Abstract
Recently, building requirements have been saturated and residents are demanding a variety of building exterior materials faced with roofs, walls, windows and doors. On the other hand, when building exterior materials are exposed with ultra violet rays during some periods, these will be influenced deterioration effects like discolorations, exfoliations and cracks and will be needed exchange of materials. In this study, main 17-provinces of Korea were collated climate data and counted the computation results with an assumption formula for calculating ultra violet rays amounts. Lastly, ultra violet rays map of Korea was made by the counted data and was considered tendencies. Accordingly, in the phase of design the designer can select the appropriate exterior materials which have durabilities and resistances of ultra violet rays. So hereafter this study can be a foundation study to sustain building exterior materials with ultra violet rays damages. Below is the summary of Korean ultra violet rays tendency. 1. Ultra violet rays during 1 year is from about $180MJ/m^2$ to about $210MJ/m^2$. 2. Southern province ultra violet rays is higher than northern province. 3. Annually counted rays is higher and higher.