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NPT Vs MIP: Working And Functionality Explained

Pipe threads and fitting sizes refer to the physical dimensions of the fittings and may not always indicate the diameter of the pipe. The measurement of thread size in the plumbing sector is called the “nominal” pipe thread size, which represents the inside diameter of the pipe size.

This distinction can be difficult because the industry uses a variety of words, and if you’re not sure what to measure or where to look, you could end up with misguided adjustments. It can be difficult to determine the appropriate type of thread by measuring the size of the pipe thread.

The dimensions of the thread are nominal and do not correspond to the standard units of measurement. Since choosing the right pipe thread type is essential for the maintenance and installation of equipment, we are proud to help you determine the pipe thread you need.

NPT Fitting

National conical tube thread, commonly known as ANSI/ASME tube threads B1.20.1, is a type of tube thread. It is a measurement standard for conical threads in threads and threaded fittings in the United States. For hydraulic liquid pipes, threaded pipes can provide a good seal. 

NPT threads, also known as MPT (male tube threads) are not interchangeable with national straight tube threads (NPS). A conical thread pulls out more firmly in contrast to straight bolt threads, resulting in a denser seal. To ensure waterproofing without leakage, apply a sealant tape or PTFE (polytetrafluoroethylene).

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  • The angle between the cone and the central axis of the pipe shall be 1° 47′ 24″ (1,7800°).
  • The roots are pruned and the tips are flat
  • Thread angle of 60 degrees
  • Tar is defined as the number of threads per inch (TPI)

External and internal pipe threads are included in the NPT thread size table. A cone rate of 1/16 to 3/4 inches per leg (62.5 mm per m) is measured by increasing the diameter at a distance in all NPT threads. The external diameter of a pipe or fitting (OD) shall also be measured; Both TPI and OD are necessary to correctly identify the size of the thread, because the TPI may vary depending on the size.

The following sizes are commonly used: 1/8, 1/4, 3/8, 12, 34, 1, 1 14, 1 12, and 2 inches. Most American suppliers use them on their pipes and fittings. Less than 1/8 size is less common because larger sizes require the use of other joining methods.

MIP Fitting

In a range of piping systems in residential, commercial and industrial settings, MIP fittings are used in combination with FIP components. Since the materials used for the production of MIP fittings differ depending on the application, it is important to choose the right ones for each job.

Before changing or installing MIP piping systems, check with local authorities to see if you have any professional training in piping. For robust threaded pipe connections, a MIP fitting is one of two components.

Male Iron Pipe is the most common abbreviation (it can also refer to other building materials such as copper or steel). The FIP, which stands for Female Iron Pipe, is the other component. Inside, the inner fitting is threaded to obtain a threaded outer tube fitting of equal diameter, with threads that shrink to create a tight seal.


To better withstand unintentional damage and avoid pipe failures, a metal thread pipe is thicker and sturdier than threadless piping. Some pressure-free plumbing systems, such as sink drains can use PVC plastic pipes with threaded connections. Plastic threads are weaker than metal wires and more susceptible to leakage.

Thread MIP pipe fittings are commonly use in high-performance pipes in high-pressure systems, as well as in pipes that carry potentially hazardous gases such as natural gas. Thread pipes are often used to make safe, airtight connections that may need to dismantle in the future.

For example, for natural gas and water connections, a flexible metal pipe with thread pipe fittings uses to facilitate the repair of a defective furnace or water heater.

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What are the similarities between NPT and MIP?

The fact that pipe fittings have so many different descriptive names causes the most confusion. 

The male iron tube or the male international tube is the abbreviation of the male iron tube. Male MPT or pipe thread is another name for the same pipe size. Fip stands for female (or international) iron tube, while FPT stands for female tube thread.  

The NPT, which represents the national threading of tubes, adds to the confusion. You can do it in the most confusing way possible by Wikipedia: male threads are sometimes saying MPT (Male Tube Thread), MNPT or NPT (M), and female threads are saying FPT (female pipe thread), FNPT, or NPT (F).

The thread diameters NPT (National Pipe Thread) are the same as those of the MIP (Male Iron Pipe) and the FIP (Female Iron Piping) or Iron Bushing.

What is the difference between NPT and MIP?

The NPT also knows as ANSI/ASME B1.20.1 pipe threads whereas the MIP is copper or steel fittings. The material of NPT is PVC and plastic but the material of MIP is copper, plastic, PVC, and steel. The shapes of both fittings are different, the NPT angle is between the centre and taper axis but the shape of MIP is straight.

We recommend application with high pressure of NPT is but MIP fitting is not. NPT is compatible with FNPT fittings and MIP is compatible with FIP fitting. The NPT has flat truncation of root and crests whereas the MIP has may be flat or non-flat truncation of root and crests.

You can apply NPT fitting for your residential area but MIP can apply on the commercial, industrial and residential systems. The tightening recommendation is only available in NPT. And the last one NPT has Sealant compound or PFTREE (Polytetrafluoroethylene) tape and MIP has Pipe dope or Teflon tape.

MIP is a heavy-duty piping system for both industrial and commercial systems whereas NPT is not that type of heavy-duty system.


Female pipe threads (FPT) (interchangeable with NPT) tube fittings that accommodate MIP (male iron tube) or MNPT (male tube national thread) are says as FPT. Internal threads are located in the pipe or lying. The threads in the pipes and MPT fittings are located on the outside of the pipe or fitting.

Choose the best fitting for your residence and your commercial area. Now you may get proper guidance in regards to NPT and MIP with their features and work. Try to read the article completely and choose your best fit!