Engineered Systems - March 2009 - (Page 22)

Commissioning BY REBECCA ELLIS, P.E. PREPARATION FOR LEED® For Existing Buildings You got the initial certification. Now what’s the best path to EB? LEED® for Existing Buildings: Operations & Maintenance (LEED EB) is to building operations what LEED for New Construction (LEED NC) is for design and construction projects. Until recently, the two programs have been applied to different buildings: existing buildings pursuing LEED EB, and new buildings and major renovations pursuing LEED NC. Now that the LEED EB rating system has been in place for four years and the LEED NC system for approximately twice as long, the USGBC would like to see new LEED NC certified buildings earn LEED EB certification after their first full year of occupancy. I also believe that this should be the natural progression for new buildings whose owners are committed to sustainability for the long run. I would like to tie my previous three columns (December 2008 and January and February 2009) into LEED EB planning and preparation. My recommendations for design and construction phase operations planning, especially for monitoring building systems performance and energy consumption, dovetail directly into some of the LEED EB credits. Many other LEED EB prerequisites and credits may also be more efficiently planned during the project than after the owner takes occupancy of a building, but I will focus on commissioning-related activities. The following are LEED EB credits that should be considered during a building’s planning and design. Doing so will help the building owner qualify for the LEED EB points more easily and less expensively than starting the planning and implementation process after the building is constructed. These are all under the LEED EB Energy & Atmosphere (EA) section. EA CREDIT 2.1: EXISTING BUILDING COMMISSIONING: INVESTIGATION & ANALYSIS This credit requires an evaluation of building systems performance and recommendations for improvement. This type of optimization should be anticipated during initial commissioning, as discussed in my December 2008 column. The new construction commissioning process can establish a performance baseline to be used to compare post-occupancy performance metrics. With careful attention to actual building loads and occupancy patterns, it is probable that system performance and efficiency can both be improved over time. The BAS monitoring points, energy submeters, and associated trend logs discussed in my January and February 2009 columns will provide much of data required by LEED EB Credit 2.1 for investigation and analysis. EA CREDIT 2.3: EXISTING BUILDING COMMISSIONING: ONGOING COMMISSIONING After the first LEED EB investigation and analysis process (and implementation of any optimization initiatives identified), ongoing commissioning is a plan for repeating the evaluation of each system’s performance on a regular basis (no less frequently than once every 24 months). Trend logs of the permanent BAS monitoring points and energy submeters will be a key element of this ongoing commissioning process and, per last month’s column, can and should be defined Waiting until the wiring and piping distribution design is near y piping distribution design is nearly comp e complete before determining what mple before determining what meters can be install meters can be installed will more lled will more i oft often than not limit the owner’s ften tha not lim the owner’s an imit wner s options for effective metering options for effective metering. t g and programmed by the controls contractor prior to initial commissioning of the building. EA CREDIT 3.1: PERFORMANCE MEASUREMENT: BUILDING AUTOMATION SYSTEM This credit is a precursor to obtaining Credits 2.1 and 2.3 as efficiently as is practical. It is through the BAS that building systems performance measurements can be collected, stored, and reported. In addition to designing, specifying, and commissioning a BAS in the original construction project, LEED EB requires that a preventive maintenance program be in place to help ensure the reliability of the BAS over time. EA CREDITS 3.2 & 3.3: PERFORMANCE MEASUREMENT: SYSTEM LEVEL METERING These credits are about submetering energy use at the systems identified as being the largest energy consumers. LEED EB defines detailed requirements regarding what percentage of energy use needs to be metered and where. If a building owner intends to pursue LEED EB after occupancy, these requirements should be considered when developing the metering plan during the design phase (February 2009). In summary, for this and my previous columns, planning for systems operations, monitoring, and optimization during the design and construction project can benefit the building owner, operators, and occupants for the life of the building. This is true whether the building owner pursues LEED EB certification or not. The upfront effort by the future building operators — and the need for understanding and collaboration from the design and construction team — is significant. This is not something that will be accomplished during one or two meetings. I strongly believe, however, that the long term benefits (reduced operating costs and increased occupant satisfaction) will be more than worth the effort for a building owner who intends to operate the new building as sustainably as possible. ES Ellis is president of Questions & Solutions Engineering, Inc. (Chaska, MN). E-mail her at rteesmag@qseng.com. 22 En g i neer ed Sy stem s March 2009

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Engineered Systems - March 2009 Contents Editor’s Note Back2Basics Case In Point Commissioning Building Automation HVACR Designer Tips Application Checklist Teaching An Old School New Tricks Basics For Absorption Chillers A New Haven For Sustainable Schools Glossary Classifieds Advertiser Index Tomorrow’s Environment

Engineered Systems - March 2009

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