- Q. Are Grade SW bricks as defined by ASTM C 216 "Standard Specification for Facing Brick" required to meet the freeze-thaw test requirements of ASTM C 67 "Standard Test Methods for Sampling and Testing Brick and Structural Clay Tile"?
A. Severe weathering bricks (Grade SW), as defined by ASTM C 216, are not required to meet the freeze-thaw testing requirements of ASTM C67. They are, however, required to have either a saturation coefficient less than 0.78 or a total average cold water absorption of less than 8%. The saturation coefficient is the 24-hour cold water absorption divided by the 5-hour boil absorption. If the units meet either of these criteria, they are classified as SW units. As shown by the testing program that was used to develop these criteria, most units that meet the requirements of the saturation coefficient or the cold water absorption will also meet the requirements of the freeze-thaw test in ASTM C 67. The freeze-thaw test is not a requirement and should be used only to qualify units that would otherwise meet neither the saturation coefficient nor the maximum cold water absorption requirement.