Tomorrow's Engineer: More On Jump-Starting The TAB Process
With owners, engineers, and builders recognizing the importance of commissioning, it is now time to finally appreciating the importance of the TAB professional. We continue to read the TAB work in Division 15 of the specification as a subcontractor to the HVAC contractor, and this is just wrong. How can a TAB firm do its job if their performance and payment-for-services is dependent on their boss, the HVAC contractor? It's truly a conflict of interest that even the HVAC contractor will usually prefer not to be associated with, yet design engineers have specified the project to be completed in this manner.
All too often, TAB selection is based on low price rather than best value. I have seen this in reviewing TAB bids for various projects. Often, the TAB proposal will state that the price is based on the contract specification and associated addendums. If you read on, the fine print will state the TAB contractor shall require contract drawings and submittals at least four weeks prior to arriving on-site to do the TAB work. This fine print on the quote is most likely in direct conflict with the specification, and it demonstrates the dilemma that exists with the TAB process today. When price drives the selection, we miss the opportunity to take advantage of the full scope of services a TAB professional brings to a project.
My solution to the TAB dilemma is to choose one of two approaches. The first approach I wrote about in the December issue of this column. The second approach is to have a TAB firm be contracted as a third-party professional in parallel with the commissioning firm and to do this in the design phase. The role of the TAB engineer would be as follows:
- Design review looking for air and water balancing issues and concerns. The design engineer remains the person responsible for the basis of design, while the TAB professional provides his expertise in foresee-ing potential for balancing problems in the construction phase.
- Write a TAB specification and locate it in the HVAC section of the specification, clearly stating the work is being done by this TAB professional or insert this specification into Division 17000-Third Party TAB and Commissioning Services along with the commissioning engineer's specification.
- TAB system flow diagrams would be produced in the design phase using the design engineer's con-tract document flow diagrams. The TAB engineer would insert anticipated pressure drops throughout the system as documentation of system performance expectations. During the construction/TAB phase, this engineer would document the "actual vs. design" data.
- In the construction phase, the TAB engineer would be required to sign off on field coordination drawings while offering his experience to the field coordination team's documents.
- Also during this phase of work, the TAB professional shall participate in meetings facilitated by the commissioning engineer in preparation for system demonstration by the commissioning team.
- A predetermined number of TAB "system readiness" site visits would be produced along with associated field visit reports similar to the commissioning engineer's field reports.
- The final TAB report would include all the above, along with the traditional TAB documents found in contract specifications.