What is a Pipe Nipple?

A pipe nipple can be simply understood as a short section of threaded pipe. Its primary function is to serve as a transition connector, bridging two components (such as elbows, tees, valves, etc.) that need to be connected within a piping system. Due to its short length and threaded ends, it is highly convenient when adjusting connection distances or altering connection methods.

Types of Pipe Nipples

1. Close Pipe Nipples

Features: Threads run the entire length of the pipe fitting, with the threads at both ends nearly touching. There is no threadless shoulder or barrel section in the middle, enabling extremely compact installation in pipe connections.

Applications: Used to tightly connect two female-threaded fittings together, leaving no exposed body of the pipe fitting. Once installed, removal is nearly impossible without specialized tools such as pipe wrenches. Commonly employed in space-constrained applications, particularly suited for short-distance connections between equipment and piping systems.

2. Hexagon Nipples

Features: The pipe fitting features a hexagonal nipple (resembling a nut) at its center, with threads at both ends.

Applications: The hexagonal design facilitates installation or removal using a wrench, providing a better grip point and leverage surface. It serves as a common transition piece for connecting different fittings. Used in pipe connections requiring frequent maintenance or disassembly.

3. Long Pipe Nipples

Features: The long pipe nipple is longer than the ordinary nipple, which can effectively extend the distance between pipes. It has threads at both ends and a non-threaded barrel part in the middle.

Applications: Used when a longer connection span is required between two connection points or when bridging obstacles. Examples include building plumbing systems and industrial pipeline networks.

4. Reducing Pipe Nipples

Features: The pipe fitting features threads of different diameters at both ends.

Applications: Used to connect two pipe fittings or pipes of different sizes, enabling gradual reduction or expansion of pipe diameter. Commonly found in petroleum, chemical, and water supply systems.

5. Barrel Nipples

Features: Threaded at both ends with a distinct smooth, unthreaded section in the middle, resembling a small barrel or featuring a “shoulder.”

Applications: This is the most common type of pipe fitting. The unthreaded section in the middle provides a grip area after connection, facilitating wrench operation and allowing some adjustment of the connection distance. Widely used in general industrial and civil piping systems, it is one of the most common types of short sections.

6. Swage Nipples

Features: Resembling a reducer, it connects two pipes of different diameters. These can be concentric (with aligned axes) or eccentric (with offset axes). Typically, one end features internal/external threads, while the other end is either a straight end or a beveled end (for welding).

Applications: Primarily used to change pipe diameters, they also serve as transitions from threaded to welded connections.Particularly suited for high-pressure or high-temperature environments, they are widely used in power generation, petrochemical, and boiler systems.

7.  Welded Pipe Nipples

Features: Welded pipe nipple feature welded ends without threads. Typically consisting of short, beveled pipe sections, they are used to connect to other components or pipes within a piping system via welding, providing a stronger, leak-proof connection.

Applications: Suitable for high-pressure, high-temperature environments or situations requiring permanent connections.

8. Threaded Pipe Nipples

Features: Refers broadly to pipe fittings with external threads at both ends, enabling direct connection to internally threaded pipe components. This is the most universal classification, encompassing types such as fully threaded, barrel-shaped, and hexagonal.

Applications: The most common connection method, linking threaded fittings to internally threaded pipe components, valves, and similar equipment. Widely used in medium- and low-pressure fluid piping systems.

9. Threaded Nipple with Thread one End

Features: External threads on one end only, with a smooth end on the other.

Applications: Typically used at pipe ends, with one end threaded for connection and the other smooth end suitable for welding or as an outlet.

10. Seamless Pipe Nipples

Features: Manufactured by cutting and processing seamless steel pipes, featuring no weld seams on the pipe body. Offers superior strength and enhanced pressure resistance.

Applications: Suitable for high-pressure applications or scenarios demanding exceptional pipe integrity, as seamless pipes deliver greater strength and reliability than welded pipes. A common choice in the power, petrochemical, and energy industries.

11. Galvanized Nipple

Features: Made of carbon steel with a hot-dip galvanized or electrogalvanized surface treatment, effectively preventing corrosion and rust.

Applications: The galvanized coating provides excellent corrosion protection. Commonly used in water pipes, fire protection systems, and general low-pressure non-corrosive medium piping systems.

12. Hose Nipple

Features: Typically features an external threaded end for connecting to piping systems, and a stepped barb connector (commonly known as a “pagoda head”) at the other end for inserting and securing hoses.

Applications: Used to connect rubber or plastic hoses, widely employed in agricultural irrigation, water systems, and machinery equipment for hose connections.

13. Stainless steel nipples

Features: Manufactured from various grades of stainless steel (e.g., 304, 316).

Applications: Offers exceptional corrosion resistance and high-temperature tolerance. Widely used in chemical processing, food manufacturing, pharmaceutical production, marine environments, and other applications demanding high cleanliness or corrosion resistance.

14. Alloy Steel Nipple

Characteristics: Manufactured from steel containing alloying elements other than carbon, such as chromium, molybdenum, nickel, etc.

Applications: Suitable for demanding conditions involving high temperatures, high pressures, or low temperatures, offering higher strength and specific corrosion resistance compared to carbon steel. Commonly used in power plants, refineries, and similar facilities.

15. Carton Steel Nipple

Characteristics: Made from carbon steel (primarily composed of iron and carbon). Offers lower cost and higher strength.

Applications: The most common material for pipe fittings. Widely used in low- and medium-pressure industrial and commercial piping systems for non-corrosive fluids such as water, oil, and gas.

Note: Prone to rusting without surface treatment (e.g., galvanization).

Pipe Nipple Sizes

Standard Sizes

Pipe nipples typically range in diameter from 1/8 inch to 12 inches. Lengths vary from short to extra-long, with the longest reaching up to 72 inches. The most commonly used sizes fall between 1/2 inch and 2 inches, accounting for 70% of industrial applications. When selecting pipe nipples, note that the actual outside diameter is approximately 1/8 inch larger than the nominal size.

Pipe Nipple Length and Diameter

Pipe fitting length refers to the measurement from one end to the other (from one threaded end to the other). Tube fitting sizes range from short tubes (1/8 inch to 1/4 inch) to long tubes (up to 72 inches). Diameter plays a vital role in matching with other components.

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As a manufacturer and exporter of Forged Fittings, we have received many orders and inquires of Galvanized Nipple. How many types do you know?. Customers describe their demands with a short sentence, but have you noticed that how much information is included in the short description?

Today, we will take the latest order of “DN25 Nipple Sch80 Galvanized API-5L-B TBE 100mm Long NPT” as an example to tell you the answer.

Threaded Barrel Nipples Long Type—Nipple Type

• What is Galvanized Pipe Nipple?

For laymen, they would never have thought that galvanized nipple is a pipe fitting, but the fact is this word have been using for more than 400 years in plumbing and engineering. We can’t finger out the first usage of “nipple” in piping system, the best we can do is find out that it comes from a root meaning “bill, beak, snout” – literally “small projection.”

The basic form of nipple is a short piece of pipe with a male thread at each end for connecting two other fittings.

• Threaded Nipple

In this order, the customer requires a long type nipple.

Basic nipple form may be referred to as a “Barrel Nipple” or “Pipe Nipple”. Based on this type, many different types are evolved.

Forged Threaded Nipple Types

Forged Pipe Nipple includes: Stainless Steel 316 Barrel Nipple, Carbon Steel A105 Long Pipe Nipple, Galvanized Nipple, Close Nipple, Black Hexagonal Nipple (Hex Nipple), Alloy Steel Long Hex Nipple, Reducing Nipple, Screwed Swage Nipple and Hose Nipple.

I’m sure there are more forms, but this time we will focus on the long pipe nipple.

Long Pipe Nipple is a basic form nipple with more distance between the threaded ends.

• Forged Pipe Nipple TBE—End type

The threaded ends are available in different patterns and you should mention your demand in orders.

Threaded End Types:

• PBE — “Plain Both Ends”.
• TBE—”Threaded Both Ends”.
• POE- TOE –“Plain One End and Threaded One End“.

Nipple Dimension Standard

Dimension standard must be described in your orders unless your manufacturer already knows.

Dimension Standard includes: ASTM A733, BS3799, ASME B16.11, ASME B36.19, and MSS SP-95.

Generally speaking, ASME B16.11 Threaded Fittings Barrel Nipple are more commonly used in the industries, but this Threaded Galvanized Nipple is complied with ASTM A733.

What is ASTM A733?

ASTM A733 is standard specification covers welded and seamless carbon steel and austenitic stainless steel pipe nipples. The mechanical requirements stated that, Pipe Nipples shall be made from new, hydrostatic tested or NDE-tested pipe, pipe and nipples shall be threaded on both ends with NPT taper pipe threads. The standard and special lengths and sizes of nipples are presented. Galvanized Nipples ordered under this specification shall be made from pipe coated on the inside and outside by the hot dip process. Samples of nipples sufficient to determine their conformance with the requirements of this specification shall be taken at random for each lot of nipples of the same pipe size, length, and material, also, samples shall be inspected to determine their conformance with the dimensional requirements, including thread dimensions

Galvanized Nipple Dimensions

The dimension is so important that they must include in markings. For ASTM A733 Threaded Nipple, it is described as DN25, Sch80, and Length is 100mm.

• Diameter

DN25 refers to it diameter. It can be expressed in NPS (Inch) and DN.

DN25 = 1 Inch, which is a common size of threaded nipples.

Diameter range: 1/8” – 12” inch, DN6 – DN300.

• Wall Thickness

ASME B16.11 Forged Threaded Fittings are expressed in 3000LB, 6000LB, but ASTM A733 Pipe Nipple are described in schedule. Sch 80 is a middle rating in ASTM A733 specifications.

Schedule range: Sch40, Sch80, Sch160, XXS.

• Length

The length 100mm refers to the overall length with thread. Length depends on diameter.

Pipe nipple length and thread length are both specified in ASTM A733.

The length in above table are generally referenced ones, manufacturer can select one of the above three series under unspecified conditions.

NPT Threaded Nipple—Threaded Type

NPT Threaded Nipple

Specify NPT or R in your order.

N.P.T. Nipples or National Pipe Threaded Nipples or Fittings are standard threaded nipples used within the United States. N.P.T. nipples consist of a tapered threading which has “imperfect threads” at the end of the threading. The “imperfect threads” create your seal when connecting a male to a female N.P.T part. The seal is created by torquing the NPT  threads. When the National Pipe Thread fittings are torqued, the threads flanks compress against each other creating a successful seal.

Carbon Steel Galvanized Nipple API-5L-B—Material

It is a carbon steel comes from ANSI/API 5L Specification for Line Pipe with the application of gas, water and oil transportation. API refers to American Petroleum Institute.

API 5L has PSL-1 series and PSL-2 series, both series have grade B. The chemical composition are little different between PSL-1 and PSL-2.

Seamless API 5L-B pipe is the row material for Carbon Steel Threaded Barrel Nipple, but this pipe is also available in welded.

API-5L-B Chemical Composition, Max %

c=(Nb+V)≤0.06%

d=(Nb+V+Ti) ≤0.15%

API 5L B Mechanical Properties

Galvanized Nipple—Coating

Carbon Steel Nipples are usually with  galvanized coating like other Carbon Steel Threaded Fittings.

Galvanized Nipple should be installed according to your local building codes and can be used for residential potable water and drainage applications. This nipple can be used to repair pipe or make an extension from a fitting or existing pipe

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