ASME B16.5 Explained: Flange Types, Pressure Ratings & 2026 Updates
Everything you need to know about ASME B16.5 — the universal blueprint for steel pipe flanges and flanged fittings.
If you work in oil & gas, power generation, chemical processing, or pipeline engineering, this standard determines whether your connections hold — or fail catastrophically. In this video, we break down the full standard: flange types, pressure-temperature curves, face geometries, surface roughness requirements, the difference between B16.5 and B16.47, and the critical 2025 edition updates (mandatory from January 1, 2026).
CHAPTERS
0:00 — Introduction: Why a flange hiss is a warning sign
1:23 — Section 1: Foundation — What ASME B16.5 actually covers (NPS 1/2 to 24, 7 pressure classes)
2:34 — Section 2: Pressure & Temperature Ratings — The inverse heat-pressure relationship (Class 150: 285 PSIG down to 170 PSIG at 500F)
3:21 — Section 3: Anatomy of Flange Types — Weld Neck, Slip-On, Blind, Socket Weld, Threaded, Lap Joint
4:10 — Section 4: Flange Faces & Sealing — Flat Face vs Raised Face vs RTJ; AARH roughness (125–250 vs below 63 microinches)
4:58 — Section 5: ASME B16.5 vs B16.47 — Series A (MSS SP44) vs Series B (API 605) for NPS 26–60
6:02 — Section 6: 2025 Edition Updates — Alloy corrections (N08800), nickel/duplex/titanium data, 100% NDT for Class 900–2500, green hydrogen & carbon capture ratings
7:15 — Closing: How will these standards evolve for liquid hydrogen and low-carbon energy?
KEY TAKEAWAYS
B16.5 governs flanges from NPS 1/2 to 24 across 7 pressure classes: 150, 300, 400, 600, 900, 1500, 2500
As temperature rises, allowable pressure drops — Class 150 flange at -20 to 100F handles 285 PSIG, but only 170 PSIG at 500F
Weld Neck = critical high-stress; Slip-On = easy alignment; Lap Joint = frequent dismantling
Raised Face serrated finish: AARH 125–250 microinches; RTJ groove: below 63 microinches
B16.47 takes over for NPS 26–60 with Series A (thicker/stronger) and Series B (more fasteners, smaller bolt circle)
2025 Edition: 100% UT/MT for Class 900–2500 high-stress zones, full traceability, hydrogen & CCS ratings
PRODUCTS WE SUPPLY (HUITONG)
We manufacture and export steel pipes, flanges, and fittings in carbon steel, stainless steel, duplex, and nickel alloys — fully compliant with ASME B16.5, B16.47, and B16.9 standards.
Our English Website：https://www.htpipe.com/
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HASHTAGS
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