An analysis of expected changes related to heating, ventilation, air conditioning
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Since its introduction in 2000, the U.S. Green Building Council’s (USGBC’s) Leadership in Energy and Environmental Design (LEED) green-building rating system has undergone many changes. More are in store, with the 2013 launch of LEED v4, formerly LEED 2012. Although the final document has yet to be approved, following is an analysis of expected changes related to HVAC.
Integrated Project Planning
Integrative project planning and design will be a prerequisite for health-care facilities under LEED v4. The intent is to maximize opportunities for the adoption of cost-effective integrated green design and construction strategies as early as pre-design. A “health mission statement” addressing triple-bottom-line (economic, environmental, social) values will be required as part of the owner’s project requirements (OPR). Meanwhile, a team including at least four project stakeholders apart from the owner or owner’s representative will be required to meet before schematic design to set rating goals, target credits to meet, and assign roles and responsibilities. The team also will be required to hold a one-day charrette to identify green design, construction, and operation strategies.
For other space types, one point will be available for:
- Performing an energy-modeling analysis before schematic design is completed to evaluate potential options associated with massing and orientation, occupancy and operation, building envelope, lighting and thermal levels, and plug and process loads. This will help project teams reduce energy loads and accomplish other synergistic sustainability goals.
- Analyzing indoor and outdoor water demand, process water, and supply sources, including alternate sources, such as on-site rainwater, greywater, reclaimed water, and HVAC condensate. This will enable project teams to prepare a budget to reduce the impact of a building and site on the municipal water supply and wastewater-treatment plant and improve aquifer recharge.
- Analyzing expenditures and savings (whole-building operational savings), productivity impacts, and tangible and intangible benefits of integrated solutions.
In short, one point will be awarded for following sustainability and LEED guidelines from project inception and analyzing and documenting green-building costs and savings.
As of the third public-comment draft, the integrative-project-planning prerequisite and integrative process do not have a category. They simply are placed at the beginning of the scorecard. That could change following the fourth public-comment period.
Location and Transportation, Sustainable Sites
LEED v4 will introduce a new category, Location and Transportation (LT). Although it was designed to protect sensitive land by minimizing development footprint, it could have implications for HVAC in terms of allowable site usage. Some of the credits under LT, such as bicycle storage, reduced parking capacity, and low-emitting vehicles, are present in LEED 2009 under the Sustainable Sites (SS) category.
A new credit for rainwater management combining the stormwater-design (quantity and quality) credits from LEED 2009 has been added under the SS category. This provides an opportunity to earn two or three points for managing on-site runoff using low-impact development and green infrastructure.
The Water Efficiency (WE) category is undergoing major changes:
WE Prerequisite 1: Outdoor Water Use Reduction. This prerequisite is applicable to projects with exterior vegetated areas, including roofs, of more than 1,000 sq ft. It applies to all irrigation water, regardless of source. There are two project options from which to choose:
- Option 1: Show the landscape does not require permanent irrigation beyond a two-year establishment period.
- Option 2: Achieve a 30-percent reduction in outdoor water use per the U.S. Environmental Protection Agency’s WaterSense Water Budget Tool. Athletic fields, playgrounds, and food gardens can be excluded from the calculations.
WE Prerequisite 2: Indoor Water Use Reduction. Formerly “Water Use Reduction,” this prerequisite still will require a 20-percent water-use reduction. Also, it will require a WaterSense label for certain fixtures and fittings, such as urinals, toilets, and faucets. It will address appliances, process water, and cooling-tower requirements per ANSI/ASHRAE/USGBC/IES Standard 189.1, Standard for the Design of High-Performance, Green Buildings Except Low-Rise Residential Buildings.
WE Prerequisite 3: Building Level Water Metering. This prerequisite is new and applicable to all project types. Its intent is to aid water management and identify opportunities to save water. Project teams will be required to install permanent meters capable of measuring water usage at least once a month or according to utility-billing intervals. Project teams must agree to share the data with the USGBC for five years following project certification or building occupancy, whichever comes first.
WE credits. Two WE credits have been added (Cooling Tower Water Use and Water Metering) and two deleted (Innovative Wastewater Technologies and Water Use Reduction).
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Energy and Atmosphere
Energy and Atmosphere (EA) will continue to be the most comprehensive section in terms of points a project can earn.
EA Prerequisite 1: Fundamental Commissioning and Verification. Formerly “Fundamental Commissioning of Building Energy Systems,” this prerequisite was modified to:
- Include indoor-environmental-systems quality and durability.
- Require an operations-and-maintenance plan documenting building-operations sequencing, occupancy scheduling, equipment run times, and HVAC-equipment setpoints and including a mechanical- and electrical-systems narrative, a preventive-maintenance plan, and a periodic-commissioning plan.
- Require a qualified third-party commissioning authority (CxA) for projects exceeding 20,000 sq ft. This is in contrast to the 50,000 sq ft under LEED 2009. For buildings less than 20,000 sq ft, 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.
- Require the CxA to verify the inclusion of building envelope in OPR, basis-of-design, and construction documents.
EA Prerequisite 2: Minimum Energy Performance/EA Credit 1: Optimize Energy Performance. Prerequisite 2 requires projects to meet the mandatory provisions of ANSI/ASHRAE/IESNA Standard 90.1, Energy Standard for Buildings Except Low-Rise Residential Buildings, or, for international projects, a USGBC-approved equivalent. Though the second draft of LEED v4 required the percentage reduction of the baseline to be measured according to the average percent of energy-cost savings and source energy usage, the third draft requires only the use of energy-cost savings (analogous to LEED 2009). Additionally:
- The reference standard was changed from the 2007 to the 2010 version of ANSI/ASHRAE/IESNA Standard 90.1.
- Improvement must be at least 10 percent for new construction, 7 percent for major renovations, and 6 percent for core-and-shell projects.
- EA Prerequisite 2 and EA Credit 1 were appended to include metric conversions; recognize equivalent energy standards for international projects; update the option for prescriptive compliance for office, retail, school, and health-care facilities to ASHRAE Advanced Energy Design Guides for 50-percent savings; include load requirements specific to retail buildings; and require that 30 percent of data-center energy savings come from building power and cooling.
EA Prerequisite 3: Building Level Energy Metering. This is a new prerequisite. It requires building-level metering or a submetering system that can be aggregated for electricity, natural gas, fuel oil, steam, chilled water, and biomass. Metered data must be shared with the USGBC for five years following occupancy or certification, whichever comes first.
Energy consumption must be tracked at one-month intervals. For core-and-shell projects, base building-level metering must be provided. In all cases, energy data must be shared for five years or until the building owner or lessee changes.
EA Prerequisite 4: Fundamental Refrigerant Management/EA Credit 5: Enhanced Refrigerant Management. The language of EA Prerequisite 4 has been refined to incorporate retail-specific requirements and metric-conversion units. The purpose of EA Credit 5 is to reduce ozone depletion through enhanced refrigerant management. While Option 1 (no refrigerant or refrigerant with an ozone-depletion potential of 0 and a global-warming potential of less than 50) and Option 2 (environmentally safe refrigerants) are unchanged from LEED 2009, guidelines addressing the use and monitoring of non-ozone-depleting refrigerants have been added for commercial refrigeration systems.
EA Credit: Advanced Energy Metering. This credit offers a prescriptive approach to monitoring whole-building systems or any system-level unit representing 10 percent or more of annual energy consumption. Meters are to record demand and consumption at least once an hour. Data are collected automatically and transmitted to a remote location for storage for at least 36 months.
EA Credit: Enhanced Commissioning. For this credit, the points were increased from two to six. For Building Design & Construction projects, the enhanced-commissioning process now includes mechanical, electrical, domestic-hot-water, and renewable-energy systems. The requirements for meeting Option 1 (five points) are unchanged. For Option 2 (five points), envelope commissioning was added, while for Option 3 (five points), monitoring-based commissioning was added. Option 4 (six points), for data centers, involves meeting the requirements of options 1, 2, and 3.
Indoor Environmental Quality
The three prerequisites under Indoor Environmental Quality (IEQ) have been modified as follows:
IEQ Prerequisite 1: Minimum Indoor Air Quality Performance. This prerequisite now addresses radon-resistant construction for projects containing residential units.
IEQ Prerequisite 2: Environmental Tobacco Smoke (ETS) Control. This prerequisite now prohibits smoking on school grounds entirely, as opposed to only inside buildings and within 25 ft of entries, outdoor-air intakes, and operable windows.
IEQ Prerequisite 3: Minimum Acoustical Performance. Applicable only to school projects, this prerequisite addresses background noise from HVAC systems, as well as noise from exterior sources. LEED v4 adds exterior-noise-control exceptions for projects in quiet areas and limits the scope of renovations in observance of historic-preservation requirements.
IEQ Credit 1: Outdoor Air Delivery Monitoring/IEQ Credit 2: Increased Ventilation. IEQ credits 1 and 2 have been removed, their requirements split between IEQ Prerequisite 1 and the new Enhanced Indoor Air Quality Strategies credit. Other IEQ credits, such as Low-Emitting Materials, Construction Indoor Air Quality Management Plan, Controllability of Systems—Lighting, Controllability of Systems—Thermal Comfort, and Daylight and Views, have been refined. A new credit embracing acoustic performance applicable to all space types has been added.
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Innovation in Design and Regional Priority
LEED v4 recognizes projects for exemplary performance, innovation, and achievements toward geographically specific environmental goals. LEED v4 necessitates that at least one project-team principal be a LEED Accredited Professional (AP) with a project-appropriate specialty, awarding one point. Originally, LEED v4 required that two people with project-appropriate specialties serve on a project team. Legacy LEED APs will need to upgrade their certification to earn the credit.
Taking the Next Step
Previous versions of LEED focused on building needs (the present), rather than building performance (the future). The inclusion of metrics and performance tools in LEED v4 is designed to promote continuing building assessment, which should lead to better operations and maintenance over the life of a building.
Also distinguishing LEED v4 are building-specific rating-system variations. For example, the rating system for data centers is different than the rating system for retail.
HVAC professionals will need to earn LEED AP certification to “take a seat at the table.” HVAC professionals may take the current versions of the LEED Green Associate and AP exams for the remainder of 2012. The exams follow the test specification and resources listed in the current candidate handbook located on the Green Building Certification Institute Website (www.gbci.org). To be eligible for the LEED AP exam, candidates should have documented experience on a LEED project.
Once LEED v4 is finalized, HVAC professionals will have to learn the changes and prepare for them. Attending workshops and certification classes will be imperative.
The director of sustainability for the Green Building Research Institute (GBRI) (www.gbrionline.org), Jeslin Varghese, PMP, LEED AP BD+C, O+M, is an engineer with nine years of experience in sustainability consulting, project management, and education. He holds a master’s degree in construction management from Texas A&M University. The director of commercial operations for GBRI, Diana Webb is a journalist and motivational speaker. She is a graduate of the University of Missouri-Kansas City School of Law.
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