Threaded (screwed) flanges for piping connections without welding. Ideal for low-pressure, non-critical applications and systems requiring frequent disassembly.
We maintain one of the largest inventories of threaded flanges in the Houston area. Every flange is manufactured to ASME, ANSI, and API standards with full material traceability and certification.
Threaded (screwed) flanges for piping connections without welding. Ideal for low-pressure, non-critical applications and systems requiring frequent disassembly.
A105, A182 F304/F316, A350 LF2
1/2" through 60" and larger custom sizes available
ASME B16.5, B16.47, API 605, MSS SP-44
NPT is the go-to threaded pipe connection across America. If you're working on a project in the U.S. or Canada, you're almost certainly dealing with NPT threads. They show up everywhere, from small instrument connections all the way up to large industrial piping systems.
The "taper" in National Pipe Taper is doing real work. NPT threads are cut on a taper of 1 inch per foot, so the diameter gradually gets smaller along the length of the thread. That taper is what makes the connection seal. Here's the basic technical breakdown:
When you thread a male NPT fitting into a female NPT fitting, the taper causes the threads to wedge together tighter and tighter the further you turn. Throw in a good thread sealant and you've got a connection that holds pressure and keeps fluid where it belongs.
The flattened crests and roots increase surface contact between the threads, which helps that metal-to-metal seal do its job. It's a simple, time-tested system - and the reason it's been the standard for as long as it has.
NPT threaded flanges range in 1/2 inch to 6" nominal pipe size for the most common, but we are able to offer threads up to 24" if needed, and custom beyond that. Larger diameter threaded connection make them less popular than a slip on or weld neck configuration due to labor costs. It may be of significantly beneficial use for an application which requires connecting and disconnecting occasionally.
| Nominal Pipe Size | OD (inches) | Threads Per Inch |
|---|---|---|
| 1/8" | 0.405 | 27 |
| 1/4" | 0.540 | 18 |
| 3/8" | 0.675 | 18 |
| 1/2" | 0.840 | 14 |
| 3/4" | 1.050 | 14 |
| 1" | 1.315 | 11.5 |
| 1-1/4" | 1.660 | 11.5 |
| 1-1/2" | 1.900 | 11.5 |
| 2" | 2.375 | 11.5 |
| 2-1/2" | 2.875 | 8 |
| 3" | 3.500 | 8 |
| 3-1/2" | 4.000 | 8 |
| 4" | 4.500 | 8 |
| 5" | 5.563 | 8 |
| 6" | 6.625 | 8 |
| 8" | 8.625 | 8 |
| 10" | 10.750 | 8 |
| 12" | 12.750 | 8 |
| 14" | 14.000 | 8 |
| 16" | 16.000 | 8 |
| 18" | 18.000 | 8 |
| 20" | 20.000 | 8 |
| 24" | 24.000 | 8 |
Low-Pressure Utility
Air Systems
Water Lines
Non-Hazardous Service
Temporary Connections
We supply flanges for data center cooling systems, fire suppression piping, and critical infrastructure. Hyperscale facilities require precision-manufactured flanges that meet demanding specifications for reliability and performance.
A threaded flange has NPT (National Pipe Thread) internal threads matching the pipe external threads. The pipe screws directly into the flange, eliminating the need for welding.
Avoid threaded flanges for temperatures above 500 degrees F (thread sealant degradation), cyclic service (thread loosening), toxic or flammable services, and pressures above Class 300.
Contact us for competitive pricing, technical specifications, and fast delivery on threaded flanges.