Fittings, flanges, and valves in the piping industry are classified into different pressure classes, indicating the maximum allowable working pressure (MAWP) they can handle. These pressure classes are defined by standards organizations such as ANSI (American National Standards Institute) and ASME (American Society of Mechanical Engineers). The most common pressure classes for fittings include:
Class 125
Class 125 fittings are designed to handle a maximum working pressure of 125 pounds per square inch (psi). Class 125 fittings are intended for use in low-pressure piping systems where elevated pressure ratings are not required. These fittings suit applications in industries such as plumbing, irrigation, and other settings where low-pressure fluid transport is common.
Class 125 fittings are often used in residential, commercial, and light industrial applications with relatively low fluid pressures.
Class 150
The Class 150 pressure class signifies that the fittings are designed to withstand a maximum working pressure of 150 pounds per square inch (psi) at ambient temperature. This pressure rating is considered relatively low and is suitable for applications where the fluid or gas being transported does not require high-pressure resistance.
Class 150 fittings are often used in low-pressure systems, including water supply, low-pressure steam, air, and other non-corrosive fluids. They are not intended for use in high-pressure or critical applications.
The material specifications depend on the specific requirements of the application, but they are generally suitable for a range of materials such as carbon steel, stainless steel, and other materials commonly used in piping systems. Class 150 fittings are designed for use within ambient temperatures. If the application involves elevated temperatures, it is important to consider the effect of temperature on the material properties and pressure ratings.
Class 300
The Class 300 pressure class signifies the fittings are designed to withstand a maximum working pressure of 300 pounds per square inch (psi) at ambient temperature. Compared to Class 150, Class 300 fittings offer a higher pressure resistance and are suitable for applications where the transported fluid or gas requires greater pressure containment. Class 300 fittings are often used in higher-pressure systems, such as steam, gas, or liquids, that require a more robust pressure containment capability. These fittings are suitable for a wide range of industrial processes and applications.
Class 300 fittings are commonly used in conjunction with Class 150 fittings. It’s important to ensure that both the fittings have matching pressure classes to maintain the integrity of the connection
Class 600
In the case of Class 600, it suggests that the component is designed to handle pressures up to 600 pounds per square inch (psi). For example, a Class 600 gate valve or a Class 600 flange would be constructed and rated to function safely under up to 600 psi pressures. This classification system helps engineers and operators select appropriate components for specific applications based on the anticipated pressure conditions in a given system.
Class 900
Class 900 fittings are designed to handle a maximum working pressure of 900 pounds per square inch (psi). Class 900 fittings are intended for high-pressure piping systems requiring elevated pressure ratings. These fittings are suitable for applications where the working conditions demand a robust design to withstand higher pressures. These fittings may find use in various industries and applications such as petrochemical, chemical processing, power generation, and other sectors where high-pressure fluid transport is necessary.
Class 1500
Class 1500 fittings can handle a maximum working pressure of 1500 psi. These fittings are suitable for applications in oil and gas, chemical processing, and other sectors that handle fluids under very high pressure. Class 1500 fittings are typically employed in critical applications where the working conditions demand fittings with robust designs to withstand critically high pressures.
Class 2500
Fittings in this class are designed for a maximum working pressure of 2500 psi. Class 2500 fittings are used in extremely high-pressure applications. These fittings are suitable for applications in industries such as oil and gas, petrochemical, and other sectors where handling fluids under extremely high pressures is common.
Engineers and designers must carefully consider the pressure class of fittings based on the specific requirements of their piping system. Factors such as the type of fluid being transported, temperature and overall pressure conditions are crucial in selecting fittings with the appropriate pressure class. This ensures the safety and integrity of the piping system under its operating conditions, especially in extremely high pressures.