In industrial piping, precision is paramount. The 1 1/2" Threaded Flange (Class 150), governed by the ASME B16.5 standard, is a critical component for connecting pipe sections without the need for welding. Whether you are in the design phase or verifying field requirements, having accurate dimensional data for a 1.5 inch NPT flange is essential for a secure fit.
Why Choose a 1 1/2" Threaded Flange?
The 1.5" threaded pipe flange offers a perfect balance of mechanical integrity and installation speed. Unlike slip-on or weld-neck flanges, the threaded variety is ideal for:
-
Systems where welding is hazardous (explosive environments or refinery maintenance).
-
Low-pressure applications (Class 150) across water treatment and HVAC.
-
Maintenance-heavy areas where frequent disassembly is required.
Technical Specification Chart: 1.5" ASME B16.5 Class 150 Flange
The following table provides the standard measurements for a 1 1/2" (DN40) threaded flange. This data integrates both Imperial and Metric units to support global engineering standards from the USA to Australia.
| Specification Item | Imperial (Inch) | Metric (mm) |
| Nominal Pipe Size (NPS) | 1 1/2" (1.5 inch) | DN40 |
| Outside Diameter (OD) | 5.00" | 127 mm |
| Thickness of Flange (Min) | 0.69" | 17.5 mm |
| Diameter of Bolt Circle | 3.88" | 98.5 mm |
| Number of Bolt Holes | 4 | 4 |
| Bolt Hole Diameter | 0.625" | 16 mm |
| Recommended Bolt Size | 1/2" x 2-1/2" | M14 x 65 |
| Thread Type | NPT (Tapered) | ASME B1.20.1 |
| Approximate Weight | 3.3 lbs | 1.5 kg |
Engineering Tip: For a leak-free 1.5" NPT connection, the hand-tight thread engagement length should be approximately 0.420 inches (10.7 mm). Always use high-quality thread sealant or PTFE tape to ensure a pressure-tight seal.
Material Selection & Regional Performance
While dimensions are standardized by ASME B16.5, choosing the right material is vital for regional environmental conditions:
-
Carbon Steel (ASTM A105): The standard for non-corrosive service. Our 1.5 inch A105 flanges are ideal for industrial projects in Texas and Florida, often provided with anti-rust oil or galvanization.
-
Stainless Steel (SS316): Best for corrosive marine environments in the Sydney Basin or chemical processing plants in Queensland.
Global Standards Compatibility
Although manufactured to ASME B16.5, our 1.5" flanges are designed for compatibility with international project requirements, including BS 4504 (UK) and AS 2129 (Australia) cross-references where applicable.
Frequently Asked Questions (FAQ)
Q: What is the bolt pattern for a 1 1/2" Class 150 flange? A: It utilizes a 4-bolt pattern on a 3.88-inch (98.5 mm) bolt circle.
Q: Can this flange be used in "hot work" restricted areas? A: Yes. Since it is a threaded connection, no welding is required, making it the safest choice for explosive or volatile environments.
Q: Is the 1.5" threaded flange suitable for high-vibration systems? A: Threaded flanges are best for steady pressure. For high-vibration service, consider our Slip-On or Weld Neck options for added security.
Conclusion
Accurate 1 1/2" threaded flange dimensions are the foundation of a safe piping layout. By utilizing these standardized specs, you can reduce downtime and avoid compatibility errors on-site.
Looking for reliable inventory? Explore our [1 1/2" Threaded Flange - ASME B16.5 Class 150 A105] product page for real-time availability and technical support.
