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). 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 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 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 the increase in throughput characteristics by 40-60% with increasing index. If the external cross section and the purpose of the structures, using the size table, the internal cross-section is determined.
During connection 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?
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
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 change 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 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.
Cost of PP pipes:
Video
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How to determine the pipe size in inches: 15 interesting facts
In this article I'm going to talk about how pipe sizes in inches and millimeters compare. In addition, the reader and I will have a short excursion into the history of length measures and into the currently valid regulatory documentation. So, let's go.
History of inch
- The origin of the word "inch" is derived from the Dutch duim, which literally means "thumb". However, another word is used as an international designation for this measure of length - inch;
- Like all old measures of length, the inch originates in human anthropometry and is equal to the length of the outer phalanx of the thumb. In addition, it is equal to 1/12 of a foot (from the English foot - foot) and 1/36 of a yard (according to legends, a yard was equal to the distance from the nose to the end of the thumb of the outstretched hand of King Henry the First of Britain);
There is an opinion that Henry's sword was one yard long.
- IN different countries and in different times the inch took on different meanings. The Viennese inch (Austria-Hungary) is 2.63 cm, the French one is 2.707, the Old Polish one is 2.48, the New Poland one is 2.4, the Prussian model of 1816 is 3.766 cm;
- In Russia, this measure of length was introduced by Peter the Great. Before this, in trade and in calculations, domestic units of measurement were used, also based on anthropometry - vershok (the length of the first phalanx of the index finger), span (it is measured between the thumb and index fingers separated to the maximum distance), arshin (the length of the step of an adult);
- Currently, the most common is the English inch. Since 1958, it has been agreed to be considered equal to 2.54 cm.
About the mess
Dear reader, do you think that it is possible to calculate the cross-section of a steel pipe or pipe in inches by using a caliper and dividing the result by 25.4? Not so.
Conditional pass
- Steel water and gas pipes, the cross-section of which is usually indicated in inches, are not marked with a diameter at all, but with a nominal bore. It is close to the internal section, but not necessarily equal to it. It only means that the appropriate pipe thread can be cut on the pipe;
- The actual internal diameter is determined by the nominal bore (more precisely, the corresponding external diameter) and the type of pipe (it can be ordinary, light or reinforced);
- The actual internal cross-section of products with the same DN (nominal bore) may differ by 0.3 cm due to the walls;
- The internal cross-sectional area and, accordingly, the throughput of lightweight and reinforced pipe with a nominal size of half an inch differ by 20%. At the same time, the throughput of a lightweight product is greater, but that of a reinforced one due to the larger wall thickness and, accordingly, larger mass per linear meter higher price.
Samples of rolled pipes produced in accordance with GOST 3262 - 75.
Standards
With all my immense respect for the Soviet standardization system, the way pipe sizes in inches and centimeters correspond according to current standards cannot be called anything other than a mess:
- The section in inches indicated in the documentation cannot be obtained by simple conversion from mm or other SI units. The conversion factor is different for each diameter and in no case does it correspond to the completely logical value of 25.4;
- To determine the number of inches based on measurement results, you will have to consult reference or regulatory documentation. However not a single GOST contains a table of pipe sizes in inches and millimeters. Actual dimensions for a certain DU and type of product can be found in GOST 3262-75, which regulates the production of black and galvanized steel water gas pipes. Meanwhile, the parameters of the corresponding threads are indicated in another GOST - number 6357-81.
The second standard specifies the crest and root dimensions of threads in SI units, but designates cylindrical pipe threads in inches.
Simpler, even simpler
So, to correlate the pipe size in inches and mm, you need to apply regulatory documents and painstakingly compare them. Right?
Dear reader, I won’t bore you and will simply post a couple of tables that are compilations of the standards mentioned above.
- Here is the correspondence between the remote control and the treasured British inches:
| DU | Inches |
| 15 | 1/2 |
| 20 | 3/4 |
| 25 | 1 |
| 32 | 1 1/4 |
| 40 | 1 1/2 |
| 50 | 2 |
| 65 | 2 1/2 |
| 80 | 3 |
| 90 | 3 1/2 |
| 100 | 4 |
| 125 | 5 |
| 150 | 6 |
In addition to those indicated, GOST 3262-75 provides for conditional passages 6, 8 and 10. However, they are not used in plumbing, and threaded fittings for them cannot be found.
The minimum cross-section used in plumbing is DN 15.
- But here is the ratio of remote control and actual dimensions:
| DU | External diameter | Wall thickness | ||
| Reinforced | Ordinary | Lightweight | ||
| 15 | 21,3 | 3,2 | 2,8 | 2,5 |
| 20 | 26,8 | 3,2 | 2,8 | 2,5 |
| 25 | 33,5 | 4 | 3,2 | 2,8 |
| 32 | 42,3 | 4 | 3,2 | 2,8 |
| 40 | 48 | 4 | 3,5 | 3 |
| 50 | 60 | 4,5 | 3,5 | 3 |
| 65 | 75,5 | 4,5 | 4 | 3,2 |
| 80 | 88,5 | 4,5 | 4 | 3,5 |
| 90 | 101,3 | 4,5 | 4 | 3,5 |
| 100 | 114 | 5,0 | 4,5 | 4 |
| 125 | 140 | 5,5 | 4,5 | 4 |
| 150 | 165 | 5,5 | 4,5 | 4 |
Using these tables, how can you calculate the actual dimensions of a 1-inch pipe with your own hands? Very simple:
In our case, one inch corresponds to a nominal bore of DN 25 and means an outer diameter of 33.5 mm. The internal diameter of the light pipe will be 28.1 mm, the ordinary one - 27.1, and the reinforced one - 25.5 mm.
Polymer and metal-polymer pipes
- They are always marked with an outer diameter in millimeters; wall thickness is indicated either in the markings or in technical documentation. To get the same throughput as a steel liner of a known size, you need to choose a product with the same internal diameter. Let me remind you that it is calculated as the difference between the diameter and twice the wall thickness;
The photo shows a metal-plastic water supply line. The marking indicates the outer diameter (16 mm) and wall thickness (2 mm).
- To simplify the task of selecting the diameter, I usually use polymer and metal-polymer products with a cross-section one step larger than that of the liner or riser. For example, instead of a DN 15 water supply line, you can install metal-plastic with an outer diameter of 20 mm, and instead of a 25 mm riser - 32 mm.
Conclusion
I hope that I was able to answer all the questions the reader had. As always, additional topical information can be learned by watching the video in this article. I would appreciate your comments and additions. Good luck, comrades!
August 1, 2016If you want to express gratitude, add a clarification or objection, or ask the author something - add a comment or say thank you!
An important parameter of a cylindrical pipe is its diameter. This value for water and gas pipes is measured not in millimeters or centimeters, but in inches. Water and gas pipelines have dimensions indicated in inches: ½, ¾, 1.2, etc. What is the diameter of a ¾-inch pipe, and how is it determined correctly?
Why are water and gas products measured in inches?
The system for measuring pipes in inches is called imperial, and in millimeters or centimeters is called metric. The Imperial measurement system was developed by the British. The history of the founding of this system goes back to 1495, when the English king Henry VII introduced an individual standard.
The metric system is more convenient, but in water and gas lines the dimensions of materials are calculated in inches. This is the generally accepted standard GOST 3262-75, which is used in water and gas lines. Going deeper, it should be noted that 1 inch equals 25.4 mm. However, if you take an inch water pipe and measure its diameter, you will get a value equal to 33.5 mm. What does this mean?
This discrepancy is due to differences between the American inch and the British one, which was approved by King Henry. In Britain, one inch was the size of a thumb. That is why today there are such disagreements with the diameters of conventional pipelines and water and gas pipelines.
One inch in the time of Henry VII was measured by the ball of the thumb, and is considered approximate.
How to distinguish metric threads from inch threads
It is not difficult to distinguish an inch pipe from a metric one. To differentiate, you need to pay attention to the thread notches. It is almost impossible to determine the degree of notch by eye, especially since the difference between metric and inch threads is only 5 degrees.
Metric threads have a cut of 60 degrees, and inch threads have a cut of 55 degrees.
Pipelines can be distinguished by rounded threads, which are visible to the naked eye. It is impossible to make a mistake, but it is used for clarification special device– thread gauge. As a last resort, to clarify the thread, you can use an ordinary ruler. The photo below shows a special coupling, which is used to connect a plumbing product to a regular one.
What diameter does a ¾ pipe have: features of determination
In Russia, as in most countries of the former USSR, the inch system is used for designation in water supply and gas supply. It follows from this that the outer diameter of the pipe ¾ according to GOST 3262-75 is 26.8 mm. The internal size of the ¾ steel pipe is 20 mm. However, this value for water supply and gas pipeline products represents the value of the nominal diameter Dу. It is also called the pipeline capacity. If the outer diameter of the pipeline corresponds to 26.8 mm, then the diameter of the external thread is approximately 26.4 mm. However, it may not always be equal to this value. It all depends on the wall thickness of the product used. Depending on the thickness of the pipeline walls, the value of the external parameter can reach 28 mm.
In America and some European countries, ¾ sizes do not correspond to the values indicated above (i.e., those used in the former countries of the union). This means that if it is necessary to join such materials, you will need to use special adapters. ¾ pipes are used for laying water and gas pipelines, as well as heating systems.
An important parameter for water and gas pipelines is the number of threads or thread pitch. For ¾ products, the number of threads is 14 per inch. This means that there are 14 threads per unit of measurement. It is important to know that inch pipes are measured by the internal diameter (the nominal diameter), while metric pipes are measured by the outer edges of the threads. Below is a table showing the parameters of pipelines in two units of measurement for different types products.
The length of the ¾ pipelines can be different, since there are corresponding standards for this. However, experts pay attention to uncut material when there are large orders. This allows you to significantly save on adapters and connectors.
When choosing pipelines, it is important to consider the purposes for which they are planned to be used. If you need to cut a thread, you can use two types of tools: a die or a die. The clamp is more convenient to use, as it can be not only manual, but also electric.
Pipe manufacturing materials ¾
Depending on the material used to manufacture the ¾ pipeline, the final product may have different parameters. Only the internal diameter of the materials cannot be changed, which is equal to 20 mm for ¾-inch products. In this case, only the outer size of the product changes.
If you need a ¾ thread on a pipe, then 3 dies are used for this. Using the first die, a roughing pass is made, through which the threads are formed. The second is intended for stripping, and the third die is used for finishing. When connecting ¾ copper pipelines, soldering technology is used. This is due to the fact that the internal diameter of such products is 19.05 mm, that is, less than necessary. The wall thickness of such products is 1.07 mm, so a threaded connection cannot be made.
All connectors, taps and valves for water and gas supply systems are appropriately marked for the diameter of the pipelines they are used for. This marking is located on the outside of factory parts.
It is recommended to cut threads directly using special equipment. Water and gas pipelines are systems that require precision, so when choosing a material, you need to take into account not only the dimensions, but also the quality of the products. After all, how long the structure will last depends on this parameter.
The main parameter characterizing a steel pipe is the diameter of the inch pipe. This characteristic indicates the scope of application of this pipe, the length of the pipeline, composition and physical parameters transported by non-substance. All diameter values must comply with standardization regulations that relate to standard sizes; all requirements for these products are carefully regulated by GOST. Each type of pipe has its own standard.
The dimensions are indicated on the markings: for steel ones - in inches, for others - in millimeters. How to find out the diameter of a steel pipe in mm? Here tables of diameters of steel products will come to the rescue.
Diameter is not the only characteristic by which steel pipes differ; an equally important parameter is the method of their production, which is also key points when choosing them.
- Straight-seam (electric welded). For their production, sheet steel (strip) is used, which, using special equipment, is bent to the required diameter, after which the edges are connected by welding. Welding work is guaranteed minimum width seam, which allows the use of these products for the construction of water and gas mains. The most common material is carbon or low-alloy steel. The indicators of finished products are regulated by the following documents: GOST 10704-91, GOST 10705-80 GOST 10706-76.
- It is necessary to pay attention to the fact that the pipe, which was manufactured in accordance with standard 10706-26, has increased strength among its peers - after the first connecting seam has been made, it is additionally reinforced with two more from the inside and two from the outside. Regulatory acts indicate the diameters of products manufactured using electric welding. Their size ranges from 10 to 1420 mm.
- Spiral seam. For the manufacture of this type of product, steel in rolls is used. These products also have a seam, but compared to the previous type of product it is wider, and accordingly the ability to withstand internal pressure is lower for such pipes. These products are used in the construction of gas pipeline systems. This type pipes are regulated by GOST 8696-74.
- Seamless. The manufacture of products of this type involves the deformation of special steel blanks. Deformation is performed as with impact high temperatures, and by the cold method (GOST 8732-78, 8731-74 and GOST 8734-75, respectively). The absence of a seam is a positive reflection on strength - the internal pressure is evenly distributed over the walls (there are no “weak” places).
Regarding diameters, it is worth noting that regulations control their production up to 250 mm. When purchasing products whose diameter is larger than specified, you only have to trust the integrity of the manufacturer.
It is important to know! If you need the strongest possible pipes, the best option will be the purchase of seamless deck molded products. The initial characteristics of the metal do not change due to exposure to temperatures, which has a positive effect on strength.
Also, if the key requirement is the ability to withstand internal pressures, round-shaped products are most suitable for this role. Profile pipes more resistant to mechanical stress (they are well suited for making various kinds frames, load-bearing structures).
What pipe diameters are there?
Theoretically, the diameter of the pipe is quite simply added to any calculations when determining certain values. But in reality, everything is much more complicated - there is a wall thickness, the diameter differs into nominal, internal and external. What concepts exist and their meaning:
- Conditional bore is the internal size of the pipe, determined in millimeters. In inches, rounding is required. It is used for the correct joining of two products, for example, a pipe and a fitting.
- Pipe wall thickness (S) – measured in millimeters, affects most quality characteristics, which includes volume, permeability. Defined as the difference between the outer and inner diameters.
- The internal diameter is a physical quantity determined in millimeters and plays a fairly large role in determining the passability of a highway. Formula for calculation: Dvn=Dn-2S.
- Outer diameter (Dn) - small sizes - 5...102 mm, medium - 103...426, large - from 427 and above.
- Nominal diameter - by definition, stands next to the nominal diameter, but has a more accurate value.
Large range of steel pipes for various purposes, manufacture, types are presented in the form of tables. It happens that the values of the masses of the product are entered into the table of diameters of steel pipes depending on its dimensions, as well as the values of the nominal diameter.
Inches or mm: where does the confusion come from?
Pipes whose diameter is determined by inches (1"", 2"") and/or fractions of inches (½'', ¾"), a generally accepted standard for water and gas supply.
Pipes used for gas or water mains are usually measured in inches rather than millimeters. The inch diameter of the pipe is 33.5 mm (see table), but the SI inch size is 24.4 mm. The thing is that the size of the pipes is determined by the internal, not the outer diameter.
Measure a diameter of 1’’ (how to measure pipes is described below) and you will have a value equal to 33.5 mm, which of course will contradict the classic linear conversion table for units of measurement.
Typically, installing inch pipes does not cause any problems. But when replacing them with plastic, copper or stainless steel, a problem arises - the discrepancy between the indicated inch value and its real value. Usually such a discrepancy causes bewilderment, but if you look deeper into the processes that occur in the pipe, then everything falls into place.
The whole point is that during the creation of a water flow the main role is assigned to the internal rather than the external diameter, and because of this it is used as a designation. But the discrepancy with the usual designation system still remains, since a regular pipe has an internal diameter of 27.1 mm, and a reinforced pipe has an internal diameter of 25.5 mm. The latter is not far from the equation that one inch is equal to 25.4, but still it is not.
The thing is that pipes are designated by a nominal diameter, which is rounded to a standard value (nominal diameter Dy).
Let's say the outer diameter of the pipe is 159 mm with a wall thickness of 7 mm, in this case the exact inner diameter will be the following value, which can be calculated using the formula D = 159 - 7 * 2 = 145 mm. With a wall thickness of 5 mm, the diameter will be 149 mm. But in both the first and second cases, the conditional passage will be the same and will be equal to 150 mm.
In cases with plastic pipes in order to solve the problem of inappropriate dimensions, transition elements are used. If it is necessary to replace or connect inch pipes with pipes that have real metric sizes made from materials such as aluminum, copper, stainless steel, you need to take into account both internal and external diameters.
Table of nominal diameter in inches:
| Nominal diameter | Inches | Nominal diameter | Inches | Nominal diameter | Inches |
| 6 | 1/8" | 150 | 6" | 900 | 36" |
| 8 | ¼" | 175 | 7" | 1000 | 40" |
| 10 | 3/8" | 200 | 8" | 1050 | 42" |
| 15 | ½" | 225 | 9" | 1100 | 44" |
| 20 | ¾" | 250 | 10" | 1200 | 48" |
| 25 | 1" | 275 | 11" | 1300 | 52" |
| 32 | 1 (¼)" | 300 | 12" | 1400 | 56" |
| 40 | 1 (½)" | 350 | 14" | 1500 | 60" |
| 50 | 2" | 400 | 16" | 1600 | 64" |
| 65 | 2 (½)" | 450 | 18" | 1700 | 68" |
| 80 | 3" | 500 | 20" | 1800 | 72" |
| 90 | 3 (½)" | 600 | 24" | 1900 | 76" |
| 100 | 4" | 700 | 28" | 2000 | 80" |
| 125 | 5" | 800 | 32" | 2200 | 88" |
The size of the nominal diameter is selected in such a way that the throughput of the pipeline increases from 40 to 60%, depending on the increase in the index value.
Which pipes are considered small, medium, large?
Quite often in many sources you can find a phrase like “Take any pipe of average diameter...”, but no one indicates the specific values of this diameter. To understand this issue, you first need to decide what diameter you need to start from: it can be either internal or external. The first is of great importance when calculating the transport characteristics of water or gas, and the second determines the ability to withstand mechanical loads.
External diameters:
- from 426 mm - large;
- 102-246 - medium;
- 5-102 - small.
If we are talking about the internal diameter, then it is better to check with a special table.
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 | ||
| Steel water/gas pipes GOST 3263-75 | Epectro-welded straight-seam steel pipes GOST 10704-91. Seamless hot-deformed steel pipes GOST 8732-78. GOST 8731-74) | Polymer pipe. PE, PP, PVC | ||
| 10 | 3/8" | 17 | 16 | 16 |
| 15 | ½" | 21.3 | 20 | 20 |
| 20 | ¾" | 26.8 | 26 | 25 |
| 25 | 1" | 33.5 | 32 | 32 |
| 32 | 1 ¼" | 42.3 | 42 | 40 |
| 40 | 1 ½" | 48 | 45 | 50 |
| 50 | 2" | 60 | 57 | 63 |
| 65 | 2 ½" | 75.5 | 76 | 75 |
| 80 | 3" | 88.5 | 89 | 90 |
| 90 | 3 ½" | 101.3 | ||
| 100 | 4" | 114 | 108 | 110 |
| 125 | 5" | 140 | 133 | 125 |
| 150 | 6" | 165 | 159 | 160 |
| 160 | 6 ½" | 180 | 180 | |
| 200 | 219 | 225 | ||
| 225 | 245 | 250 | ||
| 250 | 273 | 280 | ||
| 300 | 325 | 315 | ||
| 400 | 426 | 400 | ||
| 10 | 3/8" | 17 | 16 | 16 |
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 shut-off valves
DIN / EN - the main European standard for steel pipes according to DIN2448 / DIN2458
DU (Dy) - nominal diameter.
How to measure the diameter of a pipe?
Most often, during the purchase, you can simply ask a question to a consultant or look at the labeling. But it happens that one of the communication systems needs repair and replacement of pipes, and it is not known what diameter it is already installed pipes. There are several ways to determine the diameter, but we will tell you about the simplest ones:
Using a tape measure or measuring tape wrapped around the pipe, write down the value obtained. Now, in order to find out the diameter, you need to divide the obtained data by Pi (3.1415).
Let's assume that the pipe has a girth of 6 cm. Its diameter is calculated as follows: 6 x 3.1415 = 18.85 mm. Once the outer diameter is obtained, the inner diameter can be calculated. For this calculation, we will need to know the thickness of the walls (if there is a cut, measure it with any measuring instrument with millimeter gradations). For example, the walls have a thickness of 1 mm. This figure is multiplied by 2 (even with a thickness of 3 mm it is still multiplied by 2) and subtracted from the outer diameter.
As an example, the following calculation can be given: (18.85- (2 x 1 mm) = 16.85 mm).
Diameters and other characteristics of stainless steel pipes:
| Passage, mm | External diameter, mm | Wall thickness, mm | Weight of 1 m pipe (kg) | ||
| 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 |
A caliper is a very good help in this matter. Simply grab the pipe with measuring teeth and look at the resulting value on the scale.
Using the tables, the diameters of plastic, brass and copper pipes are determined in this way. The method of converting inch dimensions to metric ones is used when joining products made from different materials. In the case where fittings for gas or water pipes made of steel are available, installation becomes much easier - the connecting elements take this feature into account.
- However, if the work is done with your own hands, you need to know the parameters of the most used materials, one of which is a product with a given diameter. It should be understood that we are talking specifically about water and gas systems.
- It is worth noting that the diameter of the pipe in mm 3 4 inches usually depends on the wall thickness. However, if we talk about products for water supply, then the internal parameter will be 20 mm, and the external 28. In this case, attention is most often paid to bandwidth, since there are special dies in the inch system for cutting threads.
- It should also be mentioned that the length of the 3 4 pipe can also be different. The fact is that there are certain standards for this parameter, but specialists with a large order prefer to purchase uncut material. This way you can save quite a lot of money, since companies give a discount on it.
- Products with this diameter are very popular, which means you can always find products at a more reasonable price. However, you should immediately pay attention to quality. (See also the article Pipe fittings: features.)
- Standard instructions installation instructions recommend using similar pipes for the manufacture of gas and water lines. However modern man will always find a lot of additional uses for this material.
Pipe dimensions 40 mm (1+1/2 inches). Pipe 3 4 sizes
video instructions for DIY installation, features of copper products, diameter, dimensions, price, photo
When designing water supply and gas systems masters very often encounter the fact that there are various ways diameter designations. At the same time, it is necessary to say that in fact these are not only features of the designation, but also completely different products. Therefore, it is very important to know the diameter of the pipe 3 4 mm, and understand its combinations with products from other countries that have different markings.
Features of determining diameter
To begin with, it must be said that in most countries of the former Soviet Union an inch designation system is used for gas and plumbing products. However, they usually indicate the distance between the outer walls and only approximately.
At the same time, in some countries of Europe and America, pipe sizes of 3-4 inches exactly correspond to this value, which means that when joining such materials it is necessary to use special adapters.
Sizing
First of all, it is worth mentioning that when drawing up projects, specialists use reference books where all required quantities in accordance with GOST.
Therefore, they only include the designation of the required products in the plan to avoid confusion during installation.
Advice! You should never forget that plumbing systems have a certain difference from pipes that are used for other needs. It is also necessary to remember that pipe threads are a separate type of connection organization, and are not similar to other types of similar notches.
Material and thread
It is worth noting that a 3 4 mm pipe can have different parameters depending on the material from which it is made. In this case, the internal diameter is usually kept intact, and only the wall thickness is changed. That is why the designation in inches is approximate and is given in such quantities.
When 3 4 pipe threads are needed, craftsmen usually purchase three dies for cutting pipe threads. The first is a rough pass, the second is a clean pass, and the third is considered the finishing pass, since it removes all small defects and deepens the notch a little. Moreover, this manufacturing method allows you to ignore the error in the outer diameter.
If a copper pipe 3 4 is used, then you need to know that its parameters may differ significantly from steel products. For example, its internal diameter is usually 19.05 mm, and the wall thickness does not exceed 1.07 mm. Moreover, such material is sold in coils and joined using soldering.
Advice! Sometimes it is better to first make all the necessary measurements and calculations than to look for rare adapters or try to create a joint with different dimensions yourself.
Conclusion
After studying the video in this article, you can learn more about these types of pipes and their features. At the same time, taking into account the article cited above, it is worth concluding that the concept of diameter for such products is very relative, and may depend on a lot of different factors.
hydroguru.com
Pipe dimensions 40 mm (1+1/2 inches)
A B C D E F G H I K L M N O P R S T U Vhome ⇒ construction mat ⇒ rental ⇒ pipes
 Pipe |
10 (mm) | 1+1/2" | 48 (mm) |
| 6 mm | 8 mm - 1/4 dm | 10 mm - 3/8 dm | 15 mm - 1/2 dm | 20 mm - 3/4 dm | 25 mm - 1 dm | 32 mm - 1 1/4 dm | 40 mm - 1 1/2 dm |
| 50 mm - 2 dm | 65 mm - 2 1/2 dm | 80 mm - 3 dm | 90 mm - 3 1/2 dm | 100 mm - 4 dm | 125 mm - 5 dm | 150 mm - 6 dm | 160 mm - 6 1/2 dm |
| 200 mm - 8 dm | 225 mm - 9 dm | 250 mm - 10 dm | 300 mm - 12 dm | 400 mm - 16 dm | 500 mm - 20 dm | 600 mm - 24 dm | 800 mm - 32 dm |
| 1000 mm - 40 dm | 1200 mm - 48 dm |
