AWWA Flange Standards
American Water Works Association standards for water and wastewater treatment flanges. Comprehensive guide to AWWA C207 and C228 specifications for large-diameter applications.
AWWA Standards Overview
AWWA C207
Steel Pipe Flanges for Water Works Service
Scope:
4" to 144" hubbed or fabricated steel pipe flanges
Classes:
Classes B (86 psi), D (175 psi at NPS 4-12 / 150 psi above NPS 12), E (275 psi), F (300 psi, NPS 4-48 only) per AWWA C207
Materials:
ASTM A105 (forged hubs), A516 / A36 (plate, fabricated)
AWWA C228
Stainless-Steel Pipe Flanges for Waterworks Service
Scope:
Stainless steel plate (and forged) pipe flanges for cold or chemically aggressive waterworks environments where carbon steel C207 is not appropriate.
Construction:
Stainless steel plate or forging (typically 304/304L or 316/316L); flat-face geometry consistent with C207 drilling patterns.
Pairing:
Used in place of, or alongside, C207 carbon steel flanges where corrosion resistance is required. Cast and ductile iron pipe joint specs (C111/A21.11, C153/A21.53) are pipe joint standards, not flange standards.
AWWA Mission
AWWA standards are specifically designed for the water utility industry, addressing the unique requirements of municipal water treatment, distribution, and wastewater systems. Unlike ASME standards, AWWA standards emphasize materials and designs suitable for long-term water service applications.
AWWA Pressure Classes
AWWA pressure classes define maximum working pressure for water utility applications at standard reference conditions.
| AWWA Class | PSI Rating | Application | Typical Use |
|---|---|---|---|
| Class B | 86 PSI | Low-pressure water systems | Gravity-fed systems, storage tanks |
| Class D | 175 PSI (NPS 4-12) 150 PSI (NPS > 12) | Standard municipal service | Distribution, standard pumping |
| Class E | 275 PSI | Higher pressure transmission | Long-distance mains, booster stations |
| Class F | 300 PSI | Maximum AWWA C207 pressure (NPS 4-48 only) | Critical high-pressure water service |
Key Characteristics
AWWA standards address the unique requirements of water utility systems and large-diameter applications.
Large Diameter Focus
AWWA standards cover pipe diameters from 4" to 144" and beyond, addressing the complete range of municipal water distribution systems.
- ✓ Forged and fabricated steel construction
- ✓ Fabricated steel plate flanges
- ✓ Economical large-diameter options
- ✓ Bolting standardization for large flanges
Water Service Optimization
Materials and designs selected specifically for long-term water service and corrosion resistance in water environments.
- ✓ Materials specified for potable water service
- ✓ Corrosion-resistant specifications
- ✓ Interior coating considerations
- ✓ Durability in continuous water service
Cost Effectiveness
AWWA standards optimize cost for large-diameter, typically low-to-moderate pressure utility applications.
- ✓ Fabricated steel economical for large diameter water and wastewater service
- ✓ Fabricated steel for large sizes
- ✓ Pressure-optimized design
- ✓ Long service life
AWWA Applications
AWWA standards are the primary specifications for water utility infrastructure systems.
Water Treatment Plants
Clarifiers, filters, and interconnecting piping in treatment facilities
Distribution Mains
Large-diameter transmission lines and major distribution pipelines
Wastewater Treatment
Clarifiers, basins, and process equipment in wastewater plants
Pump Stations
Discharge and inlet piping in water and wastewater pumping facilities
Reservoirs & Storage
Storage tank connections and distribution outlet piping
Hydrant Systems
Fire protection mains and hydrant connection systems
Irrigation Systems
Agricultural and municipal irrigation distribution networks
Booster Stations
High-pressure intermediate pumping and pressure regulation
AWWA vs Other Standards
How AWWA specifications compare to ASME and other industrial standards.
AWWA vs ASME
Purpose:
AWWA for water utilities, ASME for industrial piping
Pressure Range:
AWWA typically low-to-moderate, ASME full range
Size Coverage:
AWWA focuses on large diameters (4"-144"+)
Materials:
AWWA C207 is steel only (forged and fabricated); ASME primarily forged steel
Key Differences
- ✓ AWWA: 4" minimum, ASME: 1/2" minimum
- ✓ AWWA: ~86-300 PSI typical (C207 Classes B/D/E/F); ASME: Class 150 through Class 2500 (up to 6170 PSI at 100°F)
- ✓ AWWA: Water utility specific, ASME: Multi-industry
- ✓ Both: Can be used in same project with considerations
Related Standards & Resources
Standards Overview
Complete guide to ASME, ANSI, AWWA, and DIN standards with comparisons.
View All Standards →Flange Products
Our complete line of flanges including AWWA-compliant options for water systems.
View Flanges →ASME Standards
Technical guide to ASME B16.5 and B16.47 for industrial applications.
View ASME Guide →Need AWWA Flanges for Your Water System?
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