The American Society of Mechanical Engineers (ASME) has developed a set of standards for designing and constructing piping systems. Two of these standards, ASME B31.3 and ASME B31.12, are particularly important for industrial piping systems. In this article, we will explore the key features of each of these standards and compare and contrast their requirements.
ASME B31.3
ASME B31.3 is the code for process piping. It applies to piping systems that transport fluids, gases, and other materials in chemical, petroleum, and other process industries. This standard sets the rules for the design, fabrication, installation, inspection, testing, and maintenance of process piping systems. Some of the key features of ASME B31.3 are:
Design Requirements:
The design requirements of ASME B31.3 are based on the principles of stress analysis. The standard requires that the design of the piping system must ensure that the piping is safe against failure due to various loads and stresses. These loads and stresses include internal and external pressure, thermal expansion, earthquake loads, wind loads, and other types of loads.
Materials:
The standard provides requirements for the selection of materials used in the construction of process piping systems. The materials must be selected based on the properties required for the intended service conditions, including the temperature, pressure, and corrosive nature of the fluid being transported. The standard also provides requirements for the allowable stresses and fatigue design of materials used in process piping systems.
Fabrication and Installation:
The standard provides requirements for the fabrication and installation of process piping systems. The requirements include procedures for welding, brazing, and other joining methods, as well as the use of flanges, valves, and other components. The standard also specifies requirements for the testing and inspection of the piping system to ensure that it meets the design requirements.
Inspection and Testing:
The standard requires that process piping systems be subject to inspection and testing to ensure that they meet the design requirements. The testing may include hydrostatic testing, pneumatic testing, or other types of testing, depending on the nature of the piping system and the intended service conditions.
ASME B31.12
ASME B31.12 is the code for hydrogen piping and pipelines. It applies to piping systems that transport hydrogen, including both high-pressure pipelines and low-pressure piping systems. Some of the key features of ASME B31.12 are:
Design Requirements:
The design requirements of ASME B31.12 are similar to those of ASME B31.3. The design of the piping system must ensure that the piping is safe against failure due to various loads and stresses, including internal and external pressure, thermal expansion, earthquake loads, wind loads, and other types of loads. However, the design requirements of ASME B31.12 are specifically tailored to the properties of hydrogen, which is a highly flammable gas.
Materials:
The standard provides requirements for the selection of materials used in the construction of hydrogen piping systems. The materials must be selected based on the properties required for the intended service conditions, including the pressure, temperature, and the corrosive nature of hydrogen. The standard also provides requirements for the allowable stresses and fatigue design of materials used in hydrogen piping systems.
Fabrication and Installation:
The standard provides requirements for the fabrication and installation of hydrogen piping systems. The requirements include procedures for welding, brazing, and other joining methods, as well as the use of flanges, valves, and other components. The standard also specifies requirements for the testing and inspection of the piping system to ensure that it meets the design requirements.
Inspection and Testing:
The standard requires that hydrogen piping systems be subject to inspection and testing to ensure that they meet the design requirements. The testing may include hydrostatic testing, pneumatic testing, or other types of testing, depending on the nature of the piping system and the intended service conditions. Additionally, the standard requires that the inspection and testing procedures be designed to identify any potential risks associated with hydrogen, such as embrittlement or hydrogen-induced cracking.
Quiz on Difference b/w ASME B31.3 & ASME B31.12: Piping Quiz – EPCLand
Key Differences between ASME B31.3 and ASME B31.12
Although ASME B31.3 and ASME B31.12 share many similarities, there are some key differences between the two standards. Some of these differences include:
- Material Requirements
ASME B31.12 includes specific requirements for the selection and use of materials in hydrogen piping systems. These requirements are based on the unique properties of hydrogen, such as its high diffusivity and potential for embrittlement. In contrast, ASME B31.3 provides more general requirements for material selection, based on the properties required for the intended service conditions.
- Welding Requirements
ASME B31.12 includes specific requirements for the welding of hydrogen piping systems, including the use of specialized welding procedures and the selection of appropriate filler materials. These requirements are intended to minimize the risk of hydrogen embrittlement and other types of hydrogen-related damage. ASME B31.3 also includes welding requirements, but these are more general in nature.
- Testing Requirements
ASME B31.12 includes specific requirements for the testing of hydrogen piping systems, including procedures for detecting hydrogen-induced cracking and other types of damage. These requirements are intended to ensure that the piping system is safe against the unique risks associated with hydrogen. ASME B31.3 also includes testing requirements, but these are more general in nature and do not specifically address hydrogen-related risks.
- Design Pressure
ASME B31.12 includes specific requirements for the design pressure of hydrogen piping systems, which are based on the flammability and explosivity of hydrogen. These requirements are intended to ensure that the piping system is designed to safely contain any potential leaks or releases of hydrogen. ASME B31.3 also includes design pressure requirements, but these are based on more general principles of stress analysis.
Conclusion
ASME B31.3 and ASME B31.12 are two important standards for the design and construction of piping systems in industrial settings. While these standards share many similarities, they also have some key differences, particularly in terms of their requirements for material selection, welding, testing, and design pressure. Companies that work with process piping or hydrogen piping systems should be familiar with both of these standards and ensure that their piping systems are designed and constructed in accordance with the appropriate requirements. By doing so, they can help to ensure the safety, reliability, and efficiency of their piping systems, as well as minimize the risk of damage or failure.
