It has recently come to our attention that 5 samples for Bacterial Filtration Efficiency (BFE), Differential Pressure (Delta P), and Particle Filtration Efficiency (PFE) may no longer be adequate for FDA submissions. In the past, many manufacturers tested a minimum of 5 samples for Delta P, BFE, and PFE and historically this amount has been successful in getting submissions approved through FDA. But with recent information we have received from FDA and multiple sponsors, is it clear that FDA is enforcing requirements for sampling as stated in the ASTM F 2100 standard as listed below:

           
7. Sampling

7.1 Testing shall be performed on materials taken from manufactured face masks.

7.2 An acceptable quality limit of 4% shall be used for all required testing to establish conformance of medical face masks to a specific performance class.

7.3 Examples of acceptable sampling plans are found in ANSI/ASQC Z1.4 and ISO2859-1.

   
 8. Number of Tests

8.1 A sufficient number of medical face mask shall be evaluated for each test to achieve the established acceptable quality limit or confidence level.

Beyond the ASTM F2100 specification, FDA has also been asking manufactures to test up to three non-consecutive lots to demonstrate lot-to-lot performance or justify why this was not performed. For FDA submissions, we recommend you take the most conservative route to prevent any delays in your submission. The table below is our current recommendation based on recent trends:

Five samples may be sufficient for periodic R&D or verification testing but is not recommended for FDA submission.