NIST tool could help hospital efforts in disinfecting N95 masks

National Institute of Standards and Technology (NIST) researchers said they have developed a tool designed to aid hospitals and medical professionals in disinfecting N95 masks.

In the wake of hospitals nationwide disinfecting N95 masks by placing them in repurposed rooms or shipping containers injected with a disinfectant known as vaporized hydrogen peroxide, or VHP, the NIST maintains it has developed a method estimating the amount of VHP masks would receive and suggests larger rooms containing fewer objects, with less-reactive surfaces and slower ventilation, maintain VHP concentration best.

“Hospitals have used VHP systems to disinfect isolation rooms after a highly infectious person has left,” Andrew Persily, chief of NIST’s Energy and Environment Division, said. “Now, there are efforts underway to do the same to disinfect masks.”

The NIST spreadsheet models where VHP settles after being injected into a room. By entering important parameters related to a room’s size, materials, and ventilation into the spreadsheet, users receive estimates of how much VHP would deposit onto the masks versus being lost through leaks or absorbed by surfaces.

“Even if you’re hitting a room with a huge dose of VHP and you’re assuming it’s all going on your masks, a lot of it may be going on your walls or ceiling,” said Dustin Poppendieck, a NIST environmental engineer and the developer of the new tool. “Then you might not be disinfecting as effectively as you think. It should be a unified approach if you’re going to do this, and this tool is just one small piece of the puzzle to figure out how to appropriately disinfect masks using VHP.”