CCTV inspection of sewers and maintenance structures
All newly constructed sewers and maintenance structures must be inspected by CCTV to ensure the pipe is without any construction defects, has no internal flow obstruction and has been constructed as per its approved design. Also, the inspection will verify the information provided with the ‘As Constructed’ drawings.
The CCTV inspection and report are also required under the development gifted asset process and must be completed prior to acceptance of sewer asset. All newly constructed sewer assets have a life expectancy of up to 100 years. All defects identified by the certifier in the initial CCTV survey must be rectified and resurveyed for the final CCTV survey.
Footage of initial CCTV survey where defects occurred must be attached to the final CCTV inspection report submitted to Power and Water for comparison. Power and Water reserves the right to undertake CCTV inspection prior to full acceptance of asset, when defects and liability period has ended. Testing of sewer assets as per Power and Water's guideline Test procedures for pressure and gravity pipes and maintenance structures must be conducted prior to final CCTV inspection.
The sewers and maintenance structures must also be cleaned and any debris removed prior to the CCTV inspection. Power and Water reserves the right to observe any CCTV inspection and require at least seven days' notice in Darwin and Alice Springs and at least fourteen (14) days' notice for all other areas.
The inspection of existing services by Power and Water should utilise the same method below
CCTV Operators must hold a Statement of Attainment in NWP331B ‘Perform conduit condition evaluation’ issued by a Registered Training Organisation (RTO) and based on WSA 05.
All CCTV inspections reports must be prepared in accordance with the latest version of the WSAA Conduit Inspection Reporting Code of Australia WSA 05 and as per the requirements below.
CCTV surveys must be accompanied by an inclination report in the form of a scaled graph that plots the pipe's altitude over the distance travelled. The following digital information must be provided on portable storage or optical media (for example USB memory stick, CD or DVD):
- A digital video file (MPEG 1 or MPEG 2 format) for each sewer segment (maintenance structure to maintenance structure).
- Digital photographs (in JPEG format) of certain defects as stated in Appendix F of WSA 05.
- One digital file with the asset information, coding information and Inclinometer readings (to an acceptable version of the latest WinCan software or other agreed digital formats).
Hardcopies of the following must be provided:
- The WinCan report with the coding information including the photographs taken.
- The inclination report.
All CCTV inspections in general must be carried out in accordance with the latest version of the WSAA Conduit Inspection Reporting Code of Australia WSA 05. The operator must use Appendix F to highlight all defects in the CCTV report.
In addition to WSA 05, the CCTV survey must comply with the following additional requirements:
1. All CCTV surveys must be accompanied by an inclination report in the form of a scaled graph that plots the pipe's altitude over the distance travelled. The inclinometer must be accurate to +/-1%. The inclinometer reading must be on screen display at all times during the recording of the CCTV survey.
2. The CCTV survey, including resurveys of rectified sewer lines, must capture the entire length of all sewer lines between maintenance structures. The survey must be carried out in the opposite direction to flow, from the centre of the downstream maintenance structure to the centre of the upstream maintenance structure. Each maintenance structure must be scanned using the pan/tilt and zoom functions of the CCTV camera and the video footage recorded as part of the overall CCTV survey.
3. All pipe joints suspected to be defective must be scanned by a 360 degree pan.
4. All changes in horizontal and vertical direction of the pipe along the survey must be coded using the appropriate WSA 05 codes.
5. A number of general photographs must be taken along the sewer surveyed as a minimum to satisfy the requirements of this standard:
- One photograph in each maintenance structure showing the condition of the structure above the pipe obvert level.
- One photograph showing each connection point (inlet/outlet) to both upstream and downstream maintenance structure.
- A photograph of each junction installed. d. A general photograph every 20 - 25 m of the pipe condition not related to any defect over the distance surveyed.
6. Where polyethylene (PE) with electrofusion joints have been constructed, the defects must be coded as per below:
- A PE pipe end not cut square in a joint must be coded as circumferential welding defect (Code WC).
- Visible welding wires in a joint must be coded as circumferential welding defect (Code WC).
- Partially melted fusion couplings in a joint must be coded as circumferential welding defect (Code WC)
For more information
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