Gauging Building Health

In the past, a building’s health may have been gauged by the levels of complaints, for example, thermal comfort coming from occupants. However, in a post-COVID-19 world, this reactive approach could prove detrimental to many organizations.

In fact, many employees are pushing back on their employers over their return to offices, often citing concerns about potentially unsafe workplaces. After requiring employees to return to in-person work in April, Apple has several times had to put those plans on hold due to increases in COVID-19 cases among employees. Employees garnered national attention with a petition against the company’s inflexibility, citing accommodations for safety, health and environmental concerns as reasons to allow remote work.

Other companies, including JPMorgan and Goldman Sachs, have faced similar pushback from employees. While there is research to support both sides of the conversation about the comparability of productivity in person versus working remotely, what has been lacking for many companies is evidence that executives can point to about the health benefits of their in-person work environments. Having seen first-hand the impact of COVID-19 on their bottom lines, corporate culture and their employees’ health, companies are looking for ways to make their operations more effective and resilient. In response to local and global concerns facing these corporations regarding health and environmental, social and governance (ESG) initiatives, business leaders have pushed for more structured programs. In 2021, the Harvard School of Public Health created the Public Health & Business Leadership (PHBL) Program to bridge public health and business interests in establishing safe workplace environments. Company owners who believe in the need to connect in person to achieve more fruitful collaborations and greater productivity and the need to meet the demands of the emerging “health-first” era must partner with their FMs to provide ongoing proof of building health.

Today’s FMs must have quality data to which they can turn to refute complaints or to show that appropriate measures have been taken to address potential health issues. FMs must be able to demonstrate the healthy building strategies that have been implemented and be prepared to discuss the metrics by which building health is measured. Corporate success and credibility may depend upon this evidence.

Looking out for building health

Since March 2020, FMs have largely sought to ensure building health by following ASHRAE recommendations for increasing filtration effectiveness, employing higher ventilation rates, and pre- and post-occupancy purge rates. While these higher rates of ventilation and frequent flush-outs may ensure healthier air – and have been shown to diffuse the risk of airborne transmission of the COVID-19 — they may also not always be necessary and instead be detrimental to other facility objectives.

Typically, these pandemic response actions were performed in the absence of specific goals based on well-defined performance objectives and lacked measurable air quality data that may indicate the presence of a problem or that FMs can reference as proof of building health. As a result, building owners and FMs are driving their operational and energy costs up and, for many, operating against their sustainability pledges without any true benefits.

Many FMs have lacked a formal process for ongoing assessment and verification of system performance. With the right strategy and performance metrics, FMs can more effectively solve problems today and plan their response to future building air quality challenges and improvements.

The foundation of any program verifying building health follows the FIRST step approach outlined below.

Focus discussions on setting meaningful and verifiable objectives and get agreement from upper management. This will get FMs a “seat at the table.”

Inspect the building regularly, using a standard approach or a trained building engineer. Although it sounds simple, it is important to know what is being looked for. For example, a visual inspection of the air handling systems can tell FMs if fans are running normally and air filters are clean and appropriately seated in their frames. It indicates that outdoor air dampers are working and discharge air temperatures are meeting expected set points even under hot and humid conditions. From there, FMs should make visual inspections of occupied spaces to look for unusual conditions. This might include inspection for stained ceiling tiles, unusual odors, temperature differences between zones, or other indications of abnormal conditions.

Retrocommission buildings to optimize system performance. Tremendous improvements can be realized by implementing proven no-cost or low-cost modifications. Further, this process can uncover significant energy savings that can often fund the initial steps and continued program.

Supplement with temporary measures as may be needed to meet goals. This may involve the use of localized filtration systems to meet specific ventilation rate requirements or use of UV lights to reduce the airborne bioburden and increase the effective air exchange rates.

Test the air quality regularly and analyze the results against established guidelines. Low-cost sensors and analysis packages are available that will permit meaningful communications to be developed that showcase the impact of the program.

Measuring health by clear metrics

Visual inspections will provide a great deal of data about where to investigate further. However, as noted above, FMs should be prepared with baseline measurements for key building metrics. This will help in documenting the need for any response actions and achievement of performance goals, as well as for communicating building health to the C-suite and building occupants.

While FMs may be familiar with some if not all of these measurements, the key is to ensure these readings are part of a formal IAQ verification process. FM teams must have a clear understanding of what the various measurements mean through easily remembered and communicated talking points. Key metrics include:

• Carbon dioxide (CO2) levels: CO2 levels are a useful gauge of outdoor air delivery, ventilation effectiveness and overall building health. In fact, research by British facilities management company EMCOR UK, conducted over two years by academics at Oxford Brookes University and LCMB Building Performance, found that people worked 60 percent faster in buildings with reduced CO2 concentrations. Employees completed tests in a mean time of 8.2 minutes, compared to 13.3 minutes in buildings with more CO2 in the atmosphere.

  For indoor air quality (IAQ), the recommended upper limit for carbon dioxide levels is 600 parts per million (ppm) of CO2 above outdoor background levels. For example, if outdoor air is 450 ppm CO2, then the recommended upper limit would be 1050 ppm CO2 and would correspond to approximately 15 cubic feet of outdoor air being supplied per person. This recommend-ed upper limit is based on ASHRAE ventilation standards for adequate ventilation and provides a more tailored assessment of outdoor air delivery rate, rather than defaulting to the “traditional” threshold of 1000 ppm as the recommended upper limit. However, as the term “adequate” implies, this standard is focused on comfort and not necessarily public health. “Good” air quality levels generally correspond to levels that will be ap-proximately 400 ppm above background. Maintaining this level of carbon dioxide in an occupied space will help achieve the benefits described above.

  As with most IAQ measurements, it is important to collect the samples in a central, occupied area but six to eight feet away from the nearest occupant (people passing by as a normal course of activity is fine). For a typical work pattern, collect the data after people have occupied the space for two to three hours and plan on taking the samples over a one- to three-hour period.

  With this information, FMs can document maintenance of appropriate amounts of outside air needed for a healthy environment and identify opportunities to reduce the amount of outside air brought into the building at certain times. This allows FMs to reduce ongoing energy demand while optimizing system performance and maintaining a healthy environment.

• Particulate levels. There are many types of particulate matter that can cause respiratory problems, throat irritation, and other ailments. These include viral particulates like SARS-CoV-2 as well as emissions from traffic, pollen, and smoke from wildfires. Although limited in number, research has shown a significant decline in cognitive tests when indoor levels of fine particulate matter, also known as PM 2.5, routinely exceed 12 ug/m3. Many reliable low-cost sensors are available to help obtain accurate measurements of PM 2.5. Samples should be collected in parallel with the CO2 measurements.

• Temperature and humidity set points. The ability to maintain occupied area temperature set points indicates that the building HVAC systems are able to adequately provide properly conditioned and dehumidified air to its spaces. Space temperature monitoring is particularly important as outdoor ventilation rates increase; a common tactic used to diffuse particulates. Many FMs periodically test HVAC system performance at high-er outdoor air ventilation rates by slowly increasing the outdoor air ventilation rates on a hot day and checking the HVAC system discharge air temperature to ensure it maintains its setpoint.

• Building and Space Pressurization. It is desirable to operate buildings at a slight positive pressure relative to outdoors. This is achievable through overall balancing of the buildings HVAC outdoor air intake rates and the mechanical exhaust rates. Buildings that operate at a negative pressure with respect to outdoors will have higher infiltration rates of unfiltered and unconditioned outdoor air, which can result in indoor thermal comfort complaints, increased indoor particulate levels and can contribute to conditions conducive to indoor surface condensation. Space to space differential pressure is also important to consider to minimize the transfer of air between occupied spaces and potential contaminant or odor source areas including restrooms, mechanical spaces and loading docks. Measuring the pressure difference between the indoors and outdoors or between specific spaces on a quarterly basis may determine the need for adjustments to mechanical systems.

• Complaints. While less scientific, this remains a useful metric to track. FMs should ensure they log all complaints received about thermal comfort and other building problems, as well as action taken to resolve them. Developing a standard collection process is critically important in analyzing complaint data to see if there is a pattern that emerges or to document success in resolving complaints. All of this information can help to build a better understanding of how a building operates and key issues to address proactively to satisfy building occupants.

What to do with the data

With all of the information available to FMs — including visual cues and the key measurements noted above — the next critical step is analysis. For some FMs, this analysis may be already available through their building automation system. A talk with a system vendor may even be able to identify opportunities to track additional data or customize reporting. For other FMs, an outside consultant may be able to more effectively monitor, analyze and track this data without burdening the FM team.

By regularly analyzing amassed data, FMs can begin to track trends, build connections and identify issues before they grow. This analysis may also prove useful as a communication tool to help building occupants feel safe as they return to work and can also help determine when system adjustments are needed.

Prior to making any changes, there are three additional considerations.

• FMs must understand the overall operational capabilities, and limitations, of their HVAC equipment. It has always been a recommended best practice to have ventilation rates consistent with ASHRAE recommendations. That does not mean it is something that is always monitored, measured and adjusted on a regular basis.

  Since COVID-19, adjustments have become more frequent, but adjusted ventilation rates are not always consistent with equipment performance capabilities or the needs of the occupants. Surprisingly, newer HVAC systems are often designed to ensure compliance with building and energy codes and no more than that. That means calls to significantly increase outdoor air ventilation may not be physically possible without sacrificing a system’s cooling or dehumidification capacity. This is particularly true during periods when outdoor temperature levels are high.

  For other systems, small adjustments can improve ventilation rates. For example, research from Washington State University indicates that nearly 50 percent of new airside economizer installations have one or more problems that reduce their effectiveness. Simply checking this and other functions with a visual inspection can maximize outdoor air flow while minimizing energy consumption.

• Examine filtration. Historically, the primary intent of HVAC filtration was to protect heating and cooling coils from clogging due to dust and other contaminants. This was accomplished using lower efficiency filters, with efficiency ratings of MERV 7 or MERV 8. It is not unusual for newer HVAC systems to be specified with higher efficiency filters, as a higher level of filtration provides both component protection and cleaner air to the occupied space. During the COVID-19 pandemic, MERV 13 filters were introduced as the recommended standard for HVAC systems filtration as these filters provide a higher capture efficiency compared to MERV 7 or MERV 8. According to ASHRAE, MERV 13 filters are at least 85 percent efficient at capturing particles ranging in size from 1 µm to 3 µm and their use in HVAC systems will result in a higher delivery rate of clean air to the occupied space. There is little benefit to be gained for typical office installations to go to a higher MERV rated filter.

  One limitation with using these higher efficiency filters is that they are more restrictive to airflow compared to MERV 7 or MERV 8. This higher resistance can result in a decrease in total HVAC system airflow. For a majority of HVAC systems, the additional pressure drop created by the higher efficiency filters may result in a negligible airflow reduction. However, for some older or smaller packaged HVAC systems, the airflow reduction may be significant and result in performance problems. This should not discourage FMs from considering higher efficient filtration systems. In general, most FMs have been able to effectively upgrade their filters in the last two years without any problem whatsoever. The key is to measure and verify performance before and after any changes.

• Control indoor source areas. The proper operation of building HVAC systems may be of primary importance when it comes to building health, but there are additional steps that can be taken to improve IAQ and occupant perception. Most buildings have similar indoor potential contaminant sources and areas where these sources are contained. Containing these source areas is important to prevent sources or odors from circulating to occupied areas. For example, in buildings with hydraulic operated elevators, elevator machine rooms are a source of odors and these rooms often require space depressurization. Other source areas include copier rooms or kitchen areas, restrooms or shower rooms and mechanical spaces and loading docks. Sources in these spaces may best be controlled by localized exhaust.

A key partner in building resiliency

Building operations are being held to a higher standard than they ever have been in the past. For those executives who see work in the building as critical for corporate success, they will rely on their FMs to have data that proves their workplace is safe and in line with their ESG and corporate objectives.

Building occupants will be looking for evidence as to how FMs are assessing potential hazards. They will want proof that a plan is in place to protect occupants from future hazards, including pandemics as well as natural disasters and the ongoing impact of global warming. Many will want assurance that their buildings are in fact safer than the dangerous conditions outside in their communities.

By taking clear, measurable action to manage HVAC system performance today, FMs can create safer and more resilient buildings for the future.