KNBA - KBC

New mobile prototype kills virus with heat to extend the life of critical gear

Apr 29, 2020

Mike Brubaker showing the wooden racks set up inside a modified trailer for sterilizing PPE (Zachariah Hughes, Alaska Public Media)

As Will Frasier opens the white metal door to a mobile trailer sitting in the corner of a parking lot, he offers some cautionary advice.

“It’s about 170 degrees in there, so you will sweat. Don’t touch anything metal, because 170 degree metal will burn you,” he said, his face covered with a mask.

Frasier is a mechanical engineer at the Alaska Native Tribal Health Consortium. He helped build a new apparatus called the “mobile PPE sanitizing unit,” or “MOPS,” for short (PPE is personal protective equipment used in medical care). ANTHC is experimenting with a new system to extend the life of N95 respirator masks. They’re cooking the virus out of the equipment, and hope to eventually build a model that is easy to replicate across the state.

The trailer is a commercial model, the kind you might hitch to a truck for hauling a snowmachine. But Frasier and others at ANTHC have reconfigured it to apply a high, even heat across wooden racks lining the walls.

“We’ve got three heaters,” Frasier said, pointing metal units poking out of the wall, stones piled over the electric heating element to provide more consistent thermal output. Hot air dumped into the room is circulated by four loud fans that roll it through the space, from top to bottom.

The heat is tolerable for a couple minutes, but not much longer.

“Long story short, it’s a really fancy sauna,” Frasier said.

Though the mechanics are a lot more complicated than that, the basic principal is the same: get an enclosed space up to around 170 degrees for an hour in order to “deactivate” any coronavirus particles that might be on the PPE. That way, healthcare workers can use the same protective masks more than once to preserve supplies.

Frasier’s team scrambled to build the MOPS unit in about a week. Doctor Holly Alfrey, ANTHC’s Chief Medical Officer, said part of the rush was in order to proactively plan for a potential spike in demand for PPE, whether that comes from a jump in hospitalizations, more people wearing masks in public, or more widespread testing.

“We realized that we might be facing a shortage of personal protective equipment,” Alfrey said. “And even though we haven’t gotten there yet–we still have an adequate supply–the one thing that we thought that we might really be running short of faster was masks.”

Alfrey says the MOPS unit, while hardly a silver bullet for critical medical care, is another tool for keeping frontline medical workers safe in the pandemic.

According to Mike Brubaker, who directs community environment and health at ANTHC, the MOPS unit can potentially sanitize thousands of masks a day.

“We want to have surge capacity in case the outbreak really takes off here in Anchorage or anywhere else in the state,” Brubaker said.

The system has limits. The masks can go through the heat treatment about three times before they start to break down. Other PPE made from rubber and plastics, like gloves, can’t withstand the temperatures necessary to deactivate viral particles. They melt.

There are other methods being tried by hospitals elsewhere to extend the life of PPE, including ultraviolet light and aerosolized hydrogen peroxide. But according to Brubaker, ANTHC is interested in models that could more easily be set up, replicated, and potentially sent out to other communities in Alaska.

“For us, the decision really came down to what kinds of materials, and what kind of capacity do we have in state to do this. And ideally, something we could even expand if we needed to. It could scale up, or scale out to communities,” Brubaker said.

This first prototype cost about $60,000 to build, although a big factor in that was how quickly the engineers and scientists bought and assembled all the parts from local venders. According to Brubaker, ANTHC is exploring how to make smaller, more portable designs for rural communities.