For carbon steel pipe sizes 12 NPS and larger, what is the standard wall thickness?

The standard wall thickness for carbon steel pipes that are 12 inches nominal pipe size (NPS) and larger is .375 inches. This dimension is established by standards such as the American National Standards Institute (ANSI) and the American Society of Mechanical Engineers (ASME).

The choice of .375 inches is grounded in the need for structural integrity and performance in various applications, balancing strength and weight. When the nominal size of a pipe increases, the wall thickness must also be sufficiently substantial to withstand internal pressures and external stresses encountered in service.

The other options, while they do represent common pipe wall thicknesses for various applications or different sizes, do not align with the specified standard for 12 NPS and larger carbon steel pipes as defined by established codes. Understanding the standard wall thicknesses is crucial for selecting the correct pipe for applications in steamfitting and ensuring compliance with safety and performance specifications.