It is the contractor who is in the driver’s seat during all phases of sustainable construction projects, including predesign and design, construction and closeout. The contractor is involved before the race starts and continues driving sustainability through to operational training.
As the second part in our “Contractor’s Role in Sustainability” series, this article focuses on the importance of the contractor during the predesign and design phases of a commercial construction project. The contractor’s role during these two critical phases sets the stage for a commercial project’s success.
On any LEED project, both the predesign and design phases are viewed as opportunities to incorporate sustainability features into the design and optimize the design for maximum efficiency to achieve the desired LEED certification level. The addition of the Integrative Process credit to LEED v4 provides an excellent insight into the direction LEED is taking. The proposed wording in the third public comment draft of LEED v4 for Building Design & Construction states, “Starting in predesign, and continuing throughout the design phases, identify and execute synergistic opportunities for high-performance outcomes across different disciplines and building systems.”
The importance of a design charrette
During the predesign stage, the contractor will participate in a design charrette. The purpose of the charrette is to hold a preschematic design collaborative session during which a project team and other building stakeholders brainstorm ideas, develop project strategies, and identify major project goals and issues all in terms of sustainable integrated building design. The key word is “integrated” because sustainable ideas and strategies should be developed across the entire design process. Think of a design charrette as a meeting where professionals can discuss creative ideas, concerns and innovative solutions.
The contractor provides the necessary input on the feasibility of implementing proposed design ideas. A successful design charrette will lead to a project conceptual design identifying proposed LEED credits. This will determine the LEED certification level based on points assigned to credits.
One of the important products of the design charrette is the meeting report which outlines team ideas, identifies goals and strategies, and determines who will participate on the project team and what their roles and responsibilities will be for the duration of the project. A proposed completion schedule is included in the report along with a conceptual design.
A project team leader, who is most likely a LEED AP, should be chosen. The team leader or the project manager is the primary project driver who facilitates communication among project stakeholders including the owner, architects, landscape architects, interior designers, mechanical and electrical engineers, equipment planners, environmental professionals, land planner and the cost estimator — all of whom are needed for successful project completion. The LEED AP team leader simultaneously functions as the primary contact with the Green Building Certification Institute (GBCI). GBCI is the certification arm of USGBC that certifies LEED projects and accredits LEED professionals.
Entering the design phase
Once the design charrette report and conceptual design are accepted by the project owner, the project enters the design phase. The Owner’s Project Requirements (OPR), Basis of Design (BOD) and Design Documents are prepared for use by the project team and for LEED submission. The schematics include the detailed design and design analysis along with the “sustainable” specifications. The sustainable specifications included in a report are:
- LEED requirements
- Intended level of certification
- Identification of specifications for credits, i.e., sustainable sites, indoor environmental quality
- Registration of project with USGBC
Currently, the LEED requirements that should be considered as a minimum include the energy systems and water systems. (LEED v4 is strengthening minimum requirements as discussed.) A cost analysis that estimates the full cost of implementing the integrated LEED guidelines should be calculated and documented.
Finally, the construction documents (CD) are prepared. The contractor will work with designers, commissioning agents and sustainability professionals to make sure all LEED requirements are incorporated including material selection guidelines, waste management goals, training requirements, indoor air quality goals and commissioning requirements.
The drawings, templates and documentation required for LEED certification are submitted to the GBCI at this stage if a two-phase LEED certification approach is followed. Prior to GBCI submission, the design documents are reviewed by a LEED team comprising the commissioning agent, a LEED AP, contractor representative and design representative to identify and rectify potential problems in construction plans before construction starts.
Utilizing a commissioning agent
LEED Commissioning — Fundamental Commissioning involves review of OPR, BOD and the creation of a commissioning plan with specifications by a commissioning agent (CXA). In addition, the CXA should also verify the installation and performance of the systems to be commissioned and complete a summary commissioning report on project completion.
In addition to the scope of fundamental commissioning, the CXA is required to perform a design and contractor submittal review, verify that requirements for building operator training is complete, review building operations within 10 months of substantial completion and make a corrective action plan to resolve outstanding commissioning-related issues. The individual serving as the CXA must be independent. If the building area is less than 50,000 square feet, the CXA could be a member of project team with design or construction responsibilities.
Only energy systems are commissioned. Commissioning activities must be completed for the following energy-related systems, at a minimum:
- Heating, ventilating, air conditioning and refrigeration
- Lighting and day lighting controls
- Domestic hot water systems
- Renewable energy systems (e.g., wind, solar)
Though building envelope commissioning is not under the scope of fundamental or enhanced commissioning under LEED v4, a LEED project may earn one point under “innovation and design” for comprehensive envelope commissioning. The third draft of LEED v4 requires a qualified third-party commissioning authority (CXA) for projects exceeding 20,000 square feet. This is in contrast to the 50,000 square feet under LEED 2009. For buildings less than 20,000 square feet, a member of the design or construction team can serve as the CXA as long as he or she is not directly responsible for construction or design activities. LEED v4 also requires the CXA to verify the inclusion of a building envelope in OPR, BOD and CD.
To read the full story Part 2: Contractor's Role During Predesign and Design Phases, click here to download the Fall 2012 issue of Sustainable Construction.
To read Part 1: Sustainability and LEED: The Contractor is in the Driver’s Seat, click here.