Breivoll Inspection Technologies (BIT) has successfully developed and implemented a new in-pipe inspection method for the condition assessment of metallic water mains, mainly cast iron. The method is based on Acoustic Resonance Technology (ART). The inspection data (acoustic signals) are stored on a hard drive prior to undertaking the detailed analysis back at the office. The assessment results are subsequently reported to the water company. It should be relatively easy to incorporate the results into the standard water company corporate data bases.
This service enables water companies to achieve large cost savings by running a more optimally planned and co-ordinated water mains rehabilitation program.
Water distribution challenges
Corrosion in water mains is worldwide an increasing and costly problem. This is complicated by the fact that the state may vary significantly from one pipe segment to the next. Until now, visual assessment of a pipeline’s condition has been difficult to perform and has revealed limited information. Without proper information this may lead to non-optimal rehabilitation projects with respect to costs, timing and also rehabilitation method.
BIT performs detailed in-pipe condition assessments. The condition assessment is performed using high-tech inspection equipment and advanced computer software. The inspection device, the so called Pipescanner, is put into the main through an entrance pipe which must be mounted in the pipeline on forehand. From this point of entrance up till approximately 900 m can be inspected. With this technology we can, along the inspected pipe line’s length and from 0 to 360°:calculate the remaining wall thickness in the range of 1.5 to 25 mm, distinguish between inside and outside corrosion and wall thickness reduction, show the position and extent of rust, rust tubercles and sedimentation, show the positions of manholes, joints, bends, narrowings, connections, valves and service pipes, show the positions and character of longitudinally displaced joints and repairs.
All these results are reported to the water company. So far condition assessments of Ø 250 to 325 mm cast iron pipes have been performed successfully in Norway and Sweden. Other sizes will be supported in the future.
Savings may be realised on four levels: Just-in-time rehabilitation decreases direct and indirect costs associated with pipe failures, while optimally using a pipeline’s life cycle. Rehabilitation costs are reduced by choosing the optimal rehabilitation method. Improved planning and co-ordination with other infrastructural projects may improve the overall efficiency and thus reduce the overall costs. The public’s negative perception of rehabilitation projects may be reduced. Additionally the assessment reports contribute to the quality of risk analyses of water supply networks.