Quick answer: Choose a pipe nipple by matching the nominal pipe size, thread type, material, and specified length to the piping system and the fittings it connects. Always check the product dimensions and connection details before ordering. A part that looks close may still have the wrong thread, size, or material for the application.
What is a pipe nipple?
A pipe nipple is a length of pipe, typically threaded on both ends, used to connect two threaded fittings or pieces of equipment.
Pipe nipples are available in different nominal sizes, lengths, materials, and end configurations. Confirm each of these details for your specific application instead of choosing a nipple by appearance alone.
How do you choose the right pipe nipple size?
Start with the nominal pipe size specified for the existing pipe and fittings.
Nominal pipe size is a standardized trade size and does not necessarily match the pipe’s measured outside diameter. If you are matching an existing installation, check the product markings or specifications and confirm the dimensions with a reliable sizing reference before ordering.
Both ends of the nipple and the mating fittings also need compatible thread sizes and thread types.
Many threaded pipe nipples used in U.S. plumbing applications use NPT tapered threads, but other thread standards and connection types exist. Always verify the exact thread specification in the product documentation.
Do not force threaded parts together if they do not engage properly.
How do you select pipe nipple length?
Start by checking the available space between the fittings and account for how the nipple will engage with each threaded connection.
Length descriptions and listed dimensions can vary depending on the product and end configuration, so review the product drawing or specifications to see how the manufacturer defines the listed length.
When replacing an existing nipple, compare the old part’s specified size and length whenever possible rather than relying only on measurements taken from the installed pipe.
Which pipe nipple material should you use?
Choose a material that is appropriate for the fluid, pressure, temperature, environment, and requirements of the piping system.
Black steel, galvanized steel, stainless steel, brass, and other materials each have different applications and characteristics. For example, black steel and galvanized steel should not automatically be treated as interchangeable.
Always review the product specifications and system requirements before making a substitution. For gas, potable water, or another regulated application, confirm that the exact product is approved for that use and follow applicable plumbing codes and project specifications.
Before you order, check these details
- Nominal size: Match the pipe and fitting specifications.
- Thread type: Confirm the thread size and thread standard for each connection.
- Length: Check the listed product measurement and available installation space.
- Material: Select a material appropriate for the piping system and environment.
- Pressure and temperature ratings: Confirm the product is rated for the intended operating conditions.
- Application approval: Review product documentation and any applicable code or project requirements.
Common pipe nipple selection mistakes
- Using outside diameter alone to identify nominal pipe size.
- Assuming every threaded pipe connection uses the same thread standard.
- Ordering a nipple without confirming NPT or another required thread type.
- Choosing a length without checking how the manufacturer measures it.
- Substituting black steel, galvanized, or another material without confirming suitability.
- Forcing together mismatched threaded components.
- Ignoring pressure, temperature, or application requirements.
- Buying based on appearance instead of checking the product specifications.
Shop pipe nipples and fittings
Browse our Pipe Nipples, Black Pipe Nipples, and Galvanized Pipe Nipples collections. For pipe furniture, shelving, décor, and similar projects, shop Fittings & Nipples For Pipe Decor.
Before ordering any pipe nipple, confirm the nominal size, thread specification, length, material, and product ratings to make sure it matches your project.
Frequently asked questions
Is nominal pipe size the same as the pipe’s measured outside diameter?
No. Nominal pipe size is a standardized trade designation and does not necessarily equal the measured outside diameter of the pipe. Use product markings, specifications, or an appropriate pipe-sizing reference to determine the correct size.
Are all pipe nipple threads the same?
No. Many pipe nipples used in U.S. plumbing applications have NPT tapered threads, but other thread standards exist. The thread size and type must be compatible with the mating fitting. Always check the product specifications rather than assuming two threaded parts will work together.
Can I replace a black steel nipple with a galvanized one?
Not automatically. Material choice depends on the piping system, environment, intended application, and applicable requirements. Check the product documentation and follow the system specifications and applicable codes before substituting materials.
