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Over the past decade, there has been a plethora of new guidance documentation about reducing the risk of Legionella and other waterborne pathogens in building water systems. The primary focus has been for the building owner to responsibly implement a water management program (WMP) for ongoing building operations using ANSI/ASHRAE Standard 188, Legionellosis: Risk Management for Building Water Systems
(https://bit.ly/3ZXSWZS).
ANSI/ASHRAE Standard 188, Section 8 (designing requirements for a building’s water systems) addresses design, construction and commissioning criteria.
In addition, ANSI/ASHRAE 514 Risk Management for Building Water Systems: Physical, Chemical, and Microbial Hazards (https://bit.ly/4gnsYFc) was published to expand WMP efforts beyond solely Legionella concerns. Although these standards inform the plumbing engineer/construction (PE/C) professional what is required, they do not tell the PE/C industry how to accomplish the work.
Water quality standards are often put in place with little to no direct training for the PE/C industry. As these standards have been integrated into various U.S. health policy initiatives, the PE/C industry focused on the performance of the building piping system without adequate knowledge about water quality within the piping.
My experience has been that PE/C professionals are intimately aware of backflow prevention. However, they lack basic knowledge about water science to achieve better water quality and safety for the construction and commissioning (C&C) of a potable building water distribution system (BWDS).
To shift this dynamic, the PE/C industry must take a larger role in the C&C phases to ensure better water quality for their completed projects. This article aims to summarize four key knowledge gaps for the PE/C industry to overcome to encourage greater industry engagement and highlight opportunities for professional service offerings to responsibly close these gaps.
Gap No. 1: Knowing the basics of water quality
PE/C design practices for a BWDS have traditionally focused on water efficiency (i.e., water and energy conservation) and less on water quality and safety. A BWDS design focused solely on efficiency without addressing water quality and safety does not maintain a sustainable water system. A sustainable BWDS must be safe and efficient (see Figure 1).
Water efficiency objectives often create a condition known as high water age (i.e., stagnant water conditions). High water age is in direct conflict with known water quality science. Potable water must routinely move through the BWDS to maintain the four essential water quality parameters. For training and recall purposes, health agencies often refer to these using the acronym STAR:
S = Avoid soil invasion, sediment from degrading pipe and construction debris;
T = Maintain adequate temperature ranges for hot and cold water valves/lines;
A = Maintain low water age with the objective of flushing the BWDS for weekly turnover of water; and
R = Maintain adequate disinfectant residual (e.g., chlorine).
It is important for every PE/C professional and building owner to clearly understand the STAR parameters of their specific BWDS project before designing or installing other potential hazard control options (e.g., water filtration or supplemental disinfection). Without knowing the basic STAR parameters, the PE/C team could recommend hazard control systems that don’t control the problem, are simply unnecessary or cause damage to the BWDS.
Avoid looking for a “magic bullet” water safety control method. These technology applications can create a false sense of water security and safety, leading to an impractical approach to water management. Yes, hazard control systems may be necessary; however, the PE/C team and building owner must establish the basic STAR parameters for the proposed project before evaluating water hazard control options.
Gap No. 2: Know construction and commissioning risk factors
Even if the building is engineered to reduce the likelihood of waterborne pathogens (e.g., Legionella) using the STAR parameters, the C&C project phases can completely derail even with the best intentions of PE/C professionals. The C&C work phases often contribute to emerging disease cases or deaths from the BWDS immediately upon opening the facility.
No building owner wants to celebrate a new opening surrounded by a community disease outbreak. Nor would your firm or professional liability insurance company welcome this.
Since 1965, construction activities have been linked to Legionella and other waterborne pathogen outbreaks in community and healthcare settings (Scanlon et al. 2020, https://bit.ly/3P3UhZ1). The nine known C&C activities contributing to the problem are:
1. Excavation. Invasion of soil and sediment into water infrastructure piping.
2. Re-pressurization. Loosens biofilms embedded in existing piping or piping connections.
3. Demolition activities. Creates debris falling into cooling towers or entering piping.
4. Improper application of efficient design. Water conservation is emphasized without proper water safety management, creating an imbalance in the BWDS.
5. Underground utility connections. Potential for invasion of soil and sediment and loosening biofilms to flow downstream from the construction point.
6. Construction equipment with water reservoirs. Equipment (e.g., power washing, misters, saw cutting, water tanks, etc.) that uses either nonpotable or highly stagnant water.
7. Water main breaks. Invasion of soil and sediment by improperly flushing large volumes of debris into the BWDS.
8. Vibration activities. Jackhammering, pile driving, saw cutting in or around construction sites or within piping systems that loosens biofilms to flow downstream, exposing building occupants.
9. Lack of effective BWDS commissioning. Activating water in the BWDS prematurely without any plan to effectively manage the water system for STAR parameters or construction activity risk factors.
Most disease cases and deaths from construction activities are associated with a lack of implementation of any form of an effective commissioning process to ensure safe water prior to opening the building to the public. Current PE/C industry practice allows the construction team to assemble the BWDS with minimal oversight (see Figure 2).
A new area of research, the building water quality commissioning (BWQC) process, is intended to close this gap and provide better PE/C engagement for water quality and safety practices.
Gap No. 3: Developing a building water quality commissioning plan
Rather than waiting until the building is occupied and operational to start the WMP process, PE/C professionals should work with the building owner to initiate a BWQC plan at the start of the construction process. The PE/C team would essentially use the same ANSI/ASHRAE Standard 188 and Standard 514 risk management process to initiate the work during construction.
Hazard controls (e.g., flushing) would be more robust during the C&C phases to reduce stagnant water conditions due to the unoccupied building. Using a BWQC process (see Figure 3) allows the facility to open with known water quality and safety data observed and recorded over several months.
A successful BWQC plan confirms that the BWDS can be properly maintained to meet water quality and safety objectives. Here are three key tips for PE/C professionals to consider jumpstarting their knowledge of BWQC best practices.
Tip No. 1. Conduct a water safety risk assessment
In pre-design, the building owner and PE/C professionals would benefit from reviewing:
BWDS construction activities and scope of work;
Knowing the building occupant exposure risk (e.g., patients, students, senior care); and
Determine which hazard control activities should be implemented (e.g., flushing, temperature checks, disinfection protocols and supplemental disinfection options).
Novel tools have been developed for water safety risk assessment for healthcare facilities (Scanlon et al. 2022, https://bit.ly/3DzKQhe) and for nonhealthcare buildings (Griffin et al 2023, https://bit.ly/4glEUap). Reviewing these risk assessment tools will give insights to communicate effectively with the building owner’s WMP team.
Tip No. 2: Integrate the BWQC plan into the construction project schedule
After the contractor fills the BWDS with water, it often sits for months or even years before the facility is occupied for public use. Key water STAR parameters are not typically measured and controlled during the C&C process. This allows waterborne pathogens associated with disease to prematurely grow and spread throughout the BWDS.
Instead, all BWDS construction tasks must be discussed with the building owner and integrated into the overall project schedule. The key phases of work are outlined in Figure 4 for a typical new construction healthcare project. An expanded specific list of key activities is outlined in Table 1, Scanlon et. al 2023 (https://bit.ly/41NyITU) about construction scheduling methods. These same phases of work can be adapted for nonhealthcare building projects.
Some building owners have found success by including water management in their pre-construction conference to bring together the building owner’s WMP team and PE/C professionals to organize and discuss water safety expectations. Items to discuss and address are:
BWQC project schedule milestones;
Alternative methods for water activation (see Tip No. 3);
Documentation (e.g., logs and reports) and communication methods;
Identify local water authority and disinfectant method (e.g., chlorine or chloramine);
Disinfectant residual readings at the point-of-entry and distal fixture locations;
Expected purging and flushing activities;
Planned disinfection and other hazard control protocols;
Analytical laboratory test methods; and
Need for additional test ports for easy access across the BWDS.
The team should also establish roles and responsibilities concerning who performs such work, as well as the frequency and duration of activities throughout the C&C phases of the project.
Tip No. 3. Consider alternative methods for early-stage construction water usage
Typically, the general contractor activates the building owner’s BWDS in an early stage of construction to gain access to water as a utility function. The contractor commonly uses water for establishing contractor hydration stations and restrooms, mixing materials (e.g., grouts, concrete or mortar) or building demolition (e.g., dust suppression or power washing). This is similar to using electricity to perform building construction work.
However, construction activities only draw a small amount of water compared to when the building is under normal facility operations. Early water activation (i.e., filling of BWDS piping) allows for the premature growth and spread of waterborne pathogens. Could the PE/C team consider an alternative water source or limit the area of BWDS pipe filling to activate the water system later in the project schedule? Items to consider include:
Installing temporary water supply piping to be abandoned later;
Using air for pressure testing water fixtures; and
Only installing distribution piping near large water volume usage areas (e.g., shell and core areas) while delaying the installation of distribution piping until a later date.
Gap No. 4: Developing professional services for implementing the building owner’s BWQC
It is challenging for PE/C professionals to build expertise and engage with the building owner without being legally contracted to perform services. The building owners are open to and need more BWQC expertise to ensure the building can operate effectively to reduce risk from waterborne pathogens, especially in healthcare facilities. Some potential PE/C service opportunities include preparing analysis, modifications and documents for:
Potable cold and hot water system piping diagrams/system mapping;
Audits of existing WMPs for inclusion of C&C practices;
Uniform facility water process flow diagram documentation;
Improving design guidelines for building water systems and fixtures;
Building owner’s contracts, general conditions or contractor supplemental instructions;
Specification sections for implementing a BWQC process including standardized test and inspection criteria;
Policies for utility disruption, or water emergency and disaster response;
Water safety or infection control policies;
Commissioning for specialty or medical equipment with water reservoirs; and
Coordinating licensing or accreditation efforts for patient care operations.
Many aspects of water management are currently outside of most PE/C professionals’ knowledge base; it will take time to learn and gain expertise. The water quality issues in the United States are increasing and would benefit from more PE/C industry engagement.
To close these gaps, consider taking formal training courses to understand the unique process and language of water management, such as the American Society of Sanitary Engineering International Certification 12080 training (https://bit.ly/3ZD7dtI) for the minimum qualifications to become a member of a water safety team.
Additionally, PE/C professionals could consider contacting a water management consultant or analytical laboratory testing specialist for additional expertise. And lastly, begin strategizing professional service offerings to building owners to address both water safety and water efficiency to achieve a sustainable water supply.
Molly M. Scanlon, PhD, FAIA, FACHA is an environmental health scientist, as well as a licensed and certified healthcare architect currently working as a research associate with the University of Arizona, Zuckerman College of Public Health. Dr. Scanlon’s work and research examine the built environment’s impact on human health. Her water quality research has created novel tools to engage architects, engineers and contractors in meeting water quality and safety regulations for construction and commissioning potable building water systems to reduce disease cases and deaths.