Mechanical stresses also occur in the manufacture of quartz glass. In quartz glass tempering, the glass is heated to a sufficiently high temperature of 1000 °C - 1200 °C and annealed for some time to relieve stresses. Nabertherm offers many standard and customized systems for quartz glass tempering. Brick-insulated chamber furnaces (Models N ../G) are ideal for smaller components. For large, heavy components where a crane or forklift truck is required for charging, top loading furnaces, bogie hearth furnaces or top hat furnaces are recommended. Optional powerful cooling systems or customized insulation with special fiber material with a low thermal mass enable fast cycle times.