Pipe diameters in inches and millimeters. Pipe Sizes Inner Pipe Size 1 2 ''

It is not possible to mount a communication system of any kind in such a way as to completely avoid connections. If only because the pipeline is ultimately supplied to some kind of consumer object - plumbing, radiator, washing machine, and is connected to the outlet of the device. And the main condition for a sealed high-quality assembly is the compliance of the pipe diameter and the size of the connecting element.

Dimensional parameters of the pipe

Regardless of the material of manufacture - polymer, metal, ceramics and so on, the product is characterized by a number of indicators, being guided by which the consumer can choose the desired product.

• Outside diameter - that is, the outside dimension of the pipe (this is only a circular section).
• Internal - the size of the working section.
• Wall thickness - largely determines the strength of the product.

The sum of the inner diameter and twice the wall thickness is the outer. The actual state of affairs corresponds to this statement. But when it comes to VGP, you need to consider the following point. Most often, water conduits are connected by a threaded method. The thread is applied to the outer part, as a result, the diameter of the thread is by no means equal to the outer dimension. And since it is important for installation to know exactly the indicators of the thread, this parameter turns out to be more important and is often indicated instead of the actual size of the product.

For example, a 1 inch water conduit is not at all equal in outer diameter to 2.54 cm, since 1 inch is an indication of the size of the thread.

This confusion is exacerbated by the use of two measuring systems on the one hand, and the variety of products available today on the other.

Conditional pass

The task of the water supply system is to evenly supply all consumers with the correct amount of water. The main calculation parameters are the throughput of the pipeline, that is, the amount of water that can pass per unit of time.

• This parameter is called conditional pass - Dn. It does not have a unit of measurement as such - it is a conditional, non-actual value, it is indicated in whole numbers and indicates the approximate conditional lumen of the pipe. The step between the values ​​is calculated theoretically, with the condition that with each subsequent increase, the throughput of the pipeline increases by 40-60%.

The convenience of the system is obvious only in practical use. It is enough to select water lines and fittings with equal nominal bore according to the table in order to guarantee a working water supply system.

Accordingly, a 1 "steel pipe has a nominal bore of 1", while its actual inner diameter is 25.5 mm, and the outer one with a thread is 33, 25.

Measuring systems

The existence of two methods of measurement has historical roots.

• Imperial - in inches, today it is used only for water and gas supply steel pipes and corresponding plumbing fittings.
• Metric - in mm, cm and m. It is used for any other pipe products.

When connecting pipelines from different materials, difficulties arise with recalculation from one system to another.

Inch and metric tubes

Both inch and standard steel conduits are available, further confusing matters. You can visually distinguish them by the type of thread - for a 1-inch pipe, the threads are rounded. The photo shows samples.

The thread pitch is measured differently. In metric products along the outer edges of the threads, in inch - along the inner ones. The distance is different for different section sizes.

• ½ and ¾ - the pitch is 1.814 mm.
• 1 "to 6 - 2, 309.

The pipe 1 inch, which is used in the imperial system, is not 2, 54 cm, as it should be, but equal to 3, 3249, since it includes both the internal size and the thickness of the walls. The exception is a ½ ”conduit.

Conversion of sizes from inch to metric

Reference literature contains corresponding tables. The same GOST, which regulates the parameters of the VGP, indicates both an inch and a millimeter nominal diameter. Unfortunately, to assemble the system into one whole, the actual value of the inner diameter is also required. While the tables are more often indicated outside.

The most convenient table contains the nominal size in inches, the outside pipe size and the equivalent diameter in mm. It indicates a bandwidth that corresponds to an inch.

For example, a 1-inch steel conduit can be connected to a polyethylene conduit, the nominal bore of which is 25 mm.

In their shape, pipes can be not only round, but also oval, rectangular, square. Despite such a variety in cross-sectional shape, all pipes have basically two types of parameters: technical and geometric. The geometric dimensions of pipes are represented by characteristics such as outside diameter, wall thickness or the ratio of outside and inside diameters, and length. , that is, the dimensions of the pipes are standardized by state standards (GOSTs). Different GOSTs are developed for pipes not only with different manufacturing methods, but also for different materials used in the production of pipes. In the Russian market, it is generally accepted to indicate pipe dimensions in mm (millimeters), but you can also find pipe dimensions in inches. The latter are most often indicated for imported pipes. The length of rolled pipes is measured in meters as standard.

The most common and popular are the following pipe sizes (diameter from larger to smaller): 1420, 1220, 1020, 920, 820, 720, 530, 426, 377, 325, 273, 219, 159. This rolled product refers to pipes of large and medium diameter. Smaller diameters are much less in demand on the market, so, of course, you can find them, but you will have to try. On the manufacturer's website there will definitely be a table of pipe sizes that the given enterprise manufactures. Usually, any manufacturer tries to cover as wide a range of pipe sizes as possible, since nowadays the market for this type of rolled products is very wide.

Until recently, Russian production did not produce seamless pipes with a diameter of more than 426 mm. But electrowelded covers almost the entire range. Spiral welded pipes can have a diameter greater than 1420, but less than 159 - not available. With longitudinal seam pipes, things are different. According to GOST, the smallest diameter of a longitudinal welded pipe is 8 mm, and the largest is 1420 mm. This is due to the fact that spiral and longitudinal welded pipes have a different manufacturing method, although both of them belong to welded pipes.

Pipe sizes are not limited to one diameter. Wall thickness is also one of the important technical indicators. Moreover, the diameter directly affects the size of the pipes, such as the wall thickness. The larger diameter allows the production of pipes with a wider range of wall thicknesses. For example, if the dimensions of longitudinal metal pipes (or rather, their diameter) are 530 cm, then the wall thickness can vary from 5 to 24 mm. The outer transverse dimensions of longitudinal steel pipes of 1020 mm make it possible to manufacture them with a wall thickness of 8 mm to 32 mm. The most popular are for pipes, for example, with a diameter of 530 mm, such wall thicknesses as 7, 8, 9 and 10 mm. For a pipe with a diameter of 1020 mm, the most common thicknesses are 10, 11, 12, and also 14 mm.

It is interesting that the dimensions of GOST pipes allow manufacturers to violate certain limits. In particular, for a longitudinal welded pipe with a diameter of 1020 mm, the deviation of the wall thickness can reach almost 1 mm. More precisely - 0.8 mm, both in the direction of greater and in the direction of lesser thickness. And since the assortment of pipes is determined with a step of 1 mm in thickness, this value is quite significant. For example, when buying a pipe with a thickness of 11 mm, do not be surprised that when measured directly, it turns out to be a pipe with walls of 10 or 12 mm. This aspect is very important when buying pipes, since the weight of the rolled product depends on the size of the pipes, such as the wall thickness. More weight - more price. Why is it customary to indicate weight, not footage? Because the cost of a pipe mainly depends on raw materials (the so-called price-forming raw material component).

Of course, weighing the pipe is too troublesome. Therefore, when calculating the price, the theoretical weight is taken into account, which is calculated by the formula: weight of 1 running meter = 0.02466 * wall thickness * (diameter-wall thickness). The wall thickness is taken in millimeters. In practice, the calculation is carried out as follows: the buyer measures the thickness of the pipes with a micrometer in order to check the deviation from the permissible values. When loading with a tape measure, the longitudinal dimensions of the pipes (i.e., length) are measured and then, having calculated the theoretical weight of 1 running meter. multiply it by the total length of the pipes.

In relation to such dimensions of steel pipes, as well as to the dimensions of pipes made of any other material, the requirements of GOSTs are quite loyal. For example: "pipes with a diameter of over 152 mm are made with a length of at least 5 m." Therefore, despite the fact that used pipes are cut a little before sale, it is impossible to distinguish them in length from new ones. It is worth remembering that many when selling straight or spiral pipes do not indicate the length. This means that the length of the pipes corresponds to GOST (usually about 11 meters). If the price list (announcement) indicates that pipes are sold cut at the seams, then their lengths are also within the limits allowed by GOSTs. Seamless pipes are allowed to be made of unmeasured length - from 4 meters to 12.5 meters. Therefore, when purchasing pipes, be interested in GOSTs.

Steel pipe diameters

The diameter of a steel pipe is determined by the outer diameter for electric-welded and seamless pipes, and for vgp - by the nominal diameter (often referred to as DN). That is, inner pipe diameter- Du, outer diameter of pipes Dн, thread diameter - G... Pipes are sized in millimeters, but WGP pipes are often denoted in inches (").

VGP pipe size (GOST 3262-75)

Main pipe dimensions: 15mm (1/2 ""); 20mm (3/4 "); 25 mm (1 "); 32 mm (1 1/4" inch and a quarter); 40 mm (1 1/2 "); 50 mm (2"). There are also the following DN: 10 mm, 65 mm, 80 mm, 90 mm, 100 mm and even 125 mm - but they are rarely used and, as a rule, are replaced by other types of steel pipes (for example, electrowelded). Most often, pipes 3/4 "are used for risers, for internal wiring 1/2".

Electric pipes (GOST 10704-91)

E / s longitudinal welded pipes are of the following outer diameters (in millimeters): 10; 12; thirteen; 14; sixteen; 17; 17.5; eighteen; nineteen; twenty; 21.3; 22; 24; 25; 26; 28; thirty; 32; 33; 33.7; 36; 38; 40; 42; 43; 45; 48; 51. With a diameter of up to 57 mm, a VGP pipe of the appropriate size is used. The most popular are longitudinal welded pipes in accordance with GOST 10704-91 in sizes from 57 mm and above. Their main diameters: 57; 60; 63.5; 76; 89; 102; 108; 114; 127; 133; 140; 146; 159; 168; 178; 193; 219; 245; 273; 325; 377; 426; 530.

Welded pipes for gas and oil pipelines (GOST 20295-85)

They start with a diameter of 159 mm and up to 530 mm come with the same dimensions as pipes in accordance with GOST 10704-91. Major larger diameters (in millimeters): 630, 720, 820, 1020, 1220, 1420.

Seamless hot-smoked pipes size (GOST 8732-78)

Commonly used hot rolled seamless pipe diameters (mm): 32; 38; 42; 45; 51; 54; 57; 60; 63,5; 68; 70; 73; 76; 83; 89; 95; 102; 108; 114; 121; 127; 133; 140; 146; 152; 159; 168; 180; 194; 203; 219; 245; 273; 325; 351; 426.

Manufacturing plants can produce any size of pipes at the request of the customer.

Internal pipe diameters

According to the standard series adopted in most countries, pipes have the following inner diameters, measured in mm: 6, 10, 15, 20, 25, 32, 40, 50, 65, 80, 100, 125, 200, etc.

The system of measurement by thread diameter in inches is also used. 1 "= 25.4 mm.

The table shows pipe dimensions(diameters) in mm and inches:

Nominal pipe diameter (Dy) mm	Thread diameter (G), inch	Outside pipe diameter (Dн), mm
		Steel water and gas pipe	Seamless	Polymer

When installing a steel pipe system for residential buildings, pipes with an inner diameter of Dy = 15, 20 and 32 mm are usually used.

Cast iron free-flow pipes with a diameter of Dу = 50 and 100 mm are the most commonly used.

Currently, pipes made of polymeric materials are increasingly used for laying indoor pipelines, which are replacing cast iron and steel.

It should be noted that, depending on the type of material used in the manufacture of pipes, different designation systems are used. In most cases, steel and cast iron pipes are designated by nominal bore or internal diameter. Copper pipes, some types of steel pipes, pipes made of polymeric materials are designated by the outer diameter. Therefore, you should carefully consider the choice of the required pipe, as well as take into account the wall thickness.

Outside pipe diameters and pipe wall thickness

Outside diameter, Dн mm	Wall thickness, mm
Steel pipes for water and gas supply GOST 3262-75
Electric-welded steel pipes GOST 10704-91 GOST 10705-80
Plastic pipes

It will not be possible to assemble any communication system without making connections, at least, because, in the end, you will need to connect plumbing equipment to it. The main thing is that the assembly is of high quality, and the diameters of all joints exactly match each other. Below we will talk a little about the inch pipe.

The difference between pipes in terms of dimensional parameters

Be it pipes made of plastic, metal or ceramics, they have a list of characteristics by which the buyer is guided when choosing them.

The main indicators include the following:

• outer section - if the pipe is round;
• inner section - is considered to be the working diameter;
• wall thickness - usually characterizes the strength of the pipe.

The outer section is formed from the inner section and the wall thickness multiplied by two. Often the pipes are threaded. The thread is applied to the outside of the pipe, after which its diameter cannot be considered equal to the outside diameter of the pipe. And due to the fact that during installation it is necessary to start from the thread section, this value becomes more important, and, as a rule, is taken into account instead of the actual pipe size.

For example, inch pipes in mm will not equal 25.4, because in this case 1 inch indicates the thread section. Things get more complicated due to the existence of two measurement systems, and due to the presence of many similar products on the market.

Conditional pipe capacity

Such a parameter is called a conditional pass and is denoted by Dn symbols. There is no specific unit of measurement, therefore, there is only a conditional, non-actual parameter, which in integer expression determines the approximate clearance of the pipe. The intervals between the values ​​are calculated theoretically, so that with a subsequent value, the throughput of the pipes increases by 40-60%.

The effectiveness of the finished system will be visible only in practice. To obtain a properly functioning water supply system, you just need to use the table, which contains a list of water pipes with the appropriate fitting sizes to match the nominal passages.

It is easy to conclude that in an inch pipe the diameter of the inner part will be 25.5 mm, while the outer section will be 33.25 mm.

Methods for measuring the cross-section of pipes

There are two pipe measuring systems:

• Imperial... The unit of calculation is inches. Used to designate only water and gas pipes and related plumbing fittings.
• Metric... It is calculated in millimeters, centimeters and meters. Suitable for pipes used for other purposes.

Differences between metric and imperial pipes

Both inch steel and standard pipes can be found on sale, which can also cause confusion. They clearly differ in the shape of the thread - for an inch pipe, the threads are rounded.

The thread pitch can be measured in various ways. For inch pipes, measurements are made along the inner boundaries of the threads, and for metric pipes, along the outer ones.

Different pipe diameters will have different distances:

• for a half-inch pipe and a three-quarter pipe, the pitch will be 1.81 mm;
• 1-6 inches - 2.31 mm.

Inch to Metric Conversion

The corresponding tables can be found in the reference books. In the same GOST, which determines the parameters of VGP, there are indicators of conditional throughput in millimeters and inches. However, to create a functioning system, indicators of the actual internal section are needed. In this case, in the tables, as a rule, you can find only the outer sections.

Ideally, the table will include the nominal capacity in inches, the outer section of the pipe and the corresponding section in millimeters.

For example, a one-inch steel pipe can be connected to a plastic one, the nominal capacity of which is 25 mm.

Pipe diameters in inches and millimeters are very important metrics. Many faced the problem of replacing or installing the pipeline, and finding the right materials for the job.

It is difficult to understand the huge number of offers on the construction market, therefore, before buying, you should study in detail what the volume of pipe rolling is and how it is used in practice.

You can immediately use the online calculator below for translation without getting acquainted with the theory.

Online calculator to convert inches to millimeters and vice versa

An example of how to enter data into a calculator

When recording the size in inches, separate the whole part of the number from the fractional part (if any) with a space: for example, 10 1/4, or 20 4/8; otherwise you get 101/4 and 204/8. Fractional numbers in millimeters are entered with a period, not a comma (25.4, not 25.4).

Enter the data for the calculation in the next. order: left-click in the corresponding parameter window for a blinking cursor to appear; enter your numbers. The fractional part of an inch is entered without a sign.

1 inch = 25.4 millimeters (mm). Nowadays, the inch, due to its clarity, is often used to measure the diameters of water-gas pipes and threads. Many parts are also multiples of inches. In addition to whole inches, measurements are taken in fourths (1/4 ″), eighths (1/8 ″), sixteenths (1/16 ″), thirty-second (1/32 ″) of an inch, etc.

If you have any questions about using the online calculator, you can always ask a question in the form of a comment. We also strongly recommend that you read the instructions (located under the calculator).

How to convert inch to metric

Conversion of inches to metric indicators of pipe volumes is carried out, guided by special tables. Here is an example of such a table:

The first diameter table ( its symbolic designation is Ø, hereinafter it will be indicated in the article) of pipes shows values ​​in millimeters, while the second table uses inches ( international designation - inch or in, hereinafter referred to in the article). An inexperienced master may wonder why this is so? And what designations are considered correct?

The reason is that the metric system is used all over the world. This system is based on two indicators: conditional and nominal volume. They approach these concepts in different ways, but in the end they show an external volume. In essence, these quantities are dimensionless, but sometimes they are indicated in millimeters.

By analyzing the tabular data, one can compare products of domestic manufacturers and analogues of foreign production.

Interesting! The measurement discrepancy appeared simultaneously with the introduction of copper systems in Europe in the second half of the 20th century. In Russia at that time the standards for metal gauge were defined in mm, not in inch, this measurement system is widely used today.

Correspondence of two notation systems

Steel pipes are widely used in water and gas systems. Their dimensions are shown in whole values ​​or their fractions. For example, a 1 inch tubular in mm would be 33.5, and a 2 inch tubular in mm would be 67.

This of course does not correspond to the declared 25.4 and 50 mm. When laying fittings with inch designations for 1 and 2 inch products, there are no difficulties, but replacement with plastic and copper products requires taking into account the discrepancy in the designations.

Why is everything so complicated? The fact is that for the formation of a fluid flow, it is important to take into account the internal size. For these reasons, this indicator began to be indicated for 1-inch, 2-inch and all other pipe-rolling materials. The most accurate indicators are considered in terms of the nominal size.

The nominal bore of 1 ", 2" and the rest of the pipe assortment is equal to the dimensions of the lumen. To designate metric sizes of 1 ", 2" and any other pipeline, it is recommended to use tables.

Exact Definitions - Calculation Formula

This knowledge is needed to calculate the amount of the transported medium. This is very important for heating systems. For example, when it is necessary to lay a heating system, it is necessary to determine and calculate the size of the assortment in the section so that all housing is heated evenly.

How to accurately determine the cross-section of each pipe in quantities such as inches can be suggested by the formula: D = sqrt ((314 ∙ Q) / (V ∙ DT)).

• D is the internal volume of the rolled pipe;
• Q is the heat flux, which is determined in kW;
• V denotes the speed of the heat carrier, it is determined in m / s;
• DT is the difference in temperature indicators, at the input and output of the network;
• sqrt - square root.

Watch the video

Despite the presence of formulas, tables help to determine Ø faster. A lot of time is gained in this way.

What is Inch Volume

The decoding of the pipe diameter, provided in inches, is simple. They are often measured in these quantities. Such one unit is equal to 3.35 cm. It has already been indicated that the decoding of this value has discrepancies, and this is due to the fact that the assortment is measured not by the external volume, but by the internal one. So, for example, the internal dimension of an inch pipe billet can be different: from 2.55 to 2.71 cm. This value varies depending on the wall thickness.

A 1 "pipe has an outer diameter of 25.4 mm, a 2" pipe has a metric dimension of 50 millimeters. Where do the numbers 33.249 and 66.498 come from in the technical parameters of the cylindrical pipe thread?

These threads on 1 and 2 inch pieces are done on the outside volume. Therefore, the ratio of the thread diameter to the internal volume is conditional. Based on this, the dimensions of 1 and 2 inch pipe products are calculated by adding the value of 25, 4 or 50 with two wall thicknesses of the pipe product.

Before decoding, you need to take into account that the measurements of the product must be performed not from the outside, but from the inside. Why is this needed? The fact is that by fastening sections of the highway from different materials, and having performed measurements only from the outside, you can get an incorrect result, which will lead to an error, since the entire assortment differs in the dimensions of the walls.

Also, when decoding, one must not forget that the standards of different manufacturers are different, they are all guided by their own indicators.

If it is difficult to perform such a decryption on your own, then you should seek help from professionals. They will provide effective assistance in choosing the right products.

Correspondence between metric and imperial parameters

All tubular products are manufactured according to a certain standard, and the pressure indicator is a fixed value. Therefore, you need to know exactly the correspondence of the Ø of all pipes shown in inches and mm. Ignoring this correspondence, it is impossible to choose the right pipe-rolling assortment.

Watch the video

When choosing a certain size, they are guided by the tabular information, and when replacing it, we serve as a guideline as close as possible. There is no exact match in two different measurement systems, therefore, pipeline elements are often equated in practice.

How this correspondence is applied in everyday life can be found in the table below:

Applying this information, you can accurately determine the correspondence of two types of measurements of dimensions, and take parts for work that exactly match each other.

Inch size expression

These indicators are prescribed as a whole number, next to it they put a double prime, for example, 3 “. Also, the dimensions of the diameter of the pipe roll, transmitted in inches, are prescribed by a fraction, for example, ½.

If we consider these dimensions on specific examples of the correspondences Du, then they will look like this:

1. The diameter of a standard 12 inch pipe is 300.
2. 3 inch tubing diameter is 80.
3. An 8-inch diameter of a standard rolled pipe is equal to 200.
4. The diameter of a standard pipe roll, at 32, when converted to inches, is shown as 1 ¼
5. Pipe diameter 40 mm in inch prescribe 1 ½
6. Ø 15 inch standard pipe expressed as ½
7. The Ø of a standard product by 4 inches in metric is 100.
8. Ø 3/4 '' pipe in metric translation equals 20.
9. The Ø of a standard 1/2 inch pipe in metric conversion shows the number 15.

Watch the video

Pipe diameters in inches and millimeters are used continuously. Knowing these dimensions, you can avoid great difficulties when connecting pipeline elements. And special tables help to find the required dimensions of the docking parts and correctly adjust them.

The most important parameters of pipe products are pipe diameters in inches and millimeters. Many property owners are faced with the need to replace the pipeline system and, accordingly, find the required materials. A high-quality assembly can be ensured provided that the pipe diameter and the dimensions of the connecting elements are the same.

Dimensional designations of modern types of pipes

When choosing the necessary products, regardless of what material they are made of, a number of indicators should be taken into account:

1. Outside diameter (Dн) in millimeters... The main characteristic of pipes. The sum of the inner section of the pipe and the doubled wall thickness is the external parameter.
2. Inner diameter (working section) in millimeters... This parameter is of great importance for determining the patency of the system. To find it out, you need to subtract the double size of the pipe wall thickness from the outer diameter.
3. Wall thickness in millimeters (S)... The quality of pipe products - their volume and strength - depends on this parameter. It is calculated as the difference between the values ​​of the outer and inner sections of the pipe.
4. Nominal size in millimeters, marked as Dу... It is the average value of the inner diameter, which is rounded up to the standard value. This dimension is taken into account when selecting suitable fittings and fittings.
5. Nominal diameter in inches... This concept was introduced to standardize the labeling of products made from different materials. The value is equal to the nominal size (read also: “What is the nominal pipe diameter? Norms and standards”). This parameter allows you to select products made from different types of raw materials when combined in the system. The fact is that the dimensions of pipes in inches are indicated on steel pipe products, but copper and aluminum are marked in millimeters. Inch values ​​must be rounded.

Measuring systems for pipes

There are two ways of measuring, the origin of which has historical roots:

• imperial system- expressed in inches. Currently, it is used exclusively for water and gas pipes made of steel and fittings for arranging water mains;
• metric system has the following units of measurement - millimeters, centimeters, meters. It is used for all other types of tubular products.

In the case of joining pipelines made of different materials, difficulties arise in recalculation in millimeters and vice versa. An ordinary inch is equal to 25.4 millimeters - it is used to measure the inner diameter. But there is also a special unit of measurement - this is a pipe inch, which is 33.249 millimeters. Its peculiarity is explained by the fact that it includes the inner diameter and the thickness of the two walls. An exception to this is a ½ ”conduit.

Differences between metric and inch measurement systems

Visually, it will not be difficult to distinguish an inch from a metric pipe. To do this, just look at the threads. At the same time, the difference in degrees between the turns with the naked eye is practically impossible to notice, since for an inch product it is 55, and for a metric one - 60. But it is almost impossible not to see that a pipe of one inch is rounded.

To measure the thread pitch, you can use a special device called a thread gauge, but if it is absent, a regular school ruler or any other measuring device will do.

Metric pipes are measured only along the outer boundaries of the threads, and inch pipes are measured exclusively along the inner surface. To find the pipe size in inches and mm,

you should use the imperial or metric system of measurement, each of which is currently in demand.

Conversion from inch to metric

If necessary, you can use the special reference literature containing the appropriate tables. For example, in GOST, which regulates the parameters of the VGP, there are values ​​of both an inch conditional transition and a millimeter one.

So, if you use the table, it becomes clear that the dimensions of the inch pipe will not be equal to 25.4 millimeters. Conditional passage - will be 25 millimeters with an outer diameter of -33.6 millimeters.

The most convenient table contains the nominal size of the pipe, expressed in inches, its outer size and the equivalent diameter in millimeters. It corresponds to an inch throughput. So a 1-inch steel pipeline segment can be connected to a polyethylene product, which has a nominal bore of 25 millimeters.

What is the size of inch pipes in mm?

In the construction market, 2 sizes of structures are popular:

• 1 \ 2 and 3 \ 4 - make up a separate category. due to special thread parameters (1.814), per 1 unit. measures account for 14 threads;
• within 1 - 6 inches, the pitch is reduced to 2.309, forming 11 threads, which does not affect the decrease or increase in the quality of the connection.

One inch is 25.4mm long, it is used to determine internal parameters, but when reinforced pipes are installed, the diameter is 33.249mm (including internal section and 2 walls). In the range of steel structures, there is an exception - products in ½ ", where the outer section is 21.25 mm. This parameter is used when calculating the dimensions of pipes with a cylindrical thread type. When calculating for pipes with a cross section of 5 inches, the inner dimension will be 12.7 cm, and the outer dimension will be 166.245 (abbreviated to 1 decimal place is allowed).

Difference between measurement systems

In terms of external parameters, inch designs do not differ from metric ones, the difference lies in the type of notches. There are 2 types of threads according to the inch system - English and American. The first option corresponds to a notch angle of 55 degrees, and the metric (American) system with an angle of 60 degrees. generally accepted.

At different degrees, it is difficult to distinguish an angle of 55 - for inch and 60 - for metric designs, and the filaments are immediately visible, an error is impossible. A thread gauge is used to measure the thread pitch, but a regular ruler or other device is well used instead.

Replacement of steel pipes with polymer

In the gas and water supply network, steel products are used, the diameter of which is indicated in inches (1 ″, 2 ″) or fractions (1/2 ″, 3/4 ″). When measuring a pipe cross-section of 1 ", the result is 33.5 mm, which corresponds to 1" (25.4 mm). When arranging pipeline reinforcing elements, where the parameters are indicated in inches, there are no difficulties. But when installing PP, copper or stainless steel products instead of steel structures, it is necessary to take into account the difference in the name and parameters.

To create a given flow rate, the internal diameter of the pipes is taken into account. For inch ordinary pipes, it is 27.1 mm, for reinforced 25.5 mm, the closest to 1 ″. Pipelines are designated in conventional units of the flow area DN (DN). It determines the parameters of the lumen of the pipes and is indicated in numerical values. The step of the nominal flow area is selected taking into account the increase in throughput characteristics by 40-60% with an increase in the index. If you know the outside cross-section and the purpose of the structures, use the dimension table to determine the inside cross-section.

In the process of connecting steel pipes with polymer structures, replacing one with another, conventional adapters are used. Dimensional mismatch results from the use of copper, aluminum or stainless steel products manufactured to metric standards. The real metric dimensions of pipes are taken into account - internal and external.

Steel pipes of the Russian Federation in comparison with the European standard

To compare the range of pipes according to GOST RF and European standards, the following table is used:

How to decide on the choice of diameter?

Their throughput characteristics depend on the diameter of the water pipes - the volume of water passed per unit. time. It depends on the rate of flow of water. With its increase, the risk of pressure drop in the line increases. Throughput characteristics are calculated according to the formulas, but when planning intra-apartment wiring, pipes of certain parameters are taken.

For the plumbing system:

For the riser, structures with an internal cross-section are used:

Taking into account the fact that the internal cross-section of half-inch polymer pipes varies in the range from 11 to 13 mm, and one-inch - from 21 to 23, an experienced plumber will be able to determine the exact parameters when replacing. With a complex type of wiring, numerous joints, bends and laying the network at a long distance, a decrease in pressure, it should be possible to perform a wiring of pipes with a large cross-section. As the diameter increases, the pressure level increases.

Below is a table for determining the permeability of steel pipes:

Steel pipe diameter

The cross-section of the pipes corresponds to a number of indicators:

• Nominal diameter (DN, Dy) - nominal parameters (in mm) of the internal cross-section of pipes or their rounded indicators, in inches.
• To the nominal parameter (Dn Dn,).
• External size. The metric system of calculations allows to classify structures into small - from 5 ... 102 mm, medium - from 102 ... 426, large - 426 mm and more.
• Wall thickness.
• Inner diameter.

The internal cross-section of pipes with different threads corresponds to the parameters:

• 1/2 inch pipeline - 1.27 cm;
• 3/4 "- 1.9 cm;
• 7/8 inches - 2.22 cm;
• 1 inch - 2.54 cm;
• 1.5 inches - 3.81 cm;
• 2 inches - 5.08 cm.

The following indicators are used to determine the thread diameter:

• 1/2 inch pipeline - 2.04 - 2.07 cm;
• 3/4 '' - 2.59 - 2.62 cm;
• 7/8 inches - 2.99 - 3 cm;
• 1 inch - 3.27 - 3.3 cm;
• 1.5 inches - 4.58 - 4.62 cm;
• 2 inches - 5.79 - 5.83 cm.

Correspondence table of the diameter of steel pipes to polymer structures:

Steel pipe prices:

PP pipe diameter

PP pipes are produced with a diameter of 0.5 to 40 cm and more. The diameter is internal and external. The first indicator allows you to find out the volume of media traversed in 1 unit. time. The outer cross-section serves for construction calculations, namely, the choice of a niche or pit for laying the highway. External parameters allow you to choose the right fittings with the appropriate internal parameters.

• Small - 0.5; one; 1.5; 2; 2.5; 3.2; 4; 5; 6.3 and 7.5 cm is used for heating systems, drainage and water supply in private buildings. An internal cross-section of 3.2 cm is most popular in multi-storey buildings.
• Average - 8; 9; 10; eleven; 12.5; sixteen; twenty; 25 and 31.5 cm is used for arranging water supply and sewerage systems, allowing you to change cast iron products with similar external parameters. Internal sizes of 8, 9 and 10 cm are ideal for chemical environments.
• Large - 40 cm or more is used for arranging cold water supply and ventilation systems.

Pipes are marked in inches and mm. When choosing structures for plumbing and heating systems, the wall thickness is taken into account, which affects the conditional permeability of highways with the same external parameters. With an increase in its parameter, an increase in pressure in the water supply system is allowed. Small dimensions allow to reduce the cost of purchasing material and water consumption.

Inch tube - dimensions in mm and diameter

Inch pipe - dimensions (in mm), specifications and prices. Correspondence table of steel and plastic products for gas and water supply. The difference between GOST and European standards.

1 inch pipe - what is the diameter

It is not possible to mount a communication system of any kind in such a way as to completely avoid connections. If only because the pipeline is ultimately supplied to some kind of consumer object - plumbing, radiator, washing machine, and is connected to the outlet of the device. And the main condition for a sealed high-quality assembly is the compliance of the pipe diameter and the size of the connecting element.

Dimensional parameters of the pipe

Regardless of the material of manufacture - polymer, metal, ceramics and so on, the product is characterized by a number of indicators, being guided by which the consumer can choose the desired product.

• Outside diameter - that is, the outside dimension of the pipe (this is only a circular section).
• Internal - the size of the working section.
• Wall thickness - largely determines the strength of the product.

The sum of the inner diameter and twice the wall thickness is the outer. The actual state of affairs corresponds to this statement. But when it comes to VGP, you need to consider the following point. Most often, water conduits are connected by a threaded method. The thread is applied to the outer part, as a result, the diameter of the thread is by no means equal to the outer dimension. And since it is important for installation to know exactly the indicators of the thread, this parameter turns out to be more important and is often indicated instead of the actual size of the product.

For example, a 1 inch water conduit is not at all equal in outer diameter to 2.54 cm, since 1 inch is an indication of the size of the thread.

This confusion is exacerbated by the use of two measuring systems on the one hand, and the variety of products available today on the other.

Conditional pass

The task of the water supply system is to evenly supply all consumers with the correct amount of water. The main calculation parameters are the throughput of the pipeline, that is, the amount of water that can pass per unit of time.

• This parameter is called conditional pass - Dn. It does not have a unit of measurement as such - it is a conditional, non-actual value, it is indicated in whole numbers and indicates the approximate conditional lumen of the pipe. The step between the values ​​is calculated theoretically, with the condition that with each subsequent increase, the throughput of the pipeline increases by 40-60%.

The convenience of the system is obvious only in practical use. It is enough to select water lines and fittings with equal nominal bore according to the table in order to guarantee a working water supply system.

Accordingly, a 1 "steel pipe has a nominal bore of 1", while its actual inner diameter is 25.5 mm, and the outer one with a thread is 33, 25.

Measuring systems

The existence of two methods of measurement has historical roots.

• Imperial - in inches, today it is used only for water and gas supply steel pipes and corresponding plumbing fittings.
• Metric - in mm, cm and m. It is used for any other pipe products.

When connecting pipelines from different materials, difficulties arise with recalculation from one system to another.

Inch and metric tubes

Both inch and standard steel conduits are available, further confusing matters. You can visually distinguish them by the type of thread - for a 1-inch pipe, the threads are rounded. The photo shows samples.

The thread pitch is measured differently. In metric products along the outer edges of the threads, in inch - along the inner ones. The distance is different for different section sizes.

The pipe 1 inch, which is used in the imperial system, is not 2, 54 cm, as it should be, but equal to 3, 3249, since it includes both the internal size and the thickness of the walls. The exception is a ½ ”conduit.

Conversion of sizes from inch to metric

Reference literature contains corresponding tables. The same GOST, which regulates the parameters of the VGP, indicates both an inch and a millimeter nominal diameter. Unfortunately, to assemble the system into one whole, the actual value of the inner diameter is also required. While the tables are more often indicated outside.

The most convenient table contains the nominal size in inches, the outside pipe size and the equivalent diameter in mm. It indicates a bandwidth that corresponds to an inch.

For example, a 1-inch steel conduit can be connected to a polyethylene conduit, the nominal bore of which is 25 mm.

Steel pipe diameters

In practice, there are diameters: nominal, internal, external, nominal bore. The values ​​are indicated in the marking of pipes: for steel - in inches, for others - in millimeters. How to determine the diameter of a steel pipe in mm? This will help the tables of correspondence of the diameters of steel products.

Steel pipes with a diameter of 100 mm

The main characteristic of a steel pipe is its diameter. This parameter determines the purpose, length of the pipeline, composition and physical characteristics of the transported substance. All diameters are standardized and regulated by regulatory documents - standard sizes and requirements for products are regulated by GOST. Each type of pipe has its own standard.

What pipe diameters exist

Theoretically, the pipe diameter is rather simplified to be added to the formulas when determining any values. In practice, everything is more complicated - they distinguish between outer, inner, nominal diameters, wall thickness. What concepts are found and what they mean:

1. Nominal bore is the internal size of the pipe, measured in millimeters. Requires rounding in inches. Used to correctly join two products, such as a pipe and a fitting.
2. Pipe wall thickness (S) is a physical quantity in millimeters, on which many quality parameters of a product depend, including permeability and volume. Defined as the difference between the outer and inner diameters.
3. Inner diameter is a physical quantity in millimeters, an important parameter for determining the cross-country ability of a highway. Formula for calculation: Dv = Dn-2S
4. The outer diameter (Dn) is small (5 ... 102 mm), medium - 103 ... 426 mm, large - 427 mm and more.
5. nominal diameter - close by definition to the nominal size, but has more accurate values.

The numerical value of the diameters of steel pipes

A huge assortment of steel pipes for various purposes, designs, types is presented in the form of tables, where the main parameters are:

• conditional passage (or nominal diameter);
• outer diameter of the pipe;
• wall thickness.

Sometimes the values ​​of the mass of the product, depending on its dimensions, as well as the parameters of the nominal diameter, are entered into the table of diameters of steel pipes.

Table values ​​of the diameters of steel pipes

It is convenient to use tables when determining the exact dimensions of products when connecting them. For example, steel pipes are most often designated in inches - this dimension is accepted in many parts of the world. While polymer products are usually calculated in millimeters, which creates some difficulties when joining metal-plastic, cast-iron, copper pipes with steel pipes in the water supply system. Correspondence tables for diameters help to determine the required dimensions of the connecting elements and connect them correctly.

In table 1, the parameters of the nominal size in mm correspond to certain values ​​\ u200b \ u200bof the inner diameter in inches. Pay attention to how the values ​​of the outer diameter differ for different types of pipes: seamless, electric-welded, metal-plastic. The difference can be up to 17 mm.

How to convert inches to millimeters correctly

Inch dimensions are rounded up when converted to millimeters. Obviously, knowing the constant 1 inch is equal to 2.54 cm, you can independently calculate the diameter values ​​according to the metric dimension. But the problem is not how to calculate, but how to correctly determine the diameter. As practical measurements of steel pipes show, their marked diameter in inches does not correspond to the measured data in millimeters. That is, the indicated size is 1 ”(respectively 25.4 mm), but in fact it turns out to be 33.5 mm. What is the reason for this discrepancy?

First of all, the inner diameter of the pipe is stamped in the designation. Secondly, the dimension of the nominal bore (DN), which is indicated in whole numbers, is taken as the unit of measurement of the diameter. Moreover, the size value increases with an increase in the index (permeability) of the pipe by 40-60% with each step. The nominal pipe passage corresponds to the internal clearance (nominal diameter) of the main line, but an integer number is taken as the final value, rounded up. The nominal bore of the main line is standardized in accordance with GOST 355-52.

To choose the right elements of gas and water supply with inch markings, the best option would be to use tables. When connecting elements of a water and gas pipeline with metric and inch measurement systems (for example, steel pipelines with products made of copper, brass, polypropylene), it is important to take into account not only the inner, but also the outer diameter.

Standard sizes of steel pipes

The generally accepted standard values ​​for the inner diameter of steel pipes are determined by a number: 6, 10, 15, 20, 25, 32, 40, 50, 65, 80, 100, 110, etc. The nominal pipe passage, calculated in inches, when converted to the metric system, is just rounded up to the nearest parameter from the standard series.

The most commonly used pipes are from 426 to 1220 mm in diameter. These are highways for water, gas, sewerage, irrigation systems.

Small-diameter pipes are used for plumbing and heating in apartments of multi-storey and private buildings. Medium diameter steel products are used for risers in urban infrastructure, as well as in the oilfield industry. These are ¾ "diameter products, for ½" routing inside.

According to the tables, the diameters of pipes made of plastic, copper, brass are similarly determined. The method of converting inch to metric is used when joining products from different materials. In the presence of fittings, the installation of gas pipelines made of steel is simplified - these nuances have already been taken into account in the connecting elements.

Steel pipe diameters: table, dimensions in inches and millimeters, GOST

In practice, there are diameters: nominal, internal, external, nominal bore. The values ​​are indicated in the marking of pipes: for steel - in inches, for others - in millimeters. How to determine the diameter of a steel pipe in mm? This will help the tables of correspondence of the diameters of steel products.