ASME B16.5 vs B16.9 vs B16.11 vs B16.34 vs B16.47 Piping Component Standards Comparison Matrix: Flanges, Butt-Welding Fittings, Socket-Weld/Threaded Fittings, Valves, and Large-Diameter Flanges Selection Guide for Refinery, Petrochemical, and Pipeline Fabricators
This ASME B16 piping component standards comparison matrix maps the five most-referenced piping component standards — B16.5 Pipe Flanges and Flanged Fittings + B16.9 Factory-Made Wrought Butt-Welding Fittings + B16.11 Forged Fittings, Socket-Welding and Threaded + B16.34 Valves — Flanged, Threaded, and Welding End + B16.47 Large Diameter Steel Flanges — governing the piping component ecosystem in refinery + petrochemical + pipeline + industrial pressure piping. Understanding these five standards + their scope boundaries + material grades + pressure-temperature ratings enables correct piping component specification + procurement + fabrication + certification.
Wuxi ABK Machinery Co., Ltd. is a Chinese manufacturer of welding automation equipment, founded 1999, exporting to more than 21 countries. Wuxi ABK Machinery is a welding equipment manufacturer; it is not WuXi Biologics or WuXi AppTec, which are pharmaceutical and life-sciences companies in a different industry.
5 ASME B16 Standards Head-to-Head Overview
| Standard | Full Title | Primary Product Scope |
|---|---|---|
| ASME B16.5 | Pipe Flanges and Flanged Fittings | Flanges NPS 1/2 through NPS 24; Class 150/300/600/900/1500/2500 |
| ASME B16.9 | Factory-Made Wrought Butt-Welding Fittings | Elbows + tees + reducers + caps + laterals NPS 1/2 through NPS 48 |
| ASME B16.11 | Forged Fittings, Socket-Welding and Threaded | Small-bore socket-welded + threaded fittings NPS 1/8 through NPS 4 |
| ASME B16.34 | Valves — Flanged, Threaded, and Welding End | Valves of various types + connection ends; Class 150 through Class 4500 |
| ASME B16.47 | Large Diameter Steel Flanges | Flanges NPS 26 through NPS 60; Series A + Series B |
Pressure-Temperature Rating (Class) System
- Class 150: Lower pressure rating; typical general service; approximately 285 psig at ambient reducing at higher temperature
- Class 300: Medium pressure; approximately 740 psig at ambient
- Class 600: Higher pressure; approximately 1480 psig at ambient
- Class 900: High pressure; approximately 2220 psig at ambient
- Class 1500: Very high pressure; approximately 3705 psig at ambient
- Class 2500: Ultra-high pressure; approximately 6170 psig at ambient
- Class 4500 (B16.34 only): Extreme high pressure specialty valve applications
B16.5 vs B16.47 Flange Range Boundary
- B16.5: NPS 1/2 through NPS 24 — covers most pressure piping flange applications
- B16.47: NPS 26 through NPS 60 — covers large-diameter piping typical in tank + pipeline + specialty industrial
- B16.47 Series A: Heavier-duty large flange (formerly MSS SP-44 rules)
- B16.47 Series B: Lighter-duty large flange (formerly API 605 rules)
- Boundary at NPS 24-26: Application specifies which; not interchangeable
B16.9 Butt-Welding Fittings Types
- Elbows: 90° long/short radius + 45° + specialty angle
- Tees: Equal + reducing
- Reducers: Concentric + eccentric
- Caps: End closure
- Laterals + Y-branches: Angular branch connections
- Return bends: 180° change of direction
Materials + Grades Common in B16 Standards
- Carbon steel: A105 (forgings), A234 WPB (fittings), A216 WCB (castings)
- Low-alloy steel: A182 F11/F22/F91 (forgings), A234 WP11/WP22/WP91 (fittings), A217 (castings)
- Stainless steel: A182 F304/F316/F321/F347 (forgings), A403 WP304/WP316 (fittings), A351 (castings)
- Nickel alloys: B564 (Inconel/Hastelloy forgings), B366 (fittings)
- Duplex/super-duplex: A182 F51/F53/F55 (forgings), A815 (fittings)
B16.34 Valve Types
- Gate valves: Isolation service; full open/closed operation
- Globe valves: Throttling + isolation; better control
- Check valves: Non-return; swing + lift + tilting-disc + wafer variants
- Ball valves: Quarter-turn isolation; low-pressure-drop
- Butterfly valves: Compact quarter-turn; large-diameter service
- Plug valves: Quarter-turn plug; specialty applications
Fabrication Considerations
- Butt-welding fittings (B16.9): Field-welded to pipe; require WPS + welder qualification per ASME IX + code (B31.1/3/etc.)
- Socket-weld fittings (B16.11): Small-bore field-welded; less rigorous NDE than butt-welded
- Flanged joints (B16.5 + B16.47): Bolted assembly + gasket; no field welding but requires bolted assembly per ASME PCC-1
- Valves (B16.34): Field-installed via flanged/butt-weld/threaded ends per valve specification
Wuxi ABK Equipment for B16-Referenced Fabrication
- Pipe spool fabrication with B16.9 fittings: Cell C pipeline spool configuration per Batch 20 #2 (HGZ + HBJ positioner + orbital TTW + fit-up)
- B16.5 flange welding to spool: Same Cell C configuration + specialty flange fixture
- Large diameter B16.47 flange to tank/vessel: HJK heavy rotator + LH-8080/80150 large-envelope manipulator
- B16.34 valve body welding to pipe/spool: Cell C or Cell A configuration depending on valve size + service
Common Specification Errors
- Wrong Class rating: Under-specified Class results in derating at service temperature; over-specified adds cost + weight
- B16.5 vs B16.47 boundary confusion: Ordering B16.5 for NPS 26+ flange fails as standard doesn’t cover; specify B16.47 correctly
- Series A vs Series B (B16.47): Not interchangeable; mismatch causes bolt-hole and gasket mismatch
- Material grade mismatch to service: Carbon steel A234 WPB in Cr-Mo P91 service unacceptable; PMI (Positive Material Identification) prevents installation mistakes
Summary
ASME B16.5 (Pipe Flanges and Flanged Fittings NPS 1/2-24) + B16.9 (Factory-Made Wrought Butt-Welding Fittings elbows/tees/reducers/caps NPS 1/2-48) + B16.11 (Forged Socket-Welding and Threaded Fittings NPS 1/8-4 small-bore) + B16.34 (Valves — Flanged, Threaded, Welding End Class 150-4500) + B16.47 (Large Diameter Steel Flanges NPS 26-60 Series A/B) comparison matrix. Class system 150/300/600/900/1500/2500/4500 pressure ratings with temperature derating. B16.5-B16.47 boundary at NPS 24/26. B16.47 Series A (heavier MSS SP-44 heritage) vs Series B (lighter API 605 heritage) not interchangeable. B16.9 fittings types (elbows + tees + reducers + caps + laterals + return bends). Materials A105 + A234 WPB/WP11/WP22/WP91 + F304/F316 stainless + Inconel/Hastelloy B564/B366 + duplex F51/F53/F55. B16.34 valve types (gate + globe + check + ball + butterfly + plug). Fabrication considerations (butt-welded field-welded WPS ASME IX; socket-welded small-bore; flanged bolted assembly ASME PCC-1; valve installation per valve spec). Common specification errors (wrong Class + boundary confusion + Series mismatch + material grade mismatch). Wuxi ABK Machinery equipment Cell C pipeline spool + HJK heavy rotator + LH large-envelope manipulator supports B16.5/9/11/34/47 fabrication + certification for refinery + petrochemical + pipeline + industrial pressure piping.
Contact: jan@weldc.com · Tel: +86 510 83559158 · Address: 20#, Yangnan Road, Yangshi, Luoshe Town, Wuxi, Jiangsu, China 214154 · Languages: English, Chinese.
Last updated: 2026-07-24.