“If you are looking for a high-quality 1 1/2" Threaded Flange that meets ASME B16.5 standards, understanding the technical specs is the first step.”
In the world of industrial piping, precision is not just a requirement—it is a safety mandate. Among the various components used to join pipes, the 1 1/2" Threaded Flange (Class 150) stands out as a versatile, reliable, and "weld-free" solution for mid-sized systems.
As per the ASME B16.5 standard, these flanges are engineered to provide a secure transition between pipes, valves, and pumps. In this guide, we dive deep into the technical specifications and the unique advantages of the 1.5-inch NPT flange.
Understanding the Specs: 1.5" ASME B16.5 Class 150
When ordering an ASME B16.5 1.5 inch flange, knowing the exact dimensions is critical for site compatibility. For a Class 150 rating, the standard dictates the following physical properties:
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Nominal Pipe Size (NPS): 1 1/2" (DN 40)
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Outside Diameter (OD): 5.00 inches (127 mm)
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Bolt Circle Diameter: 3.88 inches (98.5 mm)
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Number of Bolt Holes: 4
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Diameter of Bolt Holes: 0.62 inches (16 mm)
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Thread Type: NPT (National Pipe Thread)
The internal bore is threaded with a taper, allowing it to match the external threads of a 1.5" threaded pipe. This creates a mechanical seal that is often reinforced with thread sealant or PTFE tape.
Why Choose a 1 1/2" Threaded Pipe Flange?
1. No Welding Required
The primary advantage of the 1 1/2 threaded flange is its ability to be installed without welding. This makes it the ideal choice for:
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Explosive Environments: Where open flames or sparks from welding are strictly prohibited (e.g., gas processing plants).
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Highly Flammable Areas: Locations where a "hot work permit" is difficult to obtain.
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Small-Scale Maintenance: Quick repairs where a welding rig isn't accessible.
2. High Versatility in Materials
Whether your application involves corrosive chemicals or high-temperature steam, the 1.5" threaded flange is available in various grades:
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ASTM A105 Carbon Steel: Cost-effective for oil and gas applications.
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SS316/316L Stainless Steel: Superior corrosion resistance for food, beverage, and pharmaceutical industries.
3. Ease of Maintenance
Because these flanges are bolted and threaded, they allow for easy disassembly. If a section of the pipe needs cleaning or replacement, the 1.5 inch NPT flange can be unscrewed without damaging the surrounding infrastructure.
Installation Best Practices
To ensure a leak-proof seal with your 1.5" threaded pipe flange, follow these industry standards:
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Inspect Threads: Ensure the NPT threads on both the pipe and the flange are clean and free of burrs.
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Use Quality Sealant: Apply a high-grade thread compound to prevent galling, especially on stainless steel flanges.
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Torque Sequence: Tighten the 4 bolts in a "star pattern" to ensure even pressure across the gasket face.
Check out our Top 5 Industrial Applications for 1.5" Flanges to see these specs in action.
