The importance of thorough shutdown planning and design is clear. For large water transmission systems, once you break into a pipeline serving customers, the window can be very short to get it up again.
Best practices during pipeline shutdowns
• a performance-driven, contractor-led construction solution; and, • a technically driven, engineer-led design solution. Both approaches require design and planning and both have their place in the industry. Contractor-driven solutions — Small-diameter connections or non-critical utilities may successfully rely upon a performance-based design that gives the contractor freedom in both when and how work is executed. This approach minimizes design schedule and cost, with the engineer providing notes, callouts, and performance criteria while developing a clear line of accountability in construction. Little infor- mation is given to the contractor other than performance expectations, and he/she is expected to make ends meet in the field. As an example, a 6-inch interconnection in an undeveloped area of town is considered as a good example of a contractor-driven approach. The drawback of such an approach is increased construction risk. This relies heavily on a contractor’s ability, as he/she is expected to coordi- nate connection requirements and design with pipe manufacturers and suppliers. This can result in increased construction cost or confusion in bidding, with each bidder potentially planning execution of work dif- ferently and each having different capabilities. Accordingly, as a proj- ect and requirements grow in complexity, the level of detail in design and direction grows as well, ultimately leading to a fully engineered solution. Engineer-driven solutions —As one would expect, the cons of a con- tractor-driven solution appear as pros for the engineered alternative. As the engineer develops detailed design documents and provides specific directions, greater clarity is provided for potential bidders. Thus, with
Putting water transmission systems out of service temporarily requires planning and process to mitigate risks. By Justin Reeves, P.E.
If you work in water transmission systems, it is almost inevitable that at some point you will be designing or planning a system shutdown. This can be to establish a new system interconnection, conduct condi- tion assessment on a pipeline, or rehabilitate a portion of the system. These are the points in the project that we intentionally put customers out of service temporarily in order to maintain or improve the system. Shutdowns are, without a doubt, necessary for maintenance, operation, and growth, but they also are the times when planning and process are most important. Any failed or prolonged shutdown can result in service interruption to customers, loss of revenue to the owner, additional construction costs, negative customer impacts, and public relations nightmares. Accord- ingly, what can we, as professionals, design engineers, contractors, and owners, do to mitigate some of these risks? Design approach Prior to reviewing some best practices to improve shutdown planning, it is important to understand the two major approaches to shutdown design:
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march 2018
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