IgCC an important first step in holistic high-performance-building design and operation, but falls short in terms of Cx
The International Code Council (ICC) is breaking new ground with the International Green Construction Code (IgCC). Due this spring, it will be the first internationally acknowledged code focused on high-performance buildings. It contains a comprehensive and detailed treatment of high-performance-building strategies, including energy conservation and commissioning (Cx).
The IgCC began as a joint venture of the ICC and The American Institute of Architects (AIA) in 2009. The U.S. Green Building Council (USGBC), the Illuminating Engineering Society (IES), ASHRAE, and ASTM International subsequently lent their support.
The author of this article, a communicating member of the working committee that developed the Cx portions of the IgCC, was part of a team assembled by the AIA to review the code. This preview of the IgCC’s Cx provisions is based on Public Comment Version 2.0 from November 2010—the latest version of the IgCC available for reference—and the public-review comments accepted for inclusion in the code during the final action hearing Oct. 31, 2011, in Phoenix. Although the final code will be a bit different, the discussion contained in this article embodies the intent of the Cx sections.
Overview
The IgCC requires Cx for many disciplines involved in building design, construction, and operation, including site-impact mitigation, soil testing, HVAC design and operation, lighting and envelope validation, and post-occupancy inspection and monitoring. The code strives to define and illustrate the basic and more advanced facets of “total building commissioning,” which one day may be required by law throughout the United States.
The IgCC uses the model-code approach, which enables communities to tailor requirements to their needs. Most parts of the code are formatted with checklists allowing authorities having jurisdiction to choose the degree of detail and rigor required. ANSI/ASHRAE/USGBC/IES Standard 189.1-2011, Standard for the Design of High-Performance, Green Buildings Except Low-Rise Residential Buildings, is a jurisdictional compliance option. Cx usually is mandatory, regardless of the compliance route chosen.
Stating the Obvious
All Cx guidelines in the United States would benefit from borrowing a page from The Chartered Institution of Building Services Engineers’ (CIBSE’s) CIBSE Commissioning Code M: Commissioning Management, which states, “Building-services plant and control systems should be inherently commissionable,” and, “The contractor and client should allow sufficient time for the complete commissioning process and ensure integration into the overall program.”
Although primarily a quality-assurance process, Cx is the first step in continuous preventive maintenance. If a piece of equipment or a system cannot be commissioned, it cannot be maintained. For example, if the control panel on a variable-air-volume (VAV) terminal above a hard ceiling cannot be accessed for functional testing, it cannot be accessed for preventive maintenance, and in the long run, the unit will not be maintained. If large equipment, such as a boiler or chiller, lacks metrics proving its acceptability, it lacks benchmarks that will become future indicators of its correct operation.
Although the IgCC requires access for Cx, it does not require that systems be designed for Cx. In other words, it lacks the requirement that equipment and systems be inherently commissionable and, thus, inherently maintainable.
Scope of Cx
In many codes and guidelines, Cx is required for energy-consuming systems, such as heating, ventilation, cooling, and lighting. The IgCC expands on this by including landscape and site work, rainwater and wastewater reuse, more extensive envelope requirements, noise and radon mitigation, and more. ASHRAE has taken a more long-term approach, creating a fundamental Cx guideline (ASHRAE Guideline 0-2005, The Commissioning Process) and following that with application guides for various building components. These components reach into every aspect of a building, including walls, roofs, windows, doors, and, eventually, furniture and interior finishes.
Indoor Environmental Conditions
The IgCC emphasizes minimal energy consumption and the resulting benefits of lower operating costs and carbon-dioxide emissions, citing indoor environmental quality (IEQ) as one of a dozen factors to be considered in the recommissioning of a building 18 to 24 months after occupancy. It does not specify specific techniques for measuring and maintaining a high level of IEQ.
Commissioning Authority
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.
Design Responsibility
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.
System Handover
The handover of a finished building to the operations-and-maintenance (O&M) staff is critical. Chapter 9 of the IgCC has extensive requirements for building handover. One important facet is the definition of, and requirement for, pre- and post-occupancy Cx reports. The IgCC requires that the reports address items in an extensive multidisciplinary list. The list consists of some 60 systems and subsystems, from site management to HVAC, that require a pre- or post-occupancy report. These reports must be accepted by the code official for a certificate of occupancy to be issued.
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Post-occupancy Commissioning
Post-occupancy Cx has been slow to gain acceptance in the United States, despite overwhelming evidence of its positive effects. The IgCC requires that a post-occupancy Cx report be provided to an owner within 30 months. A post-occupancy Cx report addresses IEQ, landscape, sites, natural resources, topsoil and vegetation, percolation (drainage), stormwater management, vegetative roofs, interior and exterior lighting and controls, and more.
Section 904 of the IgCC describes the requirements of an O&M owner education manual. The description is extensive in scope and detail.
Recommendations
The IgCC is an important first step in holistic high-performance-building design and operation. However, it does not take advantage of proven Cx tools developed by others. Specifically, the Cx aspects of the code would be improved by:
A longtime member of HPAC Engineering’s Editorial Advisory Board, Ron Wilkinson, PE, LEED AP, CPMP, is the author of the first commissioning training program for the Leadership in Energy and Environmental Design for New Construction and Major Renovations Green Building Rating System, the chair of the commissioning advisory committee of The American Institute of Architects (AIA) Committee on the Environment, and the recording secretary for ASHRAE Guideline Project Committee 0.2/1.2, The Commissioning Process for Existing Building Systems and Assemblies/The Commissioning Process for Existing HVAC&R Systems. An ASHRAE Distinguished Lecturer and an AIA Continuing Education Lecturer, he has spoken on commissioning practices internationally.
Did you find this article useful? Send comments and suggestions to Executive Editor Scott Arnold at scott.arnold@penton.com.
Selected articles and columns on commissioning by Ron Wilkinson, PE, LEED AP, CPMP, appearing in HPAC Engineering: