Developing and Executing Large Diameter Water Pipeline Physical Entry Inspection Protocols

Physical entry inspections are a practical and well-proven method to obtain critical data on the interior condition of water pipelines. Pipelines are generally part of a buried infrastructure system and are not necessarily thought about as often as they should. The old idiom “out of sight, out of mind” is frequently used when discussing buried pipelines but given the critical nature of their function more emphasis needs to be placed on the need for regular inspections and assessment. Their condition needs to be assessed and maintenance activities performed. However, it can be difficult to inspect some pipelines and safety is always the top concern. Developing a physical entry inspection protocol requires detailed planning. Items that need to be considered include isolation of the pipeline from sources of water, steps to dewater the pipeline, lock-out/tag-out requirements, personnel access locations, ventilation, handling of debris in the pipeline, communications, and rescue/response procedures. These are just a few of the items to be considered. This paper reviews the development of physical entry pipeline inspection protocols for large diameter water pipelines and discusses a case study of an inspection at a large aqueduct system in the southwestern United States.