If polycarbonate sheets block UV radiation, why is there a ‘UV side’ to face outwards?
Polycarbonate blocks UV radiation by absorbing it. This absorption mechanism might degrade the material, and the sheet has to be protected against it. Protection to the sheet is achieved by coating it with a special material that converts the UV radiation into heat that emits to the external air layer. In order to protect the sheets, they must be installed with the marked UV protective layer facing outside. Although sheet products can also be UV protected on both sides, most of the sheets are protected on one side that is marked clearly.
