2023 Annual OMC Conference Workshop - Ventilation Challenges & Strategies
OMC Workshop – July 12-14, 2022
Increasing Ventilation – Three Schoolboards share their experiences.
PDSB, RCDSB and DSBONE share insights on the lessons learned during a comprehensive ‘ventilation rehabilitation program’ that is designed to drive more airflow to under-ventilated classrooms and harvest energy in over-ventilated spaces.
Panel hosted by Tony Cupido, Ph.D., P.Eng., Mohawk College, former Superintendent of facilities with Hamilton Wentworth DSB, Hamilton Catholic DSB, former AVP facilities McMaster University, former Chief of Facilities Mohawk College.
Air Auditing & System Performance
Tony: I’d like to kick off our discussion by talking about the state of your ventilation systems prior to commencing any work. I’ll ask the three of you to share what you learned during the auditing process? Carole over to you first.
Carole: I think we can all agree that during the early stages of the pandemic, we were all learning, adapting and responding based on the information and resources available to us. Ventilation quickly became a focal point so we had mechanical engineers conduct an audit of all of our current mechanical systems at our schools. We also had our maintenance dept audit our mechanical, and surely enough the need for improvements was quite evident. I wanted to take advantage of CVRIS and submitted $14 million budget of mechanical ventilation upgrades and was approved for 7.9 million. Our first step was to tackle some of the overdue and deferred maintenance, as well as fixing wiring issues and upgrading filters.
Then we shifted our focus to increasing airflow. We engaged with the Cleaner Air for Schools program though OECM, to help us quantify the air loss associated with each of our mechanical systems. The audit was a crucial step to help us understand on a classroom-by-classroom basis which spaces were under ventilated and which ones were meeting standard and others often exceeding it.
Bill: When the CVRIS funding was announced my focus was on how to keep students, teachers and staff safe. The science table, EPA, World Health Organization and other authorities were promoting more air exchange and better filtration to contain Covid. My approach was an in-depth air ventilation audit, the audit components were, Measuring the air volume being discharged by the AHU, Measuring the air discharged by air diffusers for every AHU unit and the diffusers they serve. First insight we were losing 25% of air volume between the air handler and diffuser. Second insight was the deficiencies associated with the ventilation system….loose belts, clogged coils, dislodged duct work, crushed duct work, holes in duct work all contributing to less air volume being released in the classroom. Third insight, 20 % or more of our classrooms were not meeting the 4 ACH standard we desired, this resulted in impacts to health and safety, air quality and occupant comfort.
Shahid: During the early stages of the pandemic, there was significant concern about air quality and ventilation within our facilities. To address this, we implemented the ASHRAE COVID protocol for our ventilation systems, which involved the installation of MERV 13 filters, increasing the hours of operation for our ventilation systems, and doubling the outside air quantities for these systems at a minimum. While these steps were important, we recognized the need to have end-use measurements to verify the air quality and quantities at a local individual diffuser level. The audit process we undertook provided the necessary data, and we were able to quantify that we were over-ventilating certain spaces, which allowed us to use variable frequency drives to save energy and reduce emissions.
Ventilation Rehabilitation Process
Tony: Thank you Shahid. Moving on to our next topic. We all know that any work that happens during the school year requires meticulous planning. I’d like to ask our panelists to share their experience during the actual project implementation process. You can share details about planning, scheduling of work , communication, coordination, etc. We’ll start with you this time Shahid.
Shahid: In regards to our recent project, I would like to highlight that we engaged in thorough advance planning, which included scheduling the work and communicating it to the relevant parties, such as the schools and site custodians. To minimize disruption, we conducted the work outside of regular hours and I was personally available via cell phone in case of any issues that arose. However, despite our efforts, we encountered a technical difficulty when a fan or two experienced electrical faults and would not operate. As a result, we had to ensure that all fans were functioning properly before proceeding with the duct sealing work. The presence of an HVAC Controls technician during the project proved to be highly beneficial in addressing any site communications issues.
Carole: Any renovation or renewal work that happens in our schools is normally challenging due to the fact that we are a northern and remote school board. Obtaining multiple bids and contractor availability are normally a challenge. However, with this particular program, Cleaner Air for Schools was the sole source for this technology under OECM, so it made the procurement process very easy.
Some of the work does require opening up the ceiling tiles which can create the appearance of a construction site. I told some Principals that it would be a learning opportunity for the children to see what exists in the ceiling spaces. Staff and students were extremely patient as they knew that ventilation upgrades were required. The sealing process was done on evenings and weekends so there was never any real disruption to the space.
Bill: Going forward from the school air audit, the next step was to repair and rehabilitate the air duct system and related components. This involved replacing crushed duct work, patching holes in the duct work, cleaning coils, replacing new belts where needed. Basically, reconditioning the entire air duct system connected to the AHU and the classroom diffusers.
Once this was completed, we use a product called Aeroseal, this product seals ductwork from the inside out and has the ability to seal holes in the duct work as large as 5/8ths of an inch and as fine as a hair follicle. The sealing process reduced air leakage to about 2% which is quite remarkable. That’s the equivalent of passive house buildings.
Project Results
Thank you, Bill. As you all know, Mohawk is the Measurement and Validation partner for this program so we are very familiar with all of the results. But I’d like to ask each panelist to share specific highlights about what each of them achieved so far. I’ll ask each of you to cover the results and add any comments you think our valuable for the audience. Carole, I know your board has completed 23 schools under this program. Why don’t we start with you.
Carole: In a few words, the ultimate result is more airflow. We have performance reports for each school, that outline the performance of each mechanical system. The report shows that we have 25% of systems that are under ventilating space so minimizing the ductwork leakage on those was crucial. We were able to increase airflow by an average of 24% across our board.
The reports also show us that 75% of our systems are actually over ventilating their service areas so this presents us with an opportunity to install VFDs and turn down those fan speeds. We’ll still be able to hit the ASHRAE standard of 4 ACH while reducing our energy costs and carbon emissions. Overall, having performance data just makes decision making easier as we now know where we have liabilities and opportunities. An energy manager for our board would definitely be beneficial moving forward.
Bill: Given the CVRIS funding and some additional board money we were able to address schools that have ducted supply ventilation.
When we concluded the repair and sealing of the duct work, we re-audited the air flow going to each space. So basically, mimicking the pre-audit process to measure the post seal results. As a portfolio we have captured 28% air loss and reconditioned our ventilation system which is operating at peak performance now. Areas that were previously under ventilated are now either meeting standard or cresting to nearly meet these standards. The other major insight we gained was the vast % of over ventilated classrooms, these are opportunities to harvest energy and reduce GHG. Presently I am developing a plan to harvest energy and GHG with those ventilations systems that are exceeding 4 ACH.
Shahid: We conducted a pilot project at two schools, one a secondary school and the other a K-8 school, to test the efficacy of a new technology. We utilized a proposed methodology, which involved a detailed modeling of the equipment and settings, to quantify the performance of the technology before and after implementation. Additionally, we cross-verified the estimated energy savings against real-time interval utility meters. Our findings indicate that the technology is delivering approximately 15% energy savings.
Actionable Insights – what value do the performance reports provide your board?
Tony: Reporting on ventilation performance has become a crucial aspect of facilities in the last few years. I’d like to ask our panelists how they’ve used this information and how they feel it benefits their ability to future proof schools. Carole perhaps you can kick us off, with this one.
Carole: Reporting to senior management is a big part of our role. Having third-party engineered data has made that process more fluid and transparent. We can illustrate with confidence where we are driving more air, as well as the energy and carbon savings impact. As a board, the performance reports arm us with the necessary tools to have informed conversations with staff, unions, parents and trustees.
Bill: The data received from pre air auditing and post auditing has provided me with an inventory of air volume performance for every air handler and all air diffusers related to that air handler. I can tell you the current air volume performance for every classroom in the system. I can tell you where we are under ventilated in spaces and need more attention and inform you where we are pushing way more air into the space then we need be. This is a tremendous overspend in energy and GHG cost. We all know that energy cost including carbon tax are having significant impact on our operational budget….translation fewer dollars to clean, less maintenance and fewer staff to care for our school infrastructure and service quality. An additional important learning for me was that there was no appreciable difference between older and newer buildings in terms of duct leakage. Our newest building (7 years old) was no better than installs completed 40 years ago.
Shahid: Our emphasis is on assessing and ensuring delivered ventilation performance in buildings. What is crucial is the actual air quality and quantities delivered at the individual air diffuser level, rather than relying solely on as-built engineering drawings. The performance reports generated through this work enable us to quantitatively verify the air quality levels, thus providing strong evidence for our efforts. With this method, we can verify that we are providing the necessary air quality to all students while optimizing the efficiency of the system.
The Road Ahead
Tony: Let’s face it, I think we can all agree that a heightened focus on ventilation performance is here to stay. From what we learned here today I think we can all agree that it goes beyond health and wellness. There is a direct correlation and impact on utility costs and carbon emissions. To close off the panel, I’d like to ask our panelists what they see as some of the most pressing issues over the near and long-term future in their respective boards. Shahid, let’s start with PDSB.
Shahid: We are currently facing significant inflationary pressures on our facilities and utilities budgets, which I’m sure many of you can relate to. In addition, our school board is experiencing declining enrollment due to the high cost of living in our region. This means that our revenue is decreasing while costs are increasing, putting strong pressure on us to be more efficient with our resources.
Despite these challenges, we remain committed to maintaining a high level of facilities quality & productivity. We anticipate that ventilation requirements to remain stringent in the future and we believe that any improvements we make to our ventilation systems will help us better prepare for what’s to come. We recognize the importance of doing more with less, and we’re actively seeking ways to achieve this goal.
Carole: It feels like we’ve overcome one pandemic, only to be thrown into another significant challenge which will be the financial pressure of rising utility rates and the escalating carbon tax. Unfortunately, our funding does not reflect these increases so we will have to be very diligent and creative in finding ways to reduce energy waste. We need to maximize our resources and ensure that we can control energy and carbon costs before they begin to eat away at other budgets like cleaning, maintenance, custodians, etc.
This is also a great opportunity for us as a teaching community to show leadership and empower our younger generations to become involved, passionate and empowered by sustainability.
Bill: As I pointed out in the previous question, over ventilating space is a major cost waste in energy and carbon tax. Heating and cooling outside air represents more than 50% of my energy spend. it’s the major focus next to lighting conversion which I am sure most of you have tackled or are engaged in LED retrofits. I am focused going forward to reduce energy and carbon tax cost. As a Board if we don’t take steps to reduce carbon consumption our carbon tax cost will be almost a $1M by 2030. We are committed to meeting the 2030 45% GHG reduction goal set by our federal government. To do this we need to optimize the operation of our buildings to use less energy as we move away from carbon. We in facilities have a tremendous opportunity to make a difference for our students and education as a whole by maintaining safe environments and providing quality learning environments while demonstrating climate change leadership to lower carbon and model environmental stewardship for future generations of students.
Andres Serrano M.Eng, P.Eng
Energy Solutions Advisor
Enbridge presented customized incentives on duct sealing and other energy saving measures for school boards. The custom incentive covers all gas saving measures that are not included in a fixed incentive at a standard rate of 25 cents per cubic meter of natural gas saved. This is a 25% increase from last year. For both ventilation and or energy saving improvements Enbridge is there to support you financially with these types of incentives.