Since the recent CBC marketplace report we have been getting a lot of questions about thread count of fabrics.
While the CBC Marketplace report tested filtration they failed to actually test breathability. Many months earlier in the pandemic I reached out to sheet manufacturers to find high thread count fabric. To my surprised after testing I learned all of it was unsuitable for masks due to poor breathability.
The fabric is so dense in the 600 TPI masks the air simply flows unfiltered around the gaps in the fit. When the mask is perfectly fitted it is not possible to breath.
Recently some research has come out to support this too!
A single layer of 625 tpi cotton, in this case having a pressure drop of 335 Pa (34.1 mm H2O) based on the impedance measurements given in Table 1, would not meet the minimum breathability criteria of N95 respirators
Because of this we do not plan to carry 600 TPI fabric.
So what thread counts are our fabrics?
Kona Cotton: 120 TPI
Most quilting cottons (prints and solids): 120-180 TPI
Elite Japanese Solids: 160 TPI
Robert Kaufman Brand Poplin: 200 TPI
Most Cotton Poplins: 200-220 TPI
Cotton Lawn: 200 - 260 TPI
Cotton lawn is very light weight despite the high thread count, this is because threads are very fine giving it a silky feel. Makes excellent lining and still breathable.
I also carry a small selection of higher thread count sheetings in the 200-300 range.