Pocket Reference Guide: Flange Dimension Quick View Tool

Flange Dimension Quick View: ANSI, ASME, and DIN Charts Flange dimensions must match perfectly to ensure leak-free piping systems. Engineers and technicians frequently navigate different international standards to select the right components. This guide provides a streamlined overview of ANSI, ASME, and DIN flange dimensions to help you find the correct specifications quickly. Understanding the Standards

Flange standards define pressure ratings, materials, coatings, and precise dimensions.

ANSI (American National Standards Institute): Historical US standards, now largely integrated into ASME.

ASME (American Society of Mechanical Engineers): The current US standard governing pressure technology. ASME B16.5 covers flanges up to 24 inches, while ASME B16.47 covers larger sizes.

DIN (Deutsches Institut für Normung): The German European standard. It has been largely superseded by EN 1092-1, but DIN terminology remains widely used globally. Key Differences: ASME vs. DIN

The primary conflict in piping systems arises when mixing American and European standards. They do not match directly.

Measurement Units: ASME uses imperial inches. DIN uses metric millimeters.

Pressure Rating: ASME uses “Class” (e.g., Class 150, 300). DIN uses “PN” (Pressure Nominal, e.g., PN10, PN16) measured in bars.

Bolt Holes: Bolt circle diameters and the number of holes differ between equivalent sizes, preventing cross-standard bolting. ASME B16.5 Flange Dimension Reference

The following table provides quick reference dimensions for common ASME Class 150 flanges. Nominal Pipe Size (NPS) Outer Diameter (OD) Bolt Circle Diameter (BCD) Number of Bolt Holes Bolt Hole Diameter ⁄₂” 3.50” (89 mm) 2.38” (60 mm) 0.62” (16 mm) 1” 4.25” (108 mm) 3.12” (79 mm) 0.62” (16 mm) 2” 6.00” (152 mm) 4.75” (121 mm) 0.75” (19 mm) 4” 9.00” (229 mm) 7.50” (191 mm) 0.75” (19 mm) 6” 11.00” (279 mm) 9.50” (241 mm) 0.88” (22 mm) 8” 13.50” (343 mm) 11.75” (298 mm) 0.88” (22 mm) DIN / EN 1092-1 Flange Dimension Reference

The following table provides quick reference dimensions for common DIN PN16 flanges. Nominal Diameter (DN) Outer Diameter (OD) Bolt Circle Diameter (BCD) Number of Bolt Holes Bolt Hole Diameter DN 15 (⁄₂” equiv.) DN 25 (1” equiv.) DN 50 (2” equiv.) DN 100 (4” equiv.) DN 150 (6” equiv.) DN 200 (8” equiv.) Critical Inspection Checklist

Before installing any flange, verify these four critical dimensions:

Flange OD: Ensure physical clearance in tight piping layouts.

Bolt Circle Diameter (BCD): The critical measurement for aligning bolt holes.

Bolt Hole Count: A 2-inch ASME flange has 4 holes, but an 8-inch DIN PN16 flange has 12 holes compared to the ASME Class 150 equivalent of 8 holes.

Thickness: Ensures the flange can withstand the system pressure rating without warping.

If youg., Class 300, 600) or PN ratings (e.g., PN40) you need. The exact pipe sizes you are working with. The flange type (e.g., Weld Neck, Slip-On, Blind).

I can generate a highly specific dimensions table tailored to your exact project blueprint.