Commissioning and Acceptance Testing - Design-Build for Water and Wastewater Projects - page 283

Specialty equipment. With the increasing use of membranes, ultraviolet light (UV)
irradiation, and other specialty treatment processes, it is critical that manufacturers be
involved in the planning of activities specific to their packages. Often, special attention is
required in the commissioning and acceptance testing of proprietary equipment packages
to ensure that the setup and testing are done correctly.
Facility turnover to commissioning team. As construction ends, it is important
that the team closely coordinate the transfer of control between the construction and
commissioning teams. The commissioning team should prioritize packages in advance
to allow adequate time for the construction team to finalize activities and perform any
required construction tests. Equipment should be released to the commissioning team in
a logical sequence to allow efficient use of resources. Stranding can occur when a system
or package is turned over but cannot be advanced because a supporting system (e.g.,
power or compressed air) is not available. While stranding occurs even in well-planned
efforts, if a number of packages cannot be commissioned due to nonfunctional support
systems, the overall commissioning schedule may not be met.
To minimize the likelihood of stranding, a thorough review of the systems and their
needs should occur during the checklist development and be confirmed prior to com-
missioning. The review should consider which systems require compressed air, differing
voltage classes of auxiliary power or essential power, chemical feed, or other similar sup-
port systems.
The commissioning packages act as a communication tool and as a record of activi-
ties. Special care should be taken during the planning and development of these packages
to allow quick and easy modifications, while still tracking records appropriately. Steps
should be documented with signatures of the involved parties, and proper witness and
sign-off of all testing or service performed should be documented. These records become
invaluable when disputes arise about a piece of equipment. Both owner and design-builder
benefit when activities are documented properly.
Shutdowns and tie-ins. Another critical planning and scheduling activity associated
with commissioning is shutdowns and tie-ins with existing facilities. These activities
require close communication between the design-builder and owner, and often have
special requirements that extend past the control of either party. Shutdowns and tie-ins
are often planned for off-peak demand times and are usually allotted only short time
frames. Planning is needed to ensure that the necessary components, tools, and hardware
are available to support these activities.
Steps of Commissioning
The steps or tasks of commissioning for DB project are the same as for DBB projects.
Equipment is checked first, followed by systems, and then the whole facility. A com-
missioning plan is developed and reviewed by the owner and sometimes by a regulatory
agency.
Mechanical and electrical commissioning. Mechanical commissioning is used to
prove that the mechanical equipment functions as required by the project specification.
This includes testing to show proper flow and pressure for pumping and blower systems,
mix testing of mixers, function testing of valves, and basic mechanical operation of
specialized equipment, such as mechanical residuals dewatering equipment.