3/8 inch x 4 inch Black Steel Nipple

3/8" x 4" Black Steel Nipple – Built for Pressure-Rated Gas and Water Systems

The 3/8" x 4" Black Steel Nipple is manufactured to meet the demands of high-pressure applications in commercial, industrial, and residential plumbing systems. Made from schedule 40 welded black steel pipe and threaded to ANSI/ASME B1.20.1 specifications, this nipple offers a dependable method for joining compatible pipe and fittings in gas and hydronic systems.

Commonly used in applications such as natural gas, LP gas, and closed-loop hydronic heating, this fitting provides excellent tensile strength, pressure tolerance, and dimensional stability. With a uniform black oxide coating, it offers added resistance to atmospheric corrosion during handling and storage.

Key Features

• Construction: Made from ASTM A53 Grade A or A106 seamless or welded black steel pipe
• Thread Standard: NPT male threads per ANSI/ASME B1.20.1 for compatibility and sealing integrity
• Length: 4 inches overall, pipe thread engagement adjusted for working length
• Pressure Rating: Suitable for use in pressure piping systems (ratings depend on pipe schedule and system design)
• Coating: Black oxide finish for temporary corrosion protection

Typical Applications

• Natural gas and propane piping networks
• Boiler supply and return lines
• Fire protection loop installations (non-galvanized)
• Compressed air systems (in controlled environments)

Installation Guidance

Install using a compatible thread sealant or PTFE tape appropriate for the media in service. Pipe wrench or tong tools should be used to maintain torque control during installation. Always verify proper pipe alignment and thread depth engagement to ensure a leak-resistant joint. For fuel gas applications, conform to NFPA 54 or local codes.

Note:

Black steel nipples are not approved for use with potable water systems due to corrosion risks in continuous exposure to moisture. For those applications, use galvanized or brass nipples as required by code.

Specifications

• Nominal Size: 3/8"
• Length: 4"
• Connection Type: NPT x NPT (Male Threaded)
• Material: Black Steel (ASTM A53 / A106)
• Wall Thickness: Schedule 40

The 3/8" x 4" Black Steel Nipple provides a durable, cost-effective solution for professionals requiring pressure-rated fittings for gas and hydronic systems. Backed by industry manufacturing standards and performance-tested for mechanical reliability, this nipple ensures consistent service across a range of demanding installations.