Class 125 ASTM A126 Gray Iron Casting Flange
Class 125 ASTM A126 Flange
The Class 125 ASTM A126 Flange provides a durable and dependable connection for commercial and industrial piping systems. ASTM A126 is commonly associated with gray iron castings used in valves, flanges, and pipe fittings, making these Class 125 flanges suitable for many water, utility, mechanical, and general industrial piping applications.
ASTM A126 Gray Cast Iron Construction
ASTM A126 covers gray iron castings intended for use in valves, flanges, and pipe fittings. Gray cast iron provides good compressive strength, dimensional stability, machinability, and vibration-dampening characteristics for appropriate piping applications.
Class 125 ASTM A126 flanges and compatible components are commonly found in water distribution, HVAC systems, mechanical piping, utilities, pump installations, manufacturing facilities, fire protection systems, and general industrial piping.
Because ASTM A126 specifies gray cast iron rather than forged carbon steel, material identification is important when selecting mating flanges, gaskets, and bolting.
Class 125 Flange Applications
The Class 125 designation is commonly used with cast iron flanges and flanged equipment. It represents a pressure class rather than simply indicating a maximum working pressure of 125 PSI. Actual allowable pressure depends on material grade, component design, operating temperature, size, and the applicable dimensional and pressure standard.
Class 125 flanges may be used to connect pipe, valves, pumps, strainers, fittings, and other compatible flanged equipment.
Flat-Face Flange Connections
Class 125 cast iron components commonly use a flat-face (FF) configuration. Flat-face connections help distribute gasket and bolting loads across a broader surface, an important consideration when working with more brittle cast iron components.
Proper gasket selection and controlled bolt tightening are essential to avoid excessive flange stresses.
Selecting ASTM A126 Class 125 Flanges
When specifying a Class 125 ASTM A126 flange, verify the nominal pipe size, ASTM A126 grade, flange facing, dimensional standard, drilling pattern, gasket type, bolting requirements, operating pressure, temperature, and mating component material.