Glass temperatures can rise to very high values (will over 60 °c) when the incident solar radiation is high, the absorptivity is large and the heat transfer coefficients for the surfaces are small-as would be the case for glazing with a sheltered outside exposure and stratified temperature conditions on the inside. High glazing temperatures couse stresses that can be a risk if not considered. Reference to the manufacturers should be made in such cases as Pilkington (1980) shows.