What is the difference between heat-strengthened and tempered glass?
Heat-strengthened and fully tempered glass are both heat-treated products commonly fabricated in the process described above. The American Society for Testing and Materials (ASTM) document C 1048, Standard Specification for Heat-Treated Flat Glass Kind HS, Kind FT Coated and Uncoated, specifies the requirements of the two products as follow: Kind HS: Heat-strengthened glass with thicknesses of 1/4″ (6 mm) and less shall have a surface compression between 3,500 and 7,500 pounds per square inch (24 to 52 Mpa). Kind FT: Fully tempered glass shall have a either a minimum surface compression of 10,000 pounds per square inch (69 Mpa) or an edge compression of not less than 9,700 pounds per square inch (67 Mpa) or meet ANSI Standard Z97.1 (American National Standards Institutes American National Standard for Safety Glazing Materials used in Buildings – Safety Performance Specifications and Methods of Test) or CPSC Standard 16 CFR 1201 (Consumer Product Safety Commissions Safety Standard for A
