a proper and complete design, construction risk and cost can be reduced. This approach also provides the greatest level of owner control, assuming an active role is taken in the design process to evaluate the solution, sequencing, direction, and documentation. Obvious cons for such an approach are increased design costs and prolonged design schedule; however, construction account- ability can also prove difficult. Regardless of effort expended during design, there will always remain some unknowns when working on or connecting to existing underground utilities. The more detail provided in design documents, the more op- portunity for finger-pointing and fault finding if anything is not as presented. This may not be pleasant to discuss, but it is an inevitable truth in utility work and must be kept in mind when approaching a shutdown plan from this angle. Take the right steps Because each of these solutions have their place in the industry and because each alternative presents notable and distinct chal- lenges, it is important that a team work together throughout the life of a project to plan for the shutdown. The following outlines some best practices that are most appropriate for an engineered solution but will benefit any shutdown. While these practices don’t guarantee success, following them will certainly improve • staff the job with a properly trained inspector, and • keep the design engineer on call during construction. Meetings Meeting is a word that can instill dread in the most hopeful en- gineer, contractor, or owner. However, when planning a water transmission pipeline shutdown, several meetings are critical to success. A minimum of four meetings is recommended for any shutdown of a major system. These should not get lumped into progress meetings but should rather be stand-alone, specific meetings, with the purpose of each as follows: • Conceptual shutdown criteria meeting — This is proposed for conceptual (roughly 30 percent) design phase and is usu- ally several months before any actual shutdown will occur. The purpose is to get all stakeholders in a room together to review the system, identify design criteria, review system functionality, and so on. It is critical that the owner have engineering/design, operations, maintenance, and inspection personnel at this meet- ing, as it is vital that each stakeholder see and hear the same thing from the outset of this work. the likelihood of success. The best practices include: • conduct properly structured meetings, • execute a shutdown checklist, • Detailed design review meeting — This generally occurs around 70 to 90 percent design. It should be completed only after the full shutdown approach is sufficiently documented in plans and specifications but should allow sufficient time for the engineer to make adjustments if needed before bidding. The
Engineered solutions, up to fully detailing and specifying materials, connections, equipment, timing, and construction sequence become more appropriate, if not required, with certain pipeline diameters, pipe materials, and project locations. Large- diameter line stops, urban locations, valve connections, and fittings associated with shutdowns and tie-in require engineer-driven solutions.
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march 2018
csengineermag.com
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