How To Measure NPT Fittings

NPT (National Pipe Thread) fittings are one of the most commonly used fittings in plumbing applications. They are used to connect pipes fittings to each other are available in different sizes. Measuring NPT fittings is a crucial task as it determines the compatibility of the fittings with the pipes. If the measurement is not accurate it can lead to leakage which can cause damage to the pipes fittings. Here is a guide on how to measure NPT fittings:

Understanding NPT Thread

Before measuring the NPT fitting it’s important to understthe NPT thread. NPT threads have a slight taper which means the diameter of the fitting size decreases slightly towards the end of the fitting.

Measuring the Fitting Diameter

The first step to measuring NPT fittings is to measure the fitting diameter. You can use a caliper or a ruler to measure the outside diameter (OD) of the fitting. For example if you’re measuring a ¾” NPT fitting the OD will be around 1.05 inches (26.67mm).

Measuring the Thread Pitch

The second step is to measure the thread pitch. It’s the distance between the threads is measured in threads per inch (TPI). Again you can use a caliper or a ruler to measure the TPI. For example if you’re measuring a ¾” NPT fitting the TPI will be around 14 threads per inch.

Calculating the Taper

The third step is to calculate the taper. The taper is the gradual decrease in diameter of the fitting towards the end. It’s important to understthe taper as it helps to ensure a proper fit between the fitting the pipe. The taper is usually 1/16″ per inch of length. For example if you’re measuring a 1” NPT fitting the taper will be around 1/16” or 0.0625 inches.

Conclusion

In conclusion measuring NPT fittings is an important task that protects the plumbing system from leaks damages. Understanding the NPT thread measuring the fitting diameter the thread pitch calculating the taper are crucial steps to ensure a proper fit between the fitting the pipe. By following these steps you can accurately measure NPT fittings ensure a secure tight connection.