What is npt thread

Straight thread applications are designed to simply hold pieces together, whereas a tapered thread, when torque is applied, will compress and seal the fitting.

Applications for tapered threaded pipes provide an effective seal for pipes transporting liquids, gases, steam, and hydraulic fluid. They are used in a wide range of industries—power plants, gas and oil, chemical, manufacturing, and shipping.

For example, many pressure systems onboard ships use BSP while many applications in the oil and gas industry use NPT fittings. Today, these two sealing systems are not inherently better than each other.

Each thread works effectively in spite of the two different designs. Standardization The necessity to standardize screw threads began in earnest with the onset of the Industrial Revolution in the early nineteenth century. Basics of thread Leakage testing. This site works better with javascript enabled. NPT - Pipe thread.

Other type of threads. Type of threads - Conversion factor. FAQ Basics of thread. NPTF threads have the same basic shape but with crest and root heights adjusted for an interference fit, eliminating the spiral leakage path. Need More Information? View our complete pipe fitting guide here. Recent Posts. Hold the fitting and thread gauge up to the light, looking for gaps between the gauge and thread.

This is easier to see on a male connection than a female one. Male thread diameter is measured on the OD; female thread diameter is measured on the ID. The Hose Safety Institute Handbook recommends holding the caliper at a slight angle for a more accurate male reading, and holding it perpendicular to the thread for a more accurate female reading.

If the pipe or fitting connection seals on a flared surface or inverted angle seat, determine that angle of seal with a seat angle gauge on the male connection. Place the gauge on the sealing surface; if the centerlines of connection and gauge are parallel, the correct angle has been determined.

For a female connection, insert the gauge into the connection and place it on the sealing surface. As with the male connection, if the centerlines are parallel, the correct angle has been determined. References Eaton Hydraulics.