Objective: To develop data and tools that quantify building water consumption and water quality in high-performance buildings, and to support the development of building water efficiency standards and codes.
What is the technical idea? Building designers and standards makers have traditionally focused on energy efficiency when developing “stretch” or reach codes. Interest has grown to incorporate water metering and conservation into these codes and standards (e.g., ICC Plumbing and Mechanical Code, IAPMO Green Plumbing Code, ASHRAE Standard 191P). Water labeling of residential buildings, such as EPA’s WaterSense Labeled Homes program and the proposed RESNET Water Efficiency Rating (WER) Index Standard, are gaining traction as well. In response to this activity, the technical idea is to develop a database for water rating data and models to provide baseline water consumption of similar buildings to facilitate water benchmarking. High-performance building designers have followed many guidelines such as using efficient water heating appliances, low-flow fixtures, and efficient landscape water use; however, minimal water use has also had unexpected consequences in premise plumbing (pipe in a building that conveys potable water to end uses and waste water from them). Institutions such as the EPA have stated lower flows can impact water quality, costs, energy consumption, and public health. Currently, there are few tools that can predict conditions that result in disinfectant loss and biofilm growth, which are low water flow concerns for plumbing. Another significant output is to develop these much-needed flow models.
What is the research plan? Discussions with individual stakeholders have led us to conclude that experts in water conservation, plumbing design, water quality, and public health desire more engagement with each other. This engagement would inform water use and plumbing guidelines for buildings that would satisfy their respective concerns for building occupants. Additionally, these discussions have highlighted the need for a clear research roadmap for premise plumbing issues, which does not exist today.
Our first product is to host a workshop in FY18 to formulate a research roadmap. We plan to produce a primer that would clearly state the mission of the workshop and outline the various water related issues in buildings and possible intersections between them. This document is to be distributed to the participants prior to the workshop. The major output of the workshop will be a document which summarizes the workshop events and articulates the measurement science needed to improve the efficiency and quality of water delivered through premise plumbing systems. Similar efforts hosted by the division have proven successful in identifying measurement science needs for net-zero energy buildings. With stakeholder engagement, the next few products will have several avenues of dissemination and adoption.
This project also has plans to develop several software tools or models that will assist building designers. The first is a tool that can provide data for benchmarking, or comparing a building’s water use to that of an appropriate baseline building of similar type and location. The tool may be a database with water consumption and characteristics of buildings from various locations in the U.S. gathered from surveys, literature, the Commercial Building Energy Consumption Survey, etc. It can also be a model that estimates baseline water consumption with building characteristics as inputs. Many such benchmarking tools exist for comparing residential and commercial building energy use. With enough available data from research publications and buildings databases, water use can be benchmarked as well. A publication in FY18, using the method to benchmark the NIST NZERTF and/or a commercial building will provide an example of such a tool.
The second tool is a plumbing flow and temperature model that will predict conditions in plumbing systems of various sizes, materials, and configurations. Data from the model will be helpful for determining conditions such as stagnation or low-flow that are detrimental to aspects of good water quality. Models such as this have direct impact on updating plumbing design and codes; organizations such as IAPMO and ICC have identified the need to update plumbing codes for lower flows.
 U.S. Environmental Protection Agency. https://www.epa.gov/research-grants/national-priorities-impacts-water-conservation-water-quality-premise-plumbing-and
 NIST Technical Note 1660. 2010. http://ws680.nist.gov/publication/get_pdf.cfm?pub_id=905024.