Sewer condition assessment involves the determination of defective points and status of aged sewers by a CCTV inspection according to the standard manual. Therefore, it is important to establish a reliable and effective standard manual for identifying the sewer defect. In this study, analytic reviews of the CCTV inspection manuals of the UK, New Zealand, Canada and South Korea were performed in order to compare the defect codes and the protocols of condition assessment. Through this, we also established the standardized method for defect code and revised the calculation method of assigning the condition grade. Analyses of the types and frequencies of sewer defects that obtained by CCTV inspection of 7000 case results, showed that the joint defect and lateral defect were the most frequent defects that occurred in Korea. Some defect codes are found to be modified because those did not occur at all. This study includes a proposed new sewer defect codes based on sewer characteristics.

• 손주영(중앙대학교 사회기반시스템공학부) | Jooyoung Son (School of Civil & Environmental Engineering, Urban Design and Studies, Chung-Ang University)
• 이재현(중앙대학교 사회기반시스템공학부) | Jaehyun Lee (School of Civil & Environmental Engineering, Urban Design and Studies, Chung-Ang University)
• 김정률(중앙대학교 사회기반시스템공학부) | Jungryul Kim (School of Civil & Environmental Engineering, Urban Design and Studies, Chung-Ang University)
• 오재일(중앙대학교 사회기반시스템공학부) | Jeill Oh (School of Civil & Environmental Engineering, Urban Design and Studies, Chung-Ang University) Corresponding author
• 윤성수((주)블루폭스시스템즈) | Sungsoo Yoon (Bluefox Systems Inc.)