2-1/2 inch x 3-1/2 inch Black Steel Nipple

2-1/2" x 3-1/2" Black Steel Schedule 40 Nipple – Threaded for Pipe Extensions

The 2-1/2" x 3-1/2" Black Steel Nipple is a straight pipe fitting with male NPT threads on both ends, manufactured from welded or seamless Schedule 40 black steel pipe. This component is engineered for use in industrial, commercial, and mechanical systems where a short segment is required to connect fittings, extend pipe runs, or adapt configurations in gas, water, or oil piping networks.

Black steel nipples are typically installed in low- to medium-pressure systems that do not require corrosion resistance from galvanization. Common applications include natural gas distribution, fire protection (non-pressure sprinkler systems), and general plumbing where black pipe is acceptable by code.

Specifications

• Material: ASTM A53/A106 carbon steel, Schedule 40
• Connection Type: Male NPT x Male NPT (threaded both ends – ANSI B1.20.1)
• Length: 3-1/2 inches overall (close length may vary slightly depending on thread depth)
• Nominal Pipe Size: 2-1/2 inch
• Finish: Black (uncoated)
• Pressure Rating: Rated to pipe specification; consult application-specific design pressure

Installation Guidelines

Threaded steel nipples must be installed using an appropriate thread sealant such as PTFE tape or pipe joint compound. Pipe wrenches should be applied only to the wrench flats or body of the nipple, avoiding excessive torque to prevent damage to the threads. Verify that threads are clean and undamaged prior to installation. Support piping to reduce mechanical stress on threaded joints, particularly in overhead or horizontal runs.

Application Use Cases

This nipple is commonly used to extend pipe systems, connect fittings in tight or custom configurations, or terminate lines in pressurized plumbing and HVAC systems. Typical sectors include mechanical rooms, boiler installations, industrial gas supply lines, and commercial-grade water piping systems. Not recommended for potable water unless specified by code or finished with appropriate coatings.

Material Insight

Black steel is carbon steel without galvanization, making it suitable for applications where corrosion protection is not a primary concern but strength and pressure resistance are critical. It is widely used in fire suppression and gas line work due to its ability to maintain mechanical integrity under thermal and structural stress.

The 2-1/2" x 3-1/2" Black Steel Nipple is a precision-cut, industry-standard component for use in rigid piping systems requiring secure, threaded joints. Designed for reliability and consistent performance in demanding applications, it is a fundamental part of professional-grade pipe system assemblies.