Flat glass panels use large centrifugals (1.2 to 1.6 m diameter)
Because of the glass tempering being very fast, a damper is placed at the fan output that will open and close in less than 2 seconds and making one opening/closing cycle every 30 seconds.
For this reason, the fan shall withstand pressure shocks of around 40,000 Pa.
For shaped glass panels it is necessary to adjust the tempering flow to the geometry of the glass panel. Therefore, fans are much smaller. Usually squirrel cage impellers in high temperature stainless steel are used in plug-in fans able to withstand temperatures up to 650/700 degrees centrigrade.