BU Aims to Move More, and Cleaner, Air through Buildings
BU Aims to Move More, and Cleaner, Air through Buildings
Ventilation improvements are part of a broad campuswide strategy aimed at keeping COVID-19 from spreading
- The CDC says it’s important to improve building ventilation and air circulation
- BU is increasing the airflow in many indoor spaces and upgrading air filters in HVAC systems
- Social distancing will increase the amount of air per person in indoor spaces
As scientists continue to study ways that the coronavirus can be spread, one question involves aerosol droplets that people exhale while breathing. Can those droplets circulate in the air long enough to be picked up by a ventilation system and recirculated through building ducts? There has not been a clear answer. But what scientists and the Centers for Disease Control and Prevention (CDC) have said—unequivocally—is that one of the most important things employers can do is to improve building ventilation and air circulation wherever possible.
That’s what Boston University’s Facilities Management & Operations staff is doing.
In one more move aimed at making the BU campus as safe as possible for the fall semester amid the coronavirus pandemic, workers are increasing the ventilation and improving air filtration in 120 campus buildings that have mechanical ventilation systems.
Specifically, two steps are being taken: workers are increasing airflow in indoor spaces by having HVAC systems in buildings run around the clock, instead of 12 to 16 hours a day, and new filters capable of capturing airborne viruses, including SARS-CoV-2 (the virus that causes COVID-19), are being installed in the systems that recirculate air in offices and classrooms.
That still leaves 198 buildings on campus that do not have heating, ventilation, and air conditioning systems (HVAC), where the airflow depends more on opening and closing windows.
For those buildings, teams from Facilities Management & Operations are following the advice of the CDC and planning to use window fans to circulate the air. In advice to employers for their office buildings, the CDC says a key step is to “increase circulation of outdoor air as much as possible by opening windows and doors if possible, and using fans.” The CDC also says an important step is to “increase outdoor air dilution of indoor air.” Facilities staff is also considering installing portable air purifiers with high-efficiency particulate air (HEPA) filters in buildings needing additional airflow.
The steps BU is taking, combined with requiring people on campus to monitor their health symptoms daily, to wear masks, to maintain strict social distancing, and to submit to regular COVID-19 testing (while also following BU guidelines on quarantining and isolating), are all part of a broader University-wide strategy to resume residential life on campus starting in mid-August as safely as possible.
Gary Nicksa, BU senior vice president for operations, says the steps Facilities workers are taking will help move a greater volume of cleaner air through BU’s indoor spaces.
The strategies also follow the recommendations of the CDC and the American Society of Heating, Refrigerating and Air-Conditioning Engineers. The CDC website says: “Consider running the HVAC system at maximum outside airflow for 2 hours before and after occupied times.”
The filter change should make a big difference, Nicksa says.
Another factor that should help the air quality in BU buildings is that fewer people will be in them. With social distancing, and with some students planning to take classes remotely in the fall, Nicksa says, classrooms should have 50 to 80 percent fewer people than they had last year. That means there will be significantly more air per person than previously. Increasing the amount of clean air per person in a room reduces the risk of exposure to COVID-19, he says, because clean air helps dilute any airborne virus, making contact with the virus far less likely. He says Facilities workers are inspecting 800 classrooms to confirm they are getting sufficient air (the standard rate is at least five cubic feet of air flow per minute, per person, based on the room’s maximum occupancy).
To oversee BU’s efforts to combat the airborne spread of COVID-19, Facilities Management & Operations created a team of the University’s engineering and building systems staff, in-house HVAC technicians, building area managers, and BU Environmental Health & Safety staff. The University has also hired engineering and consulting firm Environmental Health & Engineering, with expertise in HVAC system design and operation, to assist with the work.
To find out more about BU’s efforts to keep COVID-19 out of the air in indoor spaces, read a white paper written by Nicksa here. Watch a video presentation of Nicksa describing BU’s strategies to keep indoor air virus-free here.
What about ventilation in dorms like Myles Standish? Will there be a change/upgrade in the ventilation systems?
The air handlers at Myles Standish hall have been upgraded to MERV13 filtration. These air handlers provide air to all of the common areas in the building. Each bedroom has the capability of opening the window to admit fresh air for natural ventilation. Cooling and heating is accomplished through the use of a valance unit system which relies on natural circulation within the space being heated or cooled.
What about apartment buildings like Stuvi1 and 2 that have air conditioning systems? Are any upgrades being made to the ventilation systems there?
Concerned Student, the filtration in Student Village 1 and 2 have been upgraded to MERV 13, and the outside air adjusted so as to not adversely affect the heating and cooling in the buildings. As in our other buildings, setback programming has been adjusted to allow maximum ventilation.
Not exactly reassuring that ventilation has taken a major backseat to questions about cleaning surfaces when we know that COVID can remain airborne in a space (like an elevator or a classroom) for hours. It’s August 3 and these efforts are only now happening? Will there be studies done to see if these measures improve ventilation enough to hold classes indoors in some of these 198 buildings where we must currently rely on opening windows?
Now that some students have moved in, where can we find the COVID-19 public dashboard? This is critical to maintaining the transparency BU has promised.
Thank you Concerned Graduate Student for your inquiry. Facilities Management & Operations and Environmental Health & Safety have been working through the HVAC systems since March. The article and associated white paper outline what has been done and will be continue over the coming weeks. As part of the analysis of HVAC systems, each classroom is being evaluated for effective air exchange rates. If there is no mechanical HVAC equipment, the University plans to follow CDC guidance to utilize open windows to provide fresh air for the space. The combination of open windows, significant reduction of occupants, and additional HEPA filters, if required, are all designed to meet ASHRAE standards and CDC guidance.
Our current plan is to post the dashboard shortly after surveillance testing begins for the campus on August 15. Currently, we are in a pilot phase.
Hi Concerned Grad Student, my name is Julia, I’m a reporter for the campus section of Daily Free Press. I’m writing an article about the University’s ventilation improvements and I’d love to hear your thoughts. You can contact me at firstname.lastname@example.org.
Good to see these actions, but another item that is not addressed is the need to allow students to be outdoors more then indoors. As the semester starts and incoming members of BU community are asked to isolate indoors – will that not increase the likelihood of spread? Why not implement some means to keep students outside of dorms and classrooms while the weather allows?
Thank you J Tahliani for your question. This article is about what we are doing to move more, and cleaner, air through University buildings. Tables and benches are available around campus to enjoy outdoor air when the weather allows.
Window fans seem like they will create more of a problem rather than help. What about the incident where an infected person sat in the airflow of the air conditioner at a restaurant and only those also sitting in the airflow got sick? Are we just going to blow the virus around the room instead of properly filtering it out?
Thank you for posting this inquiry Another Concerned Graduate Student. Window fans are recommended when only natural ventilation is available for the space. The window fan is used to draw fresh air in from the outside which is following CDC guidelines. It is believed the highest risk of transmission is by breathing in large droplets from an infected person when someone coughs or sneezes. This is the reason why BU is implementing a robust testing and contact tracing program and why face coverings are required when on campus, including when in classrooms.
Another Concerned Graduate Student, I read the same article regarding the air conditioner at the restaurant. The main thing in that scenario is that it was recirculated air. A window fan, especially a double which draws air out, and new air in could be very effective at both cooling the room and circulating the air as the CDC recommends.
Clean Air Delivery Rate (CADR) equal to 240 is recommended for a HEPA filtering device in a 20ftx20ft room, which–assuming an 8ft ceiling–means 3200 cubic-ft of space. (An 8 ft ceiling is a bad assumption for BU classrooms, but that’s what is used in these ratings.) CADR rating is for smoke, dust and allergens. Smoke is about the size of small viral droplets and allergens are the size of big viral droplets, and HEPA filters are thought to trap a high fraction of smoke, dust and allergens. (Maybe >99.9%.) CADR = 240 means the equivalent of adding 240 cubic feet of clean air each minute, or about 13min per turnover–or about 5 room turnovers per hour. What is the estimates for CADR in classrooms after these improvements? I have no idea what is proper, but I’d like to know that someone is thinking along these lines and can give some kind of thoughtful answer about what makes sense.
Thank you for your posting Professor Loechler. The white paper goes into more detail on the filters. We have upgraded filters from a MERV 8 to a MERV 13, which capture particles to .3 microns, not unlike the HEPA filters, and are often used in clinical settings. Additionally, we are surveying each classroom to ensure that they meet ASHRAE standards and CDC guidelines, which is between 4 and 7 effective air changes per hour.
Follow up on my last CADR-related question. The article states “new filters capable of capturing airborne viruses, including SARS-CoV-2” will go into 120 buildings, but does identify them specifically as HEPA filters. So, what kind of filters are they?
Thank you for your follow up question Professor Loechler. As mentioned in the previous comment, the University has upgraded from MERV 8 to MERV 13 filters capable of capturing .3 microns.
Second followup on my CADR-related question. The article does mention that 198 buildings cannot be approached via HVAC improvements, so free-standing HEPA filter units are being considered. How will this decision be made, as it seems like it needs to be soon–and the decision must be: YES.
Thank you, again, for follow up question Professor Loechler. Our teams are in the process of evaluating all buildings. To achieve the ASHRAE and CDC guidelines for effective air changes in the spaces without mechanical ventilation, we are reducing occupancy and density of spaces, ensuring fresh air circulation from open windows, and adding portable HEPA filter units in spaces like classrooms if they are determined to be needed.
Thank you to all the work being done in this area. I really hope that some of these steps, particularly the move the MERV-13 filters and regular maintenance of those filters continues in the post COVID age. Working in a building without operable windows, not great filtration, and few ACH has always been a concern.
Thank you Staff Member for your comment and concerns. The filters are on a regular changeout schedule and will be maintained to meet ASHRAE standards and CDC guidelines. If you have particular concerns about your workspace please contact CPO/EHS with your workspace particulars.
I had a long conversation with Mr. Thomas Daley (Associate VP for Facilities Management and Operations), and I came away being very impressed with the steps BU is taking. Mr. Daley also impressed me with being extremely knowledgeable, concerned and proactive. I feel the university is in good hands, for which I’m grateful. Unfortunately, HEPA filters cannot be used in HVAC systems, but MERV-13 filters are an immense improvement–and the best possible option. I came away with the impression that stand-alone HEPA filter units are a likely possibility for buildings with no HVAC system, though this has not yet been assessed.
It is misleading to say MERV 13 is equivalent to HEPA. HEPA removes at least 99.97% of particles with a diameter of 0.3 micron. It performs even better for particles bigger and smaller than this, so for larger droplets that might carry the virus, the filtration is even better than 99.97%.. MERV 13 rating means filtration of particles within 0.3-1micron range is worse than 75%, while in the 1-3micron range the filtration is guaranteed to be >90%. So they are different.
But my question is this: who performed the simulation of air flow in the classrooms, bathrooms, offices? Having a filter is not enough to guarantee every location in the enclosed space is safe, see recent research on safe and hot spots in a ventilated classroom depending on the location of ventilation unit with respect to instructor podium: https://arxiv.org/abs/2007.03645
Facilities Management engineers and contractors conducted surveys of each classroom as well as determined the operational and filter status of all building HVAC systems. All of those systems were capable of and were upgraded to MERV 13 filters as suggested in the CDC and State guidance. In some cases, we will be adding large volume portable air machines with HEPA filters to classrooms to further enhance air quality. The other important risk reduction strategies that must be remembered are the use of a face covering by everyone, de-densification, physical distancing, frequent hand washings, surface wipe down using disinfecting wipes by users, enhanced cleaning and disinfection conducted by Facilities Management, and the implementation of a robust testing and contact tracing program.
Let me start by thanking everyone who is working hard to make BU as safe as possible. It is clear that you are making big efforts and making impressive changes.
I am concerned about the fact that MERV 13 may not be as effective as HEPA filters. Is MERV 13 enough?
(assuming the information given by concerned researcher above is correct, I wonder whether we should be worried about particles in the 0.3-1 micron range, )
Does anyone remember CDC guideline that asymptomatic persons didn’t need to wear masks? We are still learning a new thing about the transmission every day. I think it is too early to think that these guidelines will be the same in fall. If they change, how fast can BU adapt? Also, is someone going to study whether there is a correlation between new cases and certain buildings or classrooms? Is there a back up plan if a certain building is found to be higher risk?
CDC and State guidance has been updated throughout BU’s response to this pandemic. BU departments have worked closely together during this time including; Campus Planning and Operations (CPO), Occupational Health, Student Health Services, and Environmental Health and Safety (EHS). We all monitor guidance and other resources regularly in order to have the best information available to ensure the university is appropriately prepared to resume operations. These offices have worked closely with all departments across the university to ensure we develop and implement appropriate risk mitigation strategies. With that, face coverings are mandatory. This is specifically addressed in the Back2BU guide. The guide is updated as new information or guidance becomes available. As part of this strategy, the university has planned for a robust testing and contact tracing program. Additionally, a team will review dashboard data to determine if there is an increase in cases on campus, including possible clusters. If certain groups, areas on campus, or buildings are identified as a possible source, a response plan will be initiated by the Healthway medical staff in coordination with CPO and EHS.
Facilities, are you considering use of any UV lighting in conjunction with the HVAC upgrades?
FMO and EHS have evaluated HEPA air purification and UV disinfection systems. Unlike HVAC system performance, filtration and ventilation, neither CDC nor ASHRAE have issued specific suggestions for the addition of UV or HEPA filtration to building-wide HVAC systems. FMO and EHS have evaluated the suitability of these systems on a building by building basis and continue to monitor and evaluate guidance issued by CDC and other recognized authorities.
The use of the building filtration systems upgraded to MERV 13, elimination of setbacks so that systems run 24/7, and in those cases where effective air changes require it, the addition of room HEPA filtration systems are effective at meeting CDC and ASHRAE guidelines. Given the efficacy of UV disinfection for COVID-19 is not certain, UV systems are not expected to be used widely on campus at this time.
For more information, please refer to the Campus Planning & Operations Return to Campus Advisory Services and Back2BU sites.
My Son is staying in the Warren towers where I’ve been informed there is no air-conditioning therefore no air circulation, how are we going to keep clean air in those buildings .. also I was thinking about the quarantine and the loneliness and the lack of self-care while keeping distance from others .. So there’s a great possibility that some students will be ill and no one will even know is there a system in place where there’s accountability and they check in every day or the floor monitor checks with them every day. what’s the plan for that?
Hello! For Student Village 2, whether Cooling and heating is accomplished through the use of a valance unit system which relies on circulation within the space being heated or cooled? Does the air ventilation system circulate inside our own suite only? Thank you so much!
Student Village 2 (33 Harry Agganis Way) is heated and cooled by individual in suite fan coil units. These units get their air directly from the outside through an air supply system, recirculate within each individual suite, and exhausts through the bathroom vent system. The individual fan coil units have been upgraded to MERV 13 filtration. The windows are not operable. Air is not shared between suites or hallways.
And what about the riverway grad dorm at Fenway Campus? The indoor ventilation system is almost non-existent, as far as I can tell.
The common areas (hallways etc.) are provided with makeup air, some of this air is transferred into the apartments and out the bathroom exhausts. The individual apartments are naturally ventilated, and heated and cooled by fan coil units.