The exemption applies only if the building is sited at least one and a half times its height either from the boundary or from any point of a building into which people normally go.
Mae'r eithriad hwn yn berthnasol dim ond os yw'r adeilad wedi'i osod o leiaf 1.5 gwaith ei uchder i ffwrdd naill ai o'r ffin neu o unrhyw ran o adeilad y mae pobl fel arfer yn mynd i mewn iddi.