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WHAT IS AWWA?
AWWA Flange Standards differ from ANSI (American National Standards Institute) and ASME (American Society of Mechanical Engineers) certifications in a variety of ways, the most important being their specificity: AWWA standards evaluate properties that particularly affect potable water use, as opposed to broader industrial flange applications.
AWWA Certified Flange Types
Unlike ANSI and ASME standards, AWWA Flange Standards do not address welded auxiliary connections or tapping. They cover a very specific range of flange types, including:
(1)Slip-on Ring and Hub Type Flanges, fitted over a pipe
(2)Blind Flanges, to seal or close a pipe or vessel
(3)Threaded Iron Flanges, fitted to externally threaded pipes
AWWA flange specifications :
Dimensions | ANSI/ASME B16.5, B16.47 Series A & B, B16.48, BS4504, BS 10, EN-1092, DIN, etc. |
Standard | ANSI Flanges, ASME Flanges, BS Flanges, DIN Flanges, EN Flanges, etc. |
Size | 1/2″ (15 NB) to 48″ (1200NB) |
Class / Pressure | 150#, 300#, 600#, 900#, 1500#, 2500#, PN6, PN10, PN16, PN25, PN40, PN64 etc. |
Flange Face Type | Flat Face (FF), Raised Face (RF), Ring Type Joint (RTJ) |
Dimensional tolerances
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 | 12″ and Larger | 12″-18″ | +/-.06″(1.6mm) | ||
20″-42″ | +.12″(3.2mm) | ||||
O.D. of Hub | <=12″ | +.09″(2.4mm), | Diameter of | 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″ |
+/-.06″(1.6mm) | +/-.06″(1.6mm) | ||||
Bolt hole | +/-.03″(0.8mm) | Bolt hole | +/-.03″(0.8mm) | ||
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) | ||
These tolerances are a part of ANSI B16.5 and AWWA C207-01 Sec. 4.2 except where noted otherwise. The limits given are maximum. Rigid inspection procedure assures the maintenance of high standards of accuracy in regular day to day production.
