Glazed brick is beautiful, resists air pollutants, and is easy to clean. Yet too many failures of exterior glazed brick have made architects reluctant to use the product on the exterior of buildings. If water enters the masonry wall and saturates the glazed brick, it can get trapped behind the glazed facing. This entrapped water may then freeze and expand, sometimes causing the glazed facing to pop off. Water can get into the brick because of inadequate details, specifications, or workmanship. Too often an improper glazed brick is the cause. How do you get the right brick? You've got to specify it clearly and precisely. You should use ASTM C 126, the standard specification for glazed brick. ASTM C 126 sets requirements on the glazed facing of the brick. But other than compressive strength, it doesn't set requirements on the body of the brick. So you also should require that the brick meet ASTM C 216, the standard specification for face brick. This ensures that both the face and the body of the brick can withstand freeze-thaw cycles. GLAZING REQUIREMENTS Using C 126, you can specify two grades and two types of glazed brick. Grade S (select) is for use with comparatively narrow mortar joints. Grade SS (select sized or ground edge) is for use where face dimensions can vary only slightly. Type I units have only one glazed face for use where only one finished face will be exposed. Both faces of Type II units are glazed so they can be used where both faces are exposed.