What are AWWA Flanges?

The American Water Works Association (AWWA), founded in 1881, was created to establish and unify key standards for waterworks systems. Today, AWWA is an internationally recognized non-profit organization that promotes research, education, and regulatory frameworks to ensure the highest quality of water supply and treatment practices worldwide.

AWWA’s membership includes water treatment professionals, utility organizations, manufacturers, scientists, environmentalists, regulators, and researchers in water supply and public health. North America alone has 43 AWWA sections, each contributing to the advancement of water industry standards.

AWWA developed its standards program in 1908 to support regulatory requirements for products, materials, and best practices in water supply management. Today, AWWA maintains over 150 standards covering a full spectrum of water supply components and processes, including:

• Water treatment chemicals
• Filtration materials
• Meters and measurement equipment
• Disinfection practices
• Valves and storage tanks
• Utility management techniques
• Pumps, pipes, and fittings

AWWA Flange Standards are distinct from ANSI (American National Standards Institute) and ASME (American Society of Mechanical Engineers) flange standards in several ways. While ANSI and ASME flanges are designed for high-pressure applications in industrial settings such as oil, steam, and chemical processing, AWWA flanges are specifically engineered for potable water applications.

Unlike ANSI and ASME standards, AWWA Flange Standards do not include provisions for welded auxiliary connections or tapping. Instead, they focus on a specific range of flange types that support low-pressure waterworks applications.

AWWA Flanges are categorized into three primary types:

• Slip-on Ring and Hub Type Flanges – Designed to be fitted over a pipe for secure attachment.
• Blind Flanges – Used to seal or close the end of a pipe or vessel.
• Threaded Iron Flanges – Designed to be screwed onto externally threaded pipes for a secure connection.

The AWWA Standards cover a variety of materials for pipes, flanges, and fittings, including:

• Plastic
• Ductile Iron
• Steel and Stainless Steel
• Concrete
• Asbestos-Cement

AWWA C207 does not specify a particular grade of steel, as long as the flange meets minimum physical and chemical property requirements, such as:

• Maximum Sulfur: 0.05%
• Maximum Phosphorus: 0.04%
• Maximum Carbon: 0.29%
• Minimum Tensile Strength: 50,000 psi
• Minimum Yield Strength: 32,000 psi

AWWA Standard Flanges are designed for light-duty applications, typically rated for performance at or below 300 psi. The most common pressure rating is AWWA Class D, which is rated at:

• 175 psi for sizes under 12 inches
• 150 psi for larger sizes

Common industries and applications for AWWA Flanges include:

• Waterworks and municipal water supply
• Slurry and wastewater treatment
• Plant piping for water distribution

As a cost-effective solution for low-pressure piping, AWWA Flanges are a practical alternative to ANSI or ASME forged flanges, which are designed for higher pressure applications and are typically more expensive.