In this study, the concentration distribution of radon, we analyzed from 55 house, 37 government office, 54 schoolfrom June 2008-June 2011 in Chungnam area. From the result of surveying indoor radon degree of 146 facilities,the annual average geometric concentration of indoor radon was 69.4Bq/m³, 40.5Bq/m³, 51.4Bq/m³ in house,government office, school respectively. As for distribution of concentration based on seasons, the radonconcentration showed the highest concentration in winter in all facilities. According to the result of the analysisby dividing the construction year, into before 60s, 60-70s, 80-90s and 2000s, the radon concentration was lowerin all the newly constructed facilities. As for difference in radon concentration due to the presence or absence ofbasement, concentration of house, government office and schools having basement was 52.2Bq/m³, 44.5Bq/m³,36.4Bq/m³ that of having no basement was 75.2Bq/m³, 53.6Bq/m³, 67.4Bq/m³ respectively. Place having nobasement tend to show higher concentration.

With the increase in the frequency of the seismic activity in the territory of Korean Peninsula, the demand for seismic performance evaluation of existing buildings has appeared as well. In this research, a public building built in 1970s is evaluated by the Korea Infrastructure Safety Corporation guideline. As a result, this existing public building is evaluated to satisfy the life safety (LS) and the collapse prevention(CP) performance level that the KBC2009 demands for.