Piping codes and standards for natural gas applications have changed over the years to address challenges, especially in material selection and application. The industry and advising committees have provided insight for improved codes, standards and methods to engineers involved in the LNG plant piping industry, and further improvements are expected. The natural gas market has grown at its fastest rate in almost a decade. In 2019, the gas market expanded by 5 percent, while LNG grew by 10 percent. Natural gas/LNG are expected to remain the fastest-growing fossil fuel beyond 2037 due to its relatively low CO2 footprint compared to coal.
This implies that investments in LNG plants (gasification, liquefaction) and piping are needed to cater to this growing demand. LNG plants contain a significant amount of piping that is characterized by one or more of the following: large diameters, high design pressures, cryogenic temperatures, stainless steel, high velocity gas flow, large diameter-to-thickness (D/t) ratios (sometimes exceeding 100) and load cases not explicitly addressed by design codes.
These have presented challenges and exposed some of the limitations in existing piping design codes and standards. ASME B31.3 Process Piping was originally developed to serve refineries where the piping is generally carbon steel, low pressure, hot and handles liquids. LNG plant piping often has high design pressures, cryogenic temperatures, gas flows, significant use of austenitic stainless steel and larger diameters. Conventional use of carbon steels in the oil and gas industry for piping spool components is specified to ASME/ASTM requirements.
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