I had to setup a first responder today with handful of n95 and a 30% h2o2 vapor sterilization kit for reuse with protocols because they have nothing being provided by their department. He has a wife and baby at home and is living separately because he was unable to protect himself much less his family. With proper sterilization knowledge one mask can be used 50-80 times. All first responders need access to this ability. Give a first responder a mask and he will protect himself for a day. Give a first responder a mask and teach him to properly sterilize it and he can protect himself and others during the entire outbreak.
So I’m not a scientist and this is not a suggestion or recommendation. My question is would it be possible that a store bought pressure cooker could potentially be used to sterilize N95 masks similar to what you describe Supa. Questions to be determined would be does the mesh/fabric deform with stream and the mask stay usable, should water or some other liquid like H2O2 be used (and specifically the safety of using H2O2 in a retail pressure cooker), times and pressures needed to be effective on a virus verses bacteria and fungus, safety.
For comparison this study shows that retail pressure cookers can be used as effectively as an autoclave.
“All four pressure cookers tested were able to inactivate the microbes present in all of the trials except for the inactivation of G. stearothermophilus spores, in which only the Instant Pot was able to produce steam, pressure, and heat to the level necessary to achieve sterilizing conditions.”
https://journals.plos.org/plosone/ar...l.pone.0208769
“ Assessment and verification of commercially available pressure cookers for laboratory sterilization”
The first study looked at sterilization of liquids and metals.
this older one looked at syringes but with stove top pressure cookers
Christensen EA, Skadhauge K, Ravn-Jonsen A. Autoclaving of syringes in pressure cookers. Acta Pathol Microbiol Scand. 1963;58(521–527).
Here is a 3M material sheet on the material used to construct a 3M N95 mask
https://multimedia.3m.com/mws/media...pirator-8210-n95-technical-specifications.pdf
• Straps – Thermoplastic Elastomer
• Nose Clip – Aluminum
• Nose foam - Polyurethane
• Filter – Polypropylene
• Shell – Polyester
• Coverweb - Polyester
• This respirator contains no components
made from natural rubber latex
• Approximate weight of product: 0.35 oz.
and interesting enough it says that it can also be used for liquid mists
Use For
• Use for solid particulates and liquid mists in concentrations not exceeding 10X PEL/OEL
This plastic industrial spec sheet seems to show that polypropylene can achieve good sterilization in an autoclave. It seems to note that polyurethane (nose foam) and polyester (covering) don’t do as well.
https://www.industrialspec.com/resources/plastics-sterilization-compatibility/
and this notes that polyurethane (the nose foam again) is not compatible with autoclaves
https://ehs.princeton.edu/book/export/html/380
Compatible/Incompatible Materials
[TABLE="border: 0, cellpadding: 0, cellspacing: 0"]
[TR]
[/TR]
[TR]
[TD]
- Tissue Culture Flasks
- Surgical Instruments
- Glassware
- Pipette tips
- Media Solutions
- Animal food and bedding
- Waste
- Polypropylene (Secondary containers)
- Stainless steel
- Gloves
[/TD]
[TD]
- Acids, bases and organic solvent
- Chlorides, sulphates
- Seawater
- Chlorine, hypochlorite, bleach
- Non-stainless steel
- Polystyrene(PS)
- Polyethylene(PE)
- Low density (LDPE) and High
[/TD]
[/TR]
[/TABLE]
So maybe the nose piece and covering and elastic straps would be an issue.
finally the 3M technical bulletin on disinfecting disposable N95 masks
https://multimedia.3m.com/mws/media...disposable-respirators-technical-bulletin.pdf