For engineers and procurement specialists working in piping systems—especially in the oil & gas, petrochemical, and power industries—understanding international pipe fitting standards is essential. With a wide range of specifications like MSS SP-97, MSS SP-95, ASME B16.11, and ASME B16.3, choosing the correct fitting isn’t always straightforward.
It just so happens that the order we recently delivered to our Indonesian customers includes a variety of standard products.In this article, we will break down these standards, explain their key features, and help you determine when and where to use each.
MSS SP-97 ASTM A182 GR. F5A weldolets
MSS SP-97: For Integrally Reinforced Branch Outlet Fittings
MSS SP-97 is the standard for integrally reinforced forged branch outlet fittings, also known as Olets (e.g., Weldolet, Threadolet, Sockolet). These fittings are used to create 90° or angled branches from a larger run pipe to a smaller branch pipe.
Connection Types: Threaded (Threadolet), Socket Weld (Sockolet), Butt Weld (Weldolet)
Material Examples: A105N carbon steel, stainless steel grades, alloy steels
Common Applications: Pressure piping, high-temperature systems, or where reinforcement is critical
This standard ensures proper reinforcement and pressure integrity, making it ideal for high-stress industrial systems.
MSS SP-95 A234 WPB Galvanized Eccentric Swage Nipple
MSS SP-95: Swage Nipples and Bull Plugs
MSS SP-95 covers swage nipples and bull plugs, typically used for pipeline transitions and line terminations.
Fitting Types: Concentric and Eccentric Swage Nipples
End Connections: Threaded, plain end, beveled end
Material Examples: A234 WPB, A234 WPB Galvanized (for corrosion protection)
Swage nipples are useful for reducing pipe diameter in a straight line or offset configuration and are often applied in tight spaces or flow-controlled systems.
ASME B16.11 forged pipe fittings
ASME B16.11: Forged Steel Socket-Weld and Threaded Fittings
ASME B16.11 defines small-diameter forged fittings for socket-weld and threaded connections, typically up to NPS 4 (DN 100).
Common Types:
- 90° & 45° Socket Weld Elbows
- Socket Weld Tees
- Threaded Elbows and Tees
- Unions and Couplings
Material Example: A105N for carbon steel, stainless steels
These fittings are ideal for high-pressure, small bore piping systems and are widely used in oil & gas, chemical, and steam systems.
ASME B16.3: Malleable Iron Threaded Fittings
ASME B16.3 focuses on malleable iron threaded fittings, such as reducing couplings, elbows, and tees.
Common Materials: A197 and A197 Galvanized
Size Range: 1/8″ to 6″
Applications: Low-pressure plumbing, water lines, air systems
Galvanized versions offer corrosion resistance, especially for outdoor or humid environments.
ASME B16.5 A182 F316L weld neck flanges
ASME B16.5 & B16.47: Flanges
ASME B16.5: Covers flanges from NPS ½ to 24
ASME B16.47: For large-diameter flanges NPS 26 to 60, divided into Series A & B
Face Types:
FF (Flat Face): Used with cast iron and other brittle materials
RF (Raised Face): Most common for industrial applications
RTJ (Ring-Type Joint): For high-pressure/high-temperature use
Materials: A105N, A105N Galvanized, stainless steel grades
Choosing the Right Standard for Your Project
When selecting fittings for your project, consider the following:
- Pressure Rating & System Requirements
- Connection Type Preference (Socket Weld, Threaded, Flanged)
- Material Compatibility with Medium and Temperature
- Installation Space Constraints
Working with a knowledgeable supplier like Haihao Group, which supports a full range of international standards, ensures correct product selection and code compliance.
Whether you’re designing a high-pressure refinery system or maintaining a low-pressure utility line, choosing the correct fitting standard is crucial. MSS and ASME standards each serve specific applications, and understanding their scope helps prevent over-specification or compatibility issues.
If you need assistance with pipe fitting selection, Haihao Group offers comprehensive technical support and supplies a wide range of products manufactured to MSS, ASME, and other global standards.Email:sales@haihaogroup.com
