Trying to use an Instapot for quick pressure cooker cleaning of SBPP masks

[SBPP = Spunbond polypropylene a form of non-woven polypropylene that isn't melt blown or permanently electrostatically charged]  

Two masks sewn for this experiment:

1. Eight layers of 80 GSM SBPP -  640 GSM total
2. Four layers of 150 GSM SBPP - 600 GSM total

Both were the RagMask Max design of "HITTING N95 GRADE FILTRATION". The source of the SBPP for the 80 GSM fabric the same. The 150 GSM fabric was just from ebay and cut off a longer roll by the seller - unknown brand.

With a Portacount 8020A, initial results are:

1. 8x80: Ave of eight counts - 94.8507% (max 96.0748%, min 93.9819%)
2. 4x150: Ave of eight counts - 89.6791% (max 91.3433%, min 6.5934%)

You can see the punched "ports" in the photo above. Here's the Portacount testing process via pandemic-pal Gerard Hughes - https://www.youtube.com/watch?v=NFJ_11mg-jQ - my machine is identical.

Both masks very breathable - I couldn't tell them apart in that regard - lungs empty to full in half a second.

At this stage it can be determined than the 150 GSM SBPP is not better than the 80 GSM fabric. If you added one more layer it still might not be. My prior thinking was that the denser SBPP might be better filtration than the 80 GSM stuff I've been using for just under a year now. Take a look at projections for filtration versus overall GSM: 

For this graph, the filtration effectiveness above 640 GSM are just predictions based on past performance and the layering formula. You could not sew a mask with that much fabric, anyway.

The Experiment - cleaning using an Instapot

Masks in face cloth, on trivet with 1 cup of water. Instapot on pressure cooker function with 2 mins at target temp, then the pressure let to subside to where the lid can be removed without venting.  Target temp is 116-117°C (239 to 243°F) at sea level and the Instapot manages that itself. Just before start:

When the temp has dropped, the masks can be removed. They are very nearly dry. Ten mins after hanging them indoors they are dry.

Test results via Portacount 8020A again:

1. 8x80: Ave of five counts - 85.9186%
2. 4x150: Ave of three counts - 73.4932%

Conclusion

Experiment proves that the two alternate SBPP material lose filterability through this process after a sincle cleaning.  

Next experiment: See whether 10 cleaning is about double the loss of 1 cleaning, and 100 cleanings would be 3x the loss.