There have been many requests for patterns for DIY face masks and other personal protection equipment.
The CDC has reported the following: (https://www.cdc.gov/coronavirus/2019-ncov/hcp/ppe-strategy/face-masks.html)
Healthcare Personnel use of homemade masks:
In settings where facemasks are not available, Healthcare pesonnel (HCP) might use homemade masks (e.g., bandana, scarf) for care of patients with COVID-19 as a last resort. However, homemade masks are not considered personal protection equipment (PPE), since their capability to protect HCP is unknown. Caution should be exercised when considering this option. Homemade masks should ideally be used in combination with a face shield that covers the entire front (that extends to the chin or below) and sides of the face.
Here is a collection of patterns that crafters and healthcare organizations have put on the Internet. There is no recommended version with evidence support; nevertheless, here is what has been offered. If you have any suggestions, please send them to asmlibrary@natividad.com and I will post them on this website.
Thank you and remember: wash your hand and practice social distancing.
UPDATE: The Joint Commission just released a Statement on Use of Face Masks Brought From Home. 
Joint Commission public_statement_on_masks_from_home.pdf
