Authors S Darby, A Giltinan, N Smith and RD Sleator are members of the National Standards Authority of Ireland (NSAI) expert advisory group on face coverings contributing to SWiFT 19 and CWA 17553. S Darby is also a member of CEN/TC248/WG38 on face coverings. This work was funded by Science Foundation Ireland under the SFI COVID-19 Rapid Response Funding Call (proposal ID 20/COV/0253). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.