Mechanical Characteristics of Clay Masonry Units

The compressive strength varies from about 1200 to 30,000 psi. It is typically 8000 to 15,000 psi. Building brick (ASTM C62) must have a minimum compressive strength (average of 5 units, tested flatwise) of 1500 psi for Grade NW, 2500 psi for Grade MW, and 3000 psi for Grade SW. Building brick (ASTM C216) must have corresponding compressive strengths of 2500 psi for Grade MW, and 3000 psi for Grade SW. Grade NW does not exist under ASTM C216.