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Inspection of manholes As in the inspection of drains and sewers, the inspection of manholes and inspection chambers can be realised either via
The requirements for these inspections are basically the same as those for the inspection of sewers ( (Visual inspection from inside - Qualitative condition acquisition)). Direct viual inspection The following methods are used in the direct visual inspection: |
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The indirect visual inspection of manholes generally allows for an acquisition of their condition. People that access the manhole are not required for that method. The following devices and equipment are available for such inspections:
In earlier times, before TV manhole cameras and measuring robots have been developed, the manhole was often inspected … |
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Oct 15, 2019 Rehabilitation and Maintenance of Drains and Sewers (2nd edition) - Investigation Visual inspection from inside - Qualitative condition acquisition As yet, there are no specific strategies, regulations and requirements for the inspection of catch basin systems (catch basins and connection sewer). To close that gap, the research and development project “Development of concepts and strategies for the rehabilitation and maintenance of catch basin systems” was realised on behalf of the “Stiftung Industrieforschung” (Industrial Research Foundation) (Cologne, Germany) in 2008. The results that have … |
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Control unit The control unit serves to control the TV inspection system, to capture and store data and comes both as a mobile and stationary system (inspection vehicle). Basically, both systems are composed of a monitor, a user interface with control lever and keyboard as well as several ports, a computer and software. Mobile system Mobile control systems in the form of a control case, control desk or monitoring panel are portable and are mostly used … |
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Usually, the vehicle platform for inspection vehicles is a minibus with a weight ranging between 3.5 t to 5.0 t. These minibuses are equipped with a winch and a control centre toolbox. Both rooms are functionally separate and designed according to ergonomic aspects to ensure a smooth work flow. The tool box that is located at the back of the vehicle includes the following components:
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Oct 15, 2019 Rehabilitation and Maintenance of Drains and Sewers (2nd edition) - Investigation Visual inspection from inside - Qualitative condition acquisition There are cameras that can measure crack widths, pipe joint widths, displaced joints, etc. during the visual inspection. This is done through the digital evaluation of the camera image that is captured using two point lasers that are arranged at the camera head at a fixed distance in parallel and with a defined basic length [ [FI-Jtele]] or by means of a laser distance sensor that is integrated in the objective of the camera and that scans either … |
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Oct 15, 2019 Rehabilitation and Maintenance of Drains and Sewers (2nd edition) - Investigation Visual inspection from inside - Qualitative condition acquisition Apart from the used hardware, another essential component of TV inspection systems is their software that allows for the control of the system, data transfer, processing and storage, as well as a multitude of image representation modes that are implemented by means of its additional functions. The key task is the individual determination and documentation of all relevant sewer conditions that are captured by the camera and, if required, also by additional … |
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Oct 15, 2019 Rehabilitation and Maintenance of Drains and Sewers (2nd edition) - Investigation Visual inspection from inside - Qualitative condition acquisition As illustrated by the preceding statements and explanations, there currently is a multitude of different systems available for the indirect visual inspection of sewer systems with sewers of various nominal sizes, cross sectional shapes and materials. It applies to all of these inspection systems that, given a constant resolution and aperture angle of the camera, the larger the diameter of the sewer, the higher the quality decrease for the image resolution, … |
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Nov 13, 2019 Rehabilitation and Maintenance of Drains and Sewers (2nd edition) - Investigation Visual inspection from inside - Qualitative condition acquisition Adequate expertise with respect to the inspection of drains and sewers is an essential prerequisite for the staff that is responsible for the individual inspections on the part of the client, the consulting engineers and the inspector. Therefore, it is important to keep this expert knowledge up to date in further training and qualification measures at regular intervals. The latest update should never be more than three years ago [ [DWAM149-5:2010]]. … |
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Oct 15, 2019 Rehabilitation and Maintenance of Drains and Sewers (2nd edition) - Investigation Visual inspection from inside - Qualitative condition acquisition The documentation of a visual inspection measure includes the following tasks:
According to EN 13508-2 [ [EN13508-2:2011]], the following pieces … |
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Special methods for the inspection of partly filled sewers Whereas, generally, the securing of drainage capability is relatively easy for the duration of the inspection (section 5 - in progress), for man-accessible sewers with high levels of partial filling, there is the problem that a partial flow often has to be tolerated for technical and economic reasons. For this case of application, that means the inspection of larger, partly filled sewers during … |
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The “Automated inspection and cleaning system” has been developed by the Fraunhofer Institute for industrial automation (IFF) in Magdeburg, Germany, exclusively for the sewer Emscher. This deep gravity sewer tunnel is expected to be partly filled at all times in future operation [ [Elkma2004]] [ [Elkma2007]] [ [Saenz2008]] [ [Saenz2010]] [ [Saenz2010a]] [ [Elkma2010]] [ [Elkma2011]]. It comprises two separate system components:
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To carry out a complete direct inspection and even cleaning- and repair measures in gravity sewers with man-accessible cross section while they are in operation, the so-called isolation seal has been designed and put to the test as a prototype (Image 4‑83) in the laboratory at a scale of 1:1 [ [EP0872680]]. (Image: Isolation seal (prototype) to inspect, clean and repair man-accessible sewers in operation) Essential components of the isolation seal … |
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The results of the visual inspection ( (Visual inspection from inside - Qualitative condition acquisition)) are often not sufficient for a comprehensive description of the sewers’ condition and the derivation of satisfactory statements on the type and extent of damage, type and extent of rehabilitation measures and hydraulic performance capacity. That is why a quantitative determination of the actual condition might also be required for a technically … |
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Deposits Within the scope of the visual inspection from inside the pipe, deposits ( (Settled deposits (BBC))) are usually listed and assessed with respect to their effects on a reduction of the cross section just as this is done in the case of adhesive substances (incrustations / (Attached deposits (BBB))), protruding connections ( (Intruding connection (BAG) / Defective connection (BAH))) and roots. The assessment is based on a statement of the deposit … |
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Although deformations of flexible pipes ( (Deformation (BAA))), deformations of cracked rigid pipes, cross sectional measurements and thus, indirectly, internal corrosion and mechanical wear ( (Surface damage (BAF))) of sewers, but also deposits ( (Settled deposits (BBC))) can be detected in a visual inspection or an inspection by means of a sewer inspection camera, quantitative evaluations can only be made by means of appropiate systemns and methods … |
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The methods of subsoil exploration from within the sewer serve the purpose of:
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For tests in man-accessible concrete and reinforced concrete sewers, there exists a number of methods, instructions and many testing devices [ [NN86i]] [ [ACI201]] [ [Augus84]] [ [Kuhne85]] [ [Rybic79]]. A general survey on the most essential evaluation criteria, test methods and equipment can be found in Table 4‑9. For further information on the test methodology, depending on the different objectives to be achieved, please refer to [ [Larjo80]] [ [… |
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Multisensory inspection uses several sensors that are applied simultaneously to retrieve different information on the actual condition of the individual sewer, in some cases even of its bedding. In the past, various methods have been developed for that purpose, but have failed to establish themselves in practice. Amongst others, these are:
KARO-System The KARO system was particularly designed for … |
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