A gym trainer exposed 50 athletes to Covid-19, but no one else got sick because of a ventilation redesign

The new gym layout at 460 Fitness in Blacksburg, Virginia.

(CNN)A Virginia gym owner thought she had a nightmare scenario on her hands when she learned that 50 athletes were potentially exposed to Covid-19 particles by one of the gym's coaches. But not a single member ended up contracting the virus, thanks to the extra safety precautions and ventilation measures she put in place.

Velvet Minnick, 44, is the owner and head coach at 460 Fitness in Blacksburg, Virginia. Like many gym owners across the nation, she was forced to shut down the facility in March due to coronavirus. They rented out equipment and held Zoom classes, but it wasn't long before members were burned out.
As the state entered Phase 2 of reopening in June, Minnick was allowed to have athletes back inside her facility. She knew one member, however, who could help her get people back while keeping them safe.
    Linsey Marr, 46, is a professor of civil and environmental engineering at Virginia Tech and joined 460 Fitness about two years ago. She has an expertise in airborne transmission of viruses, air quality and nanotechnology.
    When gyms closed in March, there was a lot of talk in the CrossFit community about the mental health benefits of working out and some owners were lobbying for their gyms to stay open. While that didn't work, it did get them included in the early phases of reopening. And it kick-started this gym's reopening plan and safety procedures.
    Minnick consulted Marr on ventilation as well as strict hygiene and distancing protocols to keep athletes as safe as possible while they were working out.
    "I knew the virus was transmitted mainly through the air so I thought it was really important to have good ventilation so everyone wasn't able to breathe it," Marr told CNN.
    Minnick created athlete stations near the bay doors that gave each one 10 feet of space. The stations are marked on the floor with orange tape and have all of the necessary equipment located inside. There's no traveling about the gym or doing partner workouts while sharing equipment.
    The gym's new layout allows for proper airflow.
    "Ten feet of space has always been my mantra," Marr said, which is more than the recommended six feet because people in the gym would be working out and breathing heavily.
    Because Minnick built the facility, she had the engineering and HVAC documents to share with Marr.
    "I did the calculations on how big the space was, what the typical wind speeds were in the area and if the doors were open what would the resulting ventilation be?" Marr said.
    She found that the space provided far more fresh air than required by the professional organization, American Society of Heating, Refrigerating and Air-Conditioning Engineers, which gives recommendations for ventilation. Looking at other research and studies, Marr talked with experts on what ventilation rate is necessary to really cut down the risk of transmission indoors.
    "We don't see outbreaks above a certain threshold," Marr said. "And the gym with the open doors was way above that."
    The gym uses this carbon dioxide detector.
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