | 32 mm | 40 mm | 50 mm | 65 mm | 80 mm | 100 mm |
| Pa/m - mbar/m | less than 0.15 m/s | 0.15 m/s | 0.3 m/s | ||||||
| 90,0 - 0,900 | 173 | 403 | 745 | 1627 | 2488 | 4716 | 9612 | 14940 | 30240 |
| 92,5 - 0,925 | 176 | 407 | 756 | 1652 | 2524 | 4788 | 9756 | 15156 | 30672 |
| 95,0 - 0,950 | 176 | 414 | 767 | 1678 | 2560 | 4860 | 9900 | 15372 | 31104 |
| 97,5 - 0,975 | 180 | 421 | 778 | 1699 | 2596 | 4932 | 10044 | 15552 | 31500 |
| 100,0 - 1,000 | 184 | 425 | 788 | 1724 | 2632 | 5004 | 10152 | 15768 | 31932 |
| 120,0 - 1,200 | 202 | 472 | 871 | 1897 | 2898 | 5508 | 11196 | 17352 | 35100 |
| 140,0 - 1,400 | 220 | 511 | 943 | 2059 | 3143 | 5976 | 12132 | 18792 | 38160 |
| 160,0 - 1,600 | 234 | 547 | 1015 | 2210 | 3373 | 6408 | 12996 | 20160 | 40680 |
| 180,0 - 1,800 | 252 | 583 | 1080 | 2354 | 3589 | 6804 | 13824 | 21420 | 43200 |
| 200,0 - 2,000 | 266 | 619 | 1151 | 2486 | 3780 | 7200 | 14580 | 22644 | 45720 |
| 220,0 - 2,200 | 281 | 652 | 1202 | 2617 | 3996 | 7560 | 15336 | 23760 | 47880 |
| 240,0 - 2,400 | 288 | 680 | 1256 | 2740 | 4176 | 7920 | 16056 | 24876 | 50400 |
| 260,0 - 2,600 | 306 | 713 | 1310 | 2855 | 4356 | 8244 | 16740 | 25920 | 52200 |
| 280,0 - 2,800 | 317 | 742 | 1364 | 2970 | 4356 | 8566 | 17338 | 26928 | 54360 |
| 300,0 - 3,000 | 331 | 767 | 1415 | 3076 | 4680 | 8892 | 18000 | 27900 | 56160 |
Pipe capacity table depending on diameter (according to Shevelev)
The tables of F.A. and A.F. Shevelev are one of the most accurate tabular methods for calculating the throughput of a water supply system. In addition, they contain all the necessary calculation formulas for each specific material. This is a voluminous informative material used by hydraulic engineers most often.
The tables take into account:
- pipe diameters - internal and external;
- wall thickness;
- service life of the pipeline;
- line length;
- pipe assignment.
Hydraulic Calculation Formula
For water pipes, the following calculation formula applies:
Online calculator: pipe capacity calculation
If you have any questions, or if you have any guides that use methods not mentioned here, write in the comments.