For engineers, designers, and procurement professionals, precise dimensional data is the most critical information required to select and source industrial flanges. Flange dimensions—including the Outer Diameter (OD), Bolt Circle Diameter (BCD), and overall thickness—must match specific pipeline requirements to ensure joint integrity and interchangeability.
Furthermore, the weight of the flange types directly impacts stress calculations, structural support design, and shipping logistics. This guide outlines the importance of dimensional and weight charts and provides key points for comparing the three major international standards: DIN flange, ASME flange (ANSI), and JIS.
The Importance of Precise Flange Dimensions
Dimensional accuracy is non-negotiable for a leak-free flange connection:
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Bolting Alignment: The Bolt Circle Diameter (BCD) and the size/number of bolt holes must align perfectly between mating flanges and the bolting set. Misalignment is a primary cause of uneven bolt stress and subsequent gasket failure.
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Gasket Seating: The diameter and finish of the sealing face (e.g., Raised Face or Flat Face) are strictly controlled to ensure the gasket can create an effective seal under the required bolt load.
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System Integrity: Overall thickness and hub dimensions (especially on a Weld Neck flange) are tied to the pressure rating. Any deviation can compromise the flange’s ability to withstand the design pressure and temperature.
Comparing Dimensional Standards: DIN vs. ASME
While both systems define fixed pressure ratings and dimensions, their base units and common sizes differ significantly.
| Dimensional Factor | ASME Flange (ANSI) | DIN Flange |
| Primary Units | Imperial (inches) | Metric (millimeters) |
| Nominal Size | NPS (Nominal Pipe Size) | DN (Diamètre Nominal) |
| Pressure Rating | Class (e.g., Class 150, Class 300) | PN (Pressure Nominal, e.g., PN16, PN40) |
| Common OD/BCD | Dimensions are usually larger for a given nominal size compared to DIN. | Dimensions are typically smaller for a given nominal size compared to ASME. |
This fundamental difference means that ASME flange and DIN flange components are not dimensionally interchangeable, even if their nominal pressure ratings are roughly equivalent (e.g., Class 150 vs. PN16).
Related Guide: For a deeper look into the standards, see:
Comparison Between DIN, ANSI, and JIS Flanges
Weight Calculation and Relevance
The weight of an industrial flange is calculated based on its material density (e.g., carbon steel flange density vs. stainless steel flange density) and its volume, derived from the dimensions outlined in the respective standards.
Why Weight Matters:
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Structural Support: Accurate weight data is required by structural engineers to design pipe supports, hangars, and anchor points, especially for large-diameter flanges or long pipe runs.
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Logistics and Cost: Shipping costs for large projects are often determined by the total weight of the pipe fittings, making accurate weight charts essential for procurement and budgeting.
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Manufacturing Quality: Deviation from the standard weight can indicate manufacturing flaws (like voids or excessive material) or an incorrect material grade.
Accessing Dimensional and Weight Charts
Due to the voluminous nature of standard specifications (covering all sizes, ratings, and flange types like Blind, Slip-On, and Weld Neck), complete charts are best provided in a downloadable format.
We recommend using the official standards (ASME B16.5, EN 1092-1, or JIS B2220) as the final source of truth. However, summarized reference charts are invaluable for quick checks:
[Placeholder: Include a sample table snippet here, showing DN/NPS, OD, and BCD for a common rating like Class 150/PN16 to illustrate the data.]
| NPS / DN | Flange Type | Rating | Outer Diameter (mm/in) | Bolt Circle Diameter (mm/in) | Bolt Count |
| 4" / DN100 | WN / SO | ASME 150 | 228.6 / 9.0 | 190.5 / 7.5 | 8 |
| 4" / DN100 | WN / SO | DIN PN16 | 220 / 8.66 | 180 / 7.09 | 8 |
| 8" / DN200 | WN / SO | ASME 300 | 342.9 / 13.5 | 298.5 / 11.75 | 12 |
Deepen Your Flange Knowledge
Precise data leads to safe and cost-effective projects. Explore these related technical guides:
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Sealing Integrity: Ensure the dimensional accuracy translates into a tight seal:
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【锚点-Cluster Category V】Flange Bolting and Gasket Selection Guide
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Material Density: Understand how material choice influences weight and performance:
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Core Flange Resource: Return to our complete overview of all flange types and pipe fittings:
Download our complete DIN/ASME Flange Dimension and Weight Chart (PDF) for your design and procurement team.
