Commissioning--Getting It Right: Punchlists And Commissioning
I dealt with this issue in general terms in my April 1999 column and want to delve deeper into one of the more frequently discussed topics of what is the difference between a punchlist walk-through by the designers and a verification test directed by the commissioning consultant.
Making A ListThe formal punchlist process, again as defined by AIA, requires the contractor to prepare a list of incomplete items at the time of substantial completion. The design engineers are then required to take the contractor's punchlist and walk through the facility to confirm the contractor's list and identify any additional issues they may find. The difference between substantial completion and final completion is that the punchlist items (the contractor's plus the designer's) all need to be completed prior to final completion of the project.
For reasons whose discussion goes beyond the charter of this column, it is practically unheard of to have the contractor prepare the initial punchlist. As such, the designers are requested to come to the site, usually whenever substantial completion is scheduled, to conduct the punchlist walk-through. The mechanical and electrical engineers tour the building and document what they can see. Typical punchlist findings are "static" hardware installation items (missing insulation, incorrectly placed thermostats, pumps piped backwards, etc.). Unless the systems being observed are of the simplest type (light switches, fan on-off switches, etc.) most designers do not test or comment on the actual operation of the installed systems.
Testing PerformanceCommissioning verification testing, on the other hand, is designed to test the function or "dynamic" performance of the systems and is not intended to duplicate the punchlist process. The verification testing goes above and beyond the traditional AIA expectation for designers.
The designer's punchlist information is critical to the commissioning process and, ideally, would be developed by the designer and corrected by the contractor prior to the start of verification testing. Similar to the requirement that the test, adjust, and balance (TAB) work be complete on a system prior to verification testing, the punchlist is a standard project delivery process that needs to be taken seriously in order to help ensure that the systems have the greatest chance of passing their verification tests the first time around.
There could be static punchlist items that would adversely impact the results of the verification tests if not found and corrected prior to the start of that testing. An example is the absence of an actuator on the outside air intake damper. This is something the designers could "catch" during a punchlist walk-through and, if corrected by the contractor, would prevent the verification test from failing due to the system being unable to control ventilation air and/or take advantage of free cooling.
If All Else FailsHowever, there will always be operational deficiencies discovered during verification testing that couldn't be predicted by a visual inspection of the installation. In these cases, the commissioning process generates corrective action reports (CARs), documenting each deficiency discovered. How those CARs are handled varies from project to project. Some project managers choose to track them separately from the punchlist items, and others choose to amend the CARs to the designer's punchlist. In either case, final completion status should not be granted until all static (punchlist) and dynamic (verification testing) deficiencies are addressed to the owner's satisfaction.
The designer's punchlist should be preliminary to and complementary to the commissioning consultant's testing and, if scheduled properly, can actually improve the results of the verification testing and the efficiency with which it is conducted. ES