The outside diameter of the pipe is 1 2 inches. Steel pipe diameters

The geometric dimensions of the pipes are determined by the following characteristics:

• - external diameter;
• — wall thickness;
• — ratio of external and internal diameters;
• - length.

Pipe range(available sizes, specifications production and use of steel pipes) are normalized by state standards GOSTs). GOSTs are developed taking into account the technology for manufacturing pipes and steels used in the production.

In the CIS market, it is customary to indicate pipe sizes in mm (millimeters), but you can also find pipe sizes in inches. The latter are most often indicated for imported pipes. The length of the rolled pipe is measured in meters.

Steel pipe diameter

The diameter of the steel pipe is determined by:

• - outer diameter for electric-welded and seamless pipes;
• - nominal bore diameter for VGP pipes.

• — Nominal diameter(Du or Dy) — pipe inner diameter.
• — Conditional pass- a conditional value, which is the value of the actual internal diatreme, rounded up to the nearest of the standard series, and serves as a reference point for sizing other parts and equipment. Its value is standardized according to GOST 28338-89. Measured in inches or mm.
• — Inner diameter- the actual value of the parameter obtained by direct measurement, as a rule, is indicated in mm;
• — Pipe outside diameter(Dn or Dn) - the actual diameter of the pipe, taking into account the wall thickness, is indicated in mm ;.
• — Thread diameter(G).

Pipe dimensions are given in millimeters, but for pipe, the VGP is often indicated in inches (").

Correspondence table for pipe diameters in mm and inches

Nominal pipe diameter (Dy), mm	Thread diameter (G), inch	Outer pipe diameter (Dn), mm
		Pipe steel water and gas	Seamless steel pipe	Polymer

Dimensions of VGP pipes according to GOST 3262-75

Main dimensions of VGP-pipe: 15 mm (1/2" inch); 20 mm (3/4"); 25 mm (1"); 32 mm (1 1/4" quarter inch); 40 mm (1 1/2"); 50 mm (2"). There are also the following Du: 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, electric welded). Most often, 3/4" pipes are used for risers, for 1/2" internal wiring.

Dimensions of electric-welded pipes according to GOST 10704-91

Longitudinal electric-welded pipes come in the following outer diameters (in millimeters): 10; 12; 13; fourteen; 16; 17; 17.5; eighteen; 19; 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 straight-seam pipes according to GOST 10704-91 are 57 mm and above in size. 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.

Dimensions of welded pipes for gas and oil pipelines according to GOST 20295-85

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

The size of hot-rolled seamless pipes according to GOST 8732-78

Commonly used diameters of seamless hot-formed pipes (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.

Manufacturers can produce pipes of any size according to the customer's requirements.

Internal pipe diameters

According to standard row 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.

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

Outer pipe diameters and pipe wall thickness

Outer diameter, DN mm	Wall thickness, mm
Pipes steel water and gas GOST 3262-75
Electric-welded steel pipes GOST 10704-91, GOST 10705-80

Conditional pass	Outside diameter	Pipe Wall Thickness
		lungs	ordinary	reinforced
6	10,2	1,8	2,0	2,5
8	13,5	2,0	2,2	2,8
10	17,0	2,0	2,2	2,8
15	21,3	2,35	—	—
15	21,3	2,5	2,8	3,2
20	26,8	2,35	—	—
20	26,8	2,5	2,8	3,2
25	33,5	2,8	3,2	4,0
32	42,3	2,8	3,2	4,0
40	48,0	3,0	3,5	4,0
50	60,0	3,0	3,5	4,5
65	75,5	3,2	4,0	4,5
80	88,5	3,5	4,0	4,5
90	101,3	3,5	4,0	4,5
100	114,0	4,0	4,5	5,0
125	140,0	4,0	4,5	5,5
150	165,0	4,0	4,5	5,5

An inch thread is used primarily to create pipe connections: it is applied both to the pipes themselves and to the metal and plastic fittings necessary for the installation of pipe lines for various purposes. The main parameters and characteristics of the threaded elements of such connections are regulated by the relevant GOST, giving size tables inch thread which the specialists are guided by.

main parameters

The normative document, which specifies the requirements for the dimensions of a cylindrical inch thread, is GOST 6111-52. Like any other, inch thread is characterized by two main parameters: pitch and diameter. The latter usually means:

• outer diameter, measured between the upper points of the threaded ridges located on opposite sides of the pipe;
• internal diameter as a value characterizing the distance from one lowest point of the cavity between the threaded ridges to another, also located on opposite sides of the pipe.

Knowing the outer and inner diameters of an inch thread, you can easily calculate the height of its profile. To calculate this size, it is enough to determine the difference between such diameters.

The second important parameter - step - characterizes the distance at which two adjacent ridges or two adjacent depressions are located from each other. Throughout the entire section of the product on which the pipe thread is made, its pitch does not change and has the same value. If such an important requirement is not met, it will simply be inoperative, it will not be possible to pick up the second element of the created connection to it.

You can familiarize yourself with the provisions of GOST regarding inch threads by downloading the document in pdf format from the link below.

Table of sizes of inch and metric threads

Learn how metric threads relate to various types inch threads, you can use the data from the table below.

Similar sizes of metric and various varieties of inch threads in the range of approximately Ø8-64mm

Differences from metric thread

According to their external features and characteristics, metric and inch threads do not have many differences, the most significant of which include:

• threaded comb profile shape;
• the procedure for calculating the diameter and pitch.

When comparing the shapes of threaded ridges, you can see that in inch threads such elements are sharper than in metric ones. If we talk about the exact dimensions, then the angle at the top of the crest of an inch thread is 55 °.

The parameters of metric and inch threads are characterized by different units of measurement. So, the diameter and pitch of the first are measured in millimeters, and the second, respectively, in inches. However, it should be borne in mind that in relation to the inch thread, not the generally accepted one (2.54 cm), but a special one is used. pipe inch, equal to 3.324 cm. Thus, if, for example, its diameter is ¾ inch, then in terms of millimeters it will correspond to a value of 25.

To find out the main parameters of an inch thread of any size, which is fixed by GOST, just look at a special table. In the tables containing the sizes of inch threads, both integer and fractional values ​​\u200b\u200bare given. It should be borne in mind that the pitch in such tables is given in the number of cut grooves (threads) contained in one inch of the length of the product.

To check whether the pitch of the thread that has already been made corresponds to the dimensions specified by GOST, this parameter must be measured. For such measurements, carried out for both metric and inch threads according to one algorithm, standard tools are used - a comb, gauge, mechanical gauge, etc.

The easiest way to measure the pitch of an inch pipe thread is by using the following method:

• As the simplest template, a coupling or fitting is used, parameters internal thread which exactly correspond to the requirements given by GOST.
• The bolt, the parameters of the external thread of which must be measured, is screwed into a coupling or fitting.
• In the event that the bolt formed with a coupling or fitting is tight threaded connection, then the diameter and pitch of the thread, which is applied to its surface, exactly match the parameters of the template used.

If the bolt is not screwed into the template or is screwed, but creates a loose connection with it, then such measurements should be taken using a different coupling or other fitting. An internal pipe thread is also measured using a similar technique, only in such cases a product with an external thread is used as a template.

You can determine the required dimensions using a thread gauge, which is a plate with notches, the shape and other characteristics of which exactly match the parameters of the thread with a certain pitch. Such a plate, acting as a template, is simply applied to the thread being checked with its serrated part. The fact that the thread on the element under test corresponds to the required parameters will be indicated by the tight fit of the serrated part of the plate to its profile.

To measure the outside diameter of an inch or metric thread, you can use a regular caliper or micrometer.

Slicing technologies

Cylindrical pipe thread, which belongs to the inch type (both internal and external), can be cut by hand or mechanical method.

Thread cutting by hand

Threading with hand tool, which is used as a tap (for internal) or a die (for external), is performed in several steps.

1. The pipe being processed is clamped in a vice, and the tool used is fixed in a wrench (tap) or in a die holder (die).
2. The die is put on the end of the pipe, and the tap is inserted into inner part last.
3. The tool used is screwed into the pipe or screwed onto its end by rotating the knob or die holder.
4. To make the result cleaner and more accurate, you can repeat the cutting procedure several times.

Thread cutting on a lathe

Mechanically, pipe threads are cut according to the following algorithm:

1. The pipe being processed is clamped in the machine chuck, on the support of which the thread-cutting tool is fixed.
2. At the end of the pipe, using a cutter, they chamfer, after which they adjust the speed of movement of the caliper.
3. After bringing the cutter to the surface of the pipe on the machine, the threaded feed is turned on.

It should be borne in mind that the inch thread is cut mechanically using lathe only on tubular products, the thickness and rigidity of which allow this. Making pipe inch threads mechanically allows you to get a quality result, but the use of such technology requires the turner to have appropriate qualifications and the presence of certain skills.

Accuracy classes and marking rules

A thread related to the inch type, as indicated by GOST, can correspond to one of three accuracy classes - 1, 2 and 3. Next to the number indicating the accuracy class, put the letters "A" (external) or "B" (internal). The full designations of the thread accuracy classes, depending on its type, look like 1A, 2A and 3A (for external) and 1B, 2B and 3B (for internal). It should be borne in mind that the 1st class corresponds to the coarsest threads, and the 3rd - the most accurate, the dimensions of which are subject to very stringent requirements.

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 accounted for 14 strands;
• within 1 - 6 inches, the pitch is reduced to 2.309, forming 11 threads that do not affect the decrease or increase in the quality of the connection.

One inch is 25.4 mm long, it is used to determine the internal parameters, but when laying reinforced pipes, the diameter is 33.249 mm (including the internal section and 2 walls). There is an exception in the range of steel structures - products in ½ inch, where the outer section is 21.25 mm. This parameter is used when calculating the dimensions of pipes with cylindrical threads. When making calculations for pipes with a cross section of 5 inches, inner size will be 12.7 cm, and the outer one will be 166.245 (reduction to 1 decimal place is allowed).

The 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 the angle by 55 for inch and 60 for metric designs, and the rounding of the threads is immediately visible, the occurrence of an error is impossible. A thread gauge is used to measure the thread pitch, but an ordinary ruler or other device is well used instead.

Replacing steel pipes with polymer ones

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 1" pipe cross-section, 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 products made of PP, copper or stainless steel instead of steel structures, it is required to take into account the difference in the name and parameters.

To create a given level of flow, the internal diameter of the pipes is taken into account. For inch ordinary pipes, it is 27.1 mm, for reinforced 25.5 mm, closest to 1 ". Pipelines are designated in conventional units flow section Du (DN). It determines the parameters of the pipe clearance and is indicated in numerical values. The step of the conditional flow section is selected taking into account the increase in throughput characteristics by 40-60% with an increase in the index. If the external cross-section and the purpose of the structures are known, the internal cross-section is determined using the dimension table.

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 actual metric dimensions of the 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 water pipes - the volume of water passed for 1 unit. time. It depends on the speed of the water flow. With its increase, the risk of pressure drop in the line increases. Throughput characteristics are calculated according to formulas, but when planning intra-apartment wiring, they take pipes of certain parameters.

For the plumbing system:

• 1.5 cm (1/2 inch)
• 1 cm (3/8 inch).

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

• 2.5 cm (1 inch);
• 2 cm (3/4 inch).

Given that the inner cross section of the 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, turns and laying the network at a great distance, reducing the pressure, it should be possible to carry out the wiring of pipes with a large cross section. As the diameter increases, the pressure level increases.

Below is a table for determining the patency 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.
• Rated value (Dn Dn,).
• external size.

  The metric calculation system allows classifying structures into small ones - 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 following parameters:

• 1/2 inch pipeline - 1.27 cm;
• 3/4 inch - 1.9 cm;
• 7/8 inch - 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:

• pipeline 1/2 inch - 2.04 - 2.07 cm;
• 3/4 inches - 2.59 - 2.62 cm;
• 7/8 inch - 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.

Table of correspondence between the diameter of steel pipes and polymer structures:

Steel pipe prices:

Pipe diameter PP

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

• Small - 0.5; one; 1.5; 2; 2.5; 3.2; 4; five; 6.3 and 7.5 cm is used for heating systems, drains and water supply in private buildings. An internal cross section of 3.2 cm is most popular in multi-storey buildings.
• Medium - 8; nine; 10; eleven; 12.5; 16; twenty; 25 and 31.5 cm is used for arranging water supply and sewer systems, allowing you to change cast iron products with similar external parameters. Internal dimensions 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 designs for plumbing and heating system, the wall thickness is taken into account, which affects the conditional patency of highways with the same external parameters. With an increase in its parameter, an increase in pressure in the plumbing system is allowed. Small dimensions allow to reduce the level of costs for the purchase of material and water consumption.

Cost of PP pipes:

Video

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 piping system and, accordingly, the search for the required materials. High-quality assembly can be ensured provided that the diameter of the pipe and the dimensions of the connecting elements match.

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. Outer diameter (Dн) in millimeters. The main characteristic of pipes. The sum of the internal section of the pipe and twice the 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 out, it is necessary to subtract twice the size of the pipe wall thickness from the outer diameter.
3. Wall thickness in millimeters (S). The quality of pipe products - its 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 passage in millimeters, marked as Dу. It is the average value of the inner diameter, which is rounded up to the standard parameter. This size is taken into account when choosing the appropriate 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 bore (read also: “What is the nominal diameter of the pipe? Norms and standards”). This option allows you to select products made from different kind raw materials, when combining them in the system. The fact is that pipe sizes in inches are indicated on steel pipe products, but copper and aluminum are marked in millimeters. Inch values ​​must be rounded up.

Measuring systems for pipes

There are two methods of measurement, the emergence of which has historical roots:

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

In the case of joining pipelines made of various materials, and there are difficulties in converting to millimeters and vice versa. An ordinary inch is equal to 25.4 millimeters - it is used to measure the diameter of the inner. 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 two walls. The exception is the ½ inch conduit.

Differences between metric and inch systems of measurement

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

To measure the thread pitch, you can use a special device called a thread gauge, but if it is not available, 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 inner surface. To find out the pipe size in inches and mm,

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

Converting inch sizes to metric sizes

If necessary, you can use the special reference literature containing the relevant 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 size of the conditional passage of the pipe, expressed in inches, its outer dimension and equivalent diameter in millimeters. It corresponds to the inch bandwidth. So a steel pipeline section of 1 inch can be connected to a polyethylene product, in which the conditional passage is 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 accounted for 14 strands;
• within 1 - 6 inches, the pitch is reduced to 2.309, forming 11 threads that do not affect the decrease or increase in the quality of the connection.

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

The 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 the angle by 55 - for inch and 60 - for metric designs, and the rounding of the threads is immediately visible, the occurrence of an error is impossible. A thread gauge is used to measure the thread pitch, but an ordinary ruler or other device is well used instead.

Replacing steel pipes with polymer ones

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 the cross section of the pipe 1″, the result will be 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 products made of PP, copper or stainless steel instead of steel structures, it is required to take into account the difference in the name and parameters.

To create a given level of flow, the internal diameter of the pipes is taken into account. For inch ordinary pipes, it is 27.1 mm, for reinforced 25.5 mm, closest to 1 ″. Pipelines are designated in conventional units of the flow area Du (DN). It determines the parameters of the pipe clearance and is indicated in numerical values. The step of the conditional flow section is selected taking into account the increase in throughput characteristics by 40-60% with an increase in the index. If the external cross-section and the purpose of the structures are known, the internal cross-section is determined using the dimension table.

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 actual metric dimensions of the 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 water pipes - the volume of water passed for 1 unit. time. It depends on the speed of the water flow. With its increase, the risk of pressure drop in the line increases. Throughput characteristics are calculated according to formulas, but when planning intra-apartment wiring, they take pipes of certain parameters.

For the plumbing system:

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

Given that the internal cross section of half-inch polymer pipes varies from 11 to 13 mm, and one-inch pipes 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, turns and laying the network at a great distance, reducing the pressure, it should be possible to carry out the wiring of pipes with a large cross section. As the diameter increases, the pressure level increases.

Below is a table for determining the patency 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.
• Rated value (Dn Dn,).
• external size. The metric calculation system allows classifying structures into small ones - 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 following parameters:

• 1/2 inch pipeline - 1.27 cm;
• 3/4 inch - 1.9 cm;
• 7/8 inch - 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:

• pipeline 1/2 inch - 2.04 - 2.07 cm;
• 3/4 inches - 2.59 - 2.62 cm;
• 7/8 inch - 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.

Table of correspondence between the diameter of steel pipes and polymer structures:

Steel pipe prices:

Pipe diameter PP

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

• Small - 0.5; one; 1.5; 2; 2.5; 3.2; 4; five; 6.3 and 7.5 cm is used for heating systems, drains and water supply in private buildings. An internal cross section of 3.2 cm is most popular in multi-storey buildings.
• Medium - 8; nine; 10; eleven; 12.5; 16; twenty; 25 and 31.5 cm is used for arranging water supply and sewer systems, allowing you to change cast iron products with similar external parameters. Internal dimensions 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 the plumbing and heating systems, the wall thickness is taken into account, which affects the conditional patency of highways with the same external parameters. With an increase in its parameter, an increase in pressure in the plumbing system is allowed. Small dimensions allow to reduce the level of costs for the purchase of material and water consumption.

Inch pipe - 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.

Pipe 1 inch - what diameter

It is impossible to mount a communication system of any kind in such a way as to completely avoid connections. If only because the pipeline is eventually brought to some kind of consumption object - plumbing, radiator, washing machine, and connects to the outlet of the device. And the main condition for a sealed high-quality assembly is the correspondence between the diameter of the pipe 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, based on which, the consumer can choose the necessary product.

• The outside diameter is outer dimension pipes (we are talking only about a round 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 diameter. The actual state of affairs corresponds to this statement. But when it comes to VGP, it is necessary to take into account the following point. Most often, 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 size. And since for installation it is important to know exactly the thread indicators, then given parameter turns out to be more important and is often indicated instead of the actual size of the product.

For example, a 1 inch 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 currently available on the other.

Conditional pass

The task of the plumbing system is to uniformly supply all consumers with the proper 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 passage - Dn. It does not have a unit of measurement as such - it is a conditional, non-actual value, indicated in integers and indicates the approximate conditional clearance 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 conduits and fittings with an equal conditional passage according to the table in order to guarantee a working plumbing system.

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

Measuring systems

The presence of two methods of measurement has historical roots.

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

When joining conduits from different materials, difficulties arise with the recalculation from one system to another.

Inch and metric pipes

Both inch and standard steel conduits are produced, which further confuses the matter. You can visually distinguish them by the type of thread of the thread - a 1-inch pipe has rounded threads. The photos show samples.

Thread pitch is measured in different ways. In metric products, along the outer boundaries of the threads, in inch products, along the inner ones. The distance is different different sizes sections.

Pipe 1 inch, which is used in the imperial system, is not equal to 2.54 cm, as it should be, but equals 3.3249, since it includes both the internal dimension and the wall thickness. The exception is the ½ inch conduit.

Converting inch to metric sizes

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

The most convenient table contains the nominal size in inches, the external size of the pipe 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 conditional passage of which is 25 mm.

Steel pipe diameters

In practice, there are diameters: nominal, internal, external, conditional passage. 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 diameter values ​​are standardized and regulated normative 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 diameter of the pipe is quite simply added to the formulas when determining any values. In practice, everything is more complicated - they distinguish between outer, inner, nominal diameters, wall thickness. What are the terms and what do they mean?

1. Conditional passage - the internal size of the pipe, determined in millimeters. In inches requires rounding. It is used for the correct joining of two products, for example, a pipeline and a fitting.
2. The wall thickness of the pipe (S) is a physical quantity in millimeters, on which many quality indicators of the product depend, including permeability, volume. It is defined as the difference between the outer and inner diameters.
3. The inner diameter is a physical quantity in millimeters, an important parameter for determining the patency of the highway. Formula for calculation: Dvn=Dn-2S
4. Outer diameter (Dn) - has small dimensions (5 ... 102 mm), medium - 103 ... 426 mm, large - 427 mm or more.
5. nominal diameter - close by definition to the nominal diameter, 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 weight of the product is entered into the steel pipe diameter table depending on its dimensions, as well as the parameters of the nominal diameter.

Tabular values ​​​​of steel pipe diameters

Tables are convenient to use when determining the exact dimensions of products when they are connected. For example, steel pipes are most often indicated in inches - this dimension is accepted in many parts of the world. While it is customary to calculate polymer products in millimeters, which creates some difficulties when joining metal-plastic, cast iron, copper pipes with steel in the plumbing system. Diameter matching tables help determine the right dimensions connecting elements and connect them correctly.

In table 1, nominal diameters in mm correspond to certain values ​​​​of 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 units 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 size is 1 ”(respectively 25.4 mm), but in reality it turns out 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 unit of measurement of the diameter is the dimension of the conditional passage (DN), which is indicated in integers. Moreover, the value of the size increases with the growth of the index (patency) of the pipe by 40-60% with each step. The conditional passage of the pipe corresponds to the internal clearance (nominal diameter) of the line, but an integer is taken as the final value, rounding the calculated one up. The conditional passage of the line is standardized according to GOST 355-52.

To correctly select gas and water elements with inch markings, the best option tables will be used. When connecting elements of a water and gas pipeline with metric and inch systems of measurement (for example, steel pipelines with products made of copper, brass, polypropylene), it is important to consider 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 next: 6, 10, 15, 20, 25, 32, 40, 50, 65, 80, 100, 110, etc. The conditional passage of the pipe, calculated in inches, when converted to the metric system, is just rounded up to the nearest parameter from the standard range.

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

For plumbing and heating in apartments of multi-storey and private buildings, pipes of small diameter are used. Medium-diameter steel products are used for risers in urban infrastructure, as well as in the oil industry. These are products with a diameter of ¾”, for wiring inside ½”.

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

Diameters of steel pipes: table, dimensions in inches and millimeters, guests

In practice, there are diameters: nominal, internal, external, conditional passage. 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.

Diameter is one of the most important dimensional characteristics of steel pipes. Thanks to such a parameter as the diameter, all the necessary design calculations can be made.

Standard diameters steel pipes are strictly regulated by GOST 10704-91.

Purely conditionally, pipe diameters are divided into the following categories:

— large diameter(more than 508 millimeters),

- medium diameter (114-530 millimeters)

- and small diameter (no more than 114 millimeters).

Main overall characteristics

It is according to these characteristics that the diameters of steel pipes are determined according to GOSTs and TUs:

• internal diameter of pipes;
• the outer diameter of the pipes - is their main overall characteristic according to GOSTs;
• conditional diameter of the pipe. Represents the nominal size of the inner diameter of the pipe;
• pipe wall thickness;
• nominal pipe diameter.

1. The classification of steel pipes into small, medium and large is made exactly according to the outer diameter (Dn). Standard diameters are shown in the table.
   
2. Most often, steel pipes of the following diameters are used: 426, 530, 159, 219, 720, 920, 273, 325, 1420 and 1220 millimeters.
3. The small outer diameter of steel pipes is used for the construction of plumbing systems in apartments, houses and other premises.
4. Medium-diameter steel pipes are used for the installation of municipal water pipes, as well as in field systems for collecting crude oil.
5. The largest diameter steel pipes are needed for the construction of main gas and oil pipelines.

Internal diameters of steel pipes

1. The inner diameter of steel pipes (Din) at a constant outside diameter may differ significantly. To standardize the diameter of pipes, a term such as "conditional passage (diameter)" is used. It is designated Dy.
2. Nominal bore is the rounded nominal size of the inside diameter. It always rounds up. The value is determined conditional diameter steel pipes GOST 355-52.
3. The inner diameter can be calculated using the following formula: Din = Dn - 2S.
4. Steel pipes have internal diameters: 6, 15, 10, 20, 25, 50, 65, 32, 40, 80, 100, 125, 200.

Steel pipe diameters in inches

In addition to millimeters, the diameter of steel pipes can also be measured in inches. One inch equals 25.4 millimeters. The table shows the diameters of steel pipes in millimeters, as well as in inches.

Nominal pipe diameter (Dy), mm	Thread diameter (G), inch	Pipe outer diameter (Dh), mm
		Pipe steel water and gas	seamless	Polymer
10	3/8"	17	16	16
15	1/2"	21,3	20	20
20	3/4"	26,8	26	25
25	1"	33,5	32	32
32	1 1/4"	42,3	42	40
40	1 1/2"	48	45	50
50	2"	60	57	63
65	2 1/2"	75,5	76	75
80	3"	88,5	89	90
90	3 1/2"	101,3	102	110
100	4"	114	108	125
125	5"	140	133	140
150	6"	165	169	160

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