ASME B16.5 & B16.47
Comprehensive technical guide to ASME flange standards covering pressure ratings, materials, specifications, and applications for industrial piping systems worldwide.
Standard Overview
ASME B16.5
Scope:
Pipe flanges and flange fittings sizes 1/2 inch through 24 inch nominal pipe size
Pressure Classes:
150, 300, 400, 600, 900, 1500, 2500 ANSI ratings
Flange Types:
Blind, weld neck, slip-on, socket weld, threaded, lap joint, orifice
Approved Materials:
Carbon steel, stainless steel, and alloy steel specifications included
ASME B16.47
Scope:
Large diameter steel flanges for sizes 26 inch through 60 inch and larger
Series:
Series A and Series B with multiple pressure classes each
Applications:
Power generation, water systems, and large-diameter industrial piping
Materials:
Steel grades specified for strength and pressure requirements
ASME B16.5 Pressure Classes
Pressure ratings define the maximum working pressure at a reference temperature (100°F for carbon steel). Ratings decrease at elevated temperatures.
| Class Rating | Max Working Pressure | Max Service Temperature | Typical Applications |
|---|---|---|---|
| 150 | 285 PSI | 650°F | Low-pressure utility systems, general industrial |
| 300 | 740 PSI | 750°F | Standard industrial piping, process systems |
| 400 | 990 PSI | 800°F | Intermediate-pressure industrial piping |
| 600 | 1480 PSI | 850°F | High-pressure systems, elevated temperature |
| 900 | 2220 PSI | 950°F | Very high pressure, extreme temperature service |
| 1500 | 3705 PSI | 1050°F | Ultra-high pressure, critical applications |
| 2500 | 6170 PSI | 1100°F | Maximum pressure systems, specialized applications |
Approved Materials
ASME standards specify approved materials with detailed chemical composition, mechanical properties, and testing requirements.
| ASTM Standard | Material Type | Typical Applications |
|---|---|---|
| ASTM A105 | Carbon Steel Forgings | General service, standard |
| ASTM A350 | Low-temperature Steel Forgings | Cryogenic and low-temp service |
| ASTM A182 F304 | Stainless Steel | Corrosive environments, general stainless |
| ASTM A182 F316 | Molybdenum Stainless | Enhanced corrosion resistance |
| ASTM A182 F11 | Chrome-Moly | Elevated temperature power generation |
| ASTM A182 F22 | Chrome-Moly | High-temp steam systems |
| ASTM A182 F91 | Advanced Chrome-Moly | Extreme temperature applications |
Material Selection Considerations
Temperature Service
- • Carbon Steel: -20°F to 650°F normal range
- • Stainless: -20°F to 850°F
- • Alloy Steel: up to 1050°F and beyond
Corrosion Resistance
- • Stainless for general corrosion resistance
- • Alloys (duplex, super-alloys) for extreme corrosion
- • Low-temp steel for cryogenic service
ASME Flange Types Covered
ASME B16.5 specifies eight primary flange types with detailed dimensional and pressure-boundary requirements.
Blind Flanges
View Details →Weld Neck Flanges
View Details →Slip-On Flanges
View Details →Socket Weld Flanges
View Details →Threaded Flanges
View Details →Lap Joint Flanges
View Details →Orifice Flanges
View Details →Long Weld Neck Flanges
View Details →Key Specifications & Requirements
Dimensional Accuracy
ASME B16.5 specifies precise dimensional tolerances for all flange types and pressure classes.
- ✓ Bore tolerances per class
- ✓ Bolt hole location tolerances
- ✓ Facing specifications (RTJ, flat, raised)
- ✓ Thickness requirements per class
Testing & Inspection
All ASME flanges require compliance testing per standard procedures and documentation.
- ✓ Hydrostatic pressure testing
- ✓ Material certification requirements
- ✓ Dimensional verification
- ✓ Full traceability documentation
Quality Standards
Manufacturing must follow strict quality procedures to maintain ASME compliance.
- ✓ Material certs (MILL certificates)
- ✓ Pressure test reports
- ✓ Dimensional inspection certs
- ✓ Full documentation package
ASME vs Other Standards
How ASME standards compare to other major international specifications.
ASME vs DIN/EN
Rating System:
ASME uses Class (PSI-based), DIN uses PN (bar-based)
Geography:
ASME dominant in North America, DIN in Europe
Interchangeability:
Can be used together with conversion factors
ASME vs AWWA
Application Focus:
ASME for industrial, AWWA for water utilities
Size Range:
ASME up to 60", AWWA up to 144" typical
Overlap:
ASME B16.47 competes with AWWA for large diameters
ASME B16.5 vs B16.47
Size Coverage:
B16.5 up to 24", B16.47 from 26" and larger
Pressure Classes:
B16.5 has more standard classes available
Applications:
B16.47 for large industrial systems, power plants
Related Standards & Resources
All Standards
Overview of ASME, ANSI, AWWA, and DIN standards with comparisons.
View Standards Hub →Flange Products
Our complete line of ASME-certified flanges in all types and pressure classes.
View Flange Catalog →Material Standards
ASTM material specifications approved for ASME flange manufacturing.
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