tem if not properly addressed. No amount of planning can compensate for poor or uninformed decisions in the field. Understanding existing pipe material, proposed pipe material, how the two are designed to in- teract, how connections are to be made, and how thrust is to be handled are some of the key elements that must be understood by the inspector. Always have a senior inspector (someone with experience through several critical system shutdowns) onsite before a pipeline is cut. If the majority of a broader project is overseen by an inspector without this experience, ensure that a senior inspector can support him or her with oversight on the shutdown. This provides a valuable training opportu- nity while giving all parties greater peace of mind in the work planned. Engineer on call This is quite possibly the most important of all the best practices given here for any engineer-led solution. Our industry defines construction support from a design engineer in many ways. The effort required to support an owner through construction can vary from simply being available if/when called to providing a resident project engineer on- site full time. The spectrum is broad and changes with the owner and project complexity. Regardless of the general construction services philosophy of an owner, a system shutdown should be a time when the design engineer must be available. Every engineered tie-in and shutdown is unique, and regardless of details provided and meetings held, no one knows the design intent like the engineer. No one is better equipped to understand how a sur- prise in the field will affect the original design like the engineer. A qualified contractor can and will develop solutions if needed to address unknowns. A qualified inspector can evaluate those solutions from past After more than six years of struggling, the residents of Selbyville, Del., are finally enjoying what many of us take for granted — clean drinking water. In 2009, the town’s drinking water supply tested posi- tive for Methyl Tertiary Butyl Ether (MTBE), a common fuel additive used prior to 2005 to reduce smog. To combat the problem, two new wells were installed, but one of those immediately tested positive for MTBE. The presence of this contaminant in drinking water is not well studied, but data supports the conclusion that MTBE in high doses is a potential human carcinogen. Eventually, six of the town’s seven wells were impacted. Unsure of the contaminant source, Selbyville officials began search- ing for a new solution. With assistance from Davis, Bowen & Friedel, Drinking water dilemma DBF provides full-service surveying, architectural, and engineering services for a Delaware town’s water treatment facility upgrade.
experience and give good feedback on their feasibility and compli- ance with owner standards. But the engineer bears the responsibility to provide a safe and functional design and, as such, must be aware of, evaluate, and ultimately sign off on any modification. During the final shutdown meeting and as part of final “go” approval, it is recommended that the engineer remain available for any team member to contact him or her at any time (24/7) during the work. Once a pipeline is broken into and customers are without water, immediate response is required and availability should be guaranteed to address field issues. Conclusion What will your next water transmission system shutdown look like? Will it involve differing pipe materials, an urban construction environ- ment, a limited construction window, or complex connection designs? The above best practices provide a few tools to add to your toolbox to help ensure success, regardless of the project elements. Every shutdown is unique, every project site has a new challenge, and every project has a new surprise. With effective meetings, a thorough checklist, and a qualified team available during construction, the fear, anxiety, and nervousness that surrounds a system shutdown can be lessened.
JUSTIN REEVES, P.E. , is an associate and team leader at Lockwood, Andrews & Newnam, Inc. (LAN; www.lan-inc.com), a national planning, engineering, and program management firm. He has nearly 15 years of experience designing water and wastewater pipelines. He can be reached at jreeves@lan-inc.com.
A supplementary system consists of two 30-foot-tall aeration towers where water flows downward while air flows upward. Volatile contaminants such as MTBE evaporate when they touch the air and, as a result, are removed from the water.
39
march 2018
csengineermag.com
Made with FlippingBook Annual report