AWWA standard flanges

We supply AWWA standard flanges as following standards, pressures, sizes and types, if the needing flanges are not • in tables, please contact us specially, welcome to make inquiry us.

American Water Works Association (AWWA) is an international non-profit, scientific and educational association founded to improve water quality and supply. Established in 1881, it has a membership (as of 2012) of around 50,000 members worldwide.

General Information

Since the first edition of the AWWA Standard C207 was printed in 1952, AWWA flanges have commonly been used in waterworks, wastewater, slurry, plant piping, and other light duty applications. Pressure ratings for AWWA flanges range from the Class B flange rated at 86 psi to the Class F flange rated at 300 psi.

AWWA Vs. ANSI Flange Standards

Both the AWWA and ANSI have thorough standards for flanges, and the two standards are different in several ways.

Standards, Dimensions & Weightawwa-b-ring

Dimensional tolerances for AWWA pipe flanges


These tolerances are a part of ANSI B16.5 and AWWA C207-01 Sec. 4.2 except where noted otherwise.

Ring type Slip-on and Blind flanges HUB type slip-on
O.D. <=24″ +/- 0.6″(1.6mm) O.D. <=24″ +/- 0.6″(1.6mm)
>24″ +/- .12″(3.2mm) >24″ +/- .12″(3.2mm)
I.D. Socket-Welding 10″ and Samller
I.D. 10″ and Samller +.03″(0.8mm)
Slip-on and
Lap Joint
12″ and Larger
12″-18″ +/-.06″(1.6mm)
20″-42″ +.12″(3.2mm)
O.D. of Hub <=12″ +.09″(2.4mm),
Diameter of
Contact Face
0.06″ Raised Face +/-.03″(0.8mm)
14″-42″ +/-.12″(3.2mm)
Diameter of Contact face 0.06″ Raised Face +/- .03″(0.8mm) Diameter of Hub at base X<=24″ +/-.06″(1.6mm)
X>24″ +/-.12″(3.2mm)
Deameter of Contact face <=10″ +.03″(0.8mm),
Diameter of Hub at point of Welding <=5″ +.09″(2.4mm),
12″-42″ +.06″(1.6mm),
>=6″ +.16″(4.0mm),
Drilling Bolt Circle 1/2“-24″
Drilling Bolt Circle 1/2“-24″
Bolt hole
+/-.03″(0.8mm) Bolt hole
Eccentricity of Bolt circle with respect to bore .03″ Max.
Eccentricity of Bolt circle with respect to bore .03″ Max.
Thickness 18″& Small +.12″(3.2mm),-0″ Thickness 18″& Small +.12″(3.2mm),-0″
20″-42″ +.19″(1.6mm) 20″-42″ +.19″(1.6mm)
Length Thru Hub <=10″ +/-.06″(1.6mm) Length Thru Hub <=10″ +/-.06″(1.6mm)
12″-42″ +/1.12″(3.2mm) 12″-42″ +/1.12″(3.2mm)

--- Hot flanges by Sunny Steel ---

  • Blind Flanges, BL Flange, BLRF
    The blind flange is used to close ends of piping systems.