LEED 2012 – 3rd Public Comment – WE (Water Efficiency) Section
Key changes in the the WE section of LEED-NC (part of LEED BD&C) in the third public comment draft of LEED 2012 are discussed below. Do you have comments or questions on this draft? Discuss them below with your fellow LEED professionals. Substantive comments submitted here during USGBC's third public comment period here will be submitted to USGBC and considered "official" public comments.
A renamed Outdoor Water Use Reduction prerequisite (not “Landscape Water”) has simplified requirements that do not appear to represent significant changes from the second draft. Projects can avoid irrigation entirely or reduce water use for the peak watering month 30% below a baseline established by the WaterSense Water Budget Tool.
The fundamental 20% water reduction baseline is unchanged, but the name is now Indoor Water Use Reduction. As with the second draft, only fixtures in the project scope are covered, not all fixtures in the building, and water-efficiency baselines remain the same from that draft. A new Appliance and Process WaterProcess water is used for industrial processes and building systems such as cooling towers, boilers, and chillers. It can also refer to water used in operational processes, such as dishwashing, clothes washing, and ice making. Use Reduction prerequisite has been folded into this prerequisite, bringing minimum performance requirements for some appliances and processes. For example, residential clothes washers and dishwashers must be Energy Star and commercial clothes washers must be CEE Tier 3A.
The Building-Level Water Metering prerequisite has been moved here from the Performance category, which did not stick in this draft. The gist remains the same: all water conveyed to the project—regardless of source—must be metered. Reporting of metering data, including submeters, to USGBC would be required for five years. SubmeteringSubmetering is used to determine the proportion of energy use within a building attributable to specific end uses or subsystems (e.g., the heating subsystem of an HVAC system). requirements, like those for projects with significant irrigation, have been dropped.
The Outdoor Water Use Reduction credit remains similar to the prerequisite in its use of the WaterSense Water Budget Tool. The basic 50% and 100% reduction thresholds remain unchanged from LEED 2009 and from the first two drafts, but other requirements have been simplified since the last round. For example, not only can playgrounds and athletic fields be excluded from the credit calculations, but best management practices such as metering are no longer required for them.
The Indoor Water Use Reduction credit builds on the prerequisite in a straightforward fashion, while also similarly folding in the Additional Appliance and Process Water Use Reduction credit that had been introduced in a previous draft. This portion of the credit creates a menu of choices. Commercial washing machines, commercial kitchen equipment, commercial laboratory and medical equipment, commercial vehicle washing systems, and municipal steam systems all fall under this credit. Earning it means establishing eligibility for a given category (being connected to a municipal steam system, for example), and then meeting specified requirements for all of the given equipment within the project scope. In most cases, that entails meeting efficiency standards; in the case of municipal steam, projects would recover and reuse steam condensate.
The Sustainable Wastewater Management credit (Innovative Wastewater Technologies in LEED 2009) has been dropped from this draft. While USGBC had been developing the credit toward recognizing nutrient recovery from wastewater, it apparently decided that new water-related requirements included elsewhere raise the LEED 2012 bar enough.
One of those places is Cooling Tower Water Use, which is mostly intact from the previous draft, with some simplifications. Requirements for drift eliminators and control of blowdownBleed-off, or blowdown, is the release of a portion of the recirculating water from a cooling tower; this water carries dissolved solids that can cause mineral buildup. with conductivity meters are eliminated, for example, while retained requirements focus on control of scale and corrosion in the system.
A Water Metering credit is retained from previous drafts and moved to the WE category from Performance. The current version is a simplification, removing a requirement for remote reporting of data while retaining requirements for submetering that have been jettisoned from the prerequisite, notably submetering for any reclaimed water, domestic hot water, and any boiler with aggregate projected annual water use of 100,000 gallons or more.
What do you think of the proposed changes? Please post your public comments below.