Testing-Phase Design Changes
What happens when there is a design change (change order) in the middle of functional performance testing? That late in the project, design changes are often a result of functional performance testing. When a system functions as originally designed (all the right components, all the right integration, all the right control sequences, etc.) but does not meet the owner’s project requirements (OPR) performance criteria, we have a problem.
A third-party commissioning professional can efficiently identify all of the “right” things executed by the construction team and engage the design team in the troubleshooting. Without third-party commissioning, system performance problems can quickly head into a death spiral of fingerpointing, stalled progress (because no one is claiming responsibility), and the looming probability of the owner needing to move into the building with a system not performing as expected.
In the best troubleshooting scenarios, the designers, contractors, and commissioning professional will put their heads together to compare notes and brainstorm why the installed system is performing differently than anticipated during the design and submittal review processes. The designers will then prepare an official design modification for fixing the root cause. The change order could be as simple as a revised sequence of operation or it could include new or relocated equipment, sensors, or devices.
Regardless of the complexity of the change, it is critical that it be recorded by the design team and find its way through the project documentation chain into the as-built documents for future reference by the facility operators. The documentation piece is a process about which only the commissioning professional may care this late in the project, and it is important to track it via the commissioning issues log.
To keep the process rolling during the testing phase, the project team needs to deal with the change order just like they would during construction, but much quicker.
Contractors propose their cost change for implementing the design modification.
Commissioning firm proposes its cost change for commissioning the change order.
Contractors implement the change.
Commissioning professional revises the affected system test procedure(s) to reflect the new performance expectations.
Team conducts functional performance testing.
Update as-built documentation to reflect the final configuration and operation.
For the system(s) affected, following these steps gets the team back to where they were when the initial testing discovered the performance issues. This process can put a significant strain on the project schedule, and the project team will be tempted to take shortcuts and/or ignore important steps. Although some of the steps can be undertaken in parallel (e.g., implementing the changes before the contractual paperwork is complete), none of them should be skipped.
To relax the commissioning level of rigor at the end of the testing phase is to risk losing some of the benefits of the preceding commissioning efforts. Last-minute changes need to be properly implemented and documented in order to deliver accurate training and operations material to the owner’s facilities team. After the project team has left the site, the owner needs to be confident in the systems and in the staff’s understanding of the systems operation. If they run into something that doesn’t act like it is supposed to according to the training and documentation (because of a last minute change), it could shake their confidence in all other elements of the documentation.
Early project design reviews, submittal reviews, and controls integration planning are all commissioning steps that minimize the potential of testing phase design changes. However, in the few cases where unanticipated issues result in unacceptable system performance, even when the systems are functioning as designed, the commissioning professional will need to shepherd any resultant design changes through the documentation, testing, and training processes.