The diameters of steel pipes: how to plan communications

Today communication of plastics replaced the majority of metal counterparts. However, steel and still is common alloy from which the pipelines are made. One of the main characteristics of the steel pipe has an impact on the operational origin, - the diameter. This rate is mandatory for the preparation of building schemes. The diameters of the steel pipe are regulated by the respective guests.

Types of steel pipes as a process for their production

Steel pipes used in laying water-supply systems and transmission of communications. Such products have many positive attributes, among which are high strength, linear expansion resistance. A significant drawback of such products is that they have poor resistance to corrosive influences. All steel pipes are classified according to the method of production and intended use.

One of the most common types of steel pipes are electric products. They are also called longitudinal welded. Made of sheet steel. The use of welding equipment allows you to get a small flat seam. Such pipes are used in laying water-supply and transmission of communications systems. The diameters of the pipes of this type is quite easy to identify using standard documentation (GOST 10704-91). Range section dimensions in this case is 10-1420 mm.

The next type of steel pipes - spiral. These products are made of steel, which is available in rolls. Like the previous type, these items have a seam, but it is no different minimum width. Thus, the spiral tube can not withstand high pressure (in contrast to electric). Because of this, they are not used for the construction of gas transmission systems. These products are regulated by GOST 8696-74.

Modern industry makes it possible to produce structures, which do not have a seam. Seamless tube made of tailored blanks. It is worth noting that these products are made in two ways: hot and cold. Away diameters of steel pipes found in special tables containing other geometric characteristics of the products, which simplifies the search. Seamless detail regulated by GOST 8732-78 and GOST 8734-75.

The range of the diameters of products which do not have a seam, ranges from 10 to 550 mm. Lack seam greatly enhances the strength characteristics of the data pipe, which allows their use in critical communications.

Note!Regulatory documentation monitors seamless articles, it only applies to items whose diameter does not exceed 250 mm.

The diameters of steel pipes: What are these indicators and how they are defined

Knowing the exact value of the diameter, which has a pipe or a gas pipe, it becomes possible to calculate the volume of material transported through communications. The use of such pipes in the construction requires a clear definition of the dimensional characteristics required for the calculation of economic systems.

As an example the heating system. The diameter of the pipes in such communications should be clearly calculated to winter system to provide uniform heating of premises.

To date, there are several common methods to calculate the diameter of the steel pipe. Sizes that can be found in the regulatory documentation, is the most simple of them. Define this parameter can also use the online calculator. These programs are at specialized sites on the network, so finding them is easy.

Separate calculation is made by the diameter of the communication of mathematical expressions. Type of formula depends on the operational purpose of communication. For example, to determine the diameter of the heating tube used the following equation:

D = sqrt ((3,14 x Q) / (V x DT)), where:

D - the diameter (inner);
Q - rate of heat flux calculated in kW;
V - velocity of the material transported through conduit (measured in m / s);
DT - temperature difference in the initial and final point of the system (input / output);
sqrt - square root.

This formula allows to quite accurately determine the diameter of the pipe. The designation of this indicator in the circuits allows to calculate the required pressure and amount of substance transported per unit time.

What are the diameters of the pipes exist: their varieties

Today diameters are classified into several types depending on what characterizes this value. To use this parameter in the calculations is recommended to explore the types of diameters.

Conventional passage pipes (DN). Indicator of internal pipe space. This parameter is calculated in millimeters or inches. In the second case, the rounding value. Knowledge of this parameter allows you to select hardware components (fittings) of the desired size to the pipes.

Nominal diameter. This figure is very similar to the previous type, but has some differences. For example, the main characteristic of the nominal setting is its high accuracy, which can not tolerate rounding.

The inner diameter (DN). This indicator is a physical quantity which is measured in mm. The inner diameter of the pipe used in the calculation structure patency. Do not confuse this with the nominal diameter of the pipe.

Note!To calculate this parameter, there is a special formula of: Dy = Dn - 2S.

The outer diameter (Dout). By this parameter all pipes made of steel, are divided into three main groups: small, medium and large. Each group has its own range of sizes and its purpose. Define this figure the easiest way from the table steel pipes. GOST standards governing such products, you can easily find on the Internet using the search bar of your browser.

It should be noted a parameter such as the thickness of the walls. This value refers to the physical and affect the quality characteristics of the part. For example, the wall thickness of the product depend on the volume and mass. Calculated wall thickness in mm. To determine often use the following simple equation:

t = Dout - DN

Measuring systems diameter pipes: a table (millimeters and inches)

Products whose diameter is calculated in inches (e.g., 5 ") are used when installing water communication and transmission designs. On the Internet one can find tables containing this value in millimeters and in inches. Some of the schemes combine both measurement systems, which is very convenient. Five inch pipe corresponds to the standard parameter inner diameter equal to 125 mm.

Measuring the diameter of the pipe in inches is used during the installation of water and gas transmission lines, as this simplifies the overall calculation. One inch equals 25.4 mm. It is important to remember that in the measurement tube 1 in a different size, namely 33.5 mm. The reason is quite simple: the dimensions of the pipes are calculated according to the internal diameter and not on the outside. In drawing installation plans and schemes must take into account this discrepancy. Such information enables us to answer the question of how to measure the diameter of the tube and to prevent bugs at the same time.

Table 1. DN in millimeters and inch system notation steel pipe sizes:

DN, mm	Thread diameter, inches
150	6″
40	1 1/2″
80	3″
15	1/2″
100	4″
32	1 1/4″
50	2″
125	5″
25	1″

Helpful information!As a rule, no problems when installing steel products just because they are measured in inches. However, when a need to replace the old communication of steel on the plastic may occur confusion. Therefore, it is worth remembering that the actual metric and inch sizes differ.

In most cases, laying inch pipe did not cause any difficulties. Nature is disparity in the designation of steel products (water and gas), which realized and labeled nominal diameter, while their actual cross section has other sizes. As an example, a simple calculation of the pipe sizes which the outer diameter is 140 mm and the wall thickness - 5.5 mm.

To determine the actual diameter using a simple equation:

D H D = - t x 2

After the introduction of the desired values, this formula becomes: D = 140 - 5.5 x 2 = 129 mm. This figure corresponds to the actual diameter of the tube, which section of the outer wall is 140 mm. However, the nominal diameter or the inner diameter of the pipe inch (or mm) is the overriding value. In this case, this value is 125 mm, it is for it produced the majority of construction calculations.

Fittings - Special transition elements are used for the joining of steel and plastic pipes. These adapters allow to connect two pipes with different cross-section figures made from different materials. In order to avoid mistakes during installation or replacement of communication, it is advisable to take into account both external and internal diameters of steel pipes.

Tube outside diameter (D H): Classification of steel products

As already mentioned above, the inner and outer diameters different from each other. The first of them is used when referring to the individual elements of pipeline structures. The realization of steel products is also performed on the inner diameter. This index is important in that if the mounting is necessary to calculate the aqueduct or the gas line. In turn, the outer diameter is used for determining the strength characteristics of the pipeline and its resistance to mechanical stress.

Outer diameter steel tubing - characteristic, which are classified by all articles of this material. Depending on this option, there are three main types of pipelines:

• small;
• medium;
• great.

Tubes, which are a group of small, have a range of diameters from 10 to 102 mm. Medium sized products can have a cross section of 102 to 426 mm. Range of diameters of large steel pipes starting from 426 mm. In turn, the definition of the internal diameter is recommended to do at the table.

Small tubes are used for installation of communications in residential buildings. Through the medium of products laid urban water transportation lines, as well as their active operating companies which are engaged in oil production (crude). The main areas which have been used long steel products are oil and gas transportation region. Large parts of trunk lines are collected. The diameter of the gas pipes may reach 1220 mm.

Standard steel pipe diameters: a table and a description

When finding the inner diameter of indicator corresponding to the size of orifice is rounded to 0 or 5. Thus, in determining the characteristics of this size comes closest to standardization parameter metric.

Related article:

GOST steel pipes: basic standards for quality products
Different types of metal products. Varieties of pipes. Fabrication methods. Technical characteristics of the steel pipes according to the standard.

Knowing this information, it is easier to carry out the calculation of the pipe diameter. How to measure this parameter in millimeters and inches, it mentioned above.

Note!The most widely, due to operational suitability are products with diameters from 426 to 1220 mm. These pipes are made of steel are used as transmission lines for gas and oil pipelines, sewage systems, and structures used for irrigation.

In residential homes use steel water pipes, the diameter of which is 15 or 20 mm (32 times). Sewer used more dimensional product, due to the need for sewage disposal. Heating systems consist of small tubes.

Table 2. Effect on operational sphere diameter:

Operating scope	Diameter, mm
Water pipes in residential buildings	15-32
Gas pipelines in residential buildings
sewer system	50-100
Gas and oil transportation line	426-1220

Normative documents contain more detailed tables, which contain information not only on the cross section, but other geometric characteristics. With them, the easiest way to determine the pipe diameter (in millimeters and inches). It is important to remember, that by applying a special tables can calculate the necessary display section (indoor or outdoor), both steel tubes and other species.

Finding diameter steel pipes: Table GOST thicknesses

The use of special tables, which are located in the regulatory documents, allows you to quickly determine the appropriate setting. This can be internal or external diameter, and also indicates auxiliary geometrical characteristics such as wall thickness, weight and so on. D.

It should be noted that the difference between the outer diameter of metal tube and Dy may reach 7 mm (depending on the metal of species). For example, steel, electric parts used for mounting commercial communications, may be different for these indicators 5-10 mm.

Table 3. The diameters and thickness of welded steel pipes:

The inner diameter (DN), mm	The outer diameter (Dout) mm	The wall thickness, mm
80	89	3
15	20-22	1,5
50	57	3
100	108	3,5
32	42	2
20	25-28	1,5-2
40	48	3
25	30-32	2

The main index, indicating the product origin, of course, is the inner diameter. Pipes are also referred to an outer size of the cross section, which is a necessary condition in the calculation of mechanical resistance.

Note!Dimensions of products having inch markings easiest determined by tabular method. It is important to remember that during the docking lines of steel pipes of different material (eg, plastic) is necessary to take into account not only the DN, but DH.

Popularity tabular method is caused by the fact that in today's world, distributed combined pipeline construction. Such systems comprise a steel pipe and polymeric components (fittings).

Table steel tube: diameter, the price per meter rental

The price of one meter of these products is determined by their mass. In this case, a definite relationship traced: the thicker product of steel, the more its weight. a plurality of tables can be found on the Internet that provide information about the prices of different parts, which are classified according to the inner diameter. Steel pipes belong to the middle price segment. They are more expensive than plastic, but surpass them in strength and resistance to pressure.

It should be noted that for the production of steel pipes can be used various alloys and protective additives. This also has an impact on the final cost of the product. For instance, galvanized pipes or parts of stainless steel have a higher price than the elements made of ordinary steel.

Table 4. The cost of the most popular water and gas pipes of steel:

DN, mm	price, rub. (Per 1 m)
50	80-170
15	32-70
40	80-108
32	53-95
20	40-50

Thus, the diameter of water pipes and gas transporting articles affects the cost. Details which have a cross section of 100 mm, are not used in everyday life. The cost of these tubes is quite high, since 1m details may weigh over 10 kg. The heaviest tube has a diameter of 1220 mm and a wall thickness of 16 mm. Weight meter such parts is about 475 kg.

Diameter - the necessary characteristics that are essential to laying the pipeline construction. In determining this parameter, you must clearly understand that there are several versions of it. The tables, which can be found in the relevant normative documents, most often indicates an inner diameter of steel products. If you decide to use a special formula to determine the cross-section, it is recommended to pay attention to examples containing solution.