ANSI Flange Bolt Size Chart (ASME B16.5 Standard)

In industrial piping systems, flange bolts are critical components used to connect two flanges, ensuring sealing integrity and system safety.

The most widely used standard today is ANSI/ASME B16.5, which specifies bolt sizes, quantities, and arrangement based on pressure classes.

1. What Are ANSI Flange Bolts?

ANSI flange bolts are fasteners designed according to the ASME B16.5 standard, used to:

• Connect two flanges together
• Tighten sealing gaskets
• Ensure high-pressure sealing integrity

2. Function of Flange Bolts

• Secure flange connections
• Withstand internal pipeline pressure
• Prevent leakage of fluids or gases
• Maintain industrial system safety

3. ANSI B16.5 Standard Requirements

The ASME B16.5 standard defines:

• Number of bolts per flange size
• Bolt diameter
• Bolt circle diameter (BCD)
• Bolt hole spacing

4. ANSI Flange Bolt Size Chart (Overview)

By Pressure Class

👉 Note: Exact dimensions vary depending on NPS (pipe size) and flange type.

5. How to Read ANSI Bolt Specifications

A typical bolt specification includes:

• Number of bolts
• Bolt diameter
• Bolt length
• Thread type (UNC/UNF or metric depending on system)

6. Applications of ANSI Flange Bolts

• Oil & gas plants
• Petrochemical refineries
• High-pressure steam systems
• Chemical industries
• Power plants
• Heavy industrial piping systems

7. Advantages of ANSI Flange Bolts

• High mechanical strength
• Excellent pressure resistance
• Standardized and easy replacement
• Fully compatible with ANSI flanges
• Globally recognized industrial standard

8. Important Selection Notes

• Always match bolt class with flange rating
• Check bolt material (B7, B16, SS304, SS316, etc.)
• Ensure correct bolt length
• Apply proper torque during installation

9. Reliable Supplier of Flanges & Bolts

If you need technical consultation or pricing for ANSI flange bolts, please contact:

Phuc Minh Engineering Co., Ltd
🌐 Website: pm-e.vn
📧 Email: info@pm-e.vn
📱 Hotline: +84 907 450 506 – +84 902 720 814 – +84 979 737 351

👉 We supply:

• Bolts, flanges, and industrial valves
• ANSI, DIN, and JIS standards
• Full CO-CQ documentation
• Technical support for projects

Conclusion

Understanding the ANSI flange bolt size chart helps ensure proper selection, system safety, and sealing performance in industrial piping systems.