ANSI (American National Standards Institute) flanges are essential components in piping systems, ensuring secure connections between pipes, valves, and equipment. They are classified by pressure ratings, dimensions, and material specifications to ensure compatibility and safety in various industrial applications.
ANSI Flange Dimensions
ANSI flanges follow standard dimensions set by ASME B16.5 (for pipe sizes up to 24 inches) and ASME B16.47 (for larger sizes). The key dimensions include:
- Outer Diameter (OD): Determines the overall size of the flange.
- Bolt Circle Diameter (BCD): The circle on which bolt holes are located.
- Bolt Hole Diameter & Number of Holes: Essential for proper bolting alignment.
- Flange Thickness: Affects pressure handling capacity.
- Raised Face (RF) or Flat Face (FF): Determines the type of gasket seating surface.
- Hub Diameter & Length: Varies depending on flange type.
ANSI Flange Pressure Classes & Their Dimensions
Flanges are categorized based on pressure ratings, ranging from Class 150 to Class 2500. Below is a general guide to dimensions for common ANSI flange classes:
Class 150 Flange Dimensions (Example for 6″ Pipe Size)
- OD: 11.00 inches
- BCD: 9.50 inches
- Bolt Holes: 8 holes, 0.88-inch diameter
- Thickness: 0.88 inches
- Weight: Approximately 22 lbs (varies by material)
Class 300 Flange Dimensions (Example for 6″ Pipe Size)
- OD: 12.50 inches
- BCD: 10.62 inches
- Bolt Holes: 8 holes, 0.88-inch diameter
- Thickness: 1.12 inches
- Weight: Approximately 37 lbs
Class 600 Flange Dimensions (Example for 6″ Pipe Size)
- OD: 14.00 inches
- BCD: 12.00 inches
- Bolt Holes: 8 holes, 1.00-inch diameter
- Thickness: 1.50 inches
- Weight: Approximately 70 lbs
ANSI Flange Weights
The weight of a flange depends on its material, pressure rating, and size. Below is an estimated weight chart for different ANSI flange classes for a 6-inch nominal pipe size:
| Flange Class | Weight (lbs) |
|---|---|
| 150 | 22 |
| 300 | 37 |
| 600 | 70 |
| 900 | 120 |
| 1500 | 190 |
| 2500 | 320 |
For larger pipe sizes and higher pressure classes, weights increase significantly due to additional material thickness and reinforcement.
Selecting the Right Flange
When choosing an ANSI flange, consider the following factors:
- Operating Pressure & Temperature: Ensure the flange class meets system requirements.
- Material Selection: Common materials include carbon steel, stainless steel, and alloy steel.
- Gasket Compatibility: Raised Face (RF) or Ring-Type Joint (RTJ) gaskets may be required.
- Application Requirements: Flange type (weld neck, slip-on, blind, etc.) affects performance and installation.
For more detailed flange dimension charts and weight calculations, visit: TEXAS FLANGE DIMS / WEIGHTS