flanged joint

Everything You Need to Know about Flanges for Pipes and Piping Systems

flanged joint

Everything You Need to Know about Flanges for Pipes and Piping Systems

In piping applications, a flange is used to join a pipe with other equipment (another pipe, a valve, or a pump). Pipe flanges may be classified by shape (weld neck, blind, socket weld, threaded, etc), by facing type (RF, FF, RTJ), by material grade (cast and forged), and by specification (the ANSI/ASME B16.5 and B16.47 specifications cover US standard flanges for piping, the EN 1092-1 specification covers European pipe flanges).



A flange is a mechanical device to connect pipes, valves, pumps, and other equipment to form a piping system. It consists of a plate or ring that provides a mounting surface for attaching two sections of pipe or connecting a pipe to a valve, pump, or other device. Flanges are designed to be bolted together with a gasket between them to provide a tight, leak-proof seal.

steel flanges e1546116335565
Steel Flanges

Flanges are widely used in various industries, including oil and gas, chemical processing, power generation, and water treatment, due to their ease of assembly and disassembly, which facilitates inspection, cleaning, and modifications to the piping system.

Flanges can be produced by casting or forging steel. In the oil and gas industry, forged steel flanges are preferred due to their intrinsic strength and durability.


When selecting (and ordering to suppliers) flanges for piping systems, several key measures and specifications must be considered to ensure compatibility with the system, proper fit, and reliable operation under the intended service conditions. These measures include diameter, pressure class, flange facing type, and material grade.

Here’s a breakdown of these critical flange specifications:

1. Flange Type and Specification

The first parameter to consider when ordering a flange is the shape/design: welding neck, slip-on, threaded, lap joint flange. The 13 types of standard/non-standard flanges are thoroughly described in this article.

Together with the type, the buyer shall indicate also the applicable specification, i.e. ASME B16.5, ASME B16.47, type A, EN 1092-1, JIS, UNI, DIN, etc.

2. Nominal Pipe Size (NPS) and Diameter

  • Nominal Pipe Size (NPS): Refers to the standardized size designation for pipes and the corresponding flanges. It’s not the actual dimension of the pipe or flange but a nominal specification that indicates compatibility.
  • Outside Diameter (OD): The external diameter of the flange, which is larger than the OD of the pipe to accommodate bolting around the perimeter.
  • Bore Diameter: The inner diameter of the flange that matches the inner diameter of the pipe, ensuring a smooth flow of the medium.

Note: for welding neck and socket-weld flanges, the pipe schedule shall also be communicated to the manufacturer/supplier. This is a piece of information that is typically missing in requests for proposals, tenders, or purchase orders but it’s necessary.

Refer to this article for more information about NPS.

3. Pressure Class (i.e. Flange Rating)

  • Flanges are classified according to their maximum allowable pressure at a specific temperature. The pressure-temperature ratings are defined by ASME B16.5 for sizes up to 24 inches. Common classes include:
    • Class 150
    • Class 300
    • Class 600
    • Class 900
    • Class 1500
    • Class 2500
  • The class designation determines the thickness of the flange and the size and number of bolting holes required to withstand the pressure.

4. Flange Facing Type & Flange Surface Finish

The flange face is the surface area that contacts the gasket. The type of flange facing affects the seal quality and is selected based on the fluid, pressure, and operational conditions. Common types include:

  • Flat Face (FF): A flat surface that mates with another flat-faced flange, typically used for low-pressure applications.
  • Raised Face (RF): Features a raised surface around the bore, which concentrates the gasket compression, making it suitable for a wide range of pressures.
  • Ring Type Joint (RTJ): Designed for high-pressure/temperature applications, it uses a metal ring as a gasket seated in a grooved face.

According to the ASME B16.5 specification, the raised face is the standard facing for flanges (different facings, like RTJ or flat face FF, have to be ordered specifically).

The flange surface finish can be smooth, stock, concentric serrated, etc.

5. Material Grade

The material of the flange must be compatible with the piping system and the medium it will carry. Material choice impacts the flange’s strength, corrosion resistance, and suitability for specific temperatures and pressures. Common materials include:

  • Carbon Steel: Widely used for its strength and versatility. (ASTM A105 is a common specification)
  • Stainless Steel: Offers corrosion resistance for aggressive media. (e.g., ASTM A182 F304/304L, F316/316L)
  • Alloy Steel: Used for special applications requiring high strength or resistance to heat and corrosion. (e.g., ASTM A182 F11, F22)

6. Cathodic Protection

Cathodic protection is a method used to prevent corrosion in metal structures by making them the cathode of an electrochemical cell. In the context of piping systems, flanges are critical points where corrosion can lead to leaks or failure, potentially causing safety hazards and operational issues. To mitigate this risk, especially in environments prone to causing corrosion, flange isolation kits are employed as part of a cathodic protection strategy. Learn more about the use of flange isolation kits to prevent corrosion and provide cathodic protection.

7. Other Technical Considerations

  • Hub Design: Some flanges, like weld neck and slip-on, have different designs regarding their connection to the pipe (e.g., a long tapered hub for weld neck flanges).
  • Gasket Surface: The surface finish of the flange face affects the seal quality and compatibility with different gasket materials.

Selecting the right flange involves a detailed understanding of these key measures and how they interact with the system’s design requirements, ensuring a secure, leak-proof connection that can withstand operational demands.


A flanged joint is a type of connection used in piping systems, equipment, and structural components that involves the use of flanges to mechanically join two sections. This joint is formed by bolting together a pair of flanges with a gasket between them to ensure a tight, leak-proof seal. Flanged joints are widely utilized across various industries—such as oil and gas, chemical processing, water treatment, and power generation—due to their reliability, ease of assembly and disassembly, and the ability to connect different types of components, such as pipes to valves, pumps, and tanks.

Flanged joints are used to connect pipes with other piping equipment (for example, another length of pipe, a valve, or a pressure vessel). Hundreds, even thousands, of flanged joints are necessary for a piping system to function.

A flanged joint comprises:

  • Flanges: Flat, circular disks with bolt holes around the perimeter. The mating flanges (the “main” and the “companion” flange) are welded, screwed, or otherwise attached to the ends of pipes, valves, pumps, or other components. Flanges come in various types (weld neck, slip-on, blind, threaded, lap joint, and socket weld) to suit different applications and service conditions.

  • Gasket: A sealing element placed between the flanges to prevent leaks. Gaskets are made from various materials, including rubber, graphite, PTFE, and metal, chosen based on the fluid properties, pressure, and temperature of the system.

  • Bolts and Nuts: Used to bolt the flanges together, compressing the gasket to create a tight seal. The number, size, and material of the bolts and nuts depend on the flange specifications and the operating conditions.

Flanged joints are effective and economical ways to connect piping components, and feature the following characteristics:

  • Leak-Proof Seal: When properly assembled, flanged joints provide a reliable seal that prevents the escape of liquids or gases, ensuring the safety and efficiency of the piping system.

  • Ease of Assembly and Disassembly: Flanged joints can be easily bolted together or taken apart, facilitating quick installation, maintenance, repair, or modification of the piping system without the need for cutting or welding.

  • Flexibility: Flanged joints accommodate slight misalignments and are suitable for both permanent and temporary connections, offering flexibility in system design and layout.

  • Pressure and Temperature Tolerance: Designed to withstand the specific pressure and temperature conditions of the application, flanged joints are suitable for a wide range of operating environments.

Welded or Threaded Connections

A steel pipe can be welded on the flange (typical for weld neck, socket weld, slip-on, and lap joint flanges) or screwed into it (this is the case of threaded flange). Welded connections between pipes and flanges are used for high pressure and temperature applications, and diameters above 2 inches. Threaded connections are used for small-diameter piping systems that are not subject to mechanical forces such as expansion, vibration, contraction, or oscillation.

Insulation Kits

Flange insulation kits can also be used for flanged connections/joints, to protect the corrosion on flanges, bolts, and gaskets generated by the static currents running through the pipeline (this is called “cathodic protection”).

To prevent dangerous leakages in the pipeline, flanged joints shall be executed by trained personnel only (the standard TSE – TS EN 1591 Part 1-4, “Flanges and their joints” is the reference norm).

The image shows the elements of a flanged joint:

flanged joint connection


Pipe flanges are available in multiple standard types, such as welding neck, blind, socket weld, lap joint, and threaded. However, there are also some special types of flanges, like the swivel flanges, the expander/reducer flanges, the “Nipoflange” / “Weldoflange”, and the orifice flanges.

As a general rule, welding neck, slip-on, and socket weld flanges are used for high-pressure applications that require long-lasting flanged joints. Threaded flanges are used for a lower-pressure piping system, and when vibrations are not present.

Lap joint flanges are used in connection with stub ends either to facilitate the alignment of the bolts of the two mating flanges or to reduce the cost of noble materials in high-grade flanged joints (for example, in an Inconel piping system, the stub end connected to the pipe may be in Inconel, whereas the lap joint flange can be of a lower grade, thus saving the overall weight of the expensive Inconel material).


ASME (American Society of Mechanical Engineers) and API (American Petroleum Institute) set the standards for flanges used in various industries, including oil and gas, chemical, power generation, and water treatment. These standards ensure flanges are manufactured and used according to strict safety, reliability, and compatibility guidelines. Here’s an overview of key ASME and API standards related to flanges:

ASME Standards for Flanges

The ASME B16.5 specification covers flanges for piping applications up to 24 inches in diameter, whereas the ASME B16.47 specification covers pipe flanges above 24 inches (series A and B are available).

  • ASME B16.5: This standard covers pipe flanges and flanged fittings through NPS 24, including pressure-temperature ratings, materials, dimensions, tolerances, marking, and testing for flanges in classes 150, 300, 400, 600, 900, 1500, and 2500.

  • ASME B16.47: Series A & B (also known as API 605 and MSS SP-44 respectively) provide specifications for large diameter steel flanges for NPS 26 through NPS 60 for Series A, and NPS 26 through NPS 48 for Series B. It covers pressure-temperature ratings, materials, dimensions, tolerances, and markings for flanges in classes 75, 150, 300, 400, 600, and 900.

  • ASME B16.36: This standard covers Orifice Flanges in classes 300, 400, 600, 900, 1500, and 2500 across various NPS. It details dimensions, material specifications, and marking requirements.

  • ASME B16.48: Known as the “Line Blanks” standard, it specifies requirements for spectacle blinds, spades, and spacers with pressure ratings of 150, 300, 600, 900, 1500, and 2500.

Note also the following:

  • ASME B16.1: This standard applies to integral cast iron flanges and blind flanges

  • ASME B16.47-Series B replaces API 605 in sizes NPS 26 to 60 (ASME B16.47 Series B is used for pipelines and is restricted to flanges used for joints)

  • MSS SP-44 shall be used for steel pipeline flanges for sizes smaller than ASME B16.47 where the material grade is not listed in ASME B16.5

  • Flanges of unlisted materials and flanges not covered by the above standards shall be designed following ASME Section VIII Div 1, Appendix 2, and for blind flanges, under ASME Section VIII Div 1, Section UG-34

API Standards for Flanges

  • API 6A: This specification is for wellhead and Christmas tree equipment, which includes flanges used in high-pressure and high-temperature environments typically found in the oil and gas industry. It covers flanges in material classes AA, BB, CC, DD, EE, FF, and HH, incorporating designations for temperature, material type, and service susceptibility.

  • API 6D: Although focused on pipeline valves, this standard includes end flanges of valves used in pipelines for petroleum and natural gas industries. It provides specifications for dimensions, materials, and testing of such flanges.

  • API 6B & 6BX: These are specific flange standards under API 6A for different types of flange faces, with 6B covering ring-type joint (RTJ) flanges and 6BX covering flanges for extreme high pressure, both used extensively in the oil and gas sector.

European Standards for Flanges

The EN 1092-1 specification covers flanges for installation in European piping systems (weld neck flange type 11, plate flange type 01, blind flange type 05, threaded flange type 13).

Material Specifications

Both ASME and API refer to ASTM (American Society for Testing and Materials) material specifications for the construction of flanges, such as:

  • ASTM A105: For carbon steel flanges.
  • ASTM A182: For alloy and stainless steel flanges.
  • ASTM A350: For low-temperature carbon and alloy steel flanges.


ASTM (American Society for Testing and Materials) and API (American Petroleum Institute) standards include specific tolerances for the manufacturing and testing of flanges to ensure they meet the required dimensions, material properties, and performance criteria for their intended applications. While ASTM provides the material specifications and some manufacturing requirements, API standards often focus on specific applications, particularly in the oil and gas industry. ASME (American Society of Mechanical Engineers), not ASTM, primarily sets the dimensional tolerances for flanges. Here is an overview focusing on ASME and API standards regarding flanges:

ASME Dimensional Tolerances for Flanges (ASME B16.5 and ASME B16.47)
  • Diameter: The outer diameter of flanges and the diameter of bolt circles have specified tolerances to ensure proper alignment and sealing. For example, the tolerance for the outside diameter of a NPS 24 (DN 600) flange in ASME B16.5 is ±1.6 mm (±1/16 inch).

  • Thickness: The thickness of the flange must meet minimum requirements to withstand the design pressure, with tolerances ensuring the flange is not weaker than specified.

  • Bore Diameter: The tolerance for the bore diameter ensures the flange does not restrict flow or reduce the strength of the piping system.

  • Flatness and Surface Finish: The surface finish of the flange facing affects the quality of the seal. ASME specifies the surface finish tolerances for different types of facings, such as Raised Face (RF) and Ring-Type Joint (RTJ).

  • Bolt Hole Alignment: The alignment and spacing of bolt holes are critical for the proper fitting of bolts and gaskets. ASME standards specify tolerances for bolt-hole diameter and spacing to ensure compatibility with bolt and gasket dimensions.

API Tolerances for Flanges (API 6A and API 6B/6BX)
  • API 6A: Specifies requirements for wellhead and Christmas tree equipment, including tolerances for flange dimensions, materials, and performance at high pressure and high temperature. This includes tolerances for PSL (Product Specification Level) requirements, material classes, and temperature ratings.

  • Ring Grooves and Gasket Surfaces: API standards include tolerances for the dimensions of ring grooves in RTJ flanges (API 6B) and the surface finish of gasket interfaces to ensure a proper seal under high-pressure conditions.

  • API 6B/6BX: Specifies tolerances for the dimensions and surface finish of flanges with ring-type joints, including the groove depth, groove width, and pitch diameter. These tolerances are crucial for ensuring the integrity of the seal in high-pressure applications.

Material Tolerances
  • ASTM Specifications: Provide material tolerances for the chemical composition and mechanical properties of flange materials, such as ASTM A105 for carbon steel and ASTM A182 for alloy and stainless steel. These tolerances ensure the material’s suitability for the designated pressure and temperature service.

When specifying flanges for a project, it’s crucial to refer to the latest editions of these standards to ensure compliance with the required tolerances and specifications. Proper adherence to these tolerances is essential for the safety, reliability, and performance of flanged connections in piping systems.


General Overview

The key material grades for pipe flanges, examined more in detail in a separate article, are:

  • ASTM A105 (carbon steel flanges for high-temperature service)
  • ASTM A350 (CS flange for low temperature)
  • ASTM A694 (high-yield carbon steel flange for line pipes)
  • ASTM A182 F1 to F91 (alloy steel flange)
  • ASTM A182 F304, F316, F321 (stainless steel flange)
  • ASTM A182 F51, ASTM A182 F53/55 (duplex and super duplex flange), and higher grades (Inconel, Hastelloy, Monel flange).

The pipe and the flange material shall, of course, match (according to the ASTM piping materials selection chart).

Flange Materials, General Requirements:

  • Flanges and flanged fittings shall be castings, forgings, or plates
  • Bolting materials shall conform to ASME B16.5, Table 1B.
  • The material for flanges in the pipeline service shall be suitable for welding. The carbon equivalents of the used flanges shall match the pipe material

Material Types and Application

Cast Iron and Ductile Iron Flanges

  • Gray cast iron flanges shall not be used for process piping within the battery limits of any plant. The only exception shall be for fire systems applications. The material shall be ASTM A 126, Class B.
  • Ductile iron flanges may be used, in proprietary systems, for example, plastic-lined steel piping, as backup for lapped joint flanges
  • ASME B16.1 Class 125 and Class 250 cast iron flanges may be mated with ASME B 16.5 Class 150 and 300 steel flanges respectively. However, care shall be exercised to ensure that a flat-faced cast iron flange shall mate only with a flat-faced steel flange, and vice versa.

Carbon Steel Flanges

  • Carbon steel flanges shall not be used in services above 425 °C
  • High-temperature service: Standard carbon steel material shall be ASTM A 105, a material that can be safely used for temperatures between minus 29 °C and 425 °C.
  • Low-temperature Service: Carbon steel flanges used for services below minus 29 °C, shall conform to the impact-testing requirements of ASME B 31.3. ASTM A 350-LF2 shall be the standard material for low-temperature applications
  • High-Yield Service: High-strength carbon steel flanges ASTM A694 should fit API Std. 5L pipe Grade X42 to X65.

Low-Alloy Flanges

Material for low-alloy steel flanges (11/4 Cr – 1/2 Mo) shall be ASTM A 182-F11. Material for intermediate alloy steel flanges (11/2 Cr – 5 Mo) shall be ASTM A 182-F5.

Stainless Steel and Non-ferrous Flanges

  • Usually, weld neck flanges shall match the metallurgy of the pipe in any material class. Austenitic stainless steels, however, may in certain cases be interchangeable. For example, type 347 and 321 stainless steels are compatible. Flanges that are double stamped, or double graded, and are so marked. For example, low carbon grades such as 304L, and 316L may be substituted, for the ‘straight’ grade, provided that the ‘L’ grade meets the physical requirements of the application.
  • When pipe material is forged, weld neck flanges shall be forged. When pipe material is not forged, material for weld neck flanges shall be subject to client approval.
  • Non-ferrous pipe flanges (copper, cupronickel, and aluminum) are used in marine and aeronautical applications.

Pipeline Service Flanges

Flanges for pipeline service shall match SMYS, and carbon equivalency specified in ASME B31.4 and B31.8.

NACE Service Flanges

When an in-plant service has water and H2S concentrations above the limits specified in NACE MR0175, that service shall be considered as NACE service. Flanges for use in NACE service shall be by NACE MR0175 special requirements. The purchase description shall specify ‘NACE service’.

Coated, Painted, and Lined Flanges

For specific applications, flanges may be coated, painted, or internally lined (with Teflon, for example) to enhance the resistance of the metal to the aggression of corrosive or erosive fluids.


Flange marking standards are critical for identifying the materials, pressure ratings, sizes, and relevant manufacturing standards of flanges used in piping systems. These markings ensure that users can accurately identify and select the appropriate flanges for specific applications, maintaining system integrity and safety. The marking standards are generally outlined by organizations such as the American Society of Mechanical Engineers (ASME), the American National Standards Institute (ANSI), and the American Petroleum Institute (API), among others. Here’s an overview of common aspects included in flange marking standards:

1. Manufacturer’s Name or Trademark

Identifies the manufacturer of the flange, ensuring traceability and accountability.

2. Material Specifications

Indicates the material grade from which the flange is made. For example, ASTM A105 signifies a carbon steel flange, while A182 F304 indicates a stainless steel flange of grade 304.

3. Pressure Rating

Specifies the pressure class of the flange, such as Class 150, 300, 600, 900, 1500, or 2500, indicating the maximum pressure the flange is designed to handle at a specific temperature range.

4. Size

The nominal pipe size (NPS) or diameter nominal (DN) for which the flange is designed.

5. Bore Size

The bore size, if different from the nominal size, may also be included to specify the actual internal diameter of the flange.

6. Heat Code or Identification Number

A unique code that correlates to the material heat lot, enabling traceability back to the material batch and its test records.

7. Standard or Specification

The manufacturing standard to which the flange conforms, such as ASME B16.5, ASME B16.47, or API specifications.

8. Facing Type

If applicable, the type of flange facing (RF for Raised Face, FF for Flat Face, RTJ for Ring-Type Joint) might be marked to indicate the sealing surface design.

9. Special Markings

Additional markings for special applications or requirements, such as “NACE” for flanges meeting NACE MR0175/ISO 15156 for sour service applications.

Compliance and Quality Assurance

  • Compliance with the marking standards is part of the quality assurance and control processes in flange manufacturing. It assists in ensuring that the flange meets the required specifications for its intended use.

  • Proper marking helps in preventing the mismatch of components, which could lead to system failure, safety hazards, or operational inefficiencies.

Understanding these markings is essential for engineers, technicians, and procurement specialists involved in the design, maintenance, and operation of piping systems, ensuring that the selected flanges are appropriate for the service conditions and regulatory requirements of their specific applications.


Relevance of Porper Bolting

Flanges for piping should be mated using adequate stud bolts and nuts. It is absolutely critical to use the right number, diameter, length, and material to bolt flanges properly and ensure leak-free connections. Further, stud bolts shall be tightened with a proper sequence and by applying proper torque.

A flange bolting chart is a comprehensive reference that outlines the specific requirements for the number, size, and type of bolts and nuts needed to securely fasten flanges in a piping system. This chart is crucial for ensuring that all flange connections are properly sealed and can withstand operational pressures and temperatures without leaking. The bolting chart typically aligns with standards set by organizations such as the American Society of Mechanical Engineers (ASME), ensuring compatibility and safety across a wide range of industrial applications.

Key Information in a Flange Bolting Chart

Flange Size and Class:

Specifies the nominal pipe size (NPS) and pressure class of the flange. The pressure class (e.g., Class 150, 300, 600, etc.) indicates the maximum pressure the flange can handle at a specific temperature.

Bolt and Nut Specifications:

  • Bolt Size: Diameter and length of the bolts required. This is crucial for ensuring the bolts are long enough to engage the threads properly but not so long as to interfere with adjacent components.
  • Bolt Quantity: The number of bolts needed for a complete flange connection. This depends on the flange size and class.
  • Bolt Material: Material specification for the bolts, which must be compatible with the flange material and suitable for the operating environment to prevent corrosion or failure.
  • Nut Specifications: Corresponding nuts that match the bolt size and material.

Torque Values:

Recommended torque values for tightening the bolts. Proper torque is essential to ensure a leak-proof seal without over-stressing the flange or bolts.

Gasket Type:

While primarily focused on bolting, the chart may also reference compatible gasket types for the flange size and class, as the gasket plays a critical role in sealing the flange connection.

Bolt Pattern:

The arrangement of the bolts around the flange circumference. While not always detailed in the bolting chart, understanding the bolt pattern is necessary for the even distribution of force when securing the flange.

Why It’s Important:

  • Safety and Reliability: Ensures that all flange connections are capable of withstanding the system’s pressure and operational demands without leakage, which is crucial for maintaining safety and reliability.
  • Standardization: Provides a standardized reference for engineers and technicians, facilitating the correct selection and installation of flange bolts and nuts across various projects.
  • Efficiency: Helps in the quick identification of bolting requirements, reducing errors and inefficiencies in procurement and installation processes.

In practice, a flange bolting chart is an indispensable tool for anyone involved in the design, installation, maintenance, or inspection of piped systems. It aids in ensuring that flange connections are made securely and are capable of maintaining the integrity of the system under operational conditions.

The Flange Bolting Chart

Nominal Pipe Size (NPS)Class 150Class 300Class 400Class 600
# of BoltsBolt DiameterBolt Length# of BoltsBolt DiameterBolt Length# of BoltsBolt DiameterBolt Length# of BoltsBolt DiameterBolt Length
1/241/22 1/441/22 1/241/2341/23
3/441/22 1/245/8345/83 1/245/83 1/2
141/22 1/245/8345/83 1/245/83 1/2
1 1/441/22 3/445/83 1/445/83 3/445/83 3/4
1 1/241/22 3/443/43 1/243/44 1/443/44 1/4
245/83 1/485/83 1/285/84 1/485/84 1/4
2 1/245/83 1/283/4483/44 3/483/44 3/4
345/83 1/283/44 1/483/4583/45
3 1/285/83 1/283/44 1/487/85 1/287/85 1/2
485/83 1/283/44 1/287/85 1/287/85 3/4
583/43 3/483/44 3/487/85 3/4816 1/2
683/44123/44 3/4127/861216 3/4
883/44 1/4127/85 1/21216 3/4121 1/87 1/2
10127/84 1/21616 1/4161 1/87 1/2161 1/48 1/2
12127/84 3/4161 1/86 3/4161 1/48201 1/48 3/4
141215 1/4201 1/87201 1/48 1/4201 3/89 1/4
161615 1/4201 1/47 1/2201 3/88 3/4201 1/210
18161 1/85 3/4241 1/47 3/4241 3/89201 5/810 3/4
20201 1/86 1/4241 1/48241 1/29 1/2241 5/811 1/4
22201 1/46 1/2241 1/28 3/4241 5/810241 5/812
24201 1/46 3/4241 1/29241 3/410 1/2241 7/813
Nominal Pipe Size (NPS)Class 900Class 1500Class 2500
# of BoltsBolt DiameterBolt Length# of BoltsBolt DiameterBolt Length# of BoltsBolt DiameterBolt Length
1/243/44 1/443/44 1/443/44 3/4
3/443/44 1/243/44 1/243/45
147/8547/8547/85 1/2
1 1/447/8547/85416
1 1/2415 1/2415 1/241 1/86 3/4
287/85 3/487/85 3/4817
2 1/2816 1/4816 1/481 1/87 3/4
387/85 3/481 1/8781 1/48 3/4
3 1/2
481 1/86 3/481 1/47 3/481 1/210
581 1/47 1/281 1/29 3/481 3/411 3/4
6121 1/87 1/2121 3/810 1/48213 1/2
8121 3/88 3/4121 5/811 1/212215
10161 3/89 1/4121 7/813 1/4122 1/219 1/4
12201 3/81016214 3/4122 3/421 1/4
14201 1/210 3/4162 1/416
16201 5/811 1/4162 1/217 1/2
18201 7/812 3/4162 3/419 1/4
2020213 3/416321 1/4
24202 1/217 1/4163 1/224 1/4





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2 1/ 265177.822.
3 1/ 290215.923.




1/ 21595.314.
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2 1/ 265190.528.
3 1/ 290228.635.18.810.711




1/ 215120.722.
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2 1/ 265244.341.113.91514

CLASS 1500



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2 1/ 265244.341.113.91514
380266.747.8 19.919.1
4100311.253.8 29.929.9
5125374.773.2 55.458.4
6150393.782.6 68.471.8
8200482.691.9 117122
10250584.2108 194.0210.0
12300673.1124 288.0316.0
14350749.3133.4 380.0420
16400825.5146.1 485.0558.0
18450914.4162.1 644.0760.0
20500984.3177.8 775.0965.0
246001168.4203.2 1232.01558.0

CLASS 2500



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3/ 420139.731.83.73.5
1 1/ 432184.
1 1/ 240203.244.510.910.4
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About the Author

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Projectmaterials Team

Blog.projectmaterials.com is an online resource dedicated to providing in-depth information, analysis, and educational content related to the fields of project materials management, engineering, and procurement, particularly within the oil & gas, construction, shipbuilding, energy, and renewable energy sectors. It aims to serve professionals and enthusiasts in these industries by offering valuable insights into materials, equipment, and techniques used in various projects, focusing on the selection, application, and maintenance of these resources. Key features of the blog include: * Educational Articles: Comprehensive posts that cover topics ranging from the technical aspects of piping products (pipes, valves, fittings, flanges, gaskets, bolts, instrumentation) to structural steel and process equipment (including oil extraction systems, drilling rigs, wellheads, pumps, compressors, and separation systems). * Industry Insights: Updates on the latest trends, technologies, and regulatory changes affecting the industries covered. * Guides and How-Tos: Practical advice on selecting the right materials and equipment for specific applications, as well as tips on installation, maintenance, and troubleshooting. * Safety and Standards: Information on safety equipment for production sites, risk mitigation procedures, and an overview of relevant industry standards and regulatory frameworks. The website is designed to support the professional development of engineers, procurement specialists, project managers, and other stakeholders involved in project plant businesses, by disseminating critical know-how and best practices. Whether readers are new to the field or seasoned professionals, blog.projectmaterials.com offers resources to enhance their understanding and performance in managing project materials effectively.

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25 Responses

  1. Dear Friend

    We professional manufacturing
    Steel pipe; Butt weld fittings: Elbow; Tee; Reducer; Cap
    Forged fittings: Flange; Sockolet; Weldolet and so on

    C.S: A234 WPB WPC
    A.S: A234 WP 1-12-11-22-5-91-911
    S.S: A403 WP304L/A403 WP316L/A403 WP317L
    Low-Temperature Steel:A420 WPL6
    High-Strength Steel: A860 WPHY 42/52/60

    Should you have any interests of these items, please let us know, we will be happy to give you details. Pls contact us if you have any inquires. Welcome to your inquire, thanks in advance.
    Best regards!

    Export department

  2. Nice info, Goyal Steel Tubes, the oldest dealer of MS Pipes and Tubes in Delhi-NCR, deals in all sizes and variety of MS Pipes, stocked from reputed companies like APL Apollo, Jindal, Surya etc.
    Send your pipe related queries on 9650705448, call on 9910495448 or find us on google- Goyal Steel Tubes click on the first link.

  3. It’s a very informative post; you should also checkout our product Intermediates and Speciality Chemicals, Hair Dye, food color, acrylic dye suppliers, or visit our website Yellow Dyes to know more about us.

  4. Beautiful blog, very well written. Do also check out our products on aluminium bronze fasteners, Top screw manufacturer in india, Monel Fasteners Manufacturer and many more on our page Ananka Group.

  5. Hi There,
    Thanks for taking the time to discuss this I felt strongly about it and love clearing more on this topic.
    well done. keep it up.

  6. Does anyone have any information the market size for ASME B16.47 flanges (NPS 26 to NPS 60). I know they are used in industries like Oil & Gas, Water Treatment, etc… but was just curious if the market was large and if anyone knew about how many of these were sold each year.

    1. Dear Sir, it is shown on our blog (please use the full text search and type what you are looking for, will get the answer!)

  7. It’s good to know that flanges can help me join two of my boat’s pipes together. I think I’ll buy a watertight stainless square flange from a good supplier and see if they have other special types of flanges that I can buy. Since I need a flange for high-pressure applications, I’ll have to make sure that they’re compatible with the pipes that I want to bind.

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