This specification covers building bricks intended for use in structural and nonstructural masonry where external appearance is not a requirement. The bricks are prismatic units available in a variety of sizes, shapes, textures, and colors and are manufactured from clay, shale, or similar naturally occurring earthy substances by firing. The heat treatment should develop sufficient fired bond between material particulates to produce a material that conforms to the required strength and durability. During manufacture, the breaks are shaped by molding, pressing, or extrusion. Bricks are classified into grades according to their resistance to damage by freezing when wet. All the materials should comply with the requirements on appearance, durability, absorption alternate, freezing and thawing alternative, breakage, cracking, weathering index alternative, strength, and initial absorption rate.