Commissioning and Acceptance Testing - Design-Build for Water and Wastewater Projects - page 285

W ith involvement in multiple DB water plant projects, my experi-

ence has been that the goal of commissioning and acceptance testing should be to test
equipment under as many, if not all, of the possible operating conditions, especially
the most difficult ones. As the owner, I want to know that all critical systems work
properly, to prevent them from contributing to any operational problems in the future.
Oftentimes, it is critical for us to run the plant at peak flows, so, we find a way to
meet that intent during performance testing. When planning performance tests, it is
necessary to weigh the risks versus the reward for each task and know that all parties
have a stake in the outcome of the tests.
For many of our facilities, the trickiest part is to test new systems without jeopardizing
the operation of an existing facility. We've learned to be flexible, because things do not
go exactly to plan, and when problems have occurred, contingency plans have been very
helpful.
If commissioning test plans include a difficult task, such as an electrical main-tie-
main with generator back-up, then my recommendation is to have it performed with
all of the operations staff, support personnel, design-builder staff, and electrical utility
staff present during the test. The owner wants to be sure that when the water plant
loses the utility power feed, the back-up power system will operate as planned. Make
the necessary time to test all critical systems while support staff is on-site to fix any
problems.
The design-builder should have thorough commissioning and acceptance testing
plans that outline procedures to prove that everything works as promised. I am con-
vinced the progressive DB approach offers maximum collaboration and flexibility,
thus providing the best environment in which to plan and conduct these tests. In my
opinion, a measure of the design-builder's skill for executing large DB water projects
is seeing how many problems occur while starting up the facility, and how the design-
builder remedies those start-up problems.
—Mark W. Griffin, P.E., Engineering Manager—Business Transformation,
American Water

Advantages of Design-Build for Commissioning

One of the major advantages of DB is that the designer and contractor work as a team;
therefore, collaboration is available from the beginning of the project. This is especially
beneficial when planning for and executing commissioning activities. The design-builder
can plan how to incorporate temporary systems, bypass or extra pipe connections, in the
design phase. The benefit of designer and contractor collaboration is that the design is not
only for the normal plant function but also for options to allow flexibility for the tempo-
rary startup needs or to help minimize problems with construction delays or equipment
problems. For example, if a UV disinfection system is being installed, valves upstream