NPT (National Pipe Thread) and NPSM (National Pipe Straight Mechanical) are two common pipe thread standards used to connect and seal fittings in piping systems. Although they are both American National Standards, they differ in some important ways. This article will introduce the difference between NPT and NPSM to help us better understand their different uses in practical applications.
1. What are NPT?
NPT (National Pipe Thread) and NPSM (National Pipe Straight Mechanical) are two common pipe thread standards used to connect and seal fittings in piping systems. Although they are both American National Standards, they differ in some important ways. This article will introduce the difference between NPT and NPSM to help us better understand their different uses in practical applications.
2. What are the characteristics of NPT?
NPT has the following characteristics:
Tapered Design: NPT threads are tapered, with threads at a 45-degree angle. This design creates a good seal when tightened, preventing leaks. Due to the taper of the thread, when the thread is screwed in, the sealant will be squeezed and fill the gap between the threads, thus forming a sealing effect.
Watertight: NPT threads are suitable for applications requiring a high degree of sealing, such as gas and liquid transmission systems. It is designed to provide a reliable seal and reduce the risk of leakage.
Wide application: NPT thread is widely used in various industrial fields, such as chemical industry, petroleum, pharmaceutical and food processing, etc. It is considered as a common pipe thread standard and is widely adopted in many countries and regions.
Thread size: The size of NPT thread is expressed in inches, common sizes include 1/8 inch, 1/4 inch, 1/2 inch, etc. NPT threads in larger sizes are typically used for larger diameter pipe.
3. Main application fields of NPT
Industrial piping system: NPT threads are widely used in various industrial piping systems, including chemical plants, petroleum refineries, power stations, pharmaceutical plants and food processing plants, etc. They are used to connect and seal various fittings in pipelines, such as valves, joints, elbows and flanges, etc.
Liquid transmission system: NPT thread plays an important role in liquid transmission system, such as water treatment system, water supply pipeline, fire protection system and cooling system, etc. They ensure the leak-tightness of pipe connections against leakage and loss of fluids.
Gas transmission system: NPT threads are also widely used in gas transmission systems, including gas pipelines, pneumatic systems and gas supply systems, etc. They provide reliable airtightness for safety and efficiency during gas transfer.
Instrument equipment and mechanical connections: NPT threads are used to connect various instrument equipment and mechanical components, such as pressure gauges, measuring instruments, cylinders and pipe connectors, etc. They provide an easy and reliable connection for easy installation and removal.
4. How to choose NPT?
When choosing an NPT, you need to consider the following points:
Application requirements: First of all, the needs and requirements of the application must be clarified. Determine the working pressure, medium type (liquid or gas), working temperature range and sealing requirements of the piping system. NPT threads are suitable for general liquid and gas transmission systems, but for high pressure or special media applications, other thread standards may need to be considered.
Standard requirements: understand relevant standards and norms, such as ASME standards in the United States. Make sure that the selected NPT thread complies with the applicable standard requirements and meets the regulations and safety standards of the country or region in which it is located.
Size selection: Select the appropriate NPT thread size according to the pipe diameter of the piping system and the size of the required connection. Common sizes include 1/8 inch, 1/4 inch, 1/2 inch, etc. It is important to note that larger NPT threads are typically used for larger diameter pipe.
Material selection: choose the appropriate material according to the specific application environment and medium characteristics. Common NPT thread materials include copper, brass, stainless steel, and carbon steel. Make sure that the selected material has good corrosion resistance and pressure resistance.
Refer to professional advice: If you still have doubts or uncertainties when choosing an NPT thread, it is recommended to consult a professional or supplier for advice. They can provide more specific advice and guidance on a case-by-case basis, ensuring that the appropriate NPT thread type is selected.
5. What is NPSM?
NPSM (National Pipe Straight Mechanical) is a pipe thread standard, which has some differences compared with NPT (National Pipe Thread). NPSM threads are a straight-grain design for applications that do not require a high degree of sealing.
NPSM threads have a straight grain design and the threads are in a parallel shape, unlike the tapered threads of NPT. This design makes NPSM threads suitable for some situations that do not require a high degree of sealing. In contrast, NPSM threads do not provide the same sealing effect as NPT threads when tightened.
NPSM threads are commonly used for lighting, household appliances, mechanical connections, and some applications that do not involve high pressure or tightness. For example, some mechanical components or equipment installations may use NPSM threads because it provides a convenient connection and does not require a high degree of sealing performance.
6. What are the characteristics of NPSM?
NP SM has the following characteristics :
Straight grain design: NPSM thread adopts straight grain design, which is different from the tapered thread of NPT (National Pipe Thread). The straight grain design makes the installation and removal of NPSM thread more convenient and quick, and the connection can be completed without too many turns.
Suitable for low-voltage applications: NPSM threads are often used in some low-voltage applications, such as lamps, household equipment and mechanical connections. Due to the characteristics of the straight grain design, the sealing performance of the NPSM thread is relatively weak, so it is suitable for some occasions that do not require a high degree of sealing.
Multi-field application: NPSM threads are widely used in many fields. In addition to lamps and household equipment, it can also be used in mechanical components, industrial equipment and some pipeline connections with low non-tightness requirements.
Easy to identify: NPSM threads have some special markings on the thread size. The combination of letters of "NPSM" is usually used to indicate the thread type, and the specific size of the thread is indicated by the size specification.
7. NPSM main application areas
Lighting industry: NPSM threads are widely used in the connection of lighting equipment and lamps. For example, NPSM threads are often used for connection between the lamp cap and the lamp holder to ensure the stable installation and electrical connection of the lamp.
Household equipment: NPSM threads also have important applications in household equipment, such as home appliances, faucets and bathroom accessories. They are used to connect different components and pipes to ensure the stability and proper operation of the equipment.
Mechanical Engineering: NPSM threads are widely used in the field of mechanical engineering, such as mechanical parts, pneumatic systems and hydraulic systems, etc. They are used to connect pipes, valves, joints and pressure sensors etc. to ensure the reliability and functionality of mechanical components.
Industrial equipment: Some industrial equipment and machines also use NPSM threads for connections, such as compressed air systems, cooling systems, and industrial piping. The NPSM thread provides a convenient connection method and is suitable for some industrial applications with low non-tightness requirements.
8. How to choose NPSM?
The following points need to be considered when selecting NP SM :
Application requirements: First of all, the needs and requirements of the application must be clarified. Determine the working pressure, medium type (liquid or gas), working temperature range and functional requirements of the connection parts of the piping system. NPSM threads are suitable for some occasions that do not require a high degree of sealing. If the application requires high sealing performance, other thread standards may need to be considered.
Standard requirements: understand relevant standards and codes, such as ASME standards. Make sure that the selected NPSM thread complies with the applicable standard requirements and meets the regulations and safety standards of the country or region in which it is located.
Size selection: Select the appropriate NPSM thread size according to the pipe diameter of the piping system and the size of the required connector. Common sizes include 1/8 inch, 1/4 inch, 1/2 inch, etc. Make sure the size selected matches the size of the pipe and equipment that needs to be connected.
Material selection: choose the appropriate material according to the specific application environment and medium characteristics. Common NPSM thread materials include copper, brass, stainless steel, and carbon steel. Make sure that the material selected is corrosion and pressure resistant to meet the requirements of the application.
Supplier Advice: If in doubt or unsure when selecting an NPSM thread, it is advisable to seek the advice of a professional supplier. They can provide more specific advice and guidance on a case-by-case basis to ensure the proper NPSM thread type is selected.
9. What is the difference between NPT and NPSM?
The difference between them can be seen in the following aspects:
Thread shape: NPT threads are tapered threads while NPSM threads are straight threads. NPT threads have tapered thread faces to help provide a better seal. NPSM threads, on the other hand, have parallel threaded faces and are suitable for applications that do not require a high degree of sealing.
Installation method: Due to the different thread shapes, the tightening methods of NPT and NPSM threads are also different during installation. NPT threads require multiple turns to secure and seal, while NPSM threads require only a few turns to complete the connection.
Sealing performance: Due to the characteristics of the tapered design, the NPT thread can provide higher sealing performance and is suitable for applications with high pressure and high sealing requirements. In contrast, NPSM threads have poor sealing performance and are suitable for occasions that do not require a high degree of sealing.
Application fields: NPT and NPSM threads also have some differences in application fields. NPT threads are commonly used in gas and liquid transmission systems, pipe connections, and high pressure applications. The NPSM thread is mainly used in lamps, household equipment, mechanical connections and some applications that do not involve high pressure or high sealing.
Conclusion:
So when choosing the right thread type, specific application needs and requirements need to be considered. If high sealing performance and high pressure application are required, NPT thread is a more suitable choice. And if high sealing performance is not required and installation convenience is required, NPSM thread may be more suitable. The above is the difference between the two, if you still have questions, please contact us!
