Cracking the code: Part two
The second instalment in a two-part series, this article looks at the requirements to ensure a useful and accurate CCTV inspection report.
by Auscodes Managing Director Peter Slingsby
What to have in the CCTV van before starting a conduit survey
1. Terms of the contract: In the contract the customer or client should specify what the inspections are hoping to achieve, if photos are to be taken and where, whether the survey should start at the manhole wall or the centre of manhole, and which WSA coding version to use. The contract should also state that the operator is to have a ‘Conduit Inspection Reporting Code accreditation’, certificates for road safety and confined spaces, and site paperwork if required. If these instructions are not followed and the appropriate certificates are not obtained, the report could be classified as ‘Non-conforming’ and might require a re-survey
2. Plans: The operator should have paper or digital plans showing the location and conduit information of the pipes that require inspection, giving an indication of what nodes will be required for access and if any extra safety or access permissions are required. The plans should also indicate and provide header information, street location, whether the conduits are upstream or downstream, the size and material, and the length of the pipes. Finally the plans should have the node and asset numbers to be inspected. This information will help to select which camera, wheels and spacers might be required to centralise the camera in the pipe, and if the cable is long enough to do the job.
3. The WSA 05 conduit condition manual: This is probably the most important item but is seldom seen in the CCTV Inspection unit. This manual tells the operator what is required in the report and film header, maximum speeds through the pipe, where to set the 00.0 m for the start, and where to end the survey, defect codes, descriptions and pictures, defect structural and service scores, and all the information for successful inspection and report.
4. The survey: If the operator has attended an accreditation course then the manual would also have been fully explained. They will have knowledge on the best way to survey a pipe. Techniques including: stop and look at the walls, invert and obvert of concrete pipe, don’t pan and tilt while moving, if the zero is at the ‘inside face of the node’ then the survey should finish at the ‘inside face of the node. At the end of survey the operator should check that the software has saved the video and report and that the scores, structural and service grade have been calculated. The access asset should be left in a safe and clean condition.
When an operator follows the instructions in the manual and correctly identifies the defects, the computer will calculate the correct numeric grade and the appropriate rehabilitation, repair or replacement can planned and executed, if required.
Incorrect coding can lead to conduits being unnecessarily relined or conduits that have serious defects being passed over without repair, resulting in collapse. In the past this has resulted in disastrous results.
It is not just a matter of having the best CCTV unit – the quality of the unit is irrelevant if the operator does not recognise and correctly code a defect, or use the correct camera survey techniques. Without adequate training, the subsequent inspection report is probably not worth the paper it’s written on.
For more information visit the Auscodes website.
Part one of this article was published in the December edition of Trenchless Australasia and covered the guidelines for delivering useful and accurate CCTV reports.
This article was featured in the December edition of Trenchless Australasia. To view the magazine on your PC, Mac, tablet, or mobile device, click here.
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