What is in this article?:
- Commissioning Provisions of the International Green Construction Code
- Commissioning Authority
- System Handover
The International Green Construction Code (IgCC) details high-performance-building strategies, including energy conservation and commissioning (Cx).
A commissioning authority (CxA) is a person or firm with primary responsibility and control in conducting and documenting Cx. Most of the dozen or so Cx guidelines and certifications around the world agree that a CxA must have a degree of independence to confirm the “correctness” of equipment and systems. Unfortunately, the IgCC largely has sidestepped this issue.
The IgCC refers to “registered design professional(s) in responsible charge” and “approved agenc(ies).” “Approved agency” is defined as “an established and recognized agency regularly engaged in conducting tests or furnishing commissioning services, where such agency has been approved.” This does little to resolve the hotly debated issues of mandatory professional credentials for CxAs and mandatory degree of independence of CxAs from other members of a design/build team.
The best definition of a proper relationship between a CxA and other members of a design/build team comes from the USGBC’s Leadership in Energy and Environmental Design (LEED) green-building rating program, which mandates a CxA’s complete independence from design and contracting teams (except for small projects). LEED states a direct contractual relationship with the owner is preferable; when that is not possible, a contract with the project manager (owner’s representative) is acceptable, as long as the owner has direct contact with the CxA. The intent is to avoid conflict between the priorities of quality and profit. The best arrangement in any quality-assurance situation comes when the owner receives reports from the contractor and the quality-assurance person separately and decides how the balance will be struck.
The IgCC allows a “registered professional” or “engineer of record” to be a CxA.
The IgCC requires Cx specifications to be part of bid-document packages. This is good because Cx is a team effort, and bidding contractors need to know their responsibilities prior to submitting bids. However, the code lacks the requirement that a CxA provide a third-party engineering review of bid documents. The prevailing rule is that such a review is for function, conflicts, and constructability only; it is not for the sizing of boilers, chillers, piping, and wiring. A more extensive review would provide more complete quality assurance; however, if that review included sizing of equipment and materials, the time required for the review would approach that for the original design and be economically unfeasible.
The IgCC also lacks a requirement for what ASHRAE and LEED term owner’s project requirements (OPR). OPR are the first step in building quality into a project. A CxA conducts a design review in accordance with OPR. Thus, conducting a design review without OPR is difficult. A design review without OPR is speculative, based on previous practices on similar projects, and, therefore, no guarantee of success.
A CxA should review equipment submittals from installing contractors to confirm their consistency with previous reviews of OPR and design documents. This constant cross-checking tracks the evolution of the design and construction of a building. Quality is built into a project, rather than added at the end, when it is too late.
Precommissioning and Witnessing Compliance
Off-site precommissioning, by which building operators receive hands-on training for their workstation/operator interface and witness factory tests through Skype or similar widely available, economical audio-visual technique in a conventional classroom setting, should be added to the IgCC and become “business as usual” for building delivery.
The IgCC should reference a checklist procedure for the performance and documentation of testing and verification. ASHRAE does a better job in that it defines the checklist used to verify that prefunctional Cx tasks are complete. Additionally, it defines the checklist used for final verification. The use of checklists has been shown to be beneficial on so many projects over so many years that it should be strongly recommended. Checklists form the foundation of preliminary and final reports.
Systems manuals allow continuous verification of original functional tests. The IgCC systems manual contains the basics, such as systems narrative, control diagrams and sequences, and recorded setpoints. A more holistic and logical framework of requirements is needed, starting with the overall description of a building, continuing with operational and control strategies, and including maintenance procedures, metering locations, and air-permeability parameters for the finished structure.
Although the IgCC requires monitoring and metering in buildings, it does not include the details that make monitoring and metering systems usable and maintainable. Meters that are hard to access or subject to complex calibration or factoring will not be used for long. The IgCC does, however, present envelope Cx well by requiring sampling of specific wall components for insulation and water intrusion. It also requires a complete report for envelope Cx, equal in rigor to the report for HVAC, lighting, and other traditional-system Cx. This is an important statement of the critical role building envelope plays in IEQ.