Invisible No More

Infection control has become the new normal for building owners and managers who anticipate a reopening, and ultimately normalization, of building occupancy. The risk to the general public is not restricted by the type of structure interrupted by the COVID-19 pandemic. Pumps, fans, and compressors transparently move water, air, and refrigerant through every building in North America. These systems are invisible no more. During normal operation, all three mediums contribute to the mode of transmission that can impact the health of building occupants. Public health and consumer confidence hang in the balance as all industry stakeholders attempt to understand what a full return to building occupancy means — especially to ensure a safe return of all children to school.

What We Now Know About Water

Many of the buildings that have been shut down due to the quarantine may present hazardous situations due to water quality degradation caused by stagnation. Stagnant or standing water in piped systems may cause conditions that increase the risk for growth and spread of Legionella and other biofilm-associated bacteria.

The following simple procedures will assure owners, managers, and occupants of buildings that it’s safe to reopen and return to their buildings:

• Flush the piping in the entire building. This includes all appliances like ice machines, dishwashers, and water coolers.
• Inspect backflow preventers, pumps, and domestic hot water systems.

Professional guidance may be required to service, or repair devices and equipment not utilized during the shutdown of the property.

Risk Assessment for Building Water Systems

For water quality, risk to the occupant is determined through a two-part formula that results in a matrix to determine appropriate control measures. What type of building? Categorizing the building water system is based on the control points mapped on a flow diagram. The next step will be to identify the class of occupants. Building populations are stratified from lowest to highest risk. There exists a linear relationship between the type of building and the risk group. You must apply control measures and refer to the Centers for Disease Control’s (CDC) eight steps to reopen your building or business.

What Should We Know About Air?

In the 1980s, Sick Building Syndrome (SBS) was thought to be caused by being in a building or other type of enclosed space. It was attributed to poor Indoor Air Quality (IAQ). However, the precise cause is unknown. According to the Consumer Product Safety Commission, poor IAQ can be found in about 30 percent of new and remodeled buildings. Furthermore, many times diagnosing SBS can be difficult because of the wide range of symptoms. These can also mimic other conditions, such as the common cold. Increased ventilation results in decreased complaints. Until recently, bacteria and viruses were not included in the analysis.

As we fast forward forty years into the high-performance built environment, managing a building is a difficult and complex job. There are many competing demands — health and safety, building maintenance, housekeeping, and communications with occupants and tenants. Building owners and managers are under pressure to contain or reduce operating costs and increase revenues. Such fiscal pressures can easily draw attention and resources away from important elements of building management, such as IAQ.

Many organizations target known pollutants when air in a building or mechanical system is analyzed and/or treated.

For example, the U.S. Green Building Council (USGBC) WELL program sets a goal for building owners to measure and monitor at least three of the following:

1. PM2.5 or PM10 (accuracy 5 μg/m³ + 15% of reading at values between 0 and 150 μg/m³).
2. Carbon dioxide (accuracy 50 ppm + 3% of reading at values between 400 and 2000 ppm).
3. Carbon monoxide (accuracy 1 ppm at values between 0 and 10 ppm).
4. Ozone (accuracy 10 ppb at values between 0 and 100 ppb).
5. Nitrogen dioxide (accuracy 20 ppb at values between 0 and 100 ppb).
6. Total VOCs (accuracy 20 μg/m³ + 20% of reading at values between 150 and 2000 μg/m³).
7. Formaldehyde (accuracy 20 ppb at values between 0 and 100 ppb).

Industry Practices for Building Air Systems

Preventative maintenance practices for all mechanical systems serve as an adequate point of departure for recommissioning equipment that provides thermal comfort to building occupants. The following practices will minimize the transmission of pathogens through the air duct systems as well:

• Replace air filters with manufacturer’s recommended MERV-rated filter.
• Clean all coils in the building air stream with detergent.
• Clean and disinfect every condensate pan.

Enhanced Strategies

On April 14, 2020, the ASHRAE Position Document on Infectious Aerosols was released with the intent of qualifying the risk of pathogen spread. The number of people exposed can be affected, both positively and negatively, by the airflow patterns in the space. Specifically, the ASHRAE document addresses particulate settling, surface disinfection, and aerosol dissemination in the occupied space.

Additionally, a detailed sequence is recommended to reopen a building:

Hybrid application of the following air treatments may promote practical implementation:

• Ultraviolet (UV)
• Ozone
• Ionization

Airborne Dissemination

Even the most robust mechanical system cannot control all airflows and completely prevent dissemination of an infectious aerosol or disease transmission through droplets or aerosols. From ASHRAE research, one learns that pathogen dissemination through the air occurs through droplets and aerosols typically generated by coughing, sneezing, shouting, breathing, toilet flushing, some medical procedures, singing, and talking (Bischoff et al. 2013; Yan et al. 2018). Of special interest are small aerosols, which can stay airborne and infectious for extended periods (several minutes, hours, or days), and thus can travel longer distances and infect secondary hosts who had no contact with the primary host.

Determine Readiness

ASHRAE Checklist to prepare for building occupants to return:

• Create a Safety Committee that includes all stakeholders (environmental health and safety, administration, education staff, operations staff, local healthcare providers, etc.).
• Develop policies for staff and contractor personal protective equipment (PPE) requirements for completing work at facilities that follow local authority.
• Do not defer semi-annual/annual scheduled maintenance on equipment as long as it can be performed safely.
• Where worker safety could be at risk, defer semi-annual/annual maintenance on the equipment for up to 60 days until worker safety can be accomplished.
• Operate all HVAC systems in occupied mode for a minimum of one week prior to occupancy.
• Review control sequences to verify systems are operating to maintain required ventilation, temperature, and humidity conditions.

FIELD IMPLEMENTATION

Assemble the Team

The responsibility for managing risk in a facility is a shared one. A facility’s management team needs to include people who have sound understanding of the risks and control of mechanical and plumbing systems. These people should be selected based on their possessing appropriate skills and knowledge to understand the health risks and are able to coordinate the proper responses to incidents.

A multidisciplinary approach is recommended, and the team should include representatives from:

1. Infection control: To contribute expertise on microbial disease risks and management measures for residents or patients.
2. Facilities management: To contribute expertise on the layout and operation of the facility’s air and water distribution systems.
3. Health, safety, and environment: To ensure that the procedures developed are consistent with workers’ health and safety, and environmental risk management systems do not inadvertently create unintended and unacceptable risks.
4. Contractors: To provide the necessary skill sets and resources to ensure safe and reliable operation of all mechanical and plumbing systems.
5. Executive team: To provide the necessary approval and resources to manage Legionella and respond to incidents or cases.

The purpose of the management team is to safeguard that operational and engineering matters are considered in a coordinated, cohesive, cooperative, and holistic way during the process of developing and implementing a risk management plan, thus increasing the likelihood of achieving effective infection control.

Core Elements

Rooted in the language of the CDC Toolkit and ASHRAE 188 are primary directives for the air- and water-management teams to follow in their pursuit of pathogen and aerosol intervention. Each plank of the platform presents actionable verbs — identify, describe, conduct, determine, establish, and document. All tasks can then be measured with proper metrics for repeatable and reliable outcomes. The CDC toolkit not only promotes these engagements, but also utilizes practical illustrations for the successful accomplishment of each floorboard of the air- water-management program.

Goals of the Management Teams

As one learns how to apply infection control measures, these essential concepts are soon learned:

1. Identify building air/water systems for which control measures are needed
2. Assess how much risk each piped system poses to the occupants
3. Apply control measures
4. Verify and validate actions taken

Mapping

Air and water distribution system mapping should cover the entire process from where the air/water enters the facility to the distribution throughout the facility to the termination at every fixture, device, terminal, air handler, sprinkler head, and water feature. It is commonly acknowledged that in older or larger buildings, obtaining accurate “as built” drawings may be difficult. The accuracy of the plans should be confirmed using physical inspections to identify and highlight where components of the plumbing and mechanical systems may accelerate the risk to the general public.

In addition to materials used in constructing the systems, proper consideration also must be given to the components of the systems, particularly those related to temperature and disinfection. Examples would be hot or warm water systems, cooling towers, ice machines, cold water pipes, looped and recirculating systems, thermostatic mixing valves (TMVs), tempering valves, backflow prevention devices, thermal insulation of pipes, dosing systems for disinfectant or other chemicals, and filters.

Identify Control Points

To properly achieve environments while sustaining compliance with established principles, one must identify a physical, mechanical, operational, or chemical point in the plumbing and mechanical systems for the application of adequate control measures.

The following table will offer a sampling of control points of a building air and water system:

Type the Building

Categorizing the building air and water system is based on the control points mapped on the flow diagram. Therefore, systems for the facility are determined based on the complicity of the arrangement and selection of equipment/devices. Commercial structures and institutional facilities have similar building water systems, which are comprised of a point of entry, cold and hot water distribution, ventilation and exhaust air fans, and sanitary waste. More resources may be designed into the building, such as fire suppression, decorative fountains, and ice machines.

The ASHRAE Position Document on Infectious Aerosols concludes with the following:

“Various strategies have been found to be effective at controlling transmission, including optimized airflow patterns, directional airflow, zone pressurization, dilution ventilation, in-room air-cleaning systems, general exhaust ventilation, personalized ventilation, local exhaust ventilation at the source, central system filtration, ultra violet, along with controlling temperature and relative humidity.”

Comprehensive measures may require experienced tradesmen and women to support proper implementation.

Risk Groups

After identifying the piped system and devices in the building, it is time to evaluate the occupants in the facility. Building populations are stratified from lowest to highest risk. While discussing the type of air distribution and piped system residing in the building, common elements of construction for commercial and institutional markets are listed. Here, there is a clear separation of the two types, as one group of healthcare occupants are immune compromised — the patients. Additionally, many layers of patient risk are found within healthcare facilities. The infection control professional, or custodian, will delineate between a patient in the cardiology unit and someone on the oncology floor. Recognizing this variance will challenge the air/water management team to qualify the prescribed action to oblige the oncology patient’s risk.

Select a Control Measure

There exists a linear relationship between the type of building and risk group. The guidance of ASHRAE 12 serves to align the risk of the occupant when matched to the type of air/water system they are served by. A control measure is a method or procedure used to maintain the physical or chemical condition of water within a range of values monitored to reduce the occurrence of a condition that contributes to the potential for harmful human exposure.

The intensity of control measures to be applied at control locations will be determined by a compare/contrast matrix derived by the data gathered during the mapping of the facility, typing the building, and grouping the inhabitants. For every piped system, ASHRAE 12 conveys proper instruction for the mitigation of Legionella and other pathogens. The control measure matrix determines appropriate answers to a specific type and group. For example, Legionella can be transmitted by contaminated ice. Ice machines in the patient care areas will be routinely sanitized and descaled to mitigate potential transmission. Special filters will be attached to prevent Legionella from gaining access through the water supply.

For ducted systems, based on risk assessment, the use of specific HVAC strategies should be offered. Enhanced filtration over code minimums in occupant-dense spaces is not always the best solution. Analysis will be necessary to balance the available fan power to the highest MERV or HEPA filter available. Utilize source control for local exhaust ventilation protocols. Review humidity and temperature control algorithms to maintain equilibrium between comfort and aerosol dissemination in the occupied space.

COMPLIANCE WITH PUBLISHED LANGUAGE

The growing threat to public health from unsafe water and air cannot be understated. Whether contamination is from lead, bacteria, or chemicals, all piping systems can expose health risks. Over the next decade, all building water systems will require an ASHRAE 188 Water Management Plan that includes mapping, auditing, monitoring, and remediation for regulatory and legislative compliance. As a critical step to reopen buildings and schools, the CDC produced a toolkit that offers a verification and validation path to compliance with standards and guidelines related to cooling towers, water features, potable water systems, fire protection, ice machines, humidifiers, and all piped systems that currently reside in all occupied buildings.

Inside ASSE Series 12000

To be sure, ASSE/IAPMO/ANSI Series 12000-2021, Professional Qualifications Standard for Water Management and Infection Control Risk Assessment for Building Systems, is the only ANSI approved language that addresses worker protection in addition to the health of the building occupants. The United Association, to date, is the only member of North American Building Trades (NABTU) to incorporate this document into training curriculum.

ASSE 12000 (Infection Control for Construction and Maintenance Personnel) and 12020 (Infection Control for Employers) Certifications address the need for construction and maintenance personnel to become proficient in identifying and managing potential situations where they may be exposed to blood borne, waterborne, and airborne pathogens. These certifications also cover the responsibility of personnel to protect building occupants and operations from pathogens and hazards; especially within healthcare facilities.

ASSE 12060-12063 Certifications (Water Quality Program for Employers and Designated Representatives; for Plumbers; for Pipefitters and HVAC Technicians; and for Sprinkler Fitters, respectively) qualify contractors and tradespersons to participate on building water management teams. These certifications afford a verification and validation path to compliance with standards and guidelines related to cooling towers, water features, potable water systems, fire protection, ice machines, humidifiers, and all piped systems which currently reside in all occupied buildings.

ASSE 12080 (Legionella Water Safety and Management Personnel) Certification covers the minimum qualifications needed, including knowledge and competency, to become a member of a water safety team involved in the development of a risk assessment analysis, and water management and sampling plan, for protection from Legionella and other waterborne pathogens. Its purpose is to provide a curriculum of minimum criteria, identified by industry consensus, to ensure knowledge and understanding of standards and codes, and the resources, understanding, and skills needed to conduct a facility risk assessment and implement a water safety and management program to reduce the risk of infections due to Legionella.