Their classification by this parameter, as well as by the wall thickness, makes it possible to carry out design calculations for the transportation of this or that type of substance through the pipeline.
Standard pipe diameters and measuring systems
Standard diameters of steel pipes greatly facilitate the work of designers when choosing one or another type of pipeline for assembly.
Before talking about what pipe diameters are and for what type of pipeline system they can be used, you need to consider their main dimensional characteristics.
Note!
According to these parameters, the pipe diameters of TU and GOST are determined.
These are the most important values, because for each of the specific pipe diameters, GOST determines the corresponding wall thickness.
About types of pipe diameters
So, what are the diameters of steel pipes.
- Nominal diameter (DN, Dy) Is the nominal size (in millimeters) of the internal diameter of the pipe or its rounded value, in inches.
- Nominal pipe diameter (Dn Dn,).
- Outer diameter of steel pipes... They are classified precisely on this basis: small sizes - from 5 mm to 102, medium sizes - from 102 mm to 426, large sizes - 426 mm and more.
- Pipe wall thickness Is an important related parameter.
- Inner diameter of steel pipes Is also their main dimensional characteristic. This also applies to connecting elements - system fittings.
Along with an extensive range of metal analogs, pipes made of various types of plastic are now used in almost all areas of construction. As a result, regulatory documents were developed, for example, a table of steel pipe diameters and their compliance with polymer ones.
They make it possible to accurately select pipes when designing a particular transport network.
Measuring systems
| Nominal bore (Dy) of the pipe, mm | Its thread diameter (G), inches | Outside diameter (Dh), pipes, in mm |
||
| Steel seam pipe, water and gas | Seamless steel pipe | Polymer pipe |
||
The table shows the dimensions different types pipes, in millimeters and inches.
In gas and water supply, they are still actively used steel tubes... The diameter of steel pipes is calculated in inches, for example - 1 ″ or 2 ″, or their shares - 1/2 or 3/4 ″. When assembling a pipeline whose pipe diameters are defined in inches, you will not have any difficulties.
However, when there is a need for a change or installation combined systems, for example - or copper analogs, then, in order to correctly select the parameters, the table of steel pipe diameters will be an indispensable assistant for a specialist.
This document defines the exact metric dimensions of steel pipes and their compliance with plastic ones.
In accordance with the standard series adopted in most countries of the world, pipes have an inner diameter, calculated in millimeters:
- 200, etc.
A system for measuring pipe diameters in inches is also used. 1 inch is approximately 2.54 cm.
When assembling a transport system for residential buildings, consisting of steel pipes, pipes with an inner diameter of 15 mm, 20 mm or 32 mm are usually taken.
Large diameter steel pipes used in sewer systems, as well as cast iron free-flow analogs, have a diameter of 50/100 mm.
Why do you need to know exactly the diameter of the pipes to be laid
The exact value of the diameter that it has makes it possible to calculate the volume of the substance transported through the system. For household use, knowledge of all the features of the pipe diameters used is especially important.
For example, if you need to repair the heating system of your house, the diameter of the pipes must be calculated so that in winter the heating heats all living quarters evenly.
The size of steel, aluminum-plastic, or, you can easily calculate and independently, without using the appropriate tables.
To find the diameter of pipes intended for heating, there is a formula: D \u003d sqrt ((314 ∙ Q) / (V ∙ DT)), in which the symbols mean:
- D is the inner diameter of the required pipes;
- Q is the heat flow measured in kW;
- V denotes the speed of the coolant, in meters per second;
- DT is the temperature difference between the inlet and outlet of the system, in degrees Celsius;
- sqrt - square root.
Pipe diameters in inches and millimeters are very important indicators. 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.
In the construction of highways for various purposes, different pipe-rolling materials are used: steel, copper, brass, plastic and others. All these products are distinguished by their classification and measurement.
The overall dimensions of all pipe products are set by the following indicators:
- Дн - external Ø.
- Dv - inner Ø.
- h - wall thickness.
Previously, only steel lines were used, and for them they created their own sizing system. ... These are its internal dimensions. That is, this indicator takes into account not only the size of a half-inch pipe billet, but also its throughput capacity.
And the outer girth of a half-inch workpiece is 2.1 cm. Therefore, in the table, near the half-inch thread, the word pipes must be added. Knowing the exact dimensions of a half-inch and any other kind of assortment, you can quickly make right choice the required volumes.
This is clearly seen in the table:
| Dimensions (inches) | 1/2 | 3/4 | 7/8 | 1 | 1,5 | 2 |
| Internal Ø (metric) | 12,7 | 19 | 22,2 | 25,4 | 38,1 | 50,8 |
| Thread Ø (mm) | 20,4-20,7 | 25,9-26,2 | 29,9-30,0 | 32,7 – 33,0 | 45,8 – 46,2 | 57,9 – 58,3 |
Now these dimensions are usually indicated as shown in the following table provided:
The first diameter table ( its symbolic designation is Ø, hereinafter it will be indicated in the article) of pipes shows values \u200b\u200bin millimeters, and in the second table, inches ( international designation - inch or in, further will be indicated 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 result they show the 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 emerged simultaneously with the introduction of copper systems in Europe in the second half of the 20th century. In Russia at that time standards for metal gauge were defined in mm, not inch, this measurement system is widely used today.
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:
To convert the metric diameter of the pipe assortment, you need to round up in the direction of increase. When making this translation, you need to remember that according to international standards, one inch is taken into account as 2.54 cm.
With such data, the translation can be done with the simplest calculator. Now that the cross-section of the pipe-rolling assortment has been calculated, its volume should be correctly calculated.
In practice, in order to translate the measurements of steel options, you need to take into account that the inch values \u200b\u200bwhen calculating will not equal the indicator in mm. The reason is that when marking is applied, the internal volume is prescribed.
After that, the unit of measurement becomes the conditional passage, indicated by an integer. It is for these reasons that values \u200b\u200bmust be rounded to translate. It is difficult for an inexperienced master to make such a translation.
Therefore, if you need to translate these indicators, it is better to turn to professionals for help, or perform a translation based on a special table. Professionals will help you translate the required values, and help you choose the right products and other parts for the pipeline.
Correspondence of two notation systems
Steel pipes are widely used in water and gas systems. Their dimensions are shown in whole values \u200b\u200bor 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 certainly does not correspond to the declared 25.4 and 50 mm. When laying fittings with inch designations for products of 1 and 2 inch, 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 conditional passage.
The nominal bore of 1-inch, 2-inch 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 \u003d 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 tubular billet can be different: from 2.55 to 2.71 cm. This value varies depending on the wall thickness.
1 inch pipe has outside diameter at 25.4 mm, a pipe having 2 inch is 50 millimeters in metric measurement. Where from in technical parameters pipe cylindrical threads take the numbers 33.249 and 66.498?
These threads on 1 and 2 inch pieces are done on the outside. Therefore, the ratio of thread diameter to 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 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 inch 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 selecting a certain size, they are guided by tabular information, and when replacing it, we serve as a guideline as close as possible. Exact match in two different systems there is no measurement, 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 dimensions measurements, 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 with specific examples of the Dy correspondences, they will look like this:
- The diameter of a standard 12 inch pipe is 300.
- 3 inch tubing diameter is 80.
- An 8-inch diameter of a standard pipe roll equals 200.
- The diameter of a standard pipe roll, at 32, when converted to inches, is shown as 1 ¼
- Pipe diameter 40 mm in inch prescribe 1 ½
- Ø 15 inch standard pipe expressed as ½
- The Ø of a standard product by 4 inches in metric is 100.
- Ø 3/4 '' pipe roll in metric translation equals 20.
- The Ø of a standard 1/2 '' 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.
Knowledge of standards and generally accepted norms greatly simplifies the work and facilitates the choice optimal solution questions in any area. This is also facilitated by the systematization of any data, bringing them into a single table. But before moving on to it, the reader's attention should be focused on some points regarding the diameter of the pipe, regardless of its material and purpose.
The title of this parameter is in the plural. And this is not only because of the wide range of products. Experts distinguish between several "types" of steel pipe diameters, and before dealing with their numerical expressions, you should clarify how one differs from the other. It is the lack of knowledge of the nuances of terminology that is often the reason for the wrong choice of samples, misunderstanding between a specialist (for example, a locksmith who has arrived at the call, a manager in a store) and an ordinary consumer, a non-professional in this area.
What are the different pipe diameters
- Du - conditional passage. You need to know it in order to determine whether this pipe will provide, for example, the proper pressure (for water supply), an acceptable speed of the coolant (for heating circuits).
- Dн - external. This parameter indicates the convenience of mounting the "thread", fixing the samples on a wall or other base, in some cases, about the possibility (or expediency) of passing through surfaces.
- G - threads.
As you can see from the figure, they are not the same:
The difference in values \u200b\u200bis determined by the wall thickness.
Note
Experts distinguish between such diameters as nominal and internal. But for an ordinary consumer, these parameters of the pipe have no practical significance. The main ones for the "private trader" are already indicated - Dу and Dн.
How diameters are measured
This is another “barrier” that prevents a professional and an ordinary person, ignorant of such subtleties, from reaching mutual understanding. There are 2 dimensions that are used to numerically express the sections of products with a round profile - cm and inches. In centimeters, it is clear to each of us, but experts, especially when it comes to the diameters of relatively small steel pipes (for example, for gas or water), often operate with inches ().
In the Russian Federation, there is no abbreviated designation of inches as such. If you use the abbreviation "dm" by analogy with "cm", you get confusion - it is applied to decimeters. Therefore, the symbol "″" is used, which is placed after the numerical value. For example, 1½ ″ (one and a half inches).
It is not difficult to convert from one dimension to another, it is enough to multiply 1½ ″ by 2.54, and you get the same diameter, only expressed in cm (3.8). In this case, fractional values \u200b\u200bare usually rounded. For example, 1 ″ is approximately 2.5 cm (25 mm), although if you are accurate, it should be 2.54 and 25.4, respectively.
Values \u200b\u200btable
It cannot be considered absolutely complete, but everything that is required for "home and family" is reflected in it. More detailed information is easy to find on specialized sites and in the corresponding GOST (by the way, there are quite a few of them).
For the convenience of readers, the right column shows comparative data for plastic analogs. These values \u200b\u200bwill be needed if you have to join products from different materials (steel + plastic).
| Dн (depending on the type of steel pipe, mm) | Du | Dн | ||
| seamless | welded | inches | mm | polymers |
| 16 | 17 | 3/8 | 10 | 16 |
| 20 | 21,3 | ½ | 15 | 20 |
| 26 | 26,8 | ¾ | 20 | 25 |
| 32 | 33,5 | 1 | 25 | 32 |
| 42 | 42,3 | 1 ¼ | 32 | 40 |
| 45 | 48 | 1 ½ | 40 | 50 |
| 57 | 60 | 2 | 50 | 63 |
| 76 | 75,5 | 2 ½ | 65 | 75 |
| 89 | 88,5 | 3 | 80 | 90 |
| 102 | 101,3 | 3 ½ | 90 | 110 |
| 108 | 114 | 4 | 100 | 125 |
| 133 | 140 | 5 | 125 | 140 |
| 159 | 165 | 6 | 150 | 160 |
According to one of the dimensional characteristics, steel pipes differ in diameter, that is, in section. Classifying them by this indicator and wall thickness allows you to create projects and calculations for the transportation of any liquid through pipelines. In this article we will try to figure out what diameters and sizes can be found metal pipes.
Standard pipe diameters and measuring systems
Apply standard pipe sections when creating different types pipelines greatly simplifies the development of the projects themselves by specialists.
Before you figure out what the main dimensions of pipes are, and in what systems they can be used, you should understand the leading dimensional characteristics in more detail.
It should be noted that the diameters of pipes are determined specifically according to the above parameters according to TU and GOST.
These values \u200b\u200bare extremely important, because for a certain pipe diameter in accordance with GOST, you can find out about the corresponding wall thickness.
Diameter classification
Consider the varieties of steel pipe diameters:
- Nominal (DN, Dy) - is the inner diameter of the pipe (mm), or the rounded value (in inches).
- Nominal (Dn, Dn).
- External diameter. The definition, as a rule, is carried out according to this parameter: 5-102 mm - pipes of a small section; 102-426 mm - medium section pipes; 426 mm and more - large section pipes.
- Inner diameter is also considered to be an important parameter that also applies to connection fittings.
In addition to the huge number of offered steel pipes that can be found on sale, pipes made of various types of plastic are currently used in almost all areas of construction. In this regard, regulatory documentation was prepared, among which there is a table with the diameters of steel pipes and their correspondence to analogs from polymers.
Thanks to such tables, it is possible to select the correct pipe with great accuracy in the design process of any transport system.
Measuring systems
Matching pipe diameters different types in both units can be found in the corresponding table.
When creating water and gas supply systems, steel pipes are still widely used today. The cross-section of such pipes is measured in inches, for example: 2.4 "or 4", or in fractions: 1 2/3 or 5/8 ". In the process of assembling a pipeline, the cross-section of which is marked in inches, you will be deprived of any difficulties.
However, if it becomes necessary to change or install combined systems (steel together with copper or plastic pipes), for the correct determination of the required parameters, a table of dimensions of steel pipes, that is, their sections, will help the specialist in the best possible way. These standards contain the metric values \u200b\u200bof steel pipes and the corresponding cross-sections of plastic pipes.
According to standards adopted in the vast majority of countries, the inner diameter of pipes is measured in millimeters. At the same time, it is widespread to mark pipes in inches, which is considered to be 2.54 cm.
The installation of a water supply system for residential buildings often involves the use of steel pipes with an internal section of 15, 20 or 32 mm.
Pipes of large cross-sections, made of steel, and of cast iron (free-flow), used for arranging sewage systems, have a cross section equal to 50/100 mm.
The importance of choosing the correct diameter for the pipes to be laid
Due to the exact nominal diameter of the pipe for installing the water supply, you can find out the amount of transported water. For domestic purposes, it is very important to be aware of all the nuances associated with the applicability of pipe diameters in certain situations.
For example, if there is a need to maintain the heating system of a private house, the cross-section of the pipes is determined so that in winter the heating of the entire territory is the same.
The dimensions of steel, aluminum-plastic and PP pipes can be easily calculated without anyone's help, and without even using correspondence tables.
To determine the cross-section of the pipe for use in heating systems, you can use the formula, which is deciphered as described below.
D \u003d sqrt ((314 ∙ Q) / (V ∙ DT)):
- D - internal section of the selected pipes;
- Q is the heat flux, expressed in kilowatts;
- V is the speed of the coolant, m / s;
- DT is the temperature difference at both ends of the system, measured in ℃;
- sqrt - square root.
The size chart of metal pipes is very important when calculating the cross section of steel pipes. This way you can clearly optimize your work, there will be no unforeseen nuances in the process, and you will be sure of the success of its implementation. In addition, you will spend your money wisely and save a lot of work time.
Metal pipes, despite the appearance in recent decades of products from polymers and composite materials, in many industries still maintain a leading position.
Therefore, the production of such products of almost any size is widely established, which allows you to choose the right products for any task, but also poses a problem for the master of the correct calculation of the design and selection of products. Among the main parameters used in calculating product parameters, one can note the inner and outer diameters of steel pipes, which will be discussed later.
The need to standardize pipe measurements
The main purpose of the establishment standard sizes products, including wall thickness, length, outer and inner diameters of pipes - simplifying the work with these products at all stages: from design to arrangement of the circuit, carrying out scheduled or unscheduled repairs and dismantling the system.
In order not to set impossible tasks and not overly complicate the production of products, GOSTs and TUs regulate only the basic, most necessary pipe dimensions, in accordance with which the designers carry out all further calculations.
The main parameters of pipes
These parameters include:
- Nominal diameter (D y, D y) - represents the inner diameter of metal pipes, calculated in millimeters, or its rounded value in inches.
- Nominal diameter (D n, D n).
- Outside diameter iron pipe ... In addition to the classification of products into three groups: small - with a parameter of 5 ... 102 mm, medium - values \u200b\u200bin the range 102 ... 426 mm, large - from 426 mm, this measurement allows you to calculate the amount of paint or other material required for pipe insulation.
- Wall thickness - a non-independent parameter, established by GOSTs depending on the nominal diameter of a metal pipe, is often used in strength and hydraulic calculations.
- Inner diameter - the main characteristic of both the pipes themselves and the connecting fittings, in particular, couplings and angles.
Compliance with pipe diameters to standards must be observed in the production of not only metal products, but also products from other materials - be it polymers of all grades, composite materials, asbestos cement or glass.
For products from each material, their own parameter ratios have been established, which allow the production of products using a minimum amount of resources, but still maintaining its compliance with technological requirements and safety standards for humans and the surrounding world.
Product dimensions tables
To facilitate the selection of products for a planned or already operating production line or communication system, tables of the diameters of metal pipes and products from other materials have been compiled.
It is not difficult to get acquainted with their full versions. Within the framework of the article, the product measurements used in them should be listed.
Each table can include a complete list of the above parameters, or some of them. For example, nominal bore (in millimeters), thread diameter (in inches), outer diameter and wall thickness (both in millimeters).
Steel pipe diameters are traditionally indicated in inches. Such designations are more concise, since they use only whole numbers or simple fractions: 1 ″, 1½ ″, etc.
The situation is more complicated when you need to connect steel pipes with plastic ones, the dimensions of which are always indicated in millimeters. However, in this case, the master will help out the table of ratios.
Standard range of inside diameters
The standard range includes the following internal diameters in millimeters: 6, 10, 15, 20, 25, 32, 40, 50, 65, 80, 100, 110, 120, 125, 200, etc.
Although it is possible, using complex formulas, to calculate the required pipe diameter for each specific scheme or installation, usually products of traditional sizes are simply purchased.
For example, for the arrangement of communication networks, steel pipes with diameters of 15, 20 or 32 mm are used.
Sewerage pipes can have a cross-section in the range of 50 ... 100 mm.
Calculating the value of the pipe diameter
This operation is necessary when it is required to calculate the volume of the working medium carried by the pipes, in particular, in order to ensure a uniform pressure in all sections of the pipeline.
The value of the inner diameter can be found in the table or calculated using the formula.
For example, for pipes of a heating system:
D \u003d √ ((314 Q) / (V ΔT)),
where D is the inner diameter, mm;
Q is the heat flow, kW;
ΔT is the difference between the initial and final temperatures of the environment, ° С;
V is the speed of the medium, m / s.
In addition to manual calculations and the use of tables, it is possible to carry out calculations in specialized computer programs - today this is the fastest and most reliable way.
