Mask design advice

This page contains our advice on what makes a good reusable fabric mask that can be made by anyone with a sewing machine and easily found materials.

DISCLAIMER This is my own interpretation of the evidence. Do your own research and make your own decisions. The science is new and none of the reusable masks mentioned later have been subject to standard rigorous testing or been approved for medical use in any country. There has not been time due to the nature of the pandemic.

Disposable masks come is two basic shapes – a pleated rectangle and a shaped cone.

Standard surgical mask is a pleated rectangle
N95 respirator is a cone shape

The shaped cone can be permanently shaped or foldable.

Foldable cone – front view
Foldable cone – side view

Reusable fabric masks can be made using either the pleated rectangle or the foldable cone shape.

Cloth pleated mask
Cloth cone shape mask

The pleated rectangle can block droplets from coughs and sneezes or talking and was developed to protect the surgical operating field from the germs of surgeons and theatre nurses. They are also sometimes given to patients with respiratory illness to protect others from their germs. They do offer protection the other way (protect wearer from others) but potentially less so than a well-fitted cone-shaped mask, as leaks around the sides are inevitable.

The cone-shape is preferred for protective masks used in high-risk medical situations. They generally have more layers built into them and can be fitted close to the face reducing leaks to a minimum. Mask fit testing is a professional skill and can take a lot of time and effort to perfect. A poor-fitting mask is not protective. It should also be noted that valved cone-shaped masks protect only the wearer from others. The valve allows expired air out unfiltered so there is no protection of others from the mask wearer.

Designs and patterns for pleated masks – This company make various versions of a simple pleated rectangle mask using non-woven polypropylene shopping bag material.
Their ‘Surge’ variant is our preferred version as it is 3 layered, although we think that at least the inner layer should be something softer and more comfortable e.g. cotton:

Providence Healthcare in USA have sourced masks from volunteers followed by local clothing companies.

Designs and patterns for cone shaped masks

Hedley and Bennett – A clothing company in California called Hedley and Bennett are now producing their cotton ‘Wake up and Fight mask’ and cotton gowns in their factory in Los Angeles. Their mask is a good close-fitting protective design and incorporates a pocket for a filter.

Cindy Raine (ex nurse) – Cindy Raine of the Fabric Patch, Washington State has 3 videos showing her making her close-fitting protective style mask using cotton outer layers and a non-woven material stitched in place between them. She uses interfacing but discusses other moisture-resistant non-wovens like shopping bag material.

University of Florida Mask
This is an most exciting development but unfortunately is not washable, requiring an autoclave for reuse. American anaesthesiologists have come up with two designs (one pleated and one cone-shaped), both made of a non-woven polypropylene produced by medical suppliers worldwide. Follow the links to their instructions and I advise reading the FAQ, the ‘Dos and Don’ts’ and the ‘Tips and Tricks’. These masks are not washable because the fabric degrades but they are autoclavable (30mins at 165 deg F / 74 deg C).

cone type

pleated type

This video by a US doctor describes making and fit testing the University of Florida mask. Only the cone-shape design passed fit testing.

See also our own prototype design for a cose-fitting cone shape