Since the early days of the pandemic, there has been increasing awareness that Indoor Air Quality (IAQ) is a key factor in the mitigation of the spread of COVID-19 viral particles. Business managers from a wide spectrum of businesses – nursing homes, K-12 and office complexes, to name a few – have been inundated with various solutions, all with the promise of protecting building visitors and staff.
With all this information, facility managers are, at times, overwhelmed wondering which product is the best for their particular needs.
This article will explore and define a pragmatic approach to testing and verifying the performance of IAQ investments. While the real-world experiences at an upstate NY School District – New Rochelle School District – focuses on testing and verification of bi-polar ionisation (BPI), the independent testing approach I describe in this article can be applied to a host of technologies.
One morning in early April 2020, in the early days of this long pandemic, I was sitting with two colleagues – we will call them Marty and Bill, because those are, indeed, their names – trying to wrap our heads around how the deadly viral particle, SARS-CoV-2 spreads. Through our deliberations, which were based on close to 100 years of HVAC experience, we kept coming back to the same conclusion – that this very tiny, invisible viral particle, which is more than 100 times less than the diameter of fine beach sand1, would be at its most dangerous in spaces with high occupant density, lack of ventilation and sub-par relative humidity.
Over the next few months, we explored a host of IAQ strategies. Although we had experience with several of these technologies, they were historically viewed as “nice to have” air-cleaning technologies, rather than a primary defence of protecting building occupants. As we brought ourselves up to speed on the nuances of the most marketed technologies, such as photocatalytic oxidation (PCO), BPI and ultraviolet (UV-C), we came to the conclusion that testing and verification of results offered the key to determine what works, and what is
After some brainstorming, we came to the conclusion that to analyse the real-world application of these “old but new” air-cleaning technologies, we need to apply the same independent commissioning process, which is commonly applied to any major mechanical/electrical project. Be it a new air-handling system, BMS, chiller plant or what have you, the independent commissioning process is always the same: The Cx Agent will review the design criteria and specifications, develop a test and then independently test the system to determine if the new mechanical/electrical system performs to the desired outcome.
The balance of this paper will lay out a real-world example of the New Rochelle School District, a community just north of New York City, which experienced firsthand the trauma of the early days of the pandemic and how data-driven commissioning can show real-world performance of air-cleaning strategies.
PROOF OF CONCEPT
The community of New Rochelle was front and centre in the early days of the pandemic, when one of its community members, dubbed Patient Zero by the press2 , fell ill with COVID-19. The story of Patient Zero was the precursor to the viral spread, shutdowns, and the social and economic dislocation that we all experienced, here in the United States and throughout the world.
As “normalcy” began to return in the spring of 2021, the New Rochelle School District decided to embark on a case study to explore the IAQ benefits of BPI. Working with Pandemic Solutions, which is based in New Rochelle, and Atmos Air, a vendor for BPI, they came to the conclusion that before they invested in BPI for the whole district, testing the systems in a few places was more prudent.
New Rochelle reached out to Guth DeConzo Consulting Engineers to perform the testing and validation. After discussions and deliberations, my team and I set the following parameters for the test:
- Since the intent of any air-cleaning technology is to protect the occupants, testing needs to be done in the space. There is no use, other than troubleshooting, to test for IAQ in the supply ductwork, since that is not where the students and teachers are located.
- The intent of the BPI product is to increase ions in the space. While the science behind how ions clean air and neutralise particles is beyond the scope of our mechanical engineering expertise and this article, the test needs to determine that ions are brought to an appropriate level (roughly 1,500 ions-per cm^3, as established by the equipment vendor) in order to be deemed successful. It should be noted that as the independent testing team, we are not in a position to deem a space safe or unsafe if the ion target is met.
- Ozone, which is a known irritant and health hazard to human lungs, has historically been a byproduct of “some” air ionisation devices and has been a historical concern. Standards exist, namely UL 2998 here in the United States, to certify low ozone emissions. To qualify for UL2998, which the products tested in this study comply with, a product must prove it releases less than five parts per billion. Although perhaps “belts and suspenders”, since the product is already UL 2998 compliant, we tested for ozone in the space, since the school business officials anticipate that there will be questions from
the various stakeholders, including teachers and parents.
- Volatile Organic Compounds (VOCs): High levels of VOCs are also a health concern and a major factor in Sick Building Syndrome complaints. Therefore, the test included testing of VOCs to ensure that the ionisation process did not increase VOCs, but in fact could reduce VOCs and provide fresher, less odorous air. See discussion on next phase of the project on why moving forward, we determined that formaldehyde, in addition to VOCs, in general, should be included in testing.
- Particle count: One of the basic premises of BPI is that it will neutralise particles 3 and, over time, amalgamate particles, making them fewer and larger, so that air filtration and gravity can “clean them from the air”. For this reason, particles are counted, since one would expect a reduction in particle count as a result of the air ionisation.
THE PILOT TEST
The pilot test was done for a diverse set of K-12 spaces. Recognising that the intent was to determine if the ionisation could be successful under different operating conditions, two class rooms and a multipurpose room were chosen. One classroom was conditioned with a traditional unit vent, while the other classroom didn’t have mechanical ventilation. The multipurpose room was served by an air-handling unit.
The basic information for the three locations are shown below.
Figure 1: Test Basic Information-Pilot Study
Once the criteria were established, Guth DeConzo developed a testing procedure as follows:
Setup testing equipment in centre of room at desk level. Refer to Figure 1.
- Data trending of the following metrics for each 15-minute trial (Baseline & Operating):
- Ion count: Ions per cubic centimetre were logged every minute for each 15-minute trial (Alpha Lab-Model AIC2).
- Ozone (parts per million, ppm): Logged every minute for each 15-minute trial (Eco Sensors-Model C-30ZX).
- Particle count: Trending was done for 0.3 μm, 0.5 μm, 1.0 μm, 2.0 μm, 5.0 μm and 10.0 μm (per cubic foot). Total counts per cubic foot were recorded once per 15-minute trial (Fluke-985 Particle Counter).
- VOCs – Volatile Organic Compounds (parts per million, ppm): Logged every minute for each 15-minute trial (Eco Sensors-Model C-21).4
- Ensure ioniser is ON: Conduct Operating Trial of 15 minutes.
- Ensure ioniser is OFF for a minimum of fifteen minutes (prescribed time for ions to clear the space and natural conditions to return): Conduct Baseline Trial of 15 minutes
- Note: Operating Trials were conducted before Baseline Trials. It takes approximately 1-2 hours for the ions to fully saturate the room air; therefore, it was beneficial to have the ionisers already operating for a considerable amount of time prior to conducting tests.
- Record all data and ensure that ion concentration and ozone generation meet the following criteria for a PASS/FAIL designation:
- Ion Concentration: Ion concentration should increase by at least 500 ions/cm³ and maintain ion concentration range of 1,000 ions/cm³ – 1,500 ions/cm³.
- Ozone Concentration: Ozone production is certified by UL Standard 2998. However, due to historic concerns about ozone, my team and I measured ozone to provide data to decision-makers. For all spaces, ozone increase was negligible.
- All other IAQ metrics, in addition to ion and ozone concentrations, shall be presented in this report for further validation of proper operation.
Figure 2: Testing Equipment
THE PILOT TEST RESULTS
The test results for the three spaces are shown below…
Figure 3: Test Results – Pilot Study
The above chart (Figure 3) is a graphical interpretation of the particulate data. Presenting this data this way is important to educate the client and stakeholders on what is happening (that is, particle counts are being reduced) through the invisible process of air ionisation.
Figure 4: Site testing equipment and space
Figure 5: Particle Count Reduction (for multiple size particles)
A review of the data revealed the following:
- Particle count for all sizes was documented for all size ranges. In general, particles count did decrease, as expected. Note that although particle reduction target was not a criteria of the test, we did want to document particle reduction, since lack of reduction would call into question the whole premise and theory of air ionisation.
- Ion concentration exceeded the target increase of 500 ions/cm^3, and attained the target of range of approximately 1,500 ions/cm³ (the reading is actually slightly higher at 1,608 ions/cm^3).
- Ozone did increase for two of the spaces, but only slightly, which we deem as inconclusive. Note: That background ambient ozone readings were approximately 200 ppb, which coupled with UL 2998 certification should address any concerns that various stakeholders have regarding the ozone concern.
- VOCs decreased by approximately 50%.
After conferring with the client and reviewing the results, it was agreed that the testing was satisfactory; and the client elected to install the air ionisation technology throughout the District.
Once the air ionisation installation was completed for the District, Guth DeConzo was retained to perform testing for approximately 10% of all installations, which was approximately 100 spaces in total.
Also, recognising the public’s concern regarding “unintended consequences” of IAQ air cleaning, we added formaldehyde concentration, which is part of the Aldehyde family and is of special concern to public health officials, to the complement of contaminants my team and I were testing for.
At the completion of the study, a formal report was completed and provided to the owner. The study included the methodology, test results (by space for each of the approximately 100 spaces selected), cut sheets of equipment and supporting research articles on air ionisation.
The summary results of the complete testing are shown in the table, below:
Figure 6: Summary of Results – District-wide Test (District-wide average)
CONTINUOUS COMMISSIONING – BUILDING TRACING
The New Rochelle management emphasised investment in IAQ is not a one-shot deal but more of a new way of thinking of how we manage our buildings. With this in mind, New Rochelle tasked Guth DeConzo with the following additional tasks:
- Training of facility staff: The training included hands-on training of the BPI devices, along with the theory and practicality of IAQ best practices.
- Seasonal testing: Similar to traditional Cx, Guth DeConzo performed a seasonal test, six months after installation, to ensure the units are still in operation.
- Long-term Building Tracing: As part of the contract, New Rochelle invested in data-logging devices to monitor the IAQ of the spaces. As part of our Cx efforts, we commissioned these devices to ensure that they are operating correctly. The data-logging devices are used to monitor the space IAQ on a continuous basis and will inform the user when there is an issue.
THOUGHTS ON FURTHER TESTING
Currently, there is no independent testing procedure for “in use” air-cleaning devices. If building IAQ tracing is to be successful, we need to have established rules, so we all know what success looks like.
Below is a proposal for IAQ testing protocol…
- Establish performance criteria. For this test, my team and I established “Pass/Fail” criteria of increasing ions by 500 ions/cm^3 and target of reaching 1,500 ions/cm^3. There is nothing sacred about this “Pass/Fail” criteria, but it is based on vendor data of what is reasonable and stated as effective.
- Keep it simple: Only test for the variables that are key to success and keep analysis as simple as possible. While each air-cleaning technology is different, we only recommend testing for variables that are truly indicative of overall success for the particular technology, since adding testing of other secondary variables (that is, airflow, background variables, etc.) will add time and expense, which may make the testing cost prohibitive.
- Ensure proper sample size. We chose 10% of spaces for the test prescribed in this document. For smaller installations, we recommend a larger sample selection.
- Transparency: Air is invisible, therefore transparent data is needed to demonstrate results. Providing data to owner will allow for more transparency and give confidence in the testing procedure and test results.
- Test for conditions at hand. In developing the criteria for testing, my team and I did consider expanding the testing for a whole slew of other variables (that is, control variables for outdoor weather conditions, room geometry, airflow, temperature/relative humidity, etc.) with the hope of normalising the final data set. However, recognising that for independent testing to be successful it needs to be repeatable and affordable, we elected to establish simple criteria, which can be used for any type of space and any background conditions. While a more data-driven approach does have its advantages, we concluded that applying the “80/20” rule (80% of benefit for 20% of the cost) has a better chance of wide-scale implementation and support of our ultimate goal – ensuring that IAQ strategies realise the results we expect.
CONCLUSION – WHY INDEPENDENT TESTING
The pandemic served to surface the need for ensuring air quality in our facilities and buildings, and our hope is that third-party testing will lead us down a path for validating solutions that monitor for unknowns and invisible toxins that we were only made aware of as a result of the pandemic. The pandemic necessitated improvements in IAQ, but good IAQ also serves to maintain a healthy environment for non-public health emergency times, which we hope is the norm in the future.
More so, independent testing can be a catalyst for a healthy dialogue and a process for continuous improvement. As an example, only through healthy dialogue and challenge of results by the client, we concurred that we should add formaldehyde testing for future test results.
Only through independent testing, objective evaluation of the results and transparent reporting of results can we determine if the client’s investment in air cleaning devices are producing results. For decision-makers, who are concerned with results for their stakeholders, independent testing is a sure way to ensure the investment in air cleaning is worth it.
1Carmen Ang, https://www.weforum.org/agenda/2020/10/covid-19-coronavirus-disease-size-compairson-zika-health-air-pollution
2Maura Hauman and Scott Stump, May 11th 2020, Today, “New York’s coronavirus ‘patient zero’ tells his story for the first time: “Thankful that I’m alive”
3Dr Philip M. Tierno Jr, Professor of Microbiology and Pathology, New York University School of Medicine,
“Cleaning Indoor Air using Bi-Polar Ionization Technology”, April 2017