ASTM A126 Class 125 Gray Iron Castings Blind Flat-Face Flange
Class 125 ASTM A126 Gray Iron Blind Flat-Face Flange
The Class 125 ASTM A126 Gray Iron Castings Blind Flat-Face Flange provides a durable and dependable method for closing or isolating compatible commercial and industrial piping systems. Manufactured from gray cast iron with a solid blind design and flat-face sealing surface, this flange is commonly used with water, mechanical, utility, HVAC, and general industrial piping equipment.
ASTM A126 Gray Iron Castings
ASTM A126 covers gray iron castings intended for use in valves, flanges, and pipe fittings. Gray cast iron offers good compressive strength, dimensional stability, machinability, and vibration-dampening characteristics for appropriate piping applications.
Class 125 ASTM A126 components are commonly found in water distribution, HVAC systems, mechanical piping, utilities, pump installations, manufacturing facilities, fire protection systems, and general industrial piping applications.
Class 125 Blind Flange Design
A blind flange has no center bore and is designed to completely close the end of a flanged piping connection, valve, equipment nozzle, or unused system opening. Its removable bolted construction allows access when needed without permanently altering the piping system.
Blind flanges provide convenient access for system isolation, inspection, cleaning, maintenance, pressure testing, equipment servicing, piping modifications, and future expansion.
The Class 125 designation represents a pressure class rather than a maximum operating pressure of exactly 125 PSI. Actual allowable pressure depends on the material grade, component design, operating temperature, size, and applicable standard.
Flat-Face Flange Construction
The flat-face (FF) design provides a gasket seating surface extending across the flange face. Flat-face construction is commonly used with gray cast iron components because it helps distribute gasket and bolting loads across a broader area.
Proper gasket selection and controlled bolt tightening are especially important with gray cast iron because the material is more brittle than forged steel.
Selecting an ASTM A126 Blind Flange
When ordering a Class 125 ASTM A126 gray iron blind flat-face flange, verify nominal pipe size, ASTM A126 grade, Class 125 rating, flat-face configuration, dimensional standard, bolt pattern, gasket type, bolting requirements, operating temperature, and mating flange compatibility.