Minnesota teachers will report to school this week to attend training sessions, finalize lesson plans and complete another assignment: testing out school buildings that have been retrofitted and reimagined to operate in a pandemic.

In many schools, old drinking fountains and sinks have been swapped out for "touchless" fixtures. Signs pasted to the floor indicate where students should stand while they wait in line to visit the restroom or the main office. Hallways are divided so foot traffic runs in a single direction and classrooms are sparsely furnished, with desks spaced 6 feet apart. In some cases, large rooms like libraries and cafeterias have been transformed into classroom space.

Concerns about COVID-19 spreading through poorly ventilated buildings have prompted some school districts to install new air filters or haul portable air purifiers into classrooms. Carlton Schools Superintendent John Engstrom said he's awaiting delivery of about 40 air purifiers for his district south of Duluth. Especially for schools with older buildings and limited resources, figuring out how to keep the virus at bay is a major logistical challenge.

"It weighs on you heavily because all the things we would normally be doing in the summer, in terms of back-to-school planning, typical instructional and professional development, it's not happening," Engstrom said. "It's all about how can we physically manage the space."

Under orders from Gov. Tim Walz, all schools reopening this fall will have to take some of the same precautions, like mandatory mask policies, vigorous cleaning routines and making room for physical distancing inside school facilities.

But because schools have some flexibility in how — and if — they bring students back in person, and wide variation in the age, design and condition of their buildings, the changes made inside one school may differ from others.

Bruce Bomier, board chairman of the Environmental Resource Council, an Andover-based nonprofit that advises schools on environmental health, said many school leaders are facing the biggest decisions of their careers as they contemplate whether to bring students and teachers back and try to keep them safe. He said the focus should be on three different areas: the local spread of the virus, designing and enforcing good personal hygiene policies and practices, and on the health considerations of school buildings themselves.

"We're going to see variations in how they approach this," he said, "but we should be beginning to understand the rhythms and protocols that will actually protect the students and safeguard the educators and safeguard the community."

The state has begun shipping out masks and face shields for teachers and students, but individual schools and districts have been largely on their own as they've scrambled to track down cleaning supplies or contemplated updating their ventilation systems.

Bomier said airflow considerations are a big challenge for many Minnesota schools because of their design.

The small number of districts still using buildings constructed before World War II may actually have some advantages with airflow, because most have plenty of windows — and windows that open. But starting in the middle of the 20th century, Bomier said, schools around the country were purposely built to be more airtight, with fewer windows and materials that allow for movement of fresh air. Those that have been remodeled multiple times are sometimes a particular challenge, with mismatched ventilation systems, building materials that don't lend themselves to good air circulation and windows that don't open.

Guidelines from the Minnesota Department of Health suggest that schools "ensure ventilation systems operate properly and increase circulation of outdoor air as much as possible, for example by opening windows and doors."

Bomier said districts that have remodeled or built new schools with air flow in mind are in better shape for the pandemic.

"Where the districts have invested in responsible air exchange, and taken into consideration [building] occupancy, it's less of a challenge," he said.

Rethinking school spaces

In the Anoka-Hennepin district, the state's largest, teachers have raised concerns about safety plans and procedures as they prepare to return for hybrid instruction. Superintendent David Law said the district hasn't encountered any major challenges with building design or ventilation but will be using some buildings differently.

"We don't typically use our cafeteria as classroom space, but if the priority is to bring kids into the building in the hybrid model or full in-person model, we're going to need to rethink how to do this safely," he said.

In the Roseville district, spokesman Josh Collins said school leaders are still sorting out how to avoid students clustering together and potentially spreading the virus more easily. The goal is to avoid outbreaks that have happened soon after schools reopened in other parts of the country — or problematic scenes of students in packed hallways like those, including one from suburban Atlanta, that have gone viral online.

"We are looking at things like traffic patterns," Collins said. "How do you keep teenagers who maybe have backpacks, or elementary students with snow pants, how do you keep them moving in a way that doesn't all look like that photo from Georgia?"

Friendship Academy of the Arts, a Minneapolis charter school, had just started construction on its new intermediate campus when the pandemic erupted this spring. As a result, school leaders had an unusual opportunity to set up everything in the school with health concerns in mind. The building, which was once home to a millwork company, was redesigned with touchless fixtures and bathrooms without doors, much like those in an airport. The school held off on installing playground equipment, opting for open green space that could be used both for recess and class time.

B. Charvez Russell, the school's executive director, said setting up a school to operate this year has meant thinking differently about just about everything, from how classes could move outdoors to how to set up classrooms so teachers can instruct students in person and those online at home at the same time.

"In the new building, we wanted to give them more flexibility," he said.

Erin Golden • 612-673-4790