Attractive, easy to clean, and chemical resistant, structural glazed clay tile is being used to build prisons and high-traffic public buildings. Structural clay tile is distinguished from clay wall tile and flat clay floor tile by its ability to support its own weight and carry superimposed loads. Unlike glazed brick, glazed structural clay tile allows single-wythe construction of walls and partitions.
There are four basic types of structural clay tile (SCT), each covered under an ASTM standard: structural clay load-bearing wall tile (ASTM C 34), structural clay nonload-bearing wall tile (ASTM C 56), load-bearing structural clay facing tile (ASTM C 212), and load-bearing ceramic glazed facing tile (ASTM C 126). Today, most SCT used is glazed according to C 126 specifications to produce an impervious, ceramic surface. ASTM C 126 includes requirements for compressive strength, absorption rate, number of cells, shell and web thickness, dimensional tolerances, and properties of the ceramic finish such as imperviousness, fire and chemical resistance, and crazing.
Structural glazed tile can be used to build load-bearing walls, with minimum compressive strengths of 3000 psi for vertical cell units and 2000 psi for horizontal cell units required by ASTM C 126. Bearing and non-bearing walls are governed by height-to-thickness ratios in both the ACI 530/ASCE 5 Building Code Requirements for Masonry Structures and the Uniform Building Code (UBC).
Fire resistance of structural glazed tile, like other hollow masonry units, is based on equivalent solid thickness (EST), the gross volume minus the core area divided by the area of the exposed face.