Thermal Expansion: An increase in sheet length in response to a change in temperature.
Thermal Contraction: A decrease in sheet length in response to a change in temperature.
Polycarbonate sheets expand and contract under the influence of temperature change. Allowance for this difference must be taken into consideration by the system used to mount the sheets. As a rule of thumb, 120” of polycarbonate with expand/contract ½” over 100 degrees Fahrenheit.