Blind Flange is used with for isolation and piping system termination purposes.
Is mostly used in utility services, as water/air and/or small bore piping systems.
Flanges could be made of different materials, such as steel of various stainless steel grades. flanges are the most commonly used In some applications mentioned above , flanges could be lined with higher grade materials and generally would match the material of the piping system itself.
There 5 common pressure classes of forged steel flanges, according to ASME. The higher the class, the higher the pressure the flange can handle. The number below are in pounds, you may see a variation of it, e.g. 150lb, 150#, Class 150.