Laying the pipeline is not a very complex, but quite troublesome. One of the most difficult problems is the calculation of the bandwidth of the pipe, which directly affects the efficiency and performance of the structure. This article we will talk about how the throughput of the pipe is calculated.

The bandwidth is one of the most important indicators of any pipe. Despite this, in the labeling of the pipe, this indicator is rarely indicated, and there is no sense in this a bit, 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 on their own.

Methods for calculating the bandwidth of the pipeline

1. External diameter. This indicator is expressed in the distance from one side of the outer wall to the other side. In the calculations, this parameter has the designation of the day. The outer diameter of the pipes is always displayed in the marking.
2. Diameter of conditional passage. This value is defined as the diameter of the inner section, which is rounded to integer numbers. When calculating the value of the conditional passage is displayed as a remote control.

The calculation of pipe patency can be carried out according to one of the methods, choosing which is necessary depending on the specific conditions of the pipeline laying:

1. Physical calculations. In this case, a pipe bandwidth formula is used, which allows you to take into account each design indicator. The choice of formula affects the type and purpose of the pipeline - for example, for sewer systems there is a set of formulas, as for the other types of structures.
2. Table payments. You can choose the optimal amount of patency using a table with exemplary values, which is most often used to arrange a wiring in the apartment. The values \u200b\u200bspecified in the table are quite blurred, but it does not interfere with using them in the calculations. The only disadvantage of the table method is that it calculates the capacity of the pipe depending on the diameter, but the changes in the latter due to deposits are not taken into account, therefore, for highways subject to the emergence of growths, this calculation will be not the best choice. To obtain accurate results, you can use the Shevelev table, which takes into account almost all factors affecting the pipes. Such a table is perfect for mounting highways on separate land.
3. Calculation using programs. Many companies specializing in pipeline laying use computer programs in their activities to accurately calculate not only the capacity of pipes, but also a lot of other indicators. For independent calculations, you can use online calculators, which, although they have a slightly large error, are available in free mode. A good option is a great conditionally free program is "Tascope", and on the domestic space the most popular is the "hydraulic system", which also takes into account the nuances of the installation of pipelines depending on the region.

Calculation of gas pipelines

The design of the gas pipeline requires a sufficiently high accuracy - the gas has a very large compression ratio, due to which leaks are possible even through microcracks, not to mention serious breaks. That is why the correct calculation of the bandwidth of the pipe, which will be transported by gas, is very important.

If we are talking about gas transportation, the throughput capacity of pipelines, depending on the diameter, will be calculated according to the following formula:

• Qmax \u003d 0.67 DU2 * P,

Where p is the magnitude of the working pressure in the pipeline to which 0.10 MPa is added;

Du is the value of the conditional passage of the pipe.

The above formula for calculating the bandwidth of the pipe in diameter allows you to create a system that will work in domestic conditions.

In industrial construction and when performing professional calculations, the formula of a different type is applied:

• Qmax \u003d 196,386 DU2 * P / Z * T,

Where Z is the compression coefficient of the transported environment;

T - the temperature of the transported gas (K).

To avoid problems, professionals have to take into account when calculating the pipeline, climatic conditions in the region where it will pass. If the outer diameter of the pipe is less than gas pressure in the system, the pipeline with a very high probability will be damaged during operation, as a result of which the loss of the transported substance will occur and the risk of an explosion on a weakened pipe segment will increase.

With a lot of need, it is possible to determine the permeability of the gas pipe using a table, which describes the interdependence between the most common diameters of the pipes and the working level of pressure in them. By and large, the tables have the same disadvantage that has a pipeline capacity calculated in diameter, namely, it is impossible to take into account the impact of external factors.

Calculation of the bandwidth of sewer pipes

When designing a sewer system, it is necessary to calculate the throughput capacity of the pipeline, which directly depends on its type (sewer systems are pressure and non-free). For calculations, hydraulic laws are used. The calculations themselves can be carried out both with the help of the formulas and through the corresponding tables.

For hydraulic calculation of the sewer system, the following indicators are required:

• Pipe diameter - Du;
• The average speed of substances - V;
• The value of hydraulic slope - I;
• Degree of filling - H / Du.

As a rule, only the last two parameters are calculated during calculations - the rest after that can be determined without any problems. The magnitude of the hydraulic slope is usually equal to the slope of the Earth, which will ensure the flow of effluent at the speed required for self-cleaning system.

The speed and limiting level of household sewage filling are determined by the table that can be written as follows:

1. 150-250 mm - H / Du is 0.6, and the speed is 0.7 m / s.
2. The diameter of 300-400 mm - H / Du is 0.7, the speed is 0.8 m / s.
3. The diameter of 450-500 mm - H / Du is 0.75, the speed is 0.9 m / s.
4. The diameter of 600-800 mm - H / Du is 0.75, the speed is 1 m / s.
5. The diameter of 900+ mm - H / Du is 0.8, the speed is 1.15 m / s.

For a product with a small cross section, there are normative indicators of the minimum values \u200b\u200bof the pipeline liner:

• 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.

To calculate the volume of drapes, the following formula is used:

• q \u003d A * V,

Where a is the area of \u200b\u200bthe living cross section;

v is the flow rate of wastewater.

It is possible to determine the rate of transportation of the substance by such a formula:

• v \u003d C√r * i,

where R is the magnitude of the hydraulic radius,

C - wetting coefficient;

i - the degree of slope design.

From the previous formula, you can withdraw the following that will determine the value of the hydraulic slope:

• i \u003d v2 / c2 * r.

To calculate the wetting coefficient, the formula of this type is used:

• C \u003d (1 / N) * R1 / 6,

Where N is a coefficient, which takes into account the degree of roughness, which varies from 0.012 to 0.015 (depends on the material of the pipe manufacturing).

The value of R is usually equal to the usual radius, but this is relevant only if the pipe is filled in completely.

For other situations, a simple formula is used:

• R \u003d A / P,

Where a is the area of \u200b\u200bthe cross section of the water flow,

P is the length of the inside of the pipe located in direct contact with the liquid.

Tablet Calculation of sewer pipes

It is possible to identify the passability of the pipes of the sewer system using tables, and the calculations will be directly dependent on the type of system:

1. Non-free sewage. To calculate the non-pressure sewer systems, tables are used containing all the necessary indicators. Knowing the diameter of the installed pipes, you can choose all other parameters depending on it and substitute them in the formula (read also: ""). In addition, the table indicates the volume passing through the pipe fluid, which always coincides with the pipeline passability. If necessary, you can use the Lukin tables, in which the amount of bandwidth of all pipes with a diameter in the range from 50 to 2000 mm is indicated.
2. Pressure sewage. To determine the bandwidth in this type of system through the tables is somewhat simpler - it is enough to know the limiting degree of pipeline filling and the average fluid transportation rate. See also: "".

The bandwidth table of polypropylene pipes allows you to learn all the parameters you need to improve the system.

Calculation of the capacity of the water supply

Water pipes in private construction are most often applied. In any case, there is a serious load on the water supply system, so the calculation of the capacity of the pipeline is required, because it allows you to create the most comfortable operating conditions of the future design.

To determine the passability 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 excluded. An increase in the inner diameter of the pipe is directly proportional to its passability - that is, the thick pipe almost does not prevent the water movement and is less susceptible to the layering of various sediments.

However, there are other indicators that also need to be considered. For example, a very important factor is the friction coefficient of fluid on the inside of the pipe (for different materials there are eigenvalues). It is also worth considering the length of the entire pipeline and the pressure difference at the beginning of the system and the output. An important parameter is the number of various adapters present in the construction of the water pipeline.

The bandwidth of polypropylene pipes of the water supply can be calculated depending on several parameters with a tabular method. One of them is a calculation in which the main indicator is the water temperature. With increasing temperature in the system, fluid expanded, so friction increases. To determine the patency of the pipeline, you need to use the corresponding 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 the water throughput throughput allows to carry out the chapels tables. In addition to accuracy and a large number of standard values, these tables have formulas that allow you to calculate any system. This material in full describes all situations associated with hydraulic calculations, so most of the professionals in this area are most often used by the Shevelev's tables.

The main parameters that are taken into account in these tables are:

• External and internal diameters;
• Thickness of the walls of the pipeline;
• System operation period;
• Total length of highway;
• Functional system.

Conclusion

The calculation of pipe bandwidth can be performed in different ways. The choice of the optimal method of calculation depends on the large number of factors - from the size of the pipes to the destination and type of system. In each case, there are more and less accurate calculation options, so it will be able to find suitable as a professional specializing in pipeline laying and the owner who has decided to independently pave the highway at home.

Water consumption parameters:

1. The magnitude of the pipe diameter, which also determines the further bandwidth.
2. The magnitude of the walls of the pipe, which, after determining the internal pressure in the system.

The only thing that does not affect the flow is the length of communication.

If the dimer is known, the calculation can be carried out according to such data:

1. Construction material for pipe-building.
2. Technology influencing the process of assembling the pipeline.

Characteristics affect the pressure inside the water supply system and determine the water consumption.

If you are looking for an answer to the question of how to determine the water consumption, then you must learn the two calculation formulas that determine the parameters of use.

1. The formula for calculating per day - Q \u003d ΣQ × N / 100. Where σq is the annual daily use of water per 1 inhabitant, and n is the number of inhabitants in the building.
2. Formula for calculation per hour - Q \u003d Q × k / 24. Where q is a daily calculation, and K is a ratio of lowering uneven consumption (1.1-1.3).

These simple calculations will be able to help determine the expense, which will show the needs and needs of this house. There are tables that can be used in the fluid calculation.

Reference data in water

When using the tables, you should calculate all the cranes, bathtubs and water heaters in the house. Table SNiP 2.04.02-84.

Standard consumption standards:

• 60 liters - 1 person.
• 160 liters - for 1 person, if a better water supply is equipped in the house.
• 230 liters - for 1 person, in the house where high-quality water supply and bathroom are installed.
• 350 liters - for 1 person with water supply, built-in equipment, bathroom, toilet.

Why calculate water on low-speed?

How to determine the consumption of water for every day is not the most demanded information among ordinary residents of the house, but this information is required for specialists in installing pipelines. And for more, they need to know what the diameter of the connection, and what pressure in the system it supports.

But to determine these indicators you need to know how much water is needed in the pipeline.

The formula that helps determine the diameter of the pipe and the flow rate of the fluid:

Standard velocity fluid in the system without pressure is 0.7 m / s and 1.9 m / s. And the speed from the external source, such as a boiler, is determined by the source passport. When diameter knowledge, the flow rate in communications is determined.

Calculation of water pressure loss

The loss of water consumption is calculated taking into account the pressure drop in one formula:

In the formula L, denotes the lengths of the compound, and λ - the loss of friction, ρ is a pitch.

The friction indicator changes from such values:

• the level of roughness of the coating;
• an obstacle in the equipment at shut-off places;
• fluid flow rate;
• the length of the pipeline.

Easy calculation

Knowing pressure losses, fluid velocity in the pipes and the volume of water required, how to determine the flow of water and the size of the pipeline becomes much clearer. But in order to get rid of long settlements, you can use a special table.

Where D is the diameter of the pipe, Q is the consumer consumption of water, and V is the water velocity, and the course. To determine the values, they must be found in the table and connect in a straight line. Also determine the flow and diameter, while considering the slope and speed. Consequently, the easiest way to calculate is the use of tables and graphics.

Method of calculating Table Sheveleva Theoretical hydraulics SNiP 2.04.02-84

Initial data

Pipeline material: New steel without an internal protective coating or with bitumen protective coating New cast iron without an internal protective coating or with bitumen protective coating Nen steel and cast-iron without an internal protective coating or with bitumen protective coating asbestos-cement reinforced concrete vibrohydropressed reinforced concrete centrifuges steel and cast iron with ext. Plastic or polymercient cover, applied by the centrifugation of steel and cast iron, with an internal cement-sand coating applied by spraying steel and cast iron, with an internal cement-sand coating applied by centrifuging from polymeric materials (plastic) glass

Estimated flow

L / s m3 / hour

Outside diameter mM.

Wall thickness mM.

Length of the pipeline m.

Average water temperature ° C.

Eq. Roughness inside. Pipe surfaces: Stretched or with big deposits steel or cast iron old rusted steel otsink. After several years old after several years old cast iron steel galvanized new steel welded new steel seamless new brass, lead, copper glass

Amount of K-Tov Local Resistance

Payment

Pressure loss dependence on pipe diameter

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When calculating the water supply system or heating, you encounter the task of selecting the diameter of the pipeline. To solve such a task, you need to make a hydraulic calculation of your system, and for an even simpler solution - you can use hydraulic calculation onlineWhat we will do now.
Operating procedure:
1. Choose a suitable calculation method (calculation on Shevelev's tables, theoretical hydraulic or SNiP 2.04.02-84)
2. Choose pipelines material
3. Set the calculated water consumption in the pipeline
4. Set the outer diameter and thickness of the pipeline wall
5. Set the pipeline length
6. Set the average water temperature
The result of the calculation will be the graph and the values \u200b\u200bof the hydraulic calculation below.
The graph consists of two values \u200b\u200b(1 - water pressure loss, 2 - water velocity). The optimal values \u200b\u200bof the pipe diameter will be written green under the schedule.

Those. You must set the diameter so that the point on the chart is strictly over your green values \u200b\u200bof the pipeline diameter, because only such values \u200b\u200bthe water speed and pressure loss will be optimal.

Pressure loss in the pipeline show pressure loss on a given area of \u200b\u200bthe pipeline. The higher the loss, the more you have to work to deliver water to the right place.
The characteristic of the hydraulic resistance shows how efficiently the diameter of the pipe depending on the pressure loss.
For reference:
- If you need to know the speed of fluid / air / gas in the pipeline of various sections - use

35001 0 27

Pipe capacity: just about complex

How is the bandwidth of the pipe depending on the diameter? What factors, in addition to cross-section, affect this parameter? Finally, how to calculate, let approximately the passability of the water supply system with a known diameter? In the article I will try to give these questions as simple and accessible answers.

Our task is to learn to calculate the optimal cross section of the water pipes.

Why it is necessary

Hydraulic calculation allows you to get optimal minimum The value of the diameter of the water pipeline.

On the one hand, the money during construction and repair is always catastrophically lacking, and the price of the pipe meter grows with an increase in the diameter nonlinearly. On the other hand, the lowered section of the water supply will lead to an excessive drop of pressure on end devices due to its hydraulic resistance.

Upon consumption on the intermediate device, the pressure drop on the end will lead to the fact that the temperature of the water at open valves and the DHW cranes will change dramatically. As a result, you can either be icy water, or wipes boiling water.

Restrictions

I intentionally limit the area of \u200b\u200bthe tasks under consideration with a plumbing of a small private house. The reasons are two:

1. Gases and liquids of different viscosity behave when transporting through the pipeline is absolutely different. Consideration of the behavior of natural and liquefied gas, oil and other environments would increase the volume of this material several times and would lead away from my specialization - plumbers;
2. In the case of a large building with numerous plumbing devices for hydraulic calculation of the water supply, you will have to calculate the likelihood of simultaneous use of several points of water intake. In a small house, the calculation is performed for peak consumption by all available devices, which greatly simplifies the task.

Factors

The hydraulic calculation of the water supply system is a search for one of two quantities:

• Calculation of the capacity of the pipe with a known section;
• Calculation of optimal diameter with a well-known expense.

In real conditions (when designing a water supply), much more often have to perform the second task.

Household logic suggests that the maximum flow of water through the pipeline is determined by its diameter and pressure at the input. Alas, reality is much more complicated. The fact is that the pipe has hydraulic resistance: Simply put, the flow slows down due to friction about the wall. Moreover, the material and condition of the walls predictably affect the degree of braking.

Here is a complete list of factors affecting the performance of the plumbing pipe:

• Pressure At the beginning of the water supply (read - pressure in the track);
• Bias pipes (change in its height above the conditional level of soil at the beginning and end);

• Material Walls Polypropylene and polyethylene have a much smaller roughness than steel and cast iron;
• Agepipes. Over time, steel is becoming rust and lime deposits, which not only increase roughness, but also reduce the inner lumen of the pipeline;

This does not apply to glass, plastic, copper, galvanized and metal-polymer pipes. After 50 years of operation, they are in a state of new ones. The exception is tooling the water supply with a large number of weighing and the absence of filters at the entrance.

• Number and corner turns;
• Changes in diameter water supply;
• Availability or absence welds, grants from soldering and connecting fittings;

• Shut -ling fittings. Even full-risk ball valves have a definite resistance movement.

Any calculation of the bandwidth of the pipeline will be very approximate. We will have to use the averaged coefficients typical of those close to our conditions.

Torrichelli law

In the beginning of the 17th century, Evangelist Torricelli is known as the student Galileo Galilean and the author of the very concept of atmospheric pressure. It also owns a formula that describes the consumption of water, pouring from the vessel through the hole of the known dimensions.

For the performance of the Torricelli formula, it is necessary:

1. So that water is known to be known (the height of the water column above the hole);

One atmosphere in terrestrial gravity is able to raise a water column for 10 meters. Therefore, the pressure in the atmosphere is recalculated into the pressure by a simple multiplication by 10.

1. To open the hole substantially less than the diameter of the vessel, Excluding, thus, the pion loss due to the friction about the wall.

In practice, Torriercelli formula allows you to calculate water consumption through a pipe with an internal cross section of known sizes with a known instantaneous pressure during flow. Simply put: To take advantage of the formula, you need to install a pressure gauge before the crane or calculate the drop in the pressure on the water supply at a known pressure in the track.

The formula itself looks like this: V ^ 2 \u003d 2Gh. In it:

• v is the flow rate at the outlet of the hole in meters per second;
• g - acceleration of the fall (for our planet it is 9.78 m / s ^ 2);
• h - pressure (height of the water column above the hole).

How will it help in our task? What is the fact that fluid consumption (the most bandwidth) is equal S * V.where S is the cross-sectional area of \u200b\u200bthe hole, and V is the flow rate from the above formula.

Captain is an obvious suggests: knowing the area of \u200b\u200bcross section, it is not difficult to determine the inner radius of the pipe. As is known, the circle area is calculated as π * R ^ 2, where π is rounded equal to 3,14159265.

In this case, the Torricelli formula will have the form V ^ 2 \u003d 2 * 9.78 * 20 \u003d 391.2. The square root of 391.2 is rounded 90. So water will pour out from the hole at a speed of 20 m / s.

Calculate the diameter of the hole through which the flow is poured. Transferring the diameter into units of C (meters), we get 3,14159265 * 0.01 ^ 2 \u003d 0.0003141593. And now we calculate the flow of water: 20 * 0.0003141593 \u003d 0.006283186, or 6.2 liters per second.

Back to reality

Dear reader, I will venture to suggest that you have no pressure gauge in front of the mixer. Obviously, for a more accurate hydraulic calculation, some additional data is needed.

Typically, the calculated problem is solved from the opposite: with the well-known consumption of water through the plumbing devices, the length of the water supply line and its material is selected a diameter that provides a drop in the pressure to acceptable values. The limiting factor is the flow rate.

Reference data

The rate of flow rate for internal water pipes is considered to be 0.7 - 1.5 m / s.The exceeding the last value leads to the appearance of hydraulic noise (first of all - on bends and fittings).

Water consumption rates for sanitary pribers are easy to find in regulatory documentation. In particular, they are given an application to SNIP 2.04.01-85. To save the reader from long searching, I will give this table here.

The table shows the data for mixers with aerators. Their absence is equalized by consumption through the mixers of washing, washbasin and shower cabin with a flow rate through the mixer when typing bath.

Let me remind you that if you want to calculate the private house plumbing, summarize the water consumption for all installed devices. If this manual is not respected, you will be waiting for surprises like a sharp drop in the temperature in the shower when the hot water crane is opened on.

If a fire pipe is present in the building, 2.5 l / s per hydrant is added to the planned consumption. For fire water supply, the flow rate is limited to a value of 3 m / s: In case of fire, hydraulic noises are the last thing that will be nervating tenants.

When calculating the pressure, it usually proceeds from the fact that on the extreme from entering the device it should be at least 5 meters, which corresponds to the pressure of 0.5 kgf / cm2. Part of the plumbing devices (flowing water heaters, filler valves of automatic washing machines, etc.) simply not triggered if the pressure in the plumbing is below 0.3 atmospheres. In addition, you have to take into account the hydraulic losses on the device itself.

In the photo - ATM Basic flowing water heater. It turns on the heating only at a pressure of 0.3 kgf / cm2 and above.

Consumption, diameter, speed

Let me remind you that they are linked to each other by two formulas:

1. Q \u003d SV.. Water consumption in cubic meters per second is equal to the cross-sectional area in square meters multiplied by the flow rate in meters per second;
2. S \u003d π R ^ 2. The cross-sectional area is calculated as a product of the number "PI" and the square of the radius.

Where to get the values \u200b\u200bof the internal cross section?

• Steel pipes with minimal error is equal half D. (conditional passage, which marked pipe rental);
• In polymeric, metal-polymer, etc. The inner diameter is equal to the difference between the outer, which are marked with pipes, and double wall thickness (it is also usually present in the marking). Radius, respectively, is half of the inner diameter.

1. The inner diameter is 50-3 * 2 \u003d 44 mm, or 0.044 meters;
2. Radius will be 0.044 / 2 \u003d 0.022 meters;
3. The internal section area will be equal to 3,1415 * 0.022 ^ 2 \u003d 0.001520486 m2;
4. At a flow rate of 1.5 meters per second, the flow rate will be 1.5 * 0.001520486 \u003d 0.002280729 m3 / s, or 2.3 liters per second.

Loss of pressure

How to calculate how much pressure is lost on a plumbing with known parameters?

The simplest formula for calculating the falling of the pressure has the form H \u003d Il (1 + K). What do the variables in it mean?

• H - the cherished drop of pressure in meters;
• i - hydraulic slope of the meter of water pipeline;
• L is the length of the water pipe in meters;
• K - coefficientallowing you to simplify the calculation of the falling of the pressure on the shut-off valves and. It is tied to the appointment of a water supply network.

Where to get the values \u200b\u200bof these variables? Well, in addition to the length of the pipe - the roulette is still no one canceled.

The coefficient K is accepted equal:

With a hydraulic bias, the picture is much more complicated. The resistance exerted by the pipe flow depends on:

• Internal cross section;
• Roughness of the walls;
• Flow speed.

The list of values \u200b\u200bof 1000i (hydraulic slope per 1000 meters of water supply can be found in Shevelev's tables, which, in fact, serve for hydraulic calculation. The volume of tables is too large for the article, as they lead the values \u200b\u200bof 1000i for all possible diameters, flow rates and materials adjusted for service life.

Here is a small fragment of the Shevelev table for a 25 mm plastic pipe.

The author of the tables gives the values \u200b\u200bof the pressure drop is not for the inner section, but for standard sizes that are marked with pipes, adjusted to the wall thickness. However, the tables were published in 1973, when the corresponding segment of the market has not yet been formed.
When calculating, keep in mind that it is better to take values \u200b\u200bfor the metalplastic to take the values \u200b\u200bof a smaller step.

Let us use this table, we calculate the drop in the pressure on the polypropylene tube with a diameter of 25 mm and a length of 45 meters. We agree that we design a domestic water supply.

1. With a distance of 1.5 m / s as close as possible (1.38 m / s), the value of 1000i will be 142.8 meters;
2. The hydraulic slope of one meter of the pipe will be equal to 142.8 / 1000 \u003d 0.1428 meters;
3. The correction coefficient for household water pipes is 0.3;
4. The formula as a whole will acquire the view H \u003d 0.1428 * 45 (1 + 0.3) \u003d 8,3538 meters. It means that at the end of the water supply at the flow rate of 0.45 l / s (value from the left column of the table), the pressure will fall by 0.84 kgf / cm2 and at 3 atmospheres at the input will be quite acceptable 2.16 kgf / cm2.

This value can be used to determine consumption according to Torricelli formula. The calculation method with an example is given in the appropriate section of the article.

In addition, in order to calculate the maximum flow through the plumbing with known characteristics, you can choose in the "Consumption" column of the total Shevelev table such a value at which the pressure at the end of the pipe will not fall below 0.5 atmosphere.

Conclusion

Dear reader, if the given instruction, despite the limiting simplicity, still seemed to you tedious - just use one of the numerous online calculators. As always, additional information can be found in the video in this article. I will be grateful for your additions, amendments and comments. Successes, Camrads!

July 31, 2016.

If you want to express your gratitude, add clarification or objection to ask the author - add a comment or tell me thanks!

Why do you need such calculations

When drawing up a plan for the construction of a large cottage that has several bathrooms, a private hotel, a fire system organization, it is very important to have more or less accurate information about the transportation capabilities of the existing pipe, taking into account its diameter and pressure in the system. It's all about the oscillations of the pressure during the peak of water consumption: such phenomena are quite seriously affected by the quality of the services provided.

In addition, if the water supply is not equipped with water meters, then when paying for the services of public services, the settlement is taken. "Pettleness of the pipe." In this case, it is quite logical than the question of the tariffs applied at the same time.

It is important to understand that the second option does not apply to private premises (apartments and cottages), where in the absence of counters when calculating the payment take into account sanitary standards: it is usually up to 360 l / a day per person.

What depends on the passability of the pipe

What does water consumption depends on the round of the circular section? It seems that the search for the answer should not cause difficulties: the larger cross section has a pipe, the greater the volume of water it can skip over a certain time. In this case, the pressure is also remembered, because the higher the water pole, with the greater speed, the water will be joined inside the communication. However, practice shows that this is not all factors affecting water consumption.

In addition to them, the following points also have to take into account:

1. Length pipe. With an increase in its length, water turns more than its wall, which leads to a slowdown. Indeed, at the very beginning of the system, water is experiencing exclusively with pressure, but it is important and how quickly the following portions will have the opportunity to enter into communication. Braking inside the tube often reaches large values.
2. Water consumption depends on diameter In a much more difficult degree than it seems at first glance. When the size of the diameter of the pipe is small, the walls resist the aqueous stream an order of magnitude greater than in thicker systems. As a result, with a decrease in the pipe diameter, its benefit is reduced in terms of the ratio of the water flow rate to the index of the inner area on the fixed length section. If you say in a simple, thick water supply is much faster transported water than thin.
3. Material of manufacture. Another important point, directly affecting the speed of the water in the pipe. For example, smooth propylene contributes to the glide of water in much more than the rough steel walls.
4. Service duration. Over time, rust appears on steel water pipes. In addition, for steel, as for cast iron, it is characteristic of gradually accumulating lime deposits. The resistance to the water flow pipe with sediments is much higher than new steel products: this difference sometimes reaches 200 times. In addition, the tip of the pipe leads to a decrease in its diameter: even if you do not take into account the increased friction, it clearly falls. It is also important to note that products from plastic and metalplastic such problems do not have: Even after decades of intensive operation, the level of their resistance to the aqueous streams remains at the initial level.
5. Availability of turns, fittings, adapters, valves Promotes additional braking of water streams.

All of the above factors have to be considered, because it is not about some small errors, but about a serious difference several times. As an output, it can be said that a simple definition of the diameter of the pipe on water consumption is hardly possible.

New possibility of calculating water flow

If the use of water is carried out by means of a crane, it greatly simplifies the task. The main thing in this case is that the size of the water output holes were much smaller than the diameter of the water pipeline. In this case, the formula for calculating the water calculation by cross section of torrchelli V ^ 2 \u003d 2GH, where V is the speed of flow through a small hole, G is an acceleration of free fall, and H is the height of the water column over the crane (a hole having a cross section S, per unit of time Passes aqueous volume S * V). It is important to remember that the term "section" is not applied to designate the diameter, and its area. For its calculation, the formula Pi * R ^ 2 is used.

If the water column has a height of 10 meters, and the hole is the diameter of 0.01 m, the water consumption through the pipe at a pressure into one atmosphere is calculated in this way: V ^ 2 \u003d 2 * 9.78 * 10 \u003d 195.6. After removing the square root, V \u003d 13,98570698963767 comes out. After rounding, to get a simpler speed indicator, it turns out to be 14m / s. The cross section of the hole, having a diameter of 0.01 m, is calculated as: 3,14159265 * 0.01 ^ 2 \u003d 0.000314159265 m2. As a result, it turns out that the maximum water flow through the pipe corresponds to 0.000314159265 * 14 \u003d 0.00439822971 m3 / s (slightly less than 4.5 liters of water / second). As you can see, in this case, the calculation of water in the pipe cross section is quite simple. Also in free access there are special tables indicating the cost of water for the most popular plumbing products, with a minimum value of the diameter of the tap pipe.

As can already be understood, a universal simple way to calculate the diameter of the pipeline depending on the flow of water, does not exist. However, certain indicators for themselves can still be withdrawn. This is especially true if the system is equipped with plastic or metal-plastic pipes, and water consumption is carried out by cranes with a small exit cross section. In some cases, this method of calculation is applicable on steel systems, but it is primarily about new water pipelines that did not have time to be covered with internal sediments on the walls.

Water consumption for pipe diameter: determination of the diameter of the pipeline depending on the flow rate, calculation by section, the maximum flow rate at a pressure of the round section

Water consumption in the diameter of the pipe: determination of the diameter of the pipeline depending on the flow rate, calculation by section, the formula for the maximum flow rate at the pressure in the round of the circular section

Water consumption through the pipe: Is there a simple calculation?

Is it possible for a simple calculation of water consumption on the pipe diameter? Or the only way - to contact the specialists, pre-portraying a detailed map of all water pipes in the district?

After all, hydrodynamic calculations are extremely complex ...

Our task is to find out how much water can this pipe can miss

What is it for?

1. With independent calculation of water systems.

If you plan to build a large house with several guest bathtubs, a mini-hotel, produce a fire extinguishing system - it is advisable to know how much water can put a pipe of a given diameter at a certain pressure.

After all, a significant drop in the pressure in the peaks of water consumption is hardly pleased with the tenants. Yes, and a weak pitch of water from the fire hose will most likely be useless.

1. In the absence of water meters, utilities usually exhibit the account of organizations "on pipe patency".

Please note: the second scenario does not affect apartments and private houses. If there are no water meters, communal services take payment for water according to sanitary standards. For modern well-maintained houses, it is not more than 360 liters per person per day.

Need to admit: the water meter greatly simplifies relations with utilities

Factors influencing pipes

What affects the maximum water consumption in the round of the circular section?

Obvious answer

Common sense suggests that the answer should be very simple. There is a pipe for water supply. In it hole. What it is more - the more water through it will be held per unit of time. Oh, sorry, still pressure.

Obviously, the water post in 10 centimeters will urge less water through a centimeter hole than a water column with a decade-money house.

So, from the inner section of the pipe and from the pressure in the water supply, so?

Do you need something else?

Correct answer

Not. These factors are affected by consumption, but they are only the beginning of a long list. Calculate water consumption in the diameter of the pipe and pressure in it is the same as to calculate the trajectory of the rocket flying to the moon, based on the visible position of our satellite.

If you do not take into account the rotation of the Earth, the movement of the moon in its own orbit, the resistance of the atmosphere and the gravity of the celestial bodies - hardly our spacecraft will fall at least about the desired point of space.

At how much water will be poured from the pipe with a diameter x at a pressure in the route Y, not only these two factors affect, but also:

• The length of the pipe. The longer it is - the stronger the friction of water on the wall slows down the flow of water in it. Yes, the water itself affects the water itself only the pressure in it, but the following volumes of water should take its place. And the water pipe inhibits them, and as much as.

It is due to the loss of pressure in a long pipe on pipelines there are pumping stations

• The diameter of the pipe affects water consumption much more complicated than suggests "common sense". For small diameter pipes, the resistance of the wall movement is much more than for thick pipes.

The reason is that the smaller the pipe is, the less profitable in it from the point of view of the water flow rate ratio of the internal volume and surface area at a fixed length.

Simply put, in a thick pipe, water is easier to move than fine.

• Wall material - another essential factor on which the speed of water depends. If the water glides on smooth polypropylene, as the fillet part of the clumsy ladies on the sidewalk in ice, then the rough steel creates a much greater stream resistance.
• The age of the pipe is also very effect on the patency of the pipe. Steel plumbing pipes rust, in addition, steel and cast iron over the years overlap overlapping.

The overgrown tube has a much greater stream resistance (resistance of a polished new steel pipe and rusty differ in 200 times!). Moreover, the plots inside the pipe due to the overgrowth reduce their lumen; Even in ideal conditions, much less water will pass through the overgrown pipe.

What do you think it makes sense to count on the pipe diameter at the flange?

Note: the condition of the surface of plastic and metal-polymer pipes does not deteriorate over time. After 20 years, the pipe will have the same resistance to the stream of water, as at the time of installation.

• Finally, any turn, the transition of diameter, a variety of shut-off valves and fittings - all this also slows down the flow of water.

Ah, if the factors described above could be neglected! However, it is not about deviations within the error, but about the difference at times.

All this leads us to a sad conclusion: the simple calculation of the flow of water through the pipe is impossible.

Light Light in the Dark Kingdom

In the event of water consumption through the crane, however, the task may be sharply simplified. The basic condition of the simple calculation: the hole through which the water is poured, must be negligible compared to the diameter of the pipe supplying water.

Then there is a Torricechelli law: V ^ 2 \u003d 2GH, where V is the rate of leakage from the small hole, G is the acceleration of the free fall, and H is the height of the water column, which is standing above the hole. At the same time, through a hole with a cross section S per unit of time, the volume of the liquid S * V will be.

Mother left you a gift

Do not forget: the hole section is not a diameter, it is an area equal to pi * r ^ 2.

For a waters of 10 meters (which corresponds to excess pressure in one atmosphere) and the holes with a diameter of 0.01 meter the calculation will be:

Remove the square root and get V \u003d 13,98570698963767. For ease of calculations, the flow rate of up to 14 m / s is rounded.

The cross section of the hole with a diameter of 0.01 m is 3,14159265 * 0.01 ^ 2 \u003d 0.000314159265 m2.

Thus, water consumption over our hole will be 0.000314159265 * 14 \u003d 0.00439822971 m3 / s, or a little less than four and a half liters per second.

As you can see, in this embodiment, the calculation is not very complex.

In addition, in the annex to the article you will find the water consumption table with the most common plumbing devices indicating the minimum diameter of the eyeliner.

Conclusion

Here briefly and that's it. As you can see, we did not find a universal simple solution; However, let's hope, the article will be useful to you. Good luck!

How to calculate pipe bandwidth

The calculation of the bandwidth is one of the most complex tasks when laying the pipeline. In this article we will try to deal with how it is this is done for different types of pipelines and pipe materials.

High bandwidth pipes

Bandwidth is an important parameter for any pipes, channels and other heirs of the Roman aqueduct. However, not always on the pipe packaging (or on the product itself) is the bandwidth. In addition, the pipeline scheme also depends on how much fluid passes the pipe through the section. How to correctly calculate the throughput of pipelines?

Methods for calculating the bandwidth of pipelines

There are several methods for calculating this parameter, each of which is suitable for a separate case. Some notation, important when determining the capacity of the pipe:

The outer diameter is the physical size of the pipe cross section from one edge of the outer wall to another. When calculating is denoted as a day or DN. This parameter is indicated in the marking.

The diameter of the conditional passage is the approximate value of the diameter of the inner cross section of the pipe, rounded to an integer. When calculating is indicated as a DU or DU.

Physical methods for calculating pipe bandwidth

The values \u200b\u200bof the bandwidth of the pipes are determined by special formulas. For each type of product - for gas, water supply, sewage - methods for calculating their own.

Table methods of calculation

There is a table of approximate values, created to facilitate the permanent bandwidth of the intra-wood layout. In most cases, high accuracy is not required, so the values \u200b\u200bcan be applied without computing. But this table does not take into account the reduction in capacity by the appearance of sedimentary growths inside the pipe, which is typical of old highways.

There is an accurate bandwidth table, called the Shevelev table, which takes into account the pipe material and many other factors. These tables are rarely used when laying the water supply in the apartment, but in a private house with several non-standard risers can be useful.

Calculation using programs

At the disposal of modern plumbing firms there are special computer programs for calculating the bandwidth of pipes, as well as many other similar parameters. In addition, online calculators, which, although less accurate, are free, but are free and do not require installation on PC. One of the stationary programs "TASCOPE" is the creation of Western engineers, which is conventional free. In large companies, the "hydraulic system" is used - this is a domestic program that expects pipes on criteria that affects their operation in the regions of the Russian Federation. In addition to hydraulic calculation, it allows you to read other parameters of pipelines. The average price of 150,000 rubles.

How to calculate the bandwidth of the gas pipe

Gas is one of the most complex materials for transportation, in particular, because it has a compressive property and therefore it is capable of leaking through the smallest gaps in the pipes. To calculate the bandwidth of gas pipes (as well as the design of the gas system as a whole), special requirements are imposed.

The formula for calculating the bandwidth of the gas pipe

The maximum capacity of gas pipelines is determined by the formula:

Qmax \u003d 0.67 DU2 * P

where P is equal to working pressure in the system of gas pipeline + 0.10 MPa or absolute gas pressure;

Do is the conditional passage of the pipe.

There is a complex formula for calculating the bandwidth of the gas pipe. When conducting preliminary calculations, as well as at the calculations of the household gas pipeline, it is usually not used.

Qmax \u003d 196,386 DU2 * P / Z * T

where Z is the compressibility coefficient;

T- temperature of the moved gas, K;

According to this formula, the direct dependence of the temperature of the moved medium from pressure is determined. The higher the value of T, the greater the gas expands and presses on the walls. Therefore, engineers in the calculations of large highways take into account possible weather conditions in the area where the pipeline passes. If the nominal value of the DN pipe will be less than the gas pressure formed at high temperatures in summer (for example, at + 38 ... + 45 degrees Celsius), then there is likely damage to the highway. It entails the leakage of valuable raw materials, and creates the likelihood of the explosion of the pipe.

Table of gas pipe capacity depending on pressure

There is a table of calculation of the capacity of the gas pipeline for frequently used diameters and the nominal pipe pressure. To determine the characteristic of the gas line of non-standard sizes and pressure, engineering calculations will be required. Also for pressure, the speed and volume of gas affects the outdoor temperature.

The maximum speed (W) of the gas in the table is 25 m / s, and z (compressibility coefficient) is 1. The temperature (T) is equal to 20 degrees on the Celsius scale or 293 on the Kelvin scale.

Sewage Pipe Capacity

The throughput capacity of the sewer pipe is an important parameter that depends on the type of pipeline (pressure or non-puncture). The calculation formula is based on hydraulics laws. In addition to the time-consuming calculation, tables use tables to determine the bandwidth.

Formula of hydraulic calculation

For hydraulic calculation of the sewage, it is required to determine unknowns:

1. diameter of the pipeline DU;
2. the average flow rate V;
3. hydraulic bias L;
4. the degree of filling H / DB (in the calculations is repelled from the hydraulic radius, which is associated with this value).

In practice, limited to the calculation of the value of L or H / D, since the remaining parameters are easy to calculate. The hydraulic bias in preliminary calculations is considered to be equal to the slope of the surface of the Earth, in which the wastewater movement will not be lower than self-relief. Speed \u200b\u200bvalues, as well as maximum H / DU values \u200b\u200bfor household networks can be found in Table 3.

In addition, there is a normalized value of the minimum liner for pipes with a small diameter: 150 mm

(i \u003d 0.008) and 200 (i \u003d 0.007) mm.

The formula of the volume flow of liquid looks like this:

where A is the area of \u200b\u200bthe live cross section of the flow,

v - flow rate, m / s.

Speed \u200b\u200bis calculated by the formula:

where R is a hydraulic radius;

C - wetting coefficient;

From here you can withdraw the formula of the hydraulic slope:

It defines this parameter if you need to calculate.

where n is a roughness coefficient having values \u200b\u200bfrom 0.012 to 0.015, depending on the pipe material.

The hydraulic radius is considered to be an ordinary radius, but only with full filling of the pipe. In other cases, use the formula:

where a is the cross-flux area of \u200b\u200bthe liquid,

A pompeted perimeter, or the transverse length of the inner surface of the pipe, which concerns the liquid.

Bandwidth Tables Free Sewer Drops

The table takes into account all the parameters used to perform hydraulic calculation. The data is selected by the value of the pipe diameter and substitute in the formula. Here already calculated the volume flow rate of the liquid q passing through the cross section of the pipe, which can be taken for the throughput of the highway.

In addition, there are more detailed layout tables containing ready-made bandwidth values \u200b\u200bfor pipes of different diameter from 50 to 2000 mm.

Tables of bandwidth of pressure sewer systems

In the bandwidth tables of pressure pipes, the values \u200b\u200bdepend on the maximum degree of filling and the calculated medium velocity of wastewater.

Pipe capacity of the tap

Water pipes in the house are used most often. And since there is a large load on them, the calculation of the capacity of the plumbing highway becomes an important condition for reliable operation.

Patency of the pipe depending on the diameter

Diameter is not the most important parameter when calculating the pipes of the pipe, but also affects its value. The larger the inner diameter of the pipe, the higher the permeability, as well as the chance of the appearance of blockages and traffic jams. However, in addition to diameter, it is necessary to take into account the coefficient of water friction on the wall of the pipe (table value for each material), the length of the highway and the difference in the pressure of the fluid at the inlet and outlet. In addition, the number of knees and fittings in the pipeline will be strongly influenced.

Table of pipe bandwidth on the temperature of the coolant

The higher the temperature in the pipe, the lower its bandwidth, as water expands and thereby creates additional friction. For water supply, this is not important, and in heating systems is a key parameter.

There is a table for calculating heat and coolant.

Table of pipe bandwidth depending on the pressure of the coolant

There is a table that describes the bandwidth of pipes depending on the pressure.

Table of bandwidth of the pipe depending on the diameter (by Shevelev)

Tables F.A. and A. F. Shevelov are one of the most accurate table methods for calculating the throughput of the water supply. In addition, they contain all the necessary calculation formulas for each specific material. This bulk informative material used by hydraulics engineers is most often.

The tables take into account:

1. pipe diameters - internal and external;
2. wall thickness;
3. lifetime of water supply;
4. length of the highway;
5. purpose pipes.

Pipe capacity depending on the diameter, pressure: tables, calculation formulas, online calculator

The calculation of the bandwidth is one of the most complex tasks when laying the pipeline. In this article we will try to deal with how it is this is done for different types of pipelines and pipe materials.