Healthy Building O&M in Existing Buildings

Table of Contents

Introduction

This Best Practice outlines existing resources and best practices for operating and maintaining a building to promote occupant health while considering energy efficiency.

Studies have found an increase in worker productivity when improvements are made to a building’s interior conditions (Attema 2018). However, the importance and value of occupant health often goes overlooked. For example, the cost of employees to an employer account for 92 percent of building life cycle costs, with utility bills comprising only 6 percent (Fuller 2016). The indoor environmental quality (IEQ) and energy performance of a building are both very dependent on the building systems and operations and maintenance (O&M), but the interaction is generally poorly understood and goes unacknowledged. Balancing these priorities with other obligations is critical for successful building performance.

Existing healthy building practices focus on design and new construction, and O&M in existing buildings is typically a secondary consideration. For example, there are 12,405 registered Leadership in Energy and Environmental Design (LEED) existing building O&M projects and 33,058 registered LEED new construction projects despite the large existing building stock. Most buildings, even well-designed ones, do not cater to the comfort of occupants because of an inability or lack of foresight to adapt to occupancy load and activity variations; seasonal, climate, and weather patterns; and unforeseen building system interactions. With an adequate understanding of existing practices, the unique functionality and characteristics of a building, planning and prioritization, and responding to changing occupancy and weather conditions, any building can improve the health outcomes for occupants while balancing other obligations such as energy, resilience, and costs.

A “healthy building” refers to the physical attributes of the building, including thermal comfort, green cleaning, lighting quality, daylight exposure, indoor air quality (IAQ), acoustics, water quality, views and biophilia, access to nutritional foods, opportunities for physical exercise, mental health support, physical safety, social and community equity, and more. The intersection between the physical attributes of a building and the health of its occupants is not as well understood as the connections between a building’s design and its energy efficiency. There exists a growing research foundation that attempts to connect the productivity, cognitive capabilities, and satisfaction of occupants to IEQ conditions. As more research is conducted in this field, the reliability of building-centered metrics for O&M is expected to improve. The relationship between IEQ and health is complicated because every individual person has different conditions needed to achieve adequate or optimal comfort that vary throughout the time of day, week, and year and depending on the occupancy load and activity.

Furthermore, the intersection between building health strategies and building energy efficiency strategies is not well established. There is a common misconception that health and energy priorities must conflict; however, many strategies are independent of one another, and other strategies can positively affect both energy and health. For example, focusing on conditioning the spaces where occupants are situated instead of the entire building with radiant floor systems or individual thermal control devices can reduce heating and cooling of unoccupied areas while giving occupants control of their own thermal comfort.

Discussion

Relevant History

After the environmental and ecological awareness movement in the 1970s, the idea of a healthy building emerged around 1984 when the term biophilia was coined by E.O. Wilson in the context of buildings (Healthy Building Science, n.d.). He defined biophilia as humans’ innate and evolutionary affinity for living things. In the following decade, the negative health impacts of indoor air pollutants like asbestos and mold entered the public eye. It was not until the 2000s that green building rating systems like LEED and the Living Building Challenge emerged. In the 2010s, health-specific certifications like the WELL Building Standard and Fitwel came on board. The General Services Administration (GSA) and Centers for Disease Control and Prevention led this movement for the federal sector by co-creating the Fitwel certification in 2011 and gained traction by piloting 89 public facilities. The U.S. Department of Energy (DOE) became more involved with the release of FEMP’s Guiding Principles for Sustainable Federal Buildings in 2016, and started to fund occupant health research projects. GSA has produced case studies and reports for healthy buildings in the federal sector.

Interested Parties

The three main constituents of healthy building O&M are facility managers and building technicians, senior management, and occupants. As healthy buildings become a greater priority for the building industry and federal sector, facility managers must be able to integrate the resources and practices for optimizing healthy building O&M into current building operations. Senior management of corporations, public entities, and federal agencies are becoming interested in the productivity and health impacts of buildings on their occupants and what that means for their employees’ performance and satisfaction. Finally, occupants want to feel comfortable and motivated by their buildings. The feedback and participation of occupants will be essential for the advancement of healthy building O&M performance.

Existing Standards and Policies

The available resources for healthy buildings have expanded greatly in recent decades. The following selected standards relate to healthy building in commercial buildings:

  • ASHRAE Standard 32 Management for Sustainable High-Performance Operations and Maintenance
  • ASHRAE Standard 55 Thermal Environmental Conditions for Human Occupancy
  • ASHRAE Standard 62.1 Ventilation and Acceptable Indoor Air Quality
  • ASHRAE Standard 189.1 Standard for the Design of High-Performance Green Buildings
  • The Illuminating Engineering Society of North America Lighting Handbook.

These standards focus on design strategies for new construction that can be adopted into local building codes and that contain O&M materials. In addition to these standards, there are healthy building certification systems that provide guidance for optimizing occupant health in buildings. Some of the common ones in the United States are:

These systems focus on design for new construction and retrofits but have some strategies for O&M. LEED and Fitwel are both used in the federal sector, whereas the other systems have yet to gain traction there. The following resources apply specifically to the federal sector:

  • GSA Facility Standards for the Public Building Service (PBS-P100)
  • FEMP Guiding Principles for Sustainable Federal Buildings
  • GSA Tenant Satisfaction Survey.

These standards, certification systems, and other resources are discussed in further detail, including the extent of their O&M content, in the section titled Solutions and Actions.

DOE Program Interactions

DOE’s Office of Energy Efficiency and Renewable Energy has a variety of programs that relate to the field of healthy building. FEMP has two programs that are directly involved with healthy buildings: The Guiding Principles for Sustainable Federal Buildings (discussed in the Guiding Principles for Sustainable Federal Buildings subsection) and FEMP’s Healthy Building Initiative. Other existing or potential interactions include:

  • FEMP’s Re-tuning Challenge: Building Re-tuningTM is an existing building commissioning (EBCx) strategy that generally has not been incorporated into standard healthy building practices and certifications and typically has been used for energy efficiency. Planning for building automation system to support occupant comfort in addition to energy efficiency would be an appropriate application of the Re-tuning™ Challenge project.
  • ISO 50001 is an international standard for facility energy management systems. The Advanced Manufacturing Office developed the 50001 Ready Navigator to provide guidance for the 25 tasks. Some of the tasks could naturally be expanded from energy to promote healthy building O&M with little additional effort.
  • Section 432 of the Energy Independence and Security Act of 2007 (EISA) established the goal to conduct comprehensive energy and water evaluations in covered facilities every four years. One critical aspect of operating and managing buildings for occupant health is obtaining data to evaluate performance and progress. Comprehensive energy and water evaluations in combination with health-specific auditing criteria could be used to leverage health data procurement and availability at a lower marginal cost.
  • The DOE Building Technologies Office has Building Energy Asset Score and Audit Template programs that are used to collect energy data and integrate it into energy modeling opportunities and improvements. These technologies could incorporate healthy building criteria to identify opportunities that optimize energy and health priorities.

Solutions and Actions

Commissioning Options

All the standards and certifications mentioned (WELL, Fitwel, Living Building Challenge, ASHRAE, IES, etc.) have strategies for commissioning. EBCx options include recommissioning (ReCx), retrocommissioning (RCx), monitoring-based commissioning (MBCx), and BAS tuning. It is important to develop a commissioning process and strategies to include existing buildings in the healthy building movement. MBCx involves sensors and sometimes controls. BAS is one strategy of MBCx that can integrate various building systems. Including sensors and controls in healthy building strategies is important because comfort conditions are subject to unpredictable variations in occupancy, climate, weather, and other factors. If BAS systems are used for occupant comfort, re-tuning them is an important strategy to correct operational problems.

Building operating plans are not as intensive as ReCx and are typically conducted more frequently on the scale of months instead of years. A regular operating plan will set a list of tasks that must be completed regularly, the intended frequency, and a system to record and verify completion. Table 1 can be used to identify which resources are available for the EBCx options mentioned.

Healthy Building O&M Resources

Table 1. Healthy building O&M resources and EBCx methods.

 

Health Category

ReCx/RCx

MBCx

Re-tuning

Operating Plan

Occupant Survey

FEMP Guiding principles

General

X

 

 

X

 

GSA PBS-P100

General

 

 

 

X

X

GSA Tenant Survey

General

 

 

 

 

X

ASHRAE 32

General

X

X

X

X

X

ASHRAE 55

Thermal Comfort

X

 

 

 

X

ASHRAE 62.1

Ventilation

X

 

 

X

 

ASHRAE 189.1

General

X

X

 

X

 

FITWEL

General

X

 

 

X

 

WELL

General

X

X

 

X

X

LEED: EBOM

General

X

X

 

X

X

Guiding Principles for Sustainable Federal Buildings

FEMP’s most recent Guiding Principles version was released in 2016 and is currently being updated. The Guiding Principles apply to both new and existing buildings and include provisions for ventilation, thermal comfort, daylighting, electric lighting, IAQ, healthy food, clean water, and opportunities for exercise and movement. Both an integrated assessment, operation, and management plan and a four-year recommissioning process are required to promote successful O&M. For IEQ principles, the guide covers ventilation, thermal comfort, daylighting and lighting, IAQ, and occupant health and wellness. Occupant health and wellness refers to opportunities for exercise and access to proper nutrition and clean water. The Guiding Principles are a Cx/ReCx/RCx-based system and require a building operation plan. They do not include MBCx or building Re-tuning™ guidance.

In accordance with the Guiding Principles, the U.S. Department of Defense (DoD) publishes the Unified Facilities Criteria to establish criteria for high-performance and sustainable facilities applicable to all military departments, defense agencies, and DoD field activities.

Facility Standards for the Public Building Service (PBS-P100)

PBS-P100 contains GSA’s current practice and requirements for all new and retrofitted GSA-owned and -leased facilities. Other federal building and property owners may apply this standard, but it would be voluntary. PBS-P100 includes prescriptive and performance-based pathways to meet the requirements for thermal performance, acoustic control, materials, IAQ, and other healthy building topics, as well as many other sustainability provisions not related to healthy building. P100 includes a performance matrix that the project managers must use to establish the baseline building performance; occupancy surveys for acoustics, thermal comfort, ventilation, and lighting quality; and a total building commissioning process throughout the design phase and at least one year after construction. The design of the building equipment must also enable easy access, adjustments, inspections, cleaning, repair, maintenance, and replacements; this must be verified in the building design model. P100 requires that an O&M manual be available as well as a BAS and associated operation manual.

ASHRAE Standards

ASHRAE Guideline 32 discusses O&M to achieve sustainable, high-performance buildings. It applies to “commercial, institutional, industrial, multistory residential, and government buildings as they affect occupant comfort, indoor air quality, health and safety, and energy and water use” (ASHRAE 2018). ASHRAE 32 contains content and O&M strategies directed toward senior management, facility managers, and building system technicians. ASHRAE 32 mentions monitoring and BAS tuning but does not detail explicit requirements or strategies to achieve them. ASHRAE Guideline 55 specifies “the combinations of indoor thermal environment factors and personal factors that will produce thermal environmental conditions acceptable to a majority of the occupants within the space” (ASHRAE 2016). It covers four primary environmental factors: temperature, thermal radiation, humidity, and air speed. ASHRAE 55 requires compliance through design documentation, and there are two paths for evaluation—occupant surveys and physical measurements. The survey path establishes the options that should be available on the survey and the response rate that must be achieved. The physical measurement pathway gives guidelines for where to place measurement equipment, sampling duration, and instrument accuracy and range. Measurements can be compared against the thermal comfort design conditions established in the standard.

ASHRAE Guideline 62.1 outlines a prescriptive option and a performance-based option for meeting mechanical ventilation requirements. The prescriptive design option includes requirements for location of outdoor air intake, airstream surfaces, ventilation controls, envelope barriers, and other IAQ design strategies. Maintenance is critical to making sure air quality devices are effective, so ASHRAE 62.1 requires the development of an O&M manual with 31 inspection and maintenance tasks to be completed at the indicated frequencies.

ASHRAE Guideline 189.1 is the high-performance standard that meets and/or exceeds the minimum health and energy efficiency requirements of other ASHRAE standards. ASHRAE 189.1 requires measurement and verification of outdoor airflow rate, particulate matter, radon, and humidity for applicable buildings. In addition to IAQ and thermal comfort, ASHRAE 189.1 adds design requirements for acoustic control, soil gas control, lighting quality, additional humidity and moisture control, daylight access, and glare control. The standard requires a high-performance building operation plan, which includes a variety of building operating plans, such as an erosion and sediment control plan, a service life plan, a transportation management plan, a green cleaning plan, and others. The standard requires an IEQ survey that must be repeated every three years.

Third-Party Certification Systems

Certification systems can be used in the federal sector for more extensive health targets and recognition. There are 54 Fitwel-certified GSA buildings and 154 LEED-certified GSA buildings.

Fitwel was created by the Centers for Disease Control and Prevention and GSA in 2011. There are 144 possible points divided among 12 health sections. Unlike WELL, which focuses on building systems, most of Fitwel’s credits are amenities provided to occupants. The weights for each credit are determined by evidence-based research, with over 3,000 studies included. Projects receive a final score of one to three stars based on the total number of points. The system requires recertification every three years and includes credits for building operating plans, such as an integrated pest management (IPM) plan, IAQ policy, green purchasing policy, and a regular cleaning plan.

LEED is a green building certification system that has an IEQ section, which includes human-health factors relating to air quality, ventilation, acoustics, lighting, and thermal control. LEED has a set of O&M certifications, including LEED: Environmental Design for Existing Buildings: Operations and Maintenance (EBOM) for existing buildings. EBOM has “establishment” credits that must be completed upon first certification or whenever there is significant modification to the building and “performance” credits that must be verified every five years for recertification. There are operating plan strategies for green cleaning performance tracking, air filtration and quality devices, and IPM and MBCx strategies for carbon dioxide monitoring, outdoor air monitoring, and thermal comfort conditions.

The WELL scoring system awards silver, gold, or platinum-level plaques based on a score between 0 and 100 assigned in 10 categories. Recertification is required every three years, and there is an existing building path. WELL offers the Performance Verification Guidebook, which is intended to help validate the performance of many of the design strategies after construction. The guidebook includes guidance for where to take measurement samples, how many samples to take, the duration and frequency of measurements, and equipment specifications for each metric. WELL recommends that projects continuously monitor certain IEQ metrics as an MBCx strategy.

Conclusion and Next Steps

While the intersection between building health strategies and building energy efficiency strategies is not well established, there are many energy and health strategies for buildings that can positively affect both energy and health.

The next steps are to consider what the existing practices and resources are for EBCx and which ones are most applicable for the building in question. Energy goals and financial obligations should be considered in conjunction with healthy building O&M strategies and effectiveness.

Step 1: Evaluate the Building

The first step is to understand how well the building is performing and how satisfied the occupants are with their environment. Some low-cost ways to do this are giving occupant surveys, recording occupant complaints, and conducting a walkthrough visual evaluation. There are guides to creating occupant surveys in the resources listed in Table 1. It is important to be familiar with these resources and the strategies they contain to know what to look for during a walkthrough evaluation.

Some more comprehensive but potentially expensive options are ReCx/RCx and IEQ measurements. An ReCx/RCx process can be conducted in-house using the resources provided by ASHRAE and other documents mentioned in this document. Alternatively, a commissioning consultant can be hired to orchestrate the ReCx/RCx. IEQ measurements (e.g., temperature, humidity, carbon dioxide, and illuminance) can be collected with handheld instruments or monitoring equipment (MBCx). Monitoring or taking point measurements over time can help assess the seasonal, occupancy, and other variations that influence the indoor environment. The measurements collected should be compared to the standards and certifications mentioned in this document. It is important to have sufficient data to completely understand the current performance of a building before making permanent or expensive improvements.

A building evaluation is important not only for recognizing the level of performance of a building but also for establishing a baseline that can be used for comparison post-retrofit.

Step 2: Consider Potential Solutions

After the building has been properly assessed, it should be clear what areas need improvement or adjustment. If the building already has a BAS, consider employing Re-tuningTM because it is a low-cost intervention with potentially high savings. If certain areas, such as thermal comfort, IAQ, or lighting need more attention, consider adjusting the controls for those services only.

If there is no BAS, increasing the control capabilities to more efficiently and effectively operate the IEQ-related systems can automate the indoor environment and incorporate energy savings. There are O&M solutions that do not require a BAS or upgrading equipment, such as building operating plans. These plans organize routine inspection and maintenance of the building systems and operations to assure proper function. Some examples of building operating plans to consider are:

There are other O&M solutions and strategies beyond BAS and system controls and operating plans. The certification systems, standards, and guidelines presented in this Best Practice contain these strategies.

Step 3: Implement Solutions and Continuous Actions

The next step is to implement the identified solutions from Step 2 and follow through on regularly scheduled maintenance. This includes the steps and actions that comprise the building operating plan, MBCx (if chosen), and regular occupant surveys and receipt of complaints. If in-house expertise to implement the strategies is not available, the services should be purchased from a contractor or consultant that specializes in that improvement strategy.

Step 4: Provide Task Delegation and Regular Training

The next step is to review the site O&M implementation and control of activities to check that actions necessary to promote healthy buildings are integrated into O&M procedures. This should include regular training on these actions and approaches for building technicians and building managers.

Step 5: Evaluate O&M Performance

The last step is to establish a system for evaluating the performance of the O&M program. This should include key performance indicators for evaluating progress to healthier buildings, such as:

  • Number of occupant complaints
  • Percent satisfaction from occupant surveys
  • Percent of time within target zones (for MBCx metrics such as carbon dioxide, humidity, etc.).

Additional Resources

Fitwel. Resources. https://fitwel.org/resources.

GSA ─ General Services Administration. 2018. PBS-P100 Facilities Standards for the Public Buildings Service. https://www.wbdg.org/FFC/GSA/P100_2018.pdf.

---. Fitwel. https://www.gsa.gov/real-estate/facilities-management/tenant-services/cafeterias-and-vending-facilities/health-and-wellness/fitwel.

---. Sustainable Facilities Tool. https://sftool.gov/. International Living Future Institute. 2014. Living Building Challenge 3.0: A Visionary Path to a Regenerative Future. https://living-future.org/wp-content/uploads/2016/12/Living-Building-Challenge-3.0-Standard.pdf.

U.S. DoD ─ United States Department of Defense. 2018. Unified Facilities Criteria High Performance and Sustainable Building Requirements. https://www.wbdg.org/FFC/DOD/UFC/ufc_1_200_02_2016_c3.pdf.

U.S. DOE ─ United States Department of Energy. Guiding Principles for Sustainable Federal Buildings. https://www.energy.gov/eere/femp/guiding-principles-sustainable-federal-buildings.

USGBC ─ U.S. Green Building Council. 2018. LEED v4 for Building Operations and Maintenance. https://www.usgbc.org/resources/leed-v4-building-operations-and-maintenance-current-version.

WELL Building Standard. 2018. The WELL Performance Verification Guidebook. https://resources.wellcertified.com/tools/performance-verification-guidebook/.

WELL Building Standard. Overview. https://v2.wellcertified.com/v2.2/en/overview.

Definitions

  • Building Operating Plan. A building operating plan outlines a building’s regularly scheduled, ongoing O&M procedures and policies. These plans are established during the new building commissioning or retrocommissioning (RCx) phase of a project and are upheld throughout the building’s life cycle. Examples of operating plans include heating, ventilation, and air conditioning (HVAC) equipment operating schedules, integrated pest management (IPM) plans, green cleaning policies, walkthrough observations, and regular cleaning of air filters.
  • Building Re-tuning™. Building Re-tuning™ is defined as “a systematic process to identify operation problems by leveraging data collected from the building automation system (BAS) and correcting those problems at no-cost or low-cost” (PNNL 2018).
  • Existing Building Commissioning (EBCx). “EBCx is a systematic process for investigating, analyzing, and optimizing the performance of building systems… The term EBCx is intended to be a comprehensive term defining a process that encompasses the more narrowly focused process variations such as retro-commissioning, re-commissioning and ongoing commissioning that are commonly used in the industry” (BCA 2008).
  • Healthy Building. There is no general consensus on the definition of a healthy building. The World Health Organization defines health as “a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity” (WHO, n.d.). A healthy building is one that does not inflict or provoke medical issues such as Sick Building Syndrome, allergies, asthma, or heat exhaustion and goes beyond that to promote and optimize occupants’ productivity, performance, and satisfaction.
  • Indoor Environmental Quality (IEQ). Most simply described as the conditions inside the building. It includes air quality, but also access to daylight and views, pleasant acoustic conditions, and occupant control over lighting and thermal comfort. It may also include the functional aspects of space such as whether the layout provides easy access to tools and people when needed and whether there is sufficient space for occupants” (GSA, n.d.).
  • Monitoring-based Commissioning (MBCx). MBCx is a commissioning process that uses sensor and monitoring equipment to continuously collect data on system performance and IEQ that is used to support recommissioning (ReCx) and RCx and to identify building improvement opportunities.
  • Occupant Survey. Also called post-occupancy surveys, occupant surveys are administered to a buildings’ occupants and address a range of occupant experiences including thermal comfort, IAQ, cleanliness, lighting, and sound. Occupant surveys can be administered before and after a retrofit to indicate the impact of the retrofit on the occupants’ experience. They can be administered regularly to track occupants’ feedback about the building’s operation and performance over time.
  • Operations and Maintenance (O&M). The Federal Energy Management Program (FEMP) Operations and Maintenance Best Practice Guide defines O&M as “the decisions and actions regarding the control and upkeep of property and equipment” (FEMP 2010).
  • Recommissioning (ReCx) and Retrocommissioning (RCx). As defined in 42 U.S.C. 8253(f)(1)(F), “recommissioning means a process – (i) of commissioning a facility or system beyond the project development and warranty phases of the facility or system; and (ii) the primary goal of which is to ensure optimum performance of a facility, in accordance with design or current operating needs, over the useful life of the facility, while meeting building occupancy requirements” (EISA 2007). The American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) and Leadership in Energy and Environmental Design for Existing Buildings: Operations and Maintenance (LEED EBOM) define ongoing commissioning (OCx) and continuous commissioning (CCx) similarly to ReCx but include other post-occupancy commissioning processes such as MBCx and Building Re-tuning™. (ASHRAE 2019; USGBC, n.d.). RCx is similar to ReCx, but for RCx, the process is applied retroactively for buildings that were not commissioned at the time of construction.

References

ASHRAE – American Society of Heating, Refrigerating and Air-Conditioning Engineers. 2016. Thermal Environmental Conditions for Human Occupancy, Standard 55-2016. Atlanta GA: ASHRAE. https://www.ashrae.org/technical-resources/bookstore/standard-55-thermal-environmental-conditions-for-human-occupancy.

---. 2018. Management for Sustainable High-Performance Operations and Maintenance, Standard 32-2018. Atlanta GA: ASHRAE. https://www.ashrae.org/technical-resources/bookstore/guideline-32-2012.

---. 2019. Standard 1.2-2019: Technical Requirements for the Commissioning Process for Existing HVAC&R Systems and Assemblies. Atlanta, GA: ASHRAE. https://www.ashrae.org/news/esociety/commissioning-process-for-existing-systems-assemblies-outlined-in-new-guideline.

Attema JE. 2018. The Financial Case for High Performance Buildings: Quantifying the Bottom Line of Improved Productivity, Retention, and Wellness. San Francisco, CA: stok, LLC.

BCA – Building Commissioning Association. 2008. Best Practices in Commissioning Existing Buildings Building Commissioning Association. Accessed February 5th, 2021 at https://cdn2.hubspot.net/hubfs/416421/pdf/bca-ebcx-best-practices.pdf.

EISA – Energy Independence and Security Act, 42 USC 8253 et seq. 2007. Energy Independence and Security Act. Public Law 110-140, as amended. https://www.govinfo.gov/content/pkg/PLAW-110publ140/pdf/PLAW-110publ140.pdf.

FEMP ─ Federal Energy Management Program. 2010. Operations & Maintenance Best Practices: A Guide to Achieving Operational Efficiency. Release 3.0. Prepared by Pacific Northwest National Laboratory for FEMP, Richland, WA. https://www.wbdg.org/FFC/DOE/DOECRIT/femp_omguide.pdf.

Fuller, Sieglinde. 2016. Life-cycle Cost Analysis (LCCA). Whole Building Design Guide. https://www.wbdg.org/resources/life-cycle-cost-analysis-lcca.

GSA ─ General Services Administration. n.d. “Indoor Environmental Quality.” Accessed February 5th, 2021 at https://sftool.gov/learn/about/1/indoor-environmental-quality-ieq.

Healthy Building Science. n.d. Healthy Building History. https://healthybuildingscience.com/environmental-consultants/healthy-building-history/.

PNNL – Pacific Northwest National Laboratory. 2018. Large Building Re-tuning Resources. https://buildingretuning.pnnl.gov/resources.stm.

USGBC – U.S. Green Building Council. n.d. Existing building commissioning - ongoing commissioning – Energy and Atmosphere Credit 2.3. Accessed February 5th, 2021 at https://www.usgbc.org/credits/existing-buildings/v2009/eac23.

WHO – World Health Organization. n.d. WHO remains firmly committed to the principles set out in the preamble to the Constitution. Accessed February 5th, 2021 at https://www.who.int/about/who-we-are/constitution

Actions and activities recommended in this Best Practice should only be attempted by trained and certified personnel. If such personnel are not available, the actions recommended here should not be initiated.

Published May 2021