The ASME B16.48 standard covers operating line blanks in sizes NPS 1â??2 through NPS 24 for installation between ASME B16.5 flanges in the 150, 300, 600, 900, 1500, and 2500 pressure classes. A line blank is a pressure-retaining plate that is used to block off a section of pipe. It is typically made of steel or cast iron and has a variety of features, including a raised face, flat face, or grooved face. The ASME B16.48 standard specifies the dimensions, tolerances, materials, and markings for line blanks. There are two main types of line blanks: Spectacle blind flanges: These have a solid end and an open end connected by a web or tie bar. Paddle blanks: These are similar to the solid end of a spectacle blind flange, but they have a plain radial handle. Line blanks are used in a variety of applications, including: To isolate a section of pipe for maintenance or repair To prevent the flow of fluid in a pipe To provide a test point for a piping system The ASME B16.48 standard is an important specification for the design and manufacture of line blanks. It ensures that line blanks are safe and reliable, and that they meet the requirements of the applicable codes and regulations.