In order to measure the Pittsburgh 2030 District‘s success in reaching its 50% reduction goals, baselines must first be determined for each reduction category. Whereas energy reduction is measured against a national median average, there is no national average baseline for existing building water consumption by building type. Thus, a local historic water baseline was developed.
The Pittsburgh 2030 District: Downtown water baseline details individual building baselines, the process by which a building establishes a baseline, and the implications for aggregated District water use reductions.
BUILDING-SPECIFIC WATER BASELINES
In partnership with Pittsburgh Water and Sewer Authority (PWSA), Green Building Alliance (GBA) developed the Pittsburgh 2030 District: Downtown Water Baseline using aggregated, local consumption for Downtown buildings in the Pittsburgh 2030 District boundary. PWSA’s (an important District Resource Partner) summaries of historic water consumption for Downtown Pittsburgh were integral in calculating both district and individual water use intensity (WUI) baselines measured in gallons per square foot per year (gallons/ft2/year).
While there are 448 buildings in this zone, due to data availability and accuracy, the final dataset for water baseline creation included 163 buildings. To take into account seasonal and annual variations, actual usage over a four-year period (2009 through 2012) was used (when available) for all buildings, yielding an average water consumption per year. (Water consumption data before this time was not available for enough buildings to warrant inclusion.) Water consumption was then paired with building square footages to yield water use intensity (WUI) in gallons per square foot per year (gallons/ft2/year) for different building use types.
Water consumption baselines were generated for 12 unique building use types representing those most common in Downtown Pittsburgh. Each classification comprises buildings of similar size and function. Generally, a lower WUI indicates less intensive water use, but WUIs vary widely by building use type and should only be compared to buildings with similar functions. Thus, each WUI reflects a locally specific, aggregated set of similar use buildings whose total water consumption was divided by total square footage for that building use classification.