Advances in CCTV Technology for In-Service Water Mains

摘要

As the standard technology for condition assessment of gravity sewers, closed-circuit television has a long history of success and acceptance. Conventional CCTV technology requires access available through manholes, and non-surcharged operation, making it extremely difficult to apply to water transmission mains. For the past five years, inline CCTV inspections have been available for water transmission mains using a tethered inspection system that allows these inspections to take place while the mains remain in operation.This paper details the innovation and application of this technology for the past 5 years. It describes the mechanism used to pass a sensor through an in-service water main, as well as the evolution of the video technology to allow for longer surveys and better resolution. Specifications for the system, as well as case studies describing various applications of the technology, are presented.