Selection Standards and Requirements for Various Pipelines

Pipeline is a device for conveying gas, liquid or fluid with solid particles, which is connected by pipes, pipe connectors and valves. Usually, when the fluid is pressurized by blowers, compressors, pumps and boilers, it flows from the high-pressure part of the pipeline to the low-pressure part. It can also be transported by the pressure or gravity of the fluid itself. Pipeline is widely used, mainly in water supply, drainage, heating, gas supply, long-distance transportation of oil and gas, agricultural irrigation, hydraulic engineering and various industrial devices.

20190714223707 74284 - Selection Standards and Requirements for Various Pipelines

Selection Standards and Requirements for Various Pipelines

Seamless steel pipe

Article 1: Pipes (seamless steel pipes) with outer diameter φ<219mm or less are available for selection;
Article 2: Seamless steel pipe (GB8163-87), hot rolled and cold drawn ordinary carbon steel, high quality carbon steel, low alloy steel and common alloy structural seamless steel pipe, used to transport the following fluids: a steam, b compressed air, c vacuum, d brine, e weak base, f circulating water, process water, g materials without acid and alkali corrosion (production materials)
Article 3: The steel grades of seamless steel pipes are 10, 20, 09MnV, 16Mn, etc.;
Article 4: The wall thickness is selected as follows: PN ≤ 2.5MPa (common steel number 20#)

Material DN
10 15 20 25 32 40 50 65 80 100 125 150 200 250
20# 2.5 3 3 3 3 3.5 3.5 4 4 4 4 4.5 5 6
10# 2.5 3 3 3 3 3.5 3.5 4 4.5 4 5 4.5 5.5 7
16Mn 2.5 2.5 2.5 3 3 3 3 3.5 3.5 3.2 3.5 4 4.5 5

Steel pipe for petroleum cracking (GB9948-88)

Article 1: Seamless steel pipes such furnace tubes, heat exchanger tubes and pipelines used in petroleum refineries, the specifications are as follows “▲”.

OD mm    WT mm
2 2.5 3 4 5 6 8 10 12 14 16
Article 2: Steel pipe steel number: 10, 20, 12CrMo, 15CrMo, 1CrMo, 1Cr2Mo, 1Cr18Ni9, 1Cr19Ni11Nb;
Article 3: No. 10 and No. 20 tubes have good weldability and can be used as furnace tubes, and the use temperature is between -40 and 475 °C;
Article 4: 15A13MoWTi is used as high temperature heavy oil furnace tube and anti-H2S tower equipment and parts such as trays, sieve plates, etc., and the Cr5Mo furnace tubes are used at temperatures below 650 °C;
Article 1: Materials are selected according to the minimum wall thickness.
Article 2: Different steel grades are selected according to the characteristics of the medium, and 20# steel pipe is preferred.

Seamless steel tubes (GB3087-82) for medium and low pressure boilers

Article 1: This type of steel pipe is suitable for superheated steam pipes and boiling water pipes for various structural low and medium pressure boilers made of low carbon steel;
Article 2: Commonly used materials are 10 and 20 steels. The temperature of 10 and 20 steels is between -20 and 475 °C, which is widely used in wall temperature junction box and steam conduit, superheater tube with wall temperature of 500 °C, water wall tube and economizer tube in the boiler industry;
Article 3: the working temperature of 5MnV, 12MnMoV is -20 ~ 475 ° C, and these two are suitable for 20 steel boiler tube;
Article 4: the working temperature of 12MoVWBSiRe (chromium-free No. 8) is 400-580 ° C, used as a boiler superheater tube with wall temperature ≤ 580 ° C;
Article 5: 12Cr2MoWVB (102 steel) has good process performance, long-lasting plasticity of oxidation resistance, good timeliness, working temperature of 600 ~ 620 ° C, used for boiler superheater, reheater or main steam pipe with wall temperature of 600 ~ 620 °C;
Article 6: 15CrMo has good welding performance, and the use temperature is 350 ~ 560 ° C ( the low temperature can be  -40 ° C), which is widely used in the boiler industry as a water wall tube for wall temperature of high pressure boilers and a header and steam conduit of ≤550 °C.
Requirements: The type of steel pipe meets the requirements of Table 15-41 of the Second Handbook of Chemical Process Design Manual, and the weight is shown in GB8163-87. The length of the steel pipe and the water pressure test are the same as those of GB8163-87.

High-pressure seamless steel pipe for fertilizers (GB6479-86)

Article 1: This kind of steel pipe is suitable for the nominal pressure 10~32MPa, working temperature-40~400°C, and the conveying medium is synthetic ammonia feed gas (hydrogen, nitrogen) to synthesize ammonia, methanol, urea;
Article 2: The dimensional tolerance of the pipe shall be in accordance with GB8163-87. The weight of steel pipe can be found in Table 15-42 of the Chemical Engineering Design Manual.
Article 3: The applicable temperature range for each steel grade is as follows:
20, 15MnV, 12MnMoV, 10MoVNbTi ≤ 300 °C.

Stainless steel seamless pipe (GB2270-80)

Article 1: Suitable for pipelines with strong corrosive media in the chemical and petroleum industries;
Article 2: The specifications of the steel pipe are as follows:

Material PN     Mpa DN
10 15 20 25 32 40 50 65 80 100 125 150 200
321 <=1.0 2 2 2 2.5 2.5 2.5 2.5 2.5 2.5 3 3 3.5 3.5
321 1.6 2 2.5 2.5 2.5 2.5 2.5 3 3 3 3 3 3.5 3.5
321 2.5 2 2.5 2.5 2.5 2.5 2.5 3 3 3 3.5 3.5 4 4.5

Article 3:  a seamless stainless steel tube can be selected only when the outer diameter is <φ219;
Article 4: Common materials for seamless stainless steel pipes are:
0Cr13, 1Cr13, 1Cr17Ni2, 1Cr25Ti, 0Cr18Ni9Ti, 00Cr18Ni10Ti, 1Cr18Ni9, 1Cr18Ni9Ti, 00Cr17Ni14Mo2, 00Cr17Ni14Mo3, 0Cr18Ni12Mo2Ti, and the like.
Requirements: 304 (1Cr18Ni9, 0Cr18Ni9) is used for general corrosive media, 321 (0Cr18Ni9Ti, 1Cr18Ni9Ti. 304 has low intergranular corrosion resistance, 321 is heat resistant below 600 °C and has high resistance to intergranular corrosion. For highly corrosive strongly acidic solution materials, 0Cr17Ni12Mo2/(316), 00Cr17Ni14Mo2/(316L) molybdenum dititanium (0Cr18Ni12Mo2Ti), etc. are used. Molybdenum dititanium and molybdenum trititanium are heat resistant below 600 °C,without intergranular corrosion, and resistant to sulfite, boiling phosphoric acid, formic acid, acetic acid and other acids and bleaching powders and sulfite liquids. Stainless acid resistant steel, such as nickel, chromium and molybdenum, should be replaced by acid-resistant cast iron or nickel-free stainless steel and acid-resistant steel.

Materials are selected in order of priority from low to high performance.

Welded steel pipe (GB3092-93) for low-pressure fluid transportation and galvanized welded steel pipe (GB3091-93).

Article 1: It is suitable for pipelines for conveying water, compressed air, gas, steam, condensed water and heating system. Galvanized pipes are used for conveying water and the condensed water, and the non-galvanized pipes for conveying air and gas;
Article 2: Common used materials are Q215AF, Q215A, Q235AF, and Q235A.

Spiral welded steel pipe (SY5036-83, SY5037-83)

Article 1: Applicable to steam, water, air, oil and oil and gas pipelines;
Article 2: Used in DN ≥ 200 (non-corrosive medium);
Article 3: The materials are Q235AF, Q235A, SS400, SM400B, 16Mn.
Requirements: Replace seamless steel tubes and glass steel tubes in non-corrosive media, which should be widely used.

Steel coiled pipe

A. Austenitic stainless steel welded steel tubes (HG20537.2-92) for shell-and-tube heat exchangers.
Article 1: Applicable to heat transfer tubes, coils, etc. with a design pressure not greater than 4.0 MPa;
Article 2: Steel No.: 304, 304L, 321, 316, 316 L;
Requirements: Priority 321 <304 < 304L < 316 < 316 L is selected.
B. Austenitic stainless steel welded steel pipe for piping (HG20537.3-92, HG20537.4-92).
Article 1: It is applicable to chemical, pharmaceutical, biochemical, light industry, textile engineering piping and pipe fittings with pipeline pressure greater than 5.0 MPa, and can also be used for pressure vessel casing adapter tube, coil, etc.;
Article 2: The hot-rolled cold-rolled strip and steel sheet are formed by continuous process, and the welding is carried out by the process shown in Table 15-48 of the Second Handbook of Chemical Process Design Manual. HG20537.3-92 is suitable without welding wire. HG20537.4-92 is suitable for welded pipe with welding wire and with large diameter or thick wall.
Article 3: Common steel numbers 304, 321, and 304L.
The specifications of welded steel pipes are as follows:

Material PN     Mpa DN
200 250 300 350 400 450 500 600 700 800
welded carbon steel pipes (Q235, 20#) 0.25 5 5 5 5 5 5 5 6 6 6
0.6 5 5 6 6 6 6 6 7 7 7
1 5 5 6 6 6 7 7 8 8 9
1.6 6 6 7 7 8 8 9 10 12
2.5 7 8 9 9 10 11 12 13 15 16
welded stainless steel pipes 0.25 3 3 3 3 3.5 3.5 3.5 4 4
0.6 3 3 3.5 3.5 3.5 4 4.5 5 5
1 3.5 3.5 4 4.5 4.5 5 6 7 7
1.6 4 4.5 5 6 6 7 8 9 10
2.5 5 6 7 9 9 9 12 13 15

Cast iron pipe

Cast iron pipes are divided into ordinary cast iron pipes and ferrosilicon pipes.

A. Ordinary cast iron pipe

Ordinary cast iron pipes are made of high quality grey cast iron. They are often buried under the ground as water main pipe, gas main pipe and indoor drainage pipes. It can also be used to transport acid, alkali, and sexual solutions. It cannot be used to transport steam, and it cannot be used to transport explosive and toxic media. The cast iron pipe has a diameter of 50 to 1500 mm, a wall thickness of 7.5 to 30 mm, and a pipe length of 3 m, 4 m, and 6 m.
The drainage cast iron pipe has only one type of socket type, the diameter is 50-200mm, the wall thickness is 4-7mm, and the pipe length is 0.5m, 1m, 1.5m, 2, etc., but generally 2m.
B. Silicon cast iron pipe
The silicon cast iron pipe has two kinds of high silicon cast iron pipe and anti-chlorinated silicon iron pipe. The high silicon cast iron pipe can resist corrosion of various strong acids. The anti-chlorinated silicon iron pipe can resist hydrochloric acid of various concentrations and temperatures, and the ferrosilicon pipe is often used in chemical pipeline industry. High silicon cast iron pipe and anti-chlorinated silicon iron pipe are used to transport corrosive media with a nominal pressure of 0.25 MPa or less. The ferrosilicon tube has good heat resistance up to 900 °C. Ferrosilicon tubes are brittle and are prone to cracking when subjected to slight knocks, collisions, localized heat or rapid cooling. It is hard but brittle, hence difficult to maintain.

Metal hose

(1) Type P2 pressure hose

  • For conveying neutral liquids, gases, solids and mixtures;
  • Material is low carbon galvanized steel strip;
  • It is not suitable to use the straight pipe in the application occasion.
  • Specifications are shown in Table 5-56 of Volume 2 of Chemical Process Design Manual.

(2) Type P3 suction tube

  • For piping and solid conveying of ventilation and vacuum equipment;
  • Material is low carbon galvanized steel strip;
  • It is not suitable to use the straight pipe in the application occasion.
  • The specifications are listed in Table 5-57 of the following volume of Chemical Process Design Manual.

(3) PM1 type pressure tube

  • For the transportation of neutral liquids;
  • Material is low carbon galvanized steel strip;
  • It is not suitable to use the straight pipe in the application occasion.
  • Specifications are shown in Table 5-58 of Volume 2 of Chemical Process Design Manual.

(4) Stainless steel metal hose (321)

  • It is used for pumping and transporting various fluids, including vapor, hot water, acid and alkali, various oils, air, lubricants and other liquid and gas materials.
  • For non-straight pipe connections of non-usable carbon steel metal hoses.
  • For installation of asymmetric pipes.


Article 1: Replace stainless steel pipes with acid or alkali corrosive media.
Article 2: Replacing nodular cast iron pipes and cement pipes with DN1400mm or more in external pipelines is widely used in buried pipes of external pipelines, because the overall cost is lower than that of cast iron pipes and cement pipes, and replacing welded pipes with corrosive medium which can not be used for carbon steel welded pipes.
Article 3: Can not be used as a steam pipeline, generally at room temperature medium;
Article 4: Normal working temperature 80-90 C, normal diameter DN25-DN4000, maximum pressure 2.5 MPa;
Article 5: The specifications may refer to the specifications of continuous, Jiangyang and preferred manufacturers.

Carbon steel lined plastic steel pipe (cost is half of stainless steel)

Article 1: Suitable for working medium <32% hydrochloric acid,<32% sodium hydroxide; working temperature-70-80 C; working pressure <1.0 MPa and other conditions; instead of stainless steel as the workshop pipeline;
Article 2: Impregnated plastic is modified polyethylene powder, steel pipe is 20 # steel pipe;
Article 3: Used in corrosive medium of carbon steel welded pipe, carbon steel pipe and FRP pipe which can not be used.

Reinforced Polypropylene Pipe (FRPP or PPG)

Article 1: Working conditions of temperature < 120 C and pressure < 1.0 MPa;
Article 2: DN < 200mm instead of other materials (working conditions permit), instead of stainless steel tube at temperature; Article 3: Extrusion moulding with short glass fiber reinforced polypropylene as raw material has the advantages of high strength, good corrosion resistance, convenient moulding, good compactness and low price.

UPVC Pipe (Hard PVC Pipe)


Suitable for rainwater drainage pipes and domestic water pipes in industrial and civil buildings, with less industrial application, corrosion resistance and poor heat resistance.

ABS tube


Only in the pharmaceutical industry should there be more obsolete materials, chemical industry, try not to choose, civil applications in water supply, weak corrosive media.

PE pipe

Used in < 900C, generally in 700C, weak corrosive medium.
Steel-plastic Tight Lined Polypropylene Pipe

  1. The price of steel-plastic tight-lined polypropylene composite pipe is the same as that of rubber-lined pipe, only one third of stainless steel pipe, and its service life is more than two times that of rubber-lined pipe and stainless steel pipe.
  2. Medium working pressure: positive pressure 1.6 MPa, negative pressure 700 mm mercury column.
  3. Medium working temperature: -85 ~200 C
  4. Corrosion resistance: Except for strong oxidizing acids such as concentrated nitric acid, fuming sulfuric acid and chlorosulfonic acid, it can resist most organic media and inorganic acid, alkali and salt. It has good stress corrosion resistance. It can resist nitric acid, formic acid and acetic acid below 10%, hydrochloric acid below 36%, hydrofluoric acid below 20%, carbonate of various concentrations and salts at 100 ~C. Corrosion of boric acid, butyric acid, alkali and most salts, mercury, air, NH3, CO2, CO, NO2, HCL, etc.

Ceramic tube

Ceramic pipes have good chemical corrosion resistance. Except hydrofluoric acid, they are resistant to other materials (poor corrosion resistance to phosphoric acid and alkali). Ceramic pipes can be used to transport corrosive media with working pressure of 0.2 MPa and temperature below 150 C.

Glass tube

The chemical corrosion resistance of glass tube is also very good. Except hydrofluoric acid, fluorinated phosphoric acid, hot concentrated sulfuric acid and hot concentrated alkali, it is also resistant to most acids, dilute alkali solution and organic solution agent.
Nominal outer diameter 0.6 MPa approximate weight (Kg/m) 1.0 MPa

WT Approximate weight(Kg/m) WT Approximate weight (Kg/m)
17 3.0 0.13 3.0 0.13
21 3.0 0.16 3.0 0.16
27 3.0 0.22 3.5 0.32
34 3.5 0.32 4.5 0.52
48 3.5 0.47 5.5 0.89
60 3.5 0.60 6.0 1.19
75 3.9 0.88 6.2 1.35
90 4.7 1.27 7.5 1.96
110 5.7 1.59 9.1 2.91
125 6.5 2.44 10.4 3.78
140 7.2 3.06 11.6 4.73
160 8.3 4.00 13.3 6.19
180 9.3 5.04 14.9 7.81
10.3 6.20 16.6 9.66
225 11.6 7.85 18.7 12.24
250 13.6 9.70 20.7 15.06
280 14.4 12.14 23.2 18.90
315 16.2 15.36 26.1 23.93
355 18.3 19.55 29.4 30.37
400 20.6 24.8 33.2 38.64
450 23.2 31.42
500 25.7 38.68

Selection Principles of Common Pipeline Materials

In the design of pressure pipes, the material of the pipes should be selected after the diameter of the pipes has been determined by calculation. The use of common pipe materials in pressure pipes is determined by the operating conditions (such as pressure and temperature) of the medium being transported and the characteristics of the medium under these conditions.
The improper selection of materials will result in waste or bury hidden dangers of accidents. If pipes of ordinary materials can be used and pipes of more expensive materials are selected, unnecessary capital investment will be increased. The use of carbon steel in the case of acid-resistant stainless steel will directly affect the normal operation of pressure pipelines, and even leave a cause. Therefore, when choosing pipe materials, designers are required to first understand the types, specifications, performance and scope of use of the pipe, and preferably investigate the application of the pipe in other similar pressure pipes, and then determine the material of the pipe according to the following principles.
(1) Pipe material preferred
When choosing pipe material, metal material is generally considered first, and non-metal material is considered when metal material is not suitable. Steel pipes are preferred for metal materials, and non-ferrous metal materials are considered later. In steel pipes, carbon steel should be considered first, and stainless steel should be used when not applicable. When considering carbon steel materials, welded steel pipes should be considered first, and seamless steel pipes should be selected when not applicable.
(2) The influence of medium pressure
The higher the pressure of the conveying medium, the thicker the wall thickness of the pipe, and the higher the requirement for the material of the pipe.
When the medium pressure is above 1.6 MPa, seamless steel pipe or non-ferrous metal pipe can be selected. When the pressure is very high, such as in the production of synthetic ammonia, urea and methanol, some tubes have medium pressure as high as 32 MPa, and high-pressure seamless steel tubes with materials of 20 or 15CrMo are generally selected. Copper and brass pipes are usually used in vacuum equipment and oxygen pipes with pressure greater than 10 MPa.
When the medium pressure is below 1.6 MPa, welded steel pipe, cast iron pipe or non-metallic pipe can be considered. But the pressure of cast iron pipes should not be greater than 1.0 MPa. The medium pressure of non-metallic pipes is related to the variety of non-metallic materials, such as rigid polyvinyl chloride pipes, which use pressure less than or equal to 1.6 MPa; reinforced polypropylene pipes, which use pressure less than or equal to 1.0 MPa; ABS pipes, which use pressure less than or equal to 0.6 MPa.
When the water pressure is below 1.0 MPa, the welded steel pipe with Q235A is usually used; when the water pressure is above 2.5 MPa, the seamless steel pipe with 20# is usually used.
(3) The influence of medium temperature
Tubes of different materials are suitable for different temperature ranges. When the hydrogen pressure is 1.0 MPa, 20# seamless steel pipe is usually used when the temperature of hydrogen is less than 350 C. When the temperature of hydrogen is in the range of 351-400 C, 15CrMo or 12CrMo seamless steel pipe is generally used.
(4) Effect of Chemical Properties of Medium
Different media are transported and different pipes are used. Some medium is neutral, generally the material requirements are not high, can choose ordinary carbon steel pipe; some medium is acidic or alkaline, it is necessary to choose acid or alkali resistant pipe. Strong acid, strong alkali and weak acid and weak alkali have different requirements for the use of pipes. The same acid or alkali has different requirements for the material of pipes with different concentration. If water and steam are transported, carbon steel pipes can be used. For example, in urea plant, stainless steel pipes are generally used for transporting carbon dioxide, because carbon dioxide forms carbonic acid when it meets water. Carbonic acid has corrosive effect on common steel pipes. If fuming sulfuric acid can choose carbon steel pipe, dilute sulfuric acid can not use carbon steel pipe, because dilute sulfuric acid and carbon steel can react chemically and corrode carbon steel, hard aluminium pipe can be used.
(5) The effect of the tube itself on the function
Some pipes need not only the function of conveying medium, but also the function of shock absorption, coefficient thermal expansion and contraction. Under working conditions, they can often move, such as liquefied petroleum gas, oxygen and acetylene gas in the filling part. The pipes are usually made of high-pressure steel wire braided rubber tubes, but can not be moved inconveniently. Hard steel pipe.
(6) The effect of pressure drop
After the initial selection of pipe material, the calculation of pipe pressure drop and the determination of pipe inner diameter are also needed. By calculating the pressure drop, we can see whether the selected material meets the requirements. Especially in the initial selection of plastic pipes, more attention should be paid to the check of pressure drop.
In the calculation of pressure pipeline, in engineering design, material balance, energy balance and equipment calculation are generally carried out according to the production scale, and material flow rate is preliminarily determined. Referring to the relevant data, assuming a material flow rate, the inner diameter of the pipe can be calculated, the manual or standard can be consulted, and the standard pipe should be selected. The inner diameter of the standard pipe should be equal to or slightly larger than the calculated inner diameter of the pipe. Then calculate the pressure drop of the pipeline.

Source: China Pressure Pipeline Manufacturer – Yaang Pipe Industry Co., Limited (

(Yaang Pipe Industry is a leading manufacturer and supplier of nickel alloy and stainless steel products, including Super Duplex Stainless Steel Flanges, Stainless Steel Flanges, Stainless Steel Pipe Fittings, Stainless Steel Pipe. Yaang products are widely used in Shipbuilding, Nuclear power, Marine engineering, Petroleum, Chemical, Mining, Sewage treatment, Natural gas and Pressure vessels and other industries.)

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selection standards and requirements for various pipelines - Selection Standards and Requirements for Various Pipelines
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Selection Standards and Requirements for Various Pipelines
​In the design of pressure pipes, the material of the pipes should be selected after the diameter of the pipes has been determined by calculation.
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