Pipe 0 5 inches. Pipe diameters in inches and millimeters. Main dimensions

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Pipe 0 5 inches. Pipe diameters in inches and millimeters. Main dimensions

inches	mm.	inches	mm.	inches	mm.	inches	mm.	inches	mm.
-	-	1	25,4	2	50,8	3	76,2	4	101,6
1/8	3,2	1 1/8	28,6	2 1/8	54,0	3 1/8	79,4	4 1/8	104,8
1/4	6,4	1 1/4	31,8	2 1/4	57,2	3 1/4	82,6	4 1/4	108,8
3/8	9,5	1 3/8	34,9	2 3/8	60,3	3 3/8	85,7	4 3/8	111,1
1/2	12,7	1 1/2	38,1	2 1/2	63,5	3 1/2	88,9	4 1/2	114,3
5/8	15,9	1 5/8	41,3	2 5/8	66,7	3 5/8	92,1	4 5/8	117,5
3/4	19,0	1 3/4	44,4	2 3/4	69,8	3 3/4	95,2	4 3/4	120,6
7/8	22,2	1 7/8	47,6	2 7/8	73,0	3 7/8	98,4	4 7/8	123,8

Inch thread parameters

Outside diameter connected pipe		SAE Thread Rating	UNF thread rating	Outer thread diameter, mm	Average thread diameter, mm	Thread pitch
mm	inch	SAE Thread Rating	UNF thread rating	Outer thread diameter, mm	Average thread diameter, mm	mm	threads/inch
6	1/4""""	1/4""""	7/16""""-20	11,079	9,738	1,27	20
8	5/16""""	5/16""""	5/8""""-18	15,839	14,348	1,411	18
10	3/8""""	3/8""""	5/8""""-18	15,839	14,348	1,411	18
12	1/2""""	1/2""""	3/4""""-16	19,012	17,33	1,588	16
16	5/8""""	5/8""""	7/8""""-14	22,184	20,262	1,814	14
18	3/4""""	3/4""""	1""""-14	25,357	23,437	1,814	14
18	3/4""""	---	1""""1/16-14	26,947	25,024	1,814	14
20	7/8""""	---	1""""1/8-12	28,529	26,284	2,117	12
22	7/8""""	7/8""""	1""""1/4-12	31,704	29,459	2,117	12
22	7/8""""	---	1""""3/8-12	34,877	32,634	2,117	12
25	1""""	1""""	1""""1/2-12	38,052	35,809	2,117	12

Copper conductors, wires and cables

Conductor cross-section, mm	Copper conductors, wires and cables
	Voltage, 220 V		Voltage, 380 V
	current, A	power, kWt	current, A	power, kWt
1,5	19	4,1	16	10,5
2,5	27	5,9	25	16,5
4	38	8,3	30	19,8
6	46	10,1	40	26,4
10	70	15,4	50	33,0
16	85	18,7	75	49,5
25	115	25,3	90	59,4
35	135	29,7	115	75,9
50	175	38,5	145	95,7
70	215	47,3	180	118,8
95	260	57,2	220	145,2
120	300	66,0	260	171,6

Aluminum conductors, wires and cables

Cross-section of current-carrying conductor, mm	Aluminum conductors, wires and cables
	Voltage, 220 V		Voltage, 380 V
	current, A	power, kWt	current, A	power, kWt
2,5	20	4,4	19	12,5
4	28	6,1	29	15,1
6	36	7,9	30	19,8
10	50	11,0	39	25,7
16	60	13,2	55	36,3
25	85	18,7	70	46,2
35	100	22,0	85	56,1
50	135	29,7	110	72,6
70	165	36,3	140	92,4
95	200	44,0	170	112,2
120	230	50,6	200	132,0

Inch thread sizes


	Thread diameter in mm			Thread pitch in mm	Number of threads per 1"
	outer d	average d	internal d	Thread pitch in mm	Number of threads per 1"
3/16	4,762	4,085	3,408	1,058	24
1/4	6,350	5,537	4,724	1,270	20
5/16	7,938	7,034	6,131	1,411	18
3/8	9,525	8,509	7,492	1,588	16
1/2	12,700	11,345	9,989	2,117	12
5,8	15,875	14,397	12,918	2,309	11
3/4	19,05	17,424	15,798	2,540	10
7/8	22,225	20,418	18,611	2,822	9
1	25,400	23,367	21,334	3,175	8
1 1/8	28,575	26,252	23,929	3,629	7
1 1/4	31,750	29,427	27,104	3,629	7
1 1/2	38,100	35,39	32,679	4,233	6
1 3/4	44,450	41,198	37,945	5,080	5
2	50,800	47,186	43,572	5,644	4 1/2

Nominal thread diameter in inches
	Thread diameter in mm			Thread pitch in mm	Number of threads per 1"
	outer d	average d	internal d	Thread pitch in mm	Number of threads per 1"
1/8	9,729	9,148	8,567	0,907	28
1/4	13,158	12,302	11,446	1,337	19
3/8	16,663	15,807	14,951	1,337	19
1/2	20,956	19,794	18,632	1,814	14
5/8	22,912	21,750	20,588	1,814	14
3/4	26,442	25,281	24,119	1,814	14
7/8	30,202	29,040	27,878	1,814	14
1	33,250	31,771	30.293	2,309	11
1 1/8	37,898	36,420	34,941	2,309	11
1 1/4	41,912	40,433	38,954	2,309	11
1 3/8	44,325	32,846	41,367	2,309	11
1 1/2	47,805	46,326	44,847	2,309	11
1 3/4	53,748	52,270	50,791	2,309	11
2	59,616	58,137	56,659	2,309	11

Unit conversion table

Conversion of energy units	Conversion of pressure units
1 J = 0.24 cal	1 Pa = 1 N/m*m
1 kJ = 0.28 Wh	1 Pa = 0.102 kgf/m*m
1 W = 1 J/s	1 atm =0.101 mPa =1.013 bar
1 cal = 4.2 J	1 bar = 100 kPa = 0.987 atm
1 kcal/h = 1.163 W	1 PSI = 0.06895 bar = 0.06805 atm

Conversion tables for inch to metric sizes. Thread size: table of metric and inch threads

The process of selecting the required cross-sectional sizes of threads, cables and pipes often takes a lot of time. In addition to what you need to choose suitable sizes, taking into account the equipment parameters, the customer has to independently convert the data into suitable units of measurement. This process requires significant time.

We simplify this task because we invite you to use ready-made translation tables. On the page of our website you will find tables that will help you easily select the necessary threads for inch pipes, copper and aluminum wires and cables. Also, you can use the table for converting inch sizes to metric, thereby accurately calculating required dimensions sections.

Unfortunately, most equipment manufacturers leave the customer alone with the calculations. Therefore, a person has to independently search the Internet for translation tables in order to select optimal sizes wire sections and pipe diameters.

We value the time of our clients, providing everyone with the opportunity to use ready-made solutions. Translated in our tables standard sizes from inches to millimeters.

On this page you will also find translations of basic energy units and pressure units, therefore, you will be able to choose the right refrigeration equipment, taking into account the individual placement conditions and operating modes of the units.

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

What pipe diameters are there?

Theoretically, the diameter of the pipe is quite simply added to the formulas when determining any values. In practice, everything is more complicated - there are external, internal, nominal diameters, and wall thickness. What concepts are found and what do they mean:

Conditional bore is the internal size of the pipe, determined in millimeters. Inches require rounding of values. Used for the correct joining of two products, for example, a pipeline and a fitting.
Pipe wall thickness (S)– physical quantity in millimeters, on which many quality indicators of the product depend, including cross-country ability and volume. Defined as the difference between the outer and inner diameter.
Inner diameter is a physical quantity in millimeters, important parameter to determine the passability of the highway. Formula for calculation: Dvn=Dn-2S
Outer diameter (Dn) – has small dimensions (5...102 mm), medium – 103...426 mm, large – 427 mm and more.
nominal diameter - close by definition to the nominal diameter, but has more accurate values.

Numerical value of steel pipe diameters

Huge assortment steel pipes for various purposes, executions, types are presented in the form of tables, where the main parameters are:

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

Sometimes the weight of the product is entered into the table of diameters of steel pipes depending on its size, as well as the parameters of the nominal diameter.

Table values of steel pipe diameters

Tables are convenient to use 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 It is customary to calculate in millimeters, which creates some difficulties when joining metal-plastic, cast iron, copper pipes with steel in plumbing system. Diameter correspondence tables help determine required sizes connecting elements and connect them correctly.

Table 1. Standard sizes of welded and seamless steel pipes

Nominal pipe bore (Dy) mm	Thread diameter (G), inch	Pipe outer diameter (Dout), mm
Nominal pipe bore (Dy) mm	Thread diameter (G), inch	Steel water and gas pipe	Seamless steel	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	159	160

In Table 1, the parameters of the nominal bore in mm correspond to certain values of the internal diameter in inches. Notice how the outer diameters differ between different types pipes: seamless, electric-welded, metal-plastic. The difference can reach 17 mm.

How to correctly convert inches to millimeters

When converted to millimeters, the inch dimension is rounded up. 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 indicated is 1” (corresponding to 25.4 mm), but in reality it turns out to be 33.5 mm. What is the reason for this discrepancy?

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

To correctly select gas and water supply elements with inch markings, the best option There will be a use of tables. When connecting water and gas pipeline elements 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 internal, but also the external diameter.

Standard sizes of steel pipes

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

The most commonly used pipes are with diameters from 426 to 1220 mm. These are highways for water, gas, sewer, and irrigation systems.

Small-diameter pipes are used for water supply 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 oil field industry. These are products with a diameter of ¾", for wiring inside ½".
Yulia Petrichenko, expert

Using the tables, the diameters of pipes made of plastic, copper, and brass are determined in the same way. The method of converting inch dimensions into metric ones is used when connecting products from different materials. If fittings are available, the installation of gas and water mains made of steel is simplified - these nuances are already taken into account in the connecting elements.

How do you cope with calculating pipe diameters? What indicator is most important for you when installing pipelines? Share in the comments.

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. 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:

Outer diameter (Dн) in millimeters. Main characteristics of pipes. The sum of the internal cross-section of the pipe and twice the wall thickness constitutes the external parameter.
Inner diameter (working section) in millimeters. This parameter has great importance to determine the patency of the system. To find it out, you need to subtract twice the pipe wall thickness from the outer diameter.
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 external and internal sections of the pipe.
Conditional bore in millimeters, marked as Dу. Is the average value of the internal diameter, which is rounded to standard parameter to the greater side. This size is taken into account when choosing suitable fittings and fittings.
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 diameter (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 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.

Pipe measuring systems

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 made of steel and fittings for the construction 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 difficulties arise in converting to millimeters and vice versa. An ordinary inch is equal to 25.4 millimeters - it is used to measure the internal 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 internal diameter and the thickness of two walls. The exception is ½-inch water conduit.

Differences between metric and imperial measurement systems

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 one - 60. But it is almost impossible not to see that the threads of a one-inch pipe are rounded.

To measure the thread pitch you can use special device, which is called a thread gauge, but if it is not available, an ordinary 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 special reference literature containing relevant tables. For example, in GOST, which regulates the parameters of VGP, there are values for both inch and millimeter conventional transitions.

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

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

What is the size of inch pipes in mm?

On construction market 2 sizes of designs are popular:

1\2 and 3\4 - form a separate category. due to special thread parameters (1.814), per 1 unit. measures account for 14 threads;
within the range of 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). In assortment steel structures there is an exception - ½ inch products, 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, the internal dimension will be 12.7 cm, and the external dimension will be 166.245 (reduction 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 between an angle of 55 for inch and 60 for metric designs, and the rounding of the threads is immediately visible, making it impossible for an error to occur. To measure the thread pitch, a thread gauge is used, but instead of it, a regular ruler or other device can be used well.

Replacing steel pipes with polymer ones

In gas and water supply networks they are used steel products, the diameter of which is indicated in inches (1″, 2″) or fractions (1/2″, 3/4″). When measuring the cross-section of a 1″ pipe, 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, no difficulties arise. But when installing products made of PP, copper or stainless steel instead of steel structures, it is necessary to take into account the difference in name and parameters.

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

In the process of connecting steel pipes with polymer structures, replacing one with another, conventional adapters are used. Dimensional discrepancies result 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 of the Russian Federation and European standards, the following table is used:

How to decide on the diameter?

From diameter water pipes their throughput characteristics depend - the volume of water passed per 1 unit. time. It depends on the speed of water flow. As it increases, the risk of pressure drop in the line increases. Flow characteristics are calculated using 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:

Considering that the internal cross-section of half-inch polymer pipes varies in the range from 11 to 13 mm, and one-inch ones - 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 network laying on long distance, reducing pressure, it is necessary to provide for the possibility of routing 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 values, in inches.
Nominal parameter (Dn Dn,).
External size. The metric calculation system allows you 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 following parameters:

1/2 inch pipeline - 1.27 cm;
3/4 inch – 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.

To determine the thread diameter, the following indicators are used:

1/2 inch pipeline – 2.04 - 2.07 cm;
3/4 inches – 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.

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

Steel pipe prices:

PP pipe diameter

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

Small – 0.5; 1; 1.5; 2; 2.5; 3.2; 4; 5; 6.3 and 7.5 cm are used for heating systems, drainage and water supply in private buildings. An internal cross section of 3.2 cm is most popular in multi-story buildings.
Average – 8; 9; 10; eleven; 12.5; 16; 20; 25 and 31.5 cm are used for arranging water supply and sewer systems, allowing you to replace cast iron products with similar external parameters. Inner size in 8, 9 and 10 cm ideal for chemical media.
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, affecting the conditional passability 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 you to reduce the cost of purchasing material and water consumption.

Inch pipe - dimensions in mm and diameter

Inch pipe - dimensions (in mm), specifications and prices. Correspondence table for 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 impossible to install a communications system of any kind in such a way as to completely avoid connections. If only because the pipeline is ultimately supplied to some object of consumption - plumbing, radiator, washing machine, and connects to the outlet pipe 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.

Pipe dimensional parameters

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.

External diameter - that is, outer size pipes ( we're talking about only about the circular section).
Internal – the size of the working section.
Wall thickness largely determines the strength of the product.

The sum of the internal diameter and twice the wall thickness is the external diameter. The actual state of affairs corresponds to this statement. But when it comes to AIV, it is necessary to take into account this point. Most often, water conduits are connected using the 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 it is important to know the thread parameters for installation, 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 conduit is not at all equal in outer diameter to 2.54 cm, since 1 inch is an indication of the thread size.

This confusion is aggravated 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 uniformly supply all consumers with the required amount of water. The main calculation parameters are throughput 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-factual value, indicated in whole numbers 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 pipeline capacity increases by 40–60%.

The convenience of the system is obvious only during practical use. It is enough to select water conduits and fittings with equal nominal bore from the table to guarantee a working water supply system.

Accordingly, a 1-inch steel pipe has a nominal bore of 1 inch, while its actual internal diameter is 25.5 mm, and the external threaded diameter is 33.25.

Measuring systems

The presence of two measurement methods has historical roots.

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

When connecting water pipelines made of different materials, difficulties arise with conversion from one system to another.

Inch and Metric Tubes

Both inch and standard steel water conduits are available, which further confuses the matter. You can visually distinguish them by the type of threads - a 1-inch pipe has rounded threads. The photo shows samples.

Thread pitch is measured in different ways. In metric products along the outer boundaries of the threads, in inch products - along the inner boundaries. Distance varies depending on 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 size and wall thickness. The exception is ½ inch water conduit.

Converting inch to metric sizes

The reference literature contains the corresponding tables. The same GOST, which regulates the parameters of VGP, specifies both inch and millimeter nominal diameters. Unfortunately, to assemble the system into one whole, the actual value of the internal diameter is also required. While tables often indicate external.

The most convenient table contains the nominal diameter in inches, the external size of the pipe and the equivalent diameter in mm. It indicates a throughput that corresponds to inches.

For example, a 1-inch steel conduit can be connected to a polyethylene conduit whose nominal diameter 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? Tables for matching the diameters of steel products will help with this.

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 by regulatory documents - standard sizes and requirements for products are regulated by GOST. Each type of pipe has its own standard.

What pipe diameters are there?

Conditional bore is the internal size of the pipe, determined in millimeters. Inches require rounding of values. Used for the correct joining of two products, for example, a pipeline and a fitting.
Pipe wall thickness (S) is a physical quantity in millimeters on which many quality indicators of the product depend, including permeability and volume. Defined as the difference between the outer and inner diameter.
Internal diameter is a physical quantity in millimeters, an important parameter for determining the passability of the highway. Formula for calculation: Dvn=Dn-2S
Outer diameter (Dn) – has small dimensions (5...102 mm), medium – 103...426 mm, large – 427 mm and more.
nominal diameter - close by definition to the nominal diameter, but has more accurate values.

Numerical value of steel pipe diameters

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

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

Sometimes the weight of the product is entered into the table of diameters of steel pipes depending on its size, as well as the parameters of the nominal diameter.

Table values of steel pipe diameters

Tables are convenient to use 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. Diameter correspondence tables help determine the required dimensions of the joining elements and connect them correctly.

In Table 1, the parameters of the nominal bore in mm correspond to certain values of the internal diameter in inches. Please note how the outer diameter values differ for different types of pipes: seamless, electric-welded, metal-plastic. The difference can reach 17 mm.

How to correctly convert inches to millimeters

To correctly select gas and water supply elements with inch markings, the best option would be to use tables. When connecting water and gas pipeline elements 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 internal, but also the external diameter.

Standard sizes of steel pipes

The most commonly used pipes are with diameters from 426 to 1220 mm. These are highways for water, gas, sewer, and irrigation systems.

Small-diameter pipes are used for water supply 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 oil field industry. These are products with a diameter of ¾”, for wiring inside ½”.

Using the tables, the diameters of pipes made of plastic, copper, and brass are determined in the same way. The method of converting inch dimensions to metric is used when connecting products from different materials. If fittings are available, the installation of gas and water mains 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, GOST

Her Majesty the trumpet! Of course, it makes our lives better. Like that:

The key characteristic of any cylindrical pipe is its diameter. It can be internal ( Du) and external ( Dn). Pipe diameter is measured in millimeters, but the unit of pipe thread is inch.

At the junction of the metric and foreign measurement systems, the most questions usually arise.

In addition, the actual size of the internal diameter often does not coincide with Dy.

Let's take a closer look at how we can continue to live with this. Pipe thread a separate article is devoted. Read also about profile pipes, which are used for the construction of structures.

Inches vs mm. Where does the confusion come from and when is a correspondence table needed?

Pipes whose diameter is indicated in inches ( 1", 2" ) and/or fractions of inches ( 1/2", 3/4" ), are generally accepted standard in water and water gas supply.

What's the difficulty?

Take dimensions from the pipe diameter 1" (how to measure pipes is written below) and you will get 33.5 mm, which naturally does not coincide with the classical linear table for converting inches to mm ( 25.4 mm).

As a rule, installation of inch pipes occurs without difficulties, but when replacing them with pipes made of plastic, copper and of stainless steel a problem arises - the size of the designated inch does not match ( 33.5 mm) to its actual size ( 25.4 mm).

Usually this fact causes bewilderment, but if you look deeper into the processes occurring in the pipe, the logic of the size discrepancy becomes obvious to a layman. It's quite simple - read on.

The fact is that when creating a water flow, the key role is played not by the external, but by the internal diameter, and for this reason it is used for designation.

However, the discrepancy between designated and metric inches still remains, since the internal diameter standard pipe amounts to 27.1 mm, and reinforced - 25.5 mm. The last value is quite close to equality 1""=25,4 but still he is not.

The solution is that to designate the size of pipes, a nominal diameter rounded to a standard value is used (nominal bore Dy). The size of the nominal diameter is selected so that the throughput of the pipeline increases from 40 to 60% depending on the growth of the index value.

Example:

The outer diameter of the pipe system is 159 mm, pipe wall thickness 7 mm. The exact inner diameter will be D = 159 - 7*2= 145 mm. With wall thickness 5 mm size will be 149 mm. However, in both the first and second cases, the conditional passage will have the same nominal size 150 mm.

In situations with plastic pipes To solve the problem of inappropriate dimensions, transition elements are used. If it is necessary to replace or connect inch pipes with pipes made according to real metric dimensions - copper, stainless steel, aluminum, both the outer and inner diameters should be taken into account.

Table of nominal diameter in inches

Du	Inches	Du	Inches	Du	Inches
6	1/8"	150	6"	900	36"
8	1/4"	175	7"	1000	40"
10	3/8"	200	8"	1050	42"
15	1/2"	225	9"	1100	44"
20	3/4"	250	10"	1200	48"
25	1"	275	11"	1300	52"
32	1(1/4)"	300	12"	1400	56"
40	1(1/2)"	350	14"	1500	60"
50	2"	400	16"	1600	64"
65	2(1/2)"	450	18"	1700	68"
80	3"	500	20"	1800	72"
90	3(1/2)"	600	24"	1900	76"
100	4"	700	28"	2000	80"
125	5"	800	32"	2200	88"

Table. Inner and outer diameters. Stacked water/water-gas pipelines, epectros-welded longitudinal, seamless hot-deformed steel and polymer pipes

Table of correspondence between nominal diameter, thread and outer diameters of the pipeline in inches and mm.

Nominal pipe diameter Dy. mm	Thread diameter G". inch	Pipe outer diameter Dn. mm
Nominal pipe diameter Dy. mm	Thread diameter G". inch	Water/water-gas pipes GOST 3263-75	Epoxy-welded straight-seam steel pipes GOST 10704-91. Seamless hot-deformed steel pipes GOST 8732-78. GOST 8731-74 (FROM 20 TO 530 ml)	Polymer pipe. PE, PP, PVC

GOST- state standard used in heat - gas - oil - pipelines

ISO- standard for designating diameters, used in plumbing engineering systems

SMS- Swedish standard for pipe diameters and valves

DIN/EN- main European range for steel pipes according to DIN2448 / DIN2458

DU (Dy)- conditional pass

Size tables polypropylene pipes presented in the next article >>>

Conformity table for nominal pipe diameters with international markings

GOST	ISO inch	ISO mm	SMS mm	DIN mm	DU
8	1/8	10,30			5
10	1/4	13,70	6,35		8
12	3/8	17,20	9,54	12,00	10
18	1/2	21,30	12,70	18,00	15
25	3/4	26,90	19,05	23(23)	20
32	1	33,70	25,00	28,00	25
38	1 ¼	42,40	31,75	34(35)	32
45	1 ½	48,30	38,00	40,43	40
57	2	60,30	50,80	52,53	50
76	2 ½	76,10	63,50	70,00	65
89	3	88,90	76,10	84,85	80
108	4	114,30	101,60	104,00	100
133	5	139,70	129,00	129,00	125
159	6	168,30	154,00	154,00	150
219	8	219,00	204,00	204,00	200
273	10	273,00	254,00	254,00	250

Diameters and other characteristics of stainless steel pipes

Passage, mm	Diameter outer, mm	Wall thickness, mm		Weight of 1 m pipe (kg)
Passage, mm	Diameter outer, mm	standard	reinforced	standard	reinforced
10	17	2.2	2.8	0.61	0.74
15	21.3	2.8	3.2	1.28	1.43
20	26.8	2.8	3.2	1.66	1.86
25	33.5	3.2	4	2.39	2.91
32	42.3	3.2	4	3.09	3.78
40	48	3.5	4	3.84	4.34
50	60	3.5	4.5	4.88	6.16
65	75.5	4	4.5	7.05	7.88
80	88.5	4	4.5	8.34	9.32
100	114	4.5	5	12.15	13.44
125	140	4.5	5.5	15.04	18.24
150	165	4.5	5.5	17.81	21.63

Did you know?

What ingenious lamps can you assemble with your own hands from an ordinary metal pipe? Everyone can do this!

Which pipe is considered small - medium - large?

Even in serious sources I have seen phrases like: “We take any pipe of average diameter and...”, but no one indicates what this average diameter is.

To figure it out, you should first understand what diameter you need to focus on: it can be internal or external. The first is important when calculating the transport capacity of water or gas, and the second is important for determining the ability to withstand mechanical loads.

External diameters:

From 426 mm is considered large;

102-246 is called average;

5-102 is classified as small.

As for the internal diameter, it is better to look at the special table (see above).

How to find out the diameter of a pipe? Measure!

For some reason this strange question often comes to e-mail and I decided to supplement the material with a paragraph about measurement.

In most cases, when purchasing, it is enough to look at the label or ask the seller a question. But it happens that you need to repair one of the communication systems by replacing pipes, and initially it is not known what diameter the already installed ones have.

There are several ways to determine the diameter, but we will list only the simplest ones:

Arm yourself with a tape measure or a measuring tape (this is how women measure their waist). Wrap it around the pipe and record the measurement. Now, to obtain the desired characteristic, it is enough to divide the resulting figure by 3.1415 - this is the number Pi.

Example:

Let's imagine that the girth (circumference L) of your pipe is 59.2 mm. L=ΠD, resp. the diameter will be: 59.2 / 3.1415= 18.85 mm.

After obtaining the outer diameter, you can find out the inner one. Only for this you need to know the thickness of the walls (if there is a cut, just measure with a tape measure or other device with a millimeter scale).

Let's assume that the wall thickness is 1 mm. This figure is multiplied by 2 (if the thickness is 3 mm, then it is also multiplied by 2 in any case) and subtracted from the outer diameter (18.85- (2 x 1 mm) = 16.85 mm).

It’s great if you have a caliper at home. The pipe is simply grabbed by the measuring teeth. We look at the required value on a double scale.

Types of steel pipes according to their production method

Electric welded (straight seam)

For their manufacture, strips or sheet steel are used, which are bent into shape using special equipment. required diameter, and then the ends are connected by welding.

The impact of electric welding guarantees minimum width seam, which makes it possible to use them for the construction of gas pipelines or water pipelines. The metal is in most cases carbon or low alloy.

Indicators finished products are regulated by the following documents: GOST 10704-91, GOST 10705-80 GOST 10706-76.

Please note that a pipe manufactured in accordance with standard 10706-26 is distinguished by maximum strength among its peers - after creating the first connecting seam, it is strengthened by four additional ones (2 inside and 2 outside).

IN regulatory documentation The diameters of products produced by electric welding are indicated. Their size ranges from 10 to 1420 mm.

Spiral seam

The material for production is steel in rolls. The product is also characterized by the presence of a seam, but unlike the previous production method, it is wider, which means the ability to withstand high internal pressure is lower. Therefore, they are not used for the construction of gas pipeline systems.

A specific type of pipe is regulated by GOST number 8696-74 .

Seamless

Production specific type involves the deformation of specially prepared steel blanks. The deformation process can be carried out both under the influence high temperatures, and cold method (GOST 8732-78, 8731-74 and GOST 8734-75, respectively).

The absence of a seam has a positive effect on the strength characteristics - the internal pressure is evenly distributed over the walls (there are no “weak” places).

As for diameters, standards control their production with a value of up to 250 mm. When purchasing products with sizes exceeding those indicated, you have to rely only on the integrity of the manufacturer.

It is important to know!

If you want to buy the most durable material, buy seamless cold-formed pipes. The absence of temperature influences has a positive effect on preserving the original characteristics of the metal.

Also if important indicator is the ability to withstand internal pressure, then choose round products. Profile pipes cope better with mechanical loads (they are well made from metal frames and so on.).

Here are a couple more excellent slides of creative advertising for a pipe manufacturer:

There are 2 popular sizes of structures in the construction market:

1\2 and 3\4 - form 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 reduction or improvement of 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 - ½ inch products, 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, the internal dimension will be 12.7 cm, and the external dimension will be 166.245 (reduction to 1 decimal place is allowed).

Difference between measurement systems

Replacing steel pipes with polymer ones

In the gas and water supply networks, 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 a 1" pipe, 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, no difficulties arise. But when installing products made of PP, copper or stainless steel instead of steel structures, it is necessary to take into account the difference in name and parameters.

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

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

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

How to decide on the diameter?

The diameter of the water pipes determines their throughput characteristics - the volume of water passed per 1 unit. time. It depends on the speed of water flow. As it increases, the risk of pressure drop in the line increases. Flow characteristics are calculated using 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).

Taking into account the fact that the internal cross-section of half-inch polymer pipes varies from 11 to 13 mm, and one-inch ones - from 21 to 23, an experienced plumber will be able to determine the exact parameters when replacing. If the type of wiring is complex, there are numerous joints, turns, and the network is laid over a long distance, and the pressure is reduced, it is necessary to provide for the possibility of routing 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 values, in inches.
Nominal parameter (Dn Dn,).
External size.
The metric calculation system allows you 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 following parameters:

1/2 inch pipeline - 1.27 cm;
3/4 inch – 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.

To determine the thread diameter, the following indicators are used:

1/2 inch pipeline – 2.04 - 2.07 cm;
3/4 inches – 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.

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

Steel pipe prices:

PP pipe diameter

Small – 0.5; 1; 1.5; 2; 2.5; 3.2; 4; 5; 6.3 and 7.5 cm are used for heating systems, drainage and water supply in private buildings. An internal cross section of 3.2 cm is most popular in multi-story buildings.
Average – 8; 9; 10; eleven; 12.5; 16; 20; 25 and 31.5 cm are used for arranging water supply and sewer systems, allowing you to replace cast iron products with similar external parameters. The internal sizes of 8, 9 and 10 cm are ideal for chemical media.
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 systems, the thickness of the walls 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 you to reduce the cost of purchasing material and water consumption.