What are pipefittings?

What are pipefittings?

Pipefittings are general terms for components in the piping system that function as connection, control, direction change, split, seal, and support.

According to the different processing methods, it is divided into four categories, namely, butt welding pipe fittings (both welded and non-welded), socket welding pipe fittings and threaded pipe fittings and flanged pipe fittings.

20180809120907 68777 - Introduction and analysis of stainless steel pipe fittings

Chinese name 管件
Uses Coupling, changing direction, diversion, sealing, support, etc.
Application Petroleum industry; construction industry; chemical industry, etc.
This is a long article, and I organize it into 6 chapters. You can click the text below, to navigate to each chapters. If you like this article, please share it with your friends.
1 Pipe fittings introduction 3 Related applications 5 Pipe fitting specifications
2 Common classification 4 Relevant standards 6 Pipe Fitting Selection Guide

Pipe fittings introduction

Pipe fittings are a general term for various pipe joints. They can be divided into different categories according to shape, purpose and connection method. It has the characteristics of easy installation, high performance and durability, and has a wide range of applications in various pipeline construction and installation.

Common classification

There are many kinds of pipe fittings, which are classified according to their usage, connection, materials and processing methods.

Classification according to the use of pipe fittings

  1. Pipes for interconnecting pipes are flanges, live joints, pipe hoops, clamp hoops, card sleeves, throat hoops, etc.
  2. Pipe fittings that change the direction of pipe: elbow and elbow.
  3. Pipe fittings for changing pipe diameters: variable diameter (reducer), reducer elbow, branch table and reinforcement pipe.
  4. Increase pipe branching fittings: three links, four links.
  5. Pipe fittings for pipeline sealing: gasket, raw material strip, linen, flange blind plate, pipe plug, blind plate, sealing head, welding plug
  6. Pipe fittings for fixing pipes: clasps, towing hooks, rings, brackets, brackets, pipe cards, etc.

Classification by pipe fittings connection

  1. Welded pipe fittings
  2. Threaded fittings
  3. Card sleeve fittings.
  4. Clamp pipe fittings
  5. Socket pipe fittings
  6. Bonding fittings
  7. Hot-melt pipe fittings
  8. Curved and double melting pipes
  9. Rubber ring connecting fittings

Classification according to material of pipe fittings

  1. Cast steel fittings
  2. Cast iron pipe fittings
  3. Stainless steel pipe fittings
  4. Plastic pipe fittings
  5. PVC fittings
  6. Rubber fittings
  7. Graphite pipe fittings
  8. Forged steel fittings
  9. PPR fittings
  10. Alloy pipe fittings
  11. PE fittings
  12. ABS fittings

Related applications

There is no end to applications of pipe fittings so long there is no end to the applications of pipes . While the list of piping applications continues to expand, its strength, flexibility, very good flow rates and high chemical resistance are qualities which are uniquely suited for the movement or transfer of liquids, steam, solids and air from one point to another. With piping, pipe fittings have many other uses like as follows:

  • The transfer of extremely hazardous materials such as chemical and waste.
  • Protection of sensitive equipment from high pressures.
  • Protection from corrosion and other extreme weather conditions.
  • Resistance to household and industrial chemicals.

Considering the various purposes of pipe fittings, these pipe fittings are used in various industries like:

  • Chemical / Petrochemical
  • Municipal
  • Food, Beverage, and Dairy
  • Oil and Gas
  • Power
  • Process Instrumentation
  • Pulp and Paper
  • Semiconductor
  • Marine & dredging
  • Sanitation
  • Irrigation
  • Residential
  • Road & highway construction
  • Ventilation etc.

In all the above-mentioned industries pipes are used to transfer liquid, gas, slurries, and other solids and fluids from one area to another and accordingly different categories of pipe fittings are used . Thus, pipe fittings play a vital role for proper functioning of pipe and tubes in various applications.

Pipe Elbow

Pipe elbow fittings is a very important pipe fitting. When we talk about a pipe elbow, it means a length of pipe with a sharp bend in it. Pipe elbows are fitting accessories which are used widely in various industrial sectors in pipe fitting. A pipe elbow is frequently used in pressurized applications and are available in various shapes and sizes for use in different applications. A pipe elbow is a fitting installed between two lengths of pipe or tube allowing a change of direction, usually in the 90° or 45° direction.
Pipe elbows are usually constructed at a bend of 45 degree or 90 degree. There are some manufacturers who can also manufacture pipe elbows with a selectable angle. Whether you need a 1/4, 1/8, 1/16 bend or any bend in between, there are all the options available in elbows. This becomes an easy-to-use two-piece elbow that can be cut and assembled to virtually any angle. This ability of a custom made elbow is very unique and provides installers with unmatched flexibility and convenience while at the same time greatly simplifying the fitting of custom joints. Such elbows come complete with a two-piece selectable angle elbow, angle measuring templates and installation instructions.

90° Elbow

The 90° pipe elbows is used to connect tubes at a 90° angle. As the name suggests, the elbow is always a right-angle in shape. Such type of elbow is also known as “90 bends or 90 ells”. This is a pipe fitting device which is bent in such a way to produce 90° change in the direction of flow of the fluid/gas in the pipe. The elbow is used to change the direction in piping and is also sometimes called a “quarter bend”.

A 90° elbow attaches readily to pipes of various materials like plastic, copper, cast iron, steel, lead, rubber etc. In other words, the 90° elbows are used to provide a joint between two pipes at right angles to each other. They are used as railing ends or corners on a level installation.

45° Elbow

45° Pipe Elbow is also known as “45 bends or 45 ells”. The 45° pipe elbow is used to connect tubes at a 45° pipe angle. As the name suggests, this is a pipe fitting device which is bent in such a way to produce 45° change in the direction of flow of the fluid/gas in the pipe.

Like a 90° elbow, the 45° pipe elbow also attaches readily to pipes of various materials like plastic, copper, cast iron, steel, lead, rubber etc. They are typically made as LR (Long Radius) elbows. These types of elbows are available in various sizes (in mm or inches). They are available with different male to female BSP thread connections. Providing a wide choice of colors, these 45° elbows can be manufactured to meet different specifications, in terms of size and diameter.

Male Pipe Elbows & Female Pipe Elbows

Male pipe elbows and female pipe elbows are popular tube fittings which provide an angled change in the direction of a tubing run. While a male pipe elbow is used to connect fractional tube to female tapered pipe thread, a female elbow is used to connect fractional tube to male NPT thread. These types of tube fittings like male elbows and female elbows have been specifically designed for use on instrumentation, process and control systems and equipment employed in chemical, petroleum, fluid power, electronic and pulp and paper plants.

Reducing Elbow

A reducing elbow is a type of fitting which is used to join two pieces of pipe of different sizes. The reducing elbow is so called because it looks like a reducing piece and elbow combined into one. Reducing elbows have different sized openings on each end and hence they can connect two different sized pipes. They are available in different materials, sizes, finishes and colors.

Types of reducing elbow:

The reducing elbows are available in various types like:

  • 90° reducing elbow
  • 45° reducing elbow
  • 135° reducing elbow
  • 180° reducing elbow etc.

Pipe Cap

Pipe caps act as protective device and are designed to protect pipe ends of various shapes. The main purpose of using pipe caps is to waterproof the connections. They are also used to close the the ends of pipes and tubes.

Pipe Coupling

Pipe couplings are highly demanded in the pipe fitting market. Pipe couplings are fittings that help to extend or terminate pipe runs. These fittings are also used to change pipe size. Couplings extend a run by joining two lengths of pipe. They are known as reduced coupling if they are used to connect pipes of different sizes.

Couplings are also known as repair couplings. These couplings are without stops or ridges and they can be fixed anywhere along the pipe length for preventing leak of any kind.

Pipe couplings

Pipe Nipples

A pipe nipple is a length of straight pipe with male threads on both ends. It is one of the most popular category of pipe fittings. It is a connector or a coupling threaded on both ends. Pipe nipples are used to allow plumbing to be connected to a water heater or other plumbing. They are used to fit straight end hose or pipe. A combination of pipe nipples are recommended for low-pressure discharge and suction service for various compatible liquids and not for compressible products like air, nitrogen or steam.

The working pressure of pipe nipples will vary with the size and construction of the pipe, the type and number of clamps used, clamp placement, proper installation of clamps, temperature and product being conveyed. Pipe nipples are available in the widest variety of wall thicknesses and materials in the industry.

Pipe Reducer

Pipe reducer are tube fittings that are widely used in a number of industries in order to providing greatest connection flexibility in connecting fractional tubes in various installations. Pipe reducer is a kind of pipe fitting that joins two pipes of different diameter. The pipe reducers are available in a range of materials depending on the end use of the products and these fittings are manufactured in inch and metric size.

Pipereducers are special type of tube fittings that are commonly used in the demanding environments of chemical and power plants. They provide a highly reliable, sturdy and tight integral line system and these type of pipe fittings remain unaffected by shock, vibration or thermal distortion. These pipe fittings are very easy to install and they resist leakage due to thermal or pressure cycling. These reducers are sometimes chrome or nickel coated to prevent corrosion and increase the life of the product.

Concentric Reducers

Concentric Reducers are used to join pipe or tube sections on the same axis. They provide an in-line conical transition between pressurized pipes of differing diameters. A pipe reducer can be a single diameter change or a multiple diameter change. The pipes cannot recognize what the outside configuration of the pipe reducer looks like.

The pipe flow is affected by the inside diameter conical transition configuration which can be axially moved and externally reconfigured to provide for more economical reducer fittings. Thus, concentric reducers connect pipes of unequal size but have a common centerline. In other words, it is a type of pipe fitting with different size ends to join pipes of different diameter that joins pipe sections on the same axis.

Concentric reducers are designed with the small and large diameters on opposite ends and joined by a cone shaped transition section. They are available in both seamless and welded construction.

Eccentric Reducers

An eccentric reducer is designed with two female threads of different sizes with centers so that when they are joined, the pipes are not in line with each other, but the two pieces of pipes can be installed so as to provide optimum drainage of the line.

An eccentric pipe reducer fitting is manufactured with the smaller outlet off center to the larger end, which allows it to align with only one side of the inlet. The reducer must be installed with straight side up so that it can prevent trapping air at the pump suction. The eccentric pipe reducers allow simple connection of different sized pipes.

Pipe Plugs

Pipe plugs are defined as cap end of fractional tubes used in a large number of industries. These pipe plugs are designed to insert into the end of tubing to dead-end the flow. Various materials are used to manufacture high quality tube plugs in a variety of end connections.

These pipe plugs come in one piece body design and the easy to replace plug assembly make these industrial pipe fittings very easy to maintain and clean. The pipe plugs are an easy and cost effective way to plug your pipe. These pipe plugs are often plated with chrome or nickel for a superior finish and better resistance to corrosion.

Hex Plug

Hex plug is an important pipe fitting. Like a normal pipe plug, the hex pipe plug is threaded in the end and the cover or the top of the plug takes a hexagon shape. The hex pipe plugs are considered an easy and cost effective way to plug your pipe. The basic purpose is to stop the flow.

    Hex Plug

These pipe plugs are made of various materials, often plated with chrome or nickel for a superior finish and better resistance to corrosion. They are available in various sizes, depending on the size of the pipe in which it is to be fixed.

Square Plug

Square plug is another type of pipe fitting used in various applications. Square plugs are designed to be fit into holes or cavities. They are used for the ends of shafts, tubes, pipes, fittings, connectors, screws, bars, or other shapes. Pipe plugs are available in various shapes and materials. They also come in a variety of different cross sections. The most popular category is the square plug.

Square Plug

Hollow Plug

The hollow plug is a key component to in pipe fitting assembly, as the plug body provides the seal in the access fitting. A hollow plug is a valve used to restrict or isolate the flow of a liquid or gas through a pipe. There are both right-handed and left-handed threads in such plugs. This arrangement of right- and left-handed threads ensures that the functional parts of the pipe cannot become unscrewed during the extraction process.

Hollow Plug

Pipe Union

Pipe Union is a type of fitting equipment designed in such a way to unite two pipes which can be detached without causing any deformation to the pipes. Any kind of small diameter piping connections requiring a positive seal and easy assembly as well as disassembly are made with the help of pipe union. In other words, the pipe unions can disjoint two pipes very easily. They are widely demanded in the pipe fitting market.

Pipe Union

Pipe Tee

Pipe Tee is a type of pipe fitting which is T-shaped having two outlets, at 90° to the connection to the main line. It is a short piece of pipe with a lateral outlet. Pipe Tee is used to connect pipelines with a pipe at a right angle with the line. Pipe Tees are widely used as pipe fittings. They are made of various materials and available in various sizes and finishes. Pipe tees are extensively used in pipeline networks to transport two-phase fluid mixtures.

Reducing Tee

Reducing tee is another type of pipe tee used in pipe and tube fittings. Pipe Tees are available two popular forms—have all outlets of the same size or they can be reducing tees in which they are with a combination of different outlet sizes.

Reducing tee, like all pipe tees, is in the shape of T with two ends of equal size and the third one slightly smaller. In other words, reducing tee is a type of pipe fitting in which the branch port size is smaller than the ports of the run. This type of pipe fitting can also consider size reduction from one of the run ports to the other.

For different applications in various industries, the reducing tees are available in many various combinations of sizes and configurations. Apart from the standard sizes, other unusual combinations of size can also be attained using component parts of tees, reducing tee and reducers.

Pipe Wyes

Pipe wyes are used to to allow one pipe to join another pipe at some degree or angle. As the name suggests, the pipe wyes are Y-shaped pipe fitting devices. They are a popular type of pipe fitting used in various industrial applications.

pipe wyes

Pipe Sleeve

Pipe sleeve is a popular kind of pipe fitting used in various industrial applications. It is available in various sizes, materials depending on the applications in which they are applied. Sleeves are used for variety of purposes and hence widely demanded in the pipe fitting market. Pipe sleeves are user friendly to all users and specifiers like architects, mechanical and electrical engineers, network installers, designers, consultants, builders and plumbers everywhere.

pipe sleeves

Pipe Valves

Pipe valves are a popular category in pipe fittings. Pipe valves are mechanisms or devices to regulate or control the flow of liquid or gas within a pipe. While some valves are used to regulate the rate of flow, there are others that are used to stop it completely in order to prevent flooding or allow repairs to be made.

There are varieties of pipe valves in various materials, sizes and finish , and each type of valve performs a specific task. Pipe valves are known by various names like faucets, stops, bibs, taps, cocks or even drains. They can be easily custom-made for specific applications.

Pipe Valves

Pipe Fasteners

A pipe fastener is a device that mechanically joins or affixes two or more pipes together. Pipe fasteners cover both high tensile and mild steel bolts, clamps, nuts, screws, washers, studs, pins etc. All types of fasteners are used for both industrial and residential pipe fittings. Pipe fasteners are used in almost all types of industries. They are made of various materials and are available in various shapes, sizes and designs.

pipe fasteners

Relevant standards

With the rapid expansion in the global trade, standardization of various products has become an essential requirement. The standards given to various products significantly contributes towards increasing international trade which in turn bridges the quality gap between the manufacturers, producers and buyers of different nations. In pipe fittings as well, standards play a vital role. The manufacture and installation of pipe fittings is tightly regulated by various standards and codes.

The integrity of pipe fittings and flanges in the piping system depends on various principles used in design, construction and maintenance of the entire system. The components of pipe fittings are made in different materials, in a variety of types and sizes and hence should be manufactured according to common national standards or according to manufacturers’ proprietary item. Some manufacturers also use their own internal piping standards based upon national and industry sector standards.

Difference between “Standard” and “Codes”:
Piping codes imply the requirements of design, fabrication, use of materials, tests and inspection of various pipe and piping system. It has a limited jurisdiction defined by the code. On the other hand, piping standards imply application design and construction rules and requirements for pipe fittings like adapters, flanges, sleeves, elbows, union, tees, valves etc. Like a code, it also has a limited scope defined by the standard.

Factors affecting standards:

“Standards” on pipe fittings are based on certain factors like as follows:

  • Pressure-temperature ratings
  • Size
  • Design
  • Coatings
  • Materials
  • Marking
  • End connections
  • Dimensions and tolerances
  • Threading
  • Pattern taper etc.

Types of pipe fitting standards:

Some widely used pipe fitting standards are as follows:

  • ANSI: The American National Standards Institute

ANSI is a private, non-profit organization. Its main function is to administer and coordinate the U.S. voluntary standardization and conformity assessment system. It provides a forum for development of American national standards. ANSI assigns “schedule numbers”. These numbers classify wall thicknesses for different pressure uses.

  • ASME: American Society for Mechanical Engineers

This is one of the reputed organizations in the world developing codes and standards. The schedule number for pipe fitting starts from ASME/ANSI B16. The various classifications of ASME/ANSI B16 standards for different pipe fittings are as follows:

  • ASME/ANSI B16.1 – 1998 – Cast Iron Pipe Flanges and Flanged Fittings
  • ASME/ANSI B16.3 – 1998 – Malleable Iron Threaded Fittings
  • ASME/ANSI B16.4 – 1998 – Cast Iron Threaded Fittings
  • ASME/ANSI B16.5 – 1996 – Pipe Flanges and Flanged Fittings
  • ASME/ANSI B16.11 – 2001 – Forged Steel Fittings, Socket-Welding and Threaded
  • ASME/ANSI B16.14 – 1991 – Ferrous Pipe Plugs, Bushings and Locknuts with Pipe Threads
  • ASME/ANSI B16.15 – 1985 (R1994) – Cast Bronze Threaded Fittings
  • ASME/ANSI B16.25 – 1997 – Buttwelding Ends
  • ASME/ANSI B16.36 – 1996 – Orifice Flanges etc.

  • ASTM International: American Society for Testing and Materials

  1. This is one of the largest voluntary standards development organizations in the world. It was originally known as the American Society for Testing and Materials (ASTM). This is a reputed scientific and technical organization that develops and publishes voluntary standards on the basis of materials, products, systems and services. This is a trusted name for standards. The standards covered by this organization covers various types of pipes, tubes and fittings, especially made of metal, for high-temperature service, ordinary use and special applications like fire protection. The ASTM standards are published in 16 sections consisting of 67 volumes.
  2. AN: Here, “A” stands for Army and “N” stands for Navy
    The AN standard was originally designed for the U.S. Military. Whenever, a pipe fitting is AN fittings, it means that the fittings are measured on the outside diameter of the fittings, that is, in 1/16 inch increments. For example, an AN 4 fitting means a fitting with an external diameter of approximately 4/16″ or ¼”. It is to be noted that approximation is important because AN external diameter is not a direct fit with an equivalent NPT thread.
  3. BSP: British Standard Pipe
    BSP is the U.K. standard for pipe fittings. This refers to a family of standard screw thread types for interconnecting and sealing pipe ends by mating an external (male) with an internal (female) thread. This has been adopted internationally. It is also known as British Standard Pipe Taper threads (BSPT )or British Standard Pipe Parallel (Straight) threads (BSPP ). While the BSPT achieves pressure tight joints by the threads alone, the BSPP requires a sealing ring.
  4. DIN: Deutsches Institut für Normung
    This refers to the industrial pipe, tube and fittings standards and specifications from the DIN, Deutsches Institut für Normung which in English means the German Institute for Standardization. DIN is the German national organization for standardization and is ISO member body for that country.
    DIN standard designation
    The designation of a DIN standard shows its origin where # symbolizes a number:

  • DIN # : Used for German standards having mainly domestic significance or designed as the primary step toward international status.
  • DIN EN # : Used for the German edition of European standards.
  • DIN ISO # : Used for the German edition of ISO standards.
  • DIN EN ISO # : Used if the standard has also been adopted as a European standard.

        Dash (-) size
        Dash size is the standard used to refer to the inside diameter of a hose. This indicates the size by a two digit number which represents the relative ID in sixteenths of an inch. This is also used interchangeably with AN fittings. For example, a Dash “8” fitting means an AN 8 fitting. A standard hose guide is given below:

        Hose Size In Nominal ID Inch Dash Size Standard Dash Size
        1/4 3/16 -04
        3/8 5/16 -06
        1/2 13/32 -08
        3/4 5/8 -12
        1 7/8 -16
        1 ½
        1 ¼ 1 1/8 -20

      1. Flanges: Ratings in Classes and Pressure Numbers (PN)

        Flange Class

        150 300 600 900 1500 2500

        Flange Pressure Number, PN

        20 50 100 150 250 420

      2. ISO: International Organization for Standardization
        ISO is the industrial pipe, tube and fittings standards and specifications from the International Organization for Standardization. ISO standards are numbered. They have format as follows:
        “ISO[/IEC] [IS] nnnnn[:yyyy] Title” where
        nnnnn: standard number
        yyyy: year published, and
        Title: describes the subject
      3. JIS: Japanese Industrial Standards
        This is the Japanese industrial standards or the standards used for industrial activities in Japan for pipe, tube and fittings and published through Japanese Standards Associations.
      4. NPT: National Pipe Thread
        National Pipe Thread is a U.S. standard straight (NPS) threads or for tapered (NPT) threads. This is the most popular US standard for pipe fittings. NPT fittings are based on the internal diameter (ID) of the pipe fitting.
      5. Pipe fitting specifications

        For getting proper pipe fittings to be used in pipes of various sizes, certain specifications are to be known. These specifications cover the following:

        Specifications of Materials

        Various materials having different standards are used to make various types of pipe fittings like elbows, adapters, tees, flanges, etc. Some popular fabricated materials and specifications for pipe fittings are as follows:

        • Nickel and Nickel Alloys: ASTM B-366, ASME SB-366, Nickel 200 & 201 (WPN & WPNL), Inconel 600 (WPNCI), Incoloy 800(WPNIC), Incoloy 825 (WPNICMC), Monel 400 (WPNC), Alloy 20 (WP 20 CB), Hastelloy, C-276, C-4, C-22 etc.
        • Stainless Steel: ASTM A-403 and ASME SA-403, 304, 304L, 304H, 304N, 304LN, 316, 316N, 316LN, 309, 310, 317L, 321, 321H, 347 etc.
        • Chrome-molybdenum: ASTM A-234 & ASME SA-234,WP-5, WP-11, WP-9, WP-91, WP-22 etc.
        • Aluminum: ASTM B-361, 5083, 66061, 5086
        • Titanium: ASTM B-363 & ASME SB-363, WPT7, WPT12, WPT2
        • Other Materials:
        • Brass
        • Bronze
        • CPVC
        • EPDM
        • Fiberglass / Composite
        • Iron (Gray / Cast/ Ductile)
        • Elastomer
        • Neoprene
        • Nylon
        • Polyamide
        • Polyethylene (PE)
        • Polypropylene (PP)
        • PTFE
        • PVC (Polyvinyl Chloride)

                                  Specifications of Size

                                  To determine the usage of a pipe fitting, size is a very important criteria. Here, the main considerations are inside diameter and outside diameter where the inside diameter (ID) has the fitting size matched to the inside diameter of connecting line. The outside diameter (OD) has the fitting size matched to the outside diameter of connecting line. Besides these, sizes also refer to-

                                  • English / Fractional sizes: Measurement done in inches
                                  • Metric sizes: Units in mm/cm

                                  Cleaning and care tips of pipe fittings:
                                  In most of the pipe fitting systems, contamination is the leading cause of problems. This problem demands for careful installation and regular maintenance so that the fittings can prevent any blockages or system breakdown. Depending on the type of the pipe fitting, there are different cleaning methods.
                                  For example, one of the caring tips for cleaning hose or tube assembly is that the hose and tube assemblies should be blown out with filtered shop air or flushed and then should be blown out with a solvent which is chemically compatible with the hose material. The ends of the hose / tube assembly should be capped or plugged till the time the assembly is installed.

                                  Pressure and Temperature Ratings:

                                  Temperature and Pressure are the two important factors determining the safe and effective working of any industrial pipe fitting. The range of temperature and pressure depends on the final application, the material being used etc. There are various standards that are laid down in reference to the temperature and pressure parameters. These are as follows:

                                  • Standard Temperature and Pressure (STP): This is commonly used to define standard conditions for temperature and pressure. These are important for the measurements and documentation of chemical and physical processes.
                                  • Normal Temperature and Pressure (NTP): This is defined as air at 20 degree C (293.15 K, 68 degree F) and 1 atm ( 101.325 kN/m2, 101.325 kPa, 14.7 psia, 0 psig, 29.92 in Hg, 760 torr). Density is at 1.204 kg/m3 (0.075 pounds per cubic foot).
                                  • Standard Ambient Temperature and Pressure (SATP): Thisrefers to temperature at 25 deg C (298.15 K) and pressure of 101 kPa.
                                  • International Standard Atmosphere (ISA): Defined to 101.325 kPa, 15 deg C and 0% humidity.

                                  A pipe fitting published working pressure is the maximum pressure that the pipe should see while in service. A fitting’s published burst pressure is the value at which a brand new piece of pipe will fail during one time pressure test.

                                  Pipe Fitting Selection Guide

                                  Pipe fittings are available in various shapes, sizes and materials. Used to connect pipes of different lengths and sizes, these pipe fittings and flanges should make the right connections. Pipe and pipe-fittings are produced from a various materials for the transport of wide variety of solids and fluids. The wrong pipe fittings can lead to many problems like:

                                  • leaks
                                  • unwanted flow restrictions and
                                  • extra cost

                                  The proper pipe fittings and flanges let your equipment do the work that you intend it to do. The various types of pipe fittings include adapters, bulkhead fittings, plugs, rigid couplings, flexible couplings, 90 degree elbows, 45 degree elbows, reducing elbows, flanges, nipples, concentric reducers, eccentric reducers, side outlet tees, standard tees, reducing tees, bullhead tees, unions, standard wyes, reducing wyes and many more. You should select the right fitting for your application among the wide range of fitting types and sizes offered.

                                  Common points to consider:

                                  The integrity of any fitting for proper functioning depends upon the following:

                                  • Selection of correct components or fittings appropriate for the application
                                  • Careful preparation and cleaning
                                  • Careful installation and assembly
                                  • Correct tightening and loading

                                  Selecting Your Pipe Fittings:

                                  The points to consider are as follows:

                                  • Consider the Tubing Used: For instance, barbed fittings work better in flexible tubing while compression fittings work best with rigid tubing.
                                  • Determine Material Compatibility: Material selection plays a vital role in the proper working of fittings. There are certain fluids which are not compatible with fitting material and these fittings cause leakage or system damage. It is very essential to check the material compatibility of your fluid with any chemicals.
                                  • Check Temperature and Pressure Conditions: Appropriate temperature and pressure ratings are needed for proper operating conditions. It is necessary to know whether the fittings are capable of performing at their maximum temperature and maximum pressure ratings because most fittings cannot perform both the task simultaneously.

                                  Some popular fitting types:

                                  Barbed Fittings

                                  Barbed Fittings:

                                  They slide into soft tubing. For low-pressure installations, tubing elasticity holds the tubing onto the fitting.

                                  Threaded Pipe Fittings

                                  Threaded Pipe Fittings:

                                  These are the most commonly used fittings based on certain standards. For instance, there are threaded fittings of pipes in BSP (British Standard Pipe), NPT (National Pipe Taper), UNF (Unified Fine Thread) sizes for permanent, high-pressure pipe connections.

                                  Cam Fittings

                                  Cam Fittings:

                                  They are considered to be quick-disconnecting fittings which are used with pipes and hoses. For instance, you can connect a female coupler to a male adapter and for a secure connection, pull down the arms. These fittings are capable of withstanding high-pressure applications.

                                  Quick Disconnect Fittings

                                  Quick Disconnect Fittings:

                                  These fittings make and break tubing connections without separating tubing from fitting.

                                  Chromatography Fittings

                                  Chromatography Fittings:

                                  These fittings are designed for HPLC and other high-pressure applications and they can withstand pressures as high as 1000 psi.

                                  Compression Fittings

                                  Compression Fittings:

                                  These fittings have a nut that compresses rigid tubing against fitting body and are mainly used for high-pressure applications.

                                  Pipe Thread Sizes:

                                  This is a very important consideration for any pipe fitting. All pipes were manufactured with specification of a standardized outside diameter (OD) and wall thickness which in turn implies that the nominal pipe size is approximately equal to the inside diameter (ID). Nowadays, various thread configurations are used. We give below an example of British Standard Pipe (BSP) fittings for connecting systems that use both NPT and BSP thread configurations. The table shows a comparison of these two thread styles.


                                  Threads per inch




                                  1/8″ 27 28
                                  1/4″ 18 19
                                  3/8″ 18 19
                                  1/2″ 14 14
                                  3/4″ 14 14

                                  To sum up: Selection criteria for buyers:

                                  • Materials
                                  • Pressure Ratings
                                  • Design and operation
                                  • Safety information
                                  • Temperature

                                  Buyer’s assistance:

                                  Before purchasing pipe fittings and flanges, certain questions need to be answered for that particular pipe fitting and the manufacturer who is manufacturing that particular fitting. Some of these questions are as follows:

                                  • Can it handle pressure?
                                  • Can it handle high temperature?
                                  • Does it have proven long-term performance?
                                  • Are the joints or seals reliable?
                                  • Can it be fitted properly?
                                  • Does it have confidence of manufacturers?
                                  • Can it withstand outdoor storage and ultraviolet rays?
                                  • Can it resist punctures and abrasion?
                                  • Does it have widespread approval and acceptance from inspectors and engineers?
                                  • Does it have quality and value?

                                  The more the number of “YES”, the better is your product.


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