Pipe Flanges and Flanged Fittings: NPS 1/2 through NPS 24 Metric/Inch Standard
Purpose and Scope of ASME B16.5-2025
ASME B16.5, Pipe Flanges and Flanged Fittings: NPS 1/2 through NPS 24, is arguably the most widely used component standard in the piping industry worldwide. Its primary function is to provide a single, consistent set of technical and dimensional criteria for metallic flanges and flanged fittings, ensuring that a flange produced by any compliant manufacturer will correctly and safely mate with another component of the same specification.
The scope of the standard covers flanges and flanged fittings for nominal pipe sizes (NPS) from 1/2 through 24 inches (DN 15 through DN 600). It covers the full spectrum of technical requirements, including:
Application and Use
ASME B16.5 is foundational for engineers, manufacturers, and fabricators in nearly every industrial sector that uses pressurized fluid systems. It is used to govern the procurement and assembly of pipe-to-equipment connections, valve installations, and piping break points for maintenance:
Because of its comprehensive nature, B16.5 is typically specified directly in government regulations and referenced by all major ASME Piping Codes (e.g., B31.1, B31.3, B31.8) as the definitive source for component design and ratings for flanges in the NPS 1/2 to NPS 24 range.
| SDO | ASME: American Society of Mechanical Engineers |
| Document Number | B16.5 |
| Publication Date | May 30, 2025 |
| Language | en - English |
| Page Count | 274 |
| Revision Level | |
| Supercedes | |
| Committee |