A NPT pipe nipple is a short length of pipe featuring National Pipe Taper (NPT) threads on both ends. It connects two pipes or fittings that have female threads. This is used in plumbing and industrial applications. This standardized threaded connection creates a tight seal through the tapered thread design, making it essential for leak-proof joints in various piping systems.
What is a Pipe Nipple?
Pipe nipples are among the most versatile pipe-to-pipe connectors in piping systems. These short pipe sections have threads on both ends, allowing them to connect larger pipes or fittings. Unlike regular pipes, nipples are designed specifically for making connections, not for transporting fluids over long distances. They come in various materials like stainless steel, carbon steel, or brass, and can have different thread types. The "nipple" name comes from their short, stubby appearance, typically ranging from close (very short) to several inches long.
The terminology comes from the component's physical resemblance to a nipple's shape - short and protruding. This industrial naming convention dates back to early plumbing systems, where these short connectors were the "nipples" that joined larger "breasts" (main pipes) in the system. While the analogy might seem unusual today, the name stuck and became standard industry terminology worldwide.
Understanding NPT Thread Standard
The National Pipe Taper (NPT) standard is the most common type of thread used in North America to create tight seals that can hold pressure. The tapered design (1°47') creates a wedging action that seals better under pressure than straight threads. This makes NPT nipple fittings ideal for water, gas, and chemical applications.
Common NPT Pipe Nipple Sizes
Popular sizes include:
- 1/2" NPT nipple (most common for residential plumbing)
- 3/4" NPT nipple
- 1" NPT nipple
- 1 1/2" NPT nipple (common in industrial applications)
- 2" NPT nipple
How Long is a Close Pipe Nipple?
Close pipe nipples are the shortest standard length available, with virtually no unthreaded portion between the threaded ends. Their total length equals just the combined length of the two threaded sections.
These ultra-compact connectors are ideal for tight spaces where every inch counts, though they require special tools (like nipple wrenches) for proper installation due to the lack of gripping surface.
How Are Pipe Nipples Length Measured?
Understanding pipe nipple measurements is crucial for proper system design:
Overall Length (OAL): Measured from end to end, including threads
Thread Engagement Length: Typically 3-5 threads, depending on size
Nominal Size: Refers to the pipe's inner diameter (e.g., 1/2" NPT)
Pro tip: Always specify whether you need "thread to thread" or "face to face" measurements when ordering, as this affects how the nipple will fit in your assembly.
6 Main Types of Pipe Nipples
- Close Nipple: Threads touch in the center (shortest possible)
- Hex Nipple: Features a hexagonal center for wrench grip
- Toe Nipple: One end has longer threads for special applications
- Barrel Nipple: Unthreaded center section
- Reducer Nipple: Connects different pipe sizes
- Hose Nipple: Designed for hose connections
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Material Variations
- Stainless steel (304/316)
- Carbon steel (black/galvanized)
- Brass/bronze
- Plastic (PVC/CPVC)
What is a TOE Pipe Nipple?
A TOE (Threaded One End) pipe nipple has threads on only one end, with the other end left plain for welding or other connections.
TOE nipples bridge the gap between threaded and non-threaded systems, often used in retrofit applications or where mixed connection types are required.
All About NPT and BSPT Pipe Threads
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NPT (National Pipe Taper) Threads
American standard (ANSI/ASME B1.20.1)
60° thread angle with 1°47' taper
Seals through thread interference
Requires thread sealant (Teflon tape/paste)
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BSPT (British Standard Pipe Taper)
International standard (ISO 7-1)
55° thread angle with 1°47' taper
Common in Europe/Asia
Compatible with BSPP parallel threads
Both create pressure-tight joints but are not interchangeable due to differing thread angles and pitches.
BSP Vs. NPT: Which is Better?
The "better" thread depends entirely on your application:
| Feature | NPT | BSP |
| Region | Americas | Europe/Asia |
| Sealing | Thread deformation | Washer often used |
| Pressure | High pressure | Moderate pressure |
| Availability | Wide in the US | Global standard |
Why Choose Our NPT Pipe Nipples?
As a leading exporter of pipe fittings, we offer:
Full size range: From 1/8" to 4" NPT nipples
Material options: 304/316 stainless, carbon steel, brass
Custom lengths: Cut-to-order services available
Competitive pricing: Factory-direct savings
Global shipping: Reliable logistics network
Whether you need standard 1/2" NPT nipples or specialty 1 1/2" NPT nipple fittings, we've covered your piping connection needs. Contact our team today for quotes or technical support on your application requirements.
