August 13 2020
Back to School: Post-Secondary Buildings in a Post-COVID World
Following a near instantaneous exodus from campuses in March as a result of the COVID-19 pandemic, post-secondary institutions are now trying to understand what their physical infrastructure will look like at the start of the next school year, and what role these buildings will play in an evolved academic experience.
Most institutions quickly adapted to remote learning with innovative online lectures and tutorials, however, in-person experiences are a crucial component of any academic program, ranging from labs, to extra-curricular activities, and studios.
The government of Canada has released guidelines that are intended to help mitigate the risk of transmission on campus. These include physical distancing measures, such as spacing students 2m apart while in lecture, moving classes and exams online to limit the number of students on campus, and offering activities outdoors where the weather permits. There are also administrative measures, such as staggering when classes start and stop, staggering when groups of students are each on campus, and cohorting or using smaller groups of students. However, it must be acknowledged that no single approach will fit every institution, as these institutions are incredibly complex and diverse in their physical infrastructure, their student and faculty demographics, and the activities they are engaged in (teaching, research, student housing, etc.).
As we’ve seen with other types of buildings, such as and cultural, many of the mitigation measures alter how or where occupants move through a space to limit transmission. Here, we can use pedestrian modelling to test the effectiveness of these mitigation measures, compare different strategies, and determine what, if any, knock-on effects the mitigation measures may have on occupant comfort or safety.
To demonstrate this, we’ve applied pedestrian modelling to an institutional project for which we are currently providing structural engineering services. During the design stage, mass timber was considered by the team and part of the alternative solution was to look at improving the egress strategy. An evacuation model was used to quantify the effectiveness of this improved egress design, which was then extrapolated to test pandemic mitigation measures.
First, the floor plan was assessed to determine the capacity of each space. This was done using the current recommendation of 2m of physical distance. However, this may evolve in the future and should be based on the latest recommendations from the local health agency.
The image shows that in-person capacity is drastically reduced with the current 2m recommendation. What used to be 16-seat classrooms now have room for seven, including the instructor.
While this static analysis can determine the safe capacity of a given building, it does not address the transient aspect, which is how occupants move within the building. We know, for example, that before and after classes, hallways and stairs see their greatest demand and maintaining physical distance can be challenging. For this reason, we leverage dynamic modelling to understand movement patterns during these peak periods.
The building was analyzed in its current configuration to determine which areas saw the greatest crowding during these transient periods before and after classes. It was found that queues were created near the stairs. The image below shows for how long students were within 2m of each other while transitioning to their next class, with areas in red being 2 minutes or more.
To mitigate the red zones, the stairs could be used one-way only, with the feature stairs being used to ascend and the emergency stairs in concrete cores being used for descending. The benefit of this approach is that during a fire scenario, the stair direction does not change and will be familiar to occupants.
After introducing one-way stairs, it was found that crowding at the base of feature stairs still occurred. The next mitigation measure added was to stagger classes. In the model, classrooms were grouped and staggered 2.5 minutes apart both for students leaving class, and new students arriving from the floor above. This is illustrative only; a more realistic stagger would be 15 or 30 minutes to create a more manageable schedule, assuming staggering is permitted in the first place. In the video clips below, occupants that are within close proximity to one another turn are indicated by turning red. It can be seen that the one-way stairs combined with staggered classes effectively mitigated the duration that students and faculty spend in close proximity to each other, and the number of interactions they have with others as they move within the building.
In addition to the animations, the effectiveness of mitigation measures can be quantified by determining for how long occupants were within close proximity. The images below show that as each mitigation measure was added, the crowding that was observed at the base of the stair was minimized. This can be repeated throughout the building for any challenges areas observed, and for any combination of mitigation measures.
The analysis above has demonstrated that this tool can help to quantify mitigation measures used in post-secondary buildings and across campuses as students and faculty start to return, and should be leveraged among other tools and disciplines to ensure holistic strategies are developed. Pedestrian modelling can be used not only to inform decision making but can also demonstrate to stakeholders that appropriate steps are being taken to mitigate risks.
Matthew Smith is an Associate, Fire & Structural at Entuitive. To discuss this article, fire engineering or pedestrian modelling, reach out to him here.