COVID’s impact on moving people out of buildings is influencing architects and contractors to plan how to bring people back in. There is a focus on disinfection in HVAC systems and a number of air exchanges in order to directly address COVID as an airborne pathogen. Simultaneously with buildings reopening, waterborne pathogens may be present from stagnant or underutilized water. This second health threat as a COVID repercussion can result in Legionellosis to building occupants.
This scenario is accounted for in the 2021 Uniform Plumbing Code® (UPC) Appendix N, as well as the WELL Health-Safety standard from the International Well Building Institute (IWBI) — a new standard released in 2020 that has already garnered interest from 100+ organizations for certification. Similarly, Fitwel, which was originally created by the U.S. Centers for Disease Control (CDC), also accounts for this by way of their Viral Response Module within their certification. Both certifications demonstrate that a building’s design is recognized as providing a healthy environment for its occupants.
These Wellness certifications are comprised of a scorecard that lists ongoing activities: performing indoor air quality tests per the air quality policy, mold and moisture management, water quality testing, and Legionella control. Maintenance and scheduling are therefore necessary aspects of water pathogen mitigation tactics that tack onto existing building upkeep needs. Building automation systems (BAS) monitor, and computerized maintenance management systems (CMMS) keep track of necessary activities. When combined with a pre-designed and pre-built packaged plumbing and mechanical system (PPMS), such as Element from Lync by Watts, it becomes easier to both facilitate compliance and allow for building managers’ and infection control professionals’ peace of mind.
Similar to packaged rooftop air units, PPMSs are a new category of product that are off-the-shelf systems for delivering treated and hot water. Rooftop air units are an example of modular construction for a building — no need to size and select subsystems every time a new building is designed. A PPMS also allows for modular construction as a response to the decreasing labor supply relative to construction demand. Similar systems have been custom-built by contractors off-site to save on design, labor, and time, except a PPMS is factory-built. A PPMS can include water heaters, water filters, ultraviolet (UV) disinfection systems, scale mitigation systems, and overall control and monitoring systems. Systems that are designed for continuous microbiological mitigation are covered by ASSE LEC 2012-2021, Listing Evaluation Criteria for Packaged Plumbing and Mechanical Systems for Continuous Microbiological Mitigation. Because the PPMS is factory-built, the factories and their quality control systems can be audited and therefore receive third-party certifications from ASSE International and IAPMO. These systems fall in line with the new Appendix N of the 2021 UPC, which describes how to balance scalding with thermal disinfection for Legionella mitigation, as well as reporting on disinfection.
When a PPMS has an integral control system, it can blend the features of a BAS and CMMS that allow for ongoing preventive maintenance reporting. These provide demonstrable proof that a building aligns not only with the 2021 UPC, WELL and Fitwel, but also ASHRAE 12, Managing the Risk of Legionellosis Associated with Building Water Systems, ASHRAE 188, Legionellosis: Risk Management for Building Water Systems, VHA Directive 1061, Prevention of Health Care Associated Legionella Disease and Scald Injury, and CDC guidelines for waterborne pathogen mitigation. The systems have several control points for mitigation and the automatic alerts can include when to change UV bulbs and filters, and whether water heater supply or return temperatures are too low. A temperature departure can create a breeding ground for Legionella and other pathogens, especially in the range of 85 – 110°F (29.4 – 43.3°C). These alerts can go directly to staff’s phones as notifications or emails so that a corrective action, such as artificially increasing demand during low flow, adjusting equipment during periods of increased demand, or adding insulation minimize heat loss, can be made. The alert becomes the initial observation of the corrective action log.
When there are temperatures that fall outside the desired control limits, one method of corrective action includes thermal disinfection. A PPMS per LEC 2012 includes functions to disinfect the volume of water within the PPMS itself, as well as become a tool for a building-wide disinfection. Because a PPMS includes an ASSE 1017 (Temperature Actuated Mixing Valve for Hot Water Distribution Systems) distribution mixing valve, when the internal volume slowly increases in temperature, building staff can be confident that downstream point-of-use mixing valves are unaffected.
A building’s water management program may call for thermal or chemical treatment on the domestic hot water system when remedial disinfection is required due to a positive pathogen culture test or when ordered by an authority having jurisdiction. These are highly controlled events where building occupants are not present. A PPMS conforming with LEC 2012 locks out unauthorized individuals from performing such a process. It also reports back the return temperature so that a timer can start, ensuring the dwell time and temperature is sufficient for the entire loop. After that, staff can start to open distal outlets to flush individual branches. A similar activity would also be performed on domestic cold water to bring fresh disinfectant from the municipality into the building system.
Occupants of highly designed buildings take their continued trust in the water supply for granted, and in order to demonstrate that via wellness certification, water health and maintenance requires a level of granularity beyond traditional systems. Installing products certified to ASSE LEC 2012 is one way in which that confidence can continue. As society continues to manage COVID, buildings will continue to demand a focus on occupant health and providing that consistently will require additional resources in the heart of a building’s water infrastructure, whether human or digital.
A continued focus on not only the health, but also the well-being of all of us in our built environments, will protect us not only through this pandemic but also through its variants.
