Written by Mike Flenniken 5:47 pm Column

Seattle Advances Water Demand Calculator Use with Training

With an eye toward Seattle mandating use this year of IAPMO’s Uniform Plumbing Code (UPC®) Appendix M — the Water Demand Calculator® — for multifamily buildings, the county and local ASSE and IAPMO chapters recently held an in-person training for inspectors, installers and design professionals.

More than 40 installers, designers and inspectors attended the four-hour event at Green River College in Auburn, Washington. Presentations covered the development of, and history behind, the Water Demand Calculator, as well as how to use it and the benefits of doing so.

Seattle adopted Appendix M as part of the 2018 Seattle Plumbing Code — which is based on the UPC — and it has been optional. This year, it is expected to become mandatory due to a provision in the 2021 Seattle Energy Code that requires its usage for newly constructed Group R-2 occupancies, which include multifamily buildings such as apartments.

The Water Demand Calculator accurately predicts peak water demand in single-family homes and apartment buildings, reducing the carbon footprint of the structure and saving consumers on both their water and water heating-related energy utility bills for the entire life of the plumbing system. At the same time, proper sizing greatly minimizes the potential threat of bacterial growth within the system, which can lead to such serious health risks as Legionnaires’ disease.

IAPMO Vice President of Technical Services Christoph Lohr, P.E., delivered a presentation on the benefits of the Water Demand Calculator for construction, including cost, carbon footprint and water savings; impact on salmon and rivers; and water reuse offset.

“The meeting was energetic and included thoughtful audience participation,” he said. “Seattle’s plumbing industry was very interested in learning how to make the Water Demand Calculator a success for their region to improve plumbing system design and installation. I would especially like to thank Steven Hart, chief plumbing inspector of Seattle King-County, the IAPMO Seattle Chapter, and the ASPE Seattle Chapter for making this event a resounding success.”

IAPMO Senior Director of Technical Services Dan Cole and Industry Research Manager Toju Omaghomi, Ph.D., discussed how to take a methodical approach to using the Water Demand Calculator for multifamily buildings, including an overview of basic information about the calculator, mixed-used considerations to keep in mind for commercial kitchens, office and retail space, and encouraged the use of the UPC’s Appendix C, Alternate Plumbing Systems.

“The participants appreciated the explanation on how the Water Demand Calculator was developed,” Omaghomi said. “Steven Hart said it is good to know we were using the same principles as Hunter but incorporating today’s water use information to estimate peak demand for pipe-sizing purposes.”

Cole said they were happy to witness the positive interaction between the attendees and the presenters and are looking forward to seeing the use of the Water Demand Calculator pay off.

“We are excited for Seattle to experience the cost, energy, and water savings benefits when designing multifamily homes with the Water Demand Calculator,” he said.

Hart said he expects the rest of Washington state will follow Seattle as it leads the way in the implementing of the Water Demand Calculator, and they are standing by for the final details on its implementation.

“IAPMO’s presentation outlining Appendix M history and use was well received, and it raised the question of what documentation will be required to be submitted for plumbing plan check when it is used,” Hart said. “We look forward to receiving an update on the plan check guidelines.”

Mike Flenniken is a staff writer, Marketing and Communications, for IAPMO. Prior to joining IAPMO in 2010, Flenniken worked in public relations for a group of Southern California hospitals and as a journalist in writing and editing capacities for various Southern California daily newspapers.

Last modified: June 11, 2024