Tapped Blind Flange | NPT Threaded Test Flange

NPT Threaded Test Flange for Piping Systems

A Tapped Blind Flange, also known as a NPT Threaded Test Flange, is a blind flange machined with one or more NPT threaded holes.
It is primarily used for pressure testing, venting, draining, chemical injection, and instrument connection in piping systems.

Compared with standard blind flanges, tapped blind flanges provide greater flexibility during commissioning, testing, and maintenance, making them widely used in oil & gas, petrochemical, power generation, and industrial piping applications.

Test Flange is made of the blind flange,with tapped NPT Threaded hole in the middle.

Normally,the blind flange are with 1/2 npt tapped thread

These include NPT tapped holes and special threads to allow pressure test connections to be fitted.  Blind flanges are generally used to blank off the ends of pipe.  They are also used on similar valves and pressure vessel openings.  Because they are often located at the ends of systems, these flanges often are among the highest stressed flange types.

Materials Available

Tapped blind flanges can be manufactured in a wide range of materials, including:

• Carbon Steel:

  • ASTM A105 / A105N

  • ASTM A350 LF2

• Stainless Steel:

  • ASTM A182 F304 / F304L

  • ASTM A182 F316 / F316L

• Duplex & Super Duplex:

  • ASTM A182 F51 / F53 / F55

ALUMINUM – 1100, 2014, 3003, 5083, 5086, 6061, 7075

HASTALLOY – B-2, C-276, G, X

INCONEL – 600, 601, 625, 718

INCOLLOY – 800, 825

MONEL – 400

Tapped blind flanges with NPT threaded connections provide a practical and reliable solution for testing, venting, and instrumentation in pressure piping systems.
With customizable design, wide material availability, and compliance with ASME standards, these flanges are an essential component for efficient pipeline commissioning and maintenance.

Related Products

• Blind Flanges (RF / RTJ)

• Test Plugs & Pressure Testing

• Weld Neck Flanges