September 2010 - DMR is please to announce we have acquired UV Cure CIPP Lining Technology.
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Asset Management(From a Contractors Perspective)
Rate The Condition of The SewersSystem owners and consultants often compile historic sewer CCTV inspection data collected using WRC or PACP codes that permit the condition of sewers to be rated from 1 to 5, where 1 is good and 5 is a state of imminent or actual failure. While this rating of sewers is essentially automated and provides a useful way to sift through the vast amount of CCTV data most asset managers have, the real challenge is what to do next when facing a sewer in deteriorated condition.
Rehabilitation RecommendationsThere are two basic choices: rehab the pipe in some way or do nothing. When faced with thousands of defects it is a daunting or sometimes unfeasible task to individually review each video for each repair. Consultants often fall back on semi to fully automated scripts created in a spreadsheet or database that kick out rehab recommendations based on the defects documented in the reports.
Automation of rehabilitation recommendations is very popular and works in a small range of simplistic pipe and site conditions but invariably fails on most projects due to the wide variety of actual site conditions and limitations of the coding systems and operators. It is easy to fall into the trap of churning out automated or semi automated rehabilitation recommendations, without much regard to the preparatory works that are required to facilitate the repair.
For example if the CCTV report identifies a crack, it is relatively easy to have a computer program churn out the need for a spot repair whenever this condition is found - however it is quite unlikely the automated system is able to identify the repair in its full context and note that for example that the sewer is in an easement and temporary road may have to be built to get the equipment in depending on when the work is actually tendered, or that the line has a bend that prevents equipment from entering from one end. At the end of the day after the work has been tendered and awarded it is the contractor and asset owner who are ultimately left to re-jig the work on the fly to meet the site challenges in their full context. This can work both for and against the asset management owner or the contractor, but is never a win-win situation.
The "Missed" Part of Sewer Asset ManagementIncomplete rehabilitation recommendations are often the result of lack of knowledge of the trenchless industry by the reviewers and automated decision processes. While it might be easy to automatically develop a system that will call for a spot repair to cover a longitudinal crack, getting the repair to that location often requires additional work or rehabilitation. Making the sewer "rehab ready" is the most important part of the sewer rehabilitation puzzle that asset managers and Consultants often overlook. Just about any type of trenchless sewer repair requires the line to be in what we call "Rehab Ready" condition. Depending on site conditions making the pipe "Rehab Ready'; could mean simply flushing debris from the line, while other times it could involve days of reaming, robotic cutting, above ground flow diversions, difficult traffic control setups etc. Sometimes making the pipe rehab ready will cost more than the designated repair.
The wide variety of typically undisclosed or unknown preparatory work is the main reason that asset managers and consulting firms receive a wide range of prices when tender documents hit the streets. Some contractors bet on being able to game the spec and hope to go for extras, while others assume the worst. The reality is often in the middle somewhere. Some better bid documents provide relief with provisional items to cover challenges that are not disclosed to the bidder or are unknown, others put the full burden of risk onto the contractor. Either way the stage is set for an acrimonious project when the scope of work is not properly defined.
3 Practical Tips From A Contractor For Asset Management Proponents
Involve A Contractor In The ProcessThere is simply no substitute to an experienced set of eyes reviewing the specific defect that needs to be repaired in its full context of: depth, location, access, diameter, other internal pipe issues (dirt and debris, offsets, bends, protrusions, calcite, water level, hazardous atmosphere, flow rate, long distances, etc). Our recommendation to asset management owners is to have a qualified contractor involved in the process when making sewer rehabilitation recommendations. The people doing the work will know better than anyone the limitations of the equipment - trenchless sewer rehabilitation is a very specialized industry.
Full DisclosureThe full scope of work and the raw data that permits the full scope of work to be assessed should be disclosed to the contractor during the bid stage. This means CCTV reports, videos and maps need to be provided for each of the repairs. There should be a clear correlation between the line items in the tender form and the specific repairs to be made. For example, if you are preparing a tender for the installation of spot repairs and you want lump sum all in pricing, it is important to specifically identify that all preparatory works are included in the pricing. However, some types of work do not fit well into lump sum work. Cleaning and CCTV inspections are a core part of any rehabilitation work and the time and costs associated with this work can be estimated reliably. However the time and costs of removing fixed debris in pipelines is extremely variable and the work effort and therefore cost is not possible to estimate reliably in most situations.
Is Reaming, Included or Not Included & How Will it be ChargedMost trenchless rehabilitation work can be requested in a lump sum pricing or in a piece work pricing format. Most bids hit the market structured this way as it rightly puts the onus of the contractor to perform. Reaming and robotic cutting however are the parts of the work that are often over simplified or just not understood.
It not is not possible to reliably estimate the length of time some reaming requires. A simple example illustrates this: Removal of calcite at all joints in a sewer section can take anywhere from 3 hours to 3 days depending on the nature of the calcite - some is soft, some flakes, some comes right, off while other types are like concrete and require aggressive sometimes very complicated processes to remove. Consultants and owners often include reaming as ancillary to the rehabilitation, or require contractors to give a cost by the metre or as a lump sum. This is the major cause of wide variations in pricing from contractors.
Click here for more information about reaming or click here to read our article about reaming.
Getting the best price for the rehabilitation work is an important part of the Asset Management Cycle and is a major failing of today's bidding and asset management system. Adopting some of the recommendations discussed above is one small but important step in achieving this goal and rounding out the entire Asset Management Process.