For almost a century, the International Association of Plumbing and Mechanical Officials (IAPMO) has been a focal point of plumbing industry research, from creating the original IAPMO Research and Testing laboratories to leading the Plumbing Efficiency Research Coalition (PERC) efforts in drainline carry, from opening a research laboratory at Los Angeles Department of Water and Power’s La Kretz Innovation Campus to collaborating with the American Society of Plumbing Engineers (ASPE) on storm piping and roof drains.

IAPMO has not only been involved in American plumbing research, but also international efforts for more than a decade. The most notable international research entity is the International Council for Research and Innovation in Building and Construction (CIB).

CIB has numerous working commissions meetings at annual symposiums around the globe. Of the various working commissions, the Water Supply and Drainage Symposium (W062) stands out. The CIB Commission W062 was established in 1971, and the U.S. National Committee for CIB was organized in 1973 represented by Thomas Konen (Stevens Institute of Technology) and R. Wyly and M. Orloski (National Bureau of Standards). 

The National Bureau of Standards’ participation continued through Larry Galowin until 2011. IAPMO’s first participation was in 2009 with Pete DeMarco, who presented twice in 2013 on “The Drainline Transport of Solid Waste in Buildings,” and on the 2012 IAPMO Green Plumbing and Mechanical Code Supplement. 

In 2014, DeMarco presented on the World Plumbing Council research database and then provided an update in 2015. He presented in 2018 on the final PERC report for “Drainline Transfer of Solid Waste in Building Drains,” and in 2019, a paper on the development of ISO 31600. 

Dan Cole became the second IAPMO staff member to attend CIB, both in the 2017 Netherlands and 2018 Portugal events, presenting on “Calculator for Estimating Peak Water Demand in Residential Dwellings” and “Water Demand Calculator: Expected Material Cost and Energy Loss Reductions in Residential Dwellings,” respectively. 

At the 2024 W062 Symposium in Northampton, England, Cole returned to present on water reuse and was joined by Toju Omaghomi (IAPMO), who presented an update on IAPMO’s Data Research efforts on the commercial version of the Water Demand Calculator (WDC). 

In addition to IAPMO staff showcasing their research and innovation skills at the 2024 event, another highlight from this year was long-time IAPMO volunteer and ASPE member John Lansing, who presented on hot water velocity limitations. Lansing’s research directly impacts the Hot Water Recirculation Task Group, of which he is a member, that IAPMO initiated at the start of this year. 

Finally, capping an engaging conference was a tour of the National Lift Tower in Northampton, UK, where conference members witnessed high rise sanitary drainage and vent testing on an almost 50-year-old test tower. 

Challenges of Data Sourcing and Analysis of Nonresidential Water Use Data

Omaghomi delivered the first IAPMO presentation, highlighting the IAPMO efforts in data collection. While fixture-level water use flow details collected in more than 1,000 residential homes were available to develop parameters in the current WDC v2.2, to extend the calculator’s ability to nonresidential buildings, such fixture-level data is not readily available. 

Her paper and presentation discussed how a building’s flow data at the meter and the fixture details (number and type) can be used to estimate fixture probability of use from the building utilization factor relative to the fixture’s worst-case use (i.e., during congestion). In this presentation, she demonstrated how flow data collected from two office buildings were analyzed and how the data collected at the fixture and meter can be used to estimate fixture probability of use (see Figure 1).

Her presentation also explored the key challenges in data sourcing of nonresidential water use data and proposed a potential solution to overcome these hurdles. Key takeaways from Omaghomi’s presentation are:

• The type of data collected, and its accompanying details is important.

• Ideally, data collected at each fixture is desired; however, water use data collected at the meter can be used to estimate the fixture p-values via the utilization factor approach.

• The utilization factor approach is new; it allows less expensive data collection at the building water meter to be used in estimating fixture p-values.

Treatment Methods for Onsite Alternate Water Treatment Systems

Cole presented his paper, titled “Treatment Methods for Onsite Alternate Water Treatment Systems,” which was his first of a two-part paper series. In the first part, Cole reviewed the treatment train and regulatory requirements around onsite alternate water treatment systems (also known as decentralized nonpotable water systems). A planned part two will review a case study where onsite treatment of alternate water has been implemented in the United States. 

As readers are likely aware, onsite alternate water treatment systems represent a significant opportunity to alter how water is managed in buildings. By matching alternate water sources with the right end use, such as irrigating landscapes and flushing toilets and urinals, onsite alternate water systems offset potable water supplies and unlock the potential for more resilient and sustainable water management. 

A current challenge is that the U.S. regulatory landscape for onsite alternate water treatment methods is not uniform or standardized. Cole surveyed the leading U.S. organizations advancing the design and best management practices to support the use of alternate water treatment systems for individual buildings or at a local scale. 

These organizations are the San Francisco Public Utilities Commission, the Water Research Foundation, the National Blue Ribbon Commission (NBRC) for Onsite Nonpotable Water Systems (ONWS), the US Water Alliance, the Water Environment & Reuse Foundation and IAPMO. As Cole explained, the system design and validation from risk-based guidance on estimated log10 reduction targets (LRTs) for pathogens were codified in the American National Standard Institute’s Water Efficiency and Sanitation Standard for the Built Environment (WE•Stand), which provides the regulatory framework at the state or local level for adoption. 

Key takeaways from Cole’s presentation are as follows: 

• Treatment trains for ONWS are emerging technologies in the United States and without standardization.

• The NBRC risk-based framework to determine LRTs guides current state regulations for treatment methodologies.

• LRTs are used to evaluate the performance of multibarrier processes to target and remove pathogens, particulates and organics from alternate water sources.

• Treatment trains treating blackwater, greywater and stormwater for nonpotable water reuse incorporate multibarrier processes combined variously to meet the LRTs.

• Continuous monitoring using sensor validation is recommended to ensure the treatment processes are continuously meeting performance goals. 

• Additional treatment parameters are needed to protect product components in water closets and urinals.

IAPMO’s Hot Water Recirculation Task Group Presentation

Earlier this year, IAPMO convened its first meetings of a special task group focused on hot water recirculation systems. The task group’s goal is the creation of a manual that will promote practices to improve the safety and efficiency of hot water recirculation system performance. This includes design, installation, commissioning and operations. 

John Lansing, a senior plumbing designer with PAE and a task group member, discussed hot water velocities, one of the items under scrutiny by the hot water recirculation task group. 

His presentation focused on how the diameter selection for domestic hot water (DHW) return piping carries significant impacts in terms of energy, material lifespan and biofilm development. Globally, there is a lack of consensus on appropriate maximum velocity values, with recommendations ranging between 0.3 meter/second (1 foot/second) and 1.5 meter/second (5 feet/second), depending on the design standard. 

Undersized return piping can result in material failure in the form of pinhole leaks due to erosion corrosion degradation at high velocities. Oversized return piping may impose additional energy on the system to maintain temperature as a result of heat loss (see Figure 2). Oversized return piping is also associated with low velocities that promote sediment accumulation and a larger internal surface area for biofilm growth. 

A review of various international design recommendations on the subject of DHW return piping velocities were outlined to define the material and energy impacts and support the development of generalized design recommendations. Most energy codes require thicker insulation for larger-diameter piping. 

While a system designed for a high velocity will require more energy from the circulation pump, the additional energy required of the circulation pump is generally insignificant for domestic hot water systems in comparison to the energy gained with lower heat loss from the smaller-diameter piping.

Key findings from Lansing’s presentation include:

• Significant variability in recommended maximum velocities, depending on the design standard (0.3 m/s to 1.5m/s, 1 ft/s to 5 ft/s).

• High maximum velocities are beneficial from an energy standpoint due to the smaller pipe size but minimum velocity recommendations may also be worth including in standards.

• Lack of generalized guidance that accounts for temperature, water composition and pipe material. Without the development of generalized guidance, excessive heat loss and piping system failures will continue to be a common feature in DHW circulation systems.

National Lift Tower Tour

A highlight of the conference was the tour of the National Lift Tower (NLT), a 50-year-old test tower owned and operated by Aliaxis. The tour provided attendees with an opportunity to witness flow tests and configurations on vertical drainage and vent stacks, using clear piping and a smoke generator for enhanced observation. 

The NLT serves as a valuable testing ground for researchers and universities, allowing for the real-time observation of water flow and system configurations. You can see a water flow video at https://bit.ly/3UCfkF3.

The CIB Water Supply and Drainage Symposium (W062) has been a significant platform for building science research since 1972. U.S. contributions, beginning in the 1970s by NIST and, more recently, by IAPMO, continue to push the boundaries of plumbing science. 

At the 2024 symposium, IAPMO experts Cole and Omaghomi presented groundbreaking research on water reuse and data collection for the WDC. Lansing’s work on hot water velocity limitations further emphasized the need for better design standards in hot water recirculation systems. This year’s CIB conference made one thing clear: IAPMO continues to be at the forefront of plumbing research and innovation.

Christoph Lohr is IAPMO’s vice president of technical services and research, where he provides a systems-based approach to departmental leadership and strategy development, represents the organization in numerous committees and speaking engagements, and supplies technical support to IAPMO’s business units. Lohr has more than a decade of experience in designing plumbing systems and is a results-oriented expert, particularly in the realm of balancing waterborne pathogen prevention and water sustainability. Contact him at Christoph.Lohr@iapmo.org.