ASHRAE Journal - October 2012 - 62

Cx Process for Design/Build Net Zero Energy School
For a real-life net zero school project, the key owner’s project requirements included the goals of being CHPS compliant, Living Buildings Challenge certified, and net zero energy within surrounding site. This high performance building used a modified commissioning process to accommodate the design/build delivery method.
Commissioning Authority (CxA) is first consultant hired by owner (prior to developing bridging documents or issuing design/build RFP) CxA develops OPR prior to Design/Build team selection CxA performs initial design review of Design/Build bridging documents prior to bid CxA performs phased design review of Design/Build packages as they are issued throughout the project Cx specifications are issued with bridging documents and include: Cx schedule, required to be incorporated into master project schedule Formal Cx notifications protocol, while reserving the right to communicate informally with sub-consultants and sub-contractors when expeditious Requirements for formal submittals from trade contractors for review by engineer of record All related submittals required prior to review, i.e., controls product data will not be reviewed by CxA until controls engineering drawings are provided Requirements for timely responses to Cx design issues by engineer of record Requirements for CxA to receive reviewed design package and approved submittals prior to delivery or start of installation of each system or component Engineer of record required to attendance of at least six Cx meetings during construction Design/build team required to review draft PFCs and FPTs prior to implementation Requirements to perform & document start-up, TAB, & controls point to point checks prior to FPTs Required response in the event of repeated failures of FPTs on major components Required response in the event of numerous failures of FPTs on repetitive components such as VAV boxes Requirements to provide As-Builts, O&Ms, final controls programming and setpoints, and other detailed information to CxA Draft PFCs and FPTs before construction, and finalize based on approved submittals after construction start Single Cx issues log includes all issues whether from design review, construction, FPTs, or other source CxA provides monthly briefing to owner’s project manager summarizing Cx status and noting Cx issues where owner’s help to expedite Design/Build team response is requested

Design Review
Planning commissioning design reviews so that they occur at the appropriate phase of design is complicated by the design/build approach, since design is occurring well into the construction phase. Since the bridging documents set the bar for the quality that the design/build team will have to deliver, commissioning review is very important. On a recent simple dormitory project, a small, fast track LEED-NC 2009 project with simple MEP systems, the second design review was coordinated with the design/build team to occur near the end of coordination when the MEP design was “locked down.” This was effective because the design of the commissioned systems were all completed around the same time.

design review could not be performed until two months prior to completion of construction. The resulting discontinuity in the commissioning design reviews from the bridging documents to construction diminished the impact of the second design review, since the ability to influence the design had dropped so far by the time the review was performed. Another approach is to offer a phased design review process, with necessary fee adjustments to cover the additional effort. This allows timely commissioning review of each aspect of the design as it is completed, before it is too late to influence that area of the design.

Submittal Review
The commissioning authority will often have to perform submittal review in phases over an extended period of time on design/build projects. This is particularly true when different aspects of the design are completed early on, while other aspects of design are still in flux. In some cases, it may be appropriate to insist on waiting to perform commissioning review if related submittals have not yet been received. For example, controls product submittals are rarely reviewed prior to receipt of the controls engineering plans, since it is typically infeasible to review the product submittals without the controls plans in hand. Design/build bridging documents should clearly require a formal submittal review process. On projects without this, deashrae.org October 2012

Phased Design Review
On more complex design/build projects, the design does not typically become fixed early in the construction phase. To further complicate planning the commissioning process, different aspects of the design may be completed early on, while other aspects of design are still not fixed. This can delay the second commissioning design review and, as shown previously, also diminishes the extent to which the commissioning review can influence the design. To address this complication on a recent college athletics center with natatorium, a large, complex project with extensive MEP and on-site renewable energy systems, the second
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ASHRAE Journal - October 2012

Table of Contents for the Digital Edition of ASHRAE Journal - October 2012
