Covid-19 Mask Guidelines

What are the current US and UK guidelines for protective masks?

The Centers for Disease Control and Prevention (CDC) in the USA have had to relax their guidelines to healthcare organisations to optimize the supply of facemasks. This includes a mention of ‘homemade masks’ as a last resort in Covid-19 in settings where facemasks are not available.

April 4 – see my post about CDC guidance on public mask wearing.

The UK NHS Supply Chain web site now (March 20) allows more prolonged use of the most protective PPE masks, acknowledging (though not explicitly) that they may become scarce: If you are working in Intensive care/High dependency where several symptomatic patients are cohorted, the FFP3 masks can be used continually, provided the seal remains intact for at least an hour.

Public Health England in the UK updated their guidance on March 27, 2020 to allow for more extended single use of FFP3 (equivalent to N95) facemasks: “A FFP3 respirator, although ‘single use’, can be worn for as long as comfortable, for example for the duration of a ward round or providing clinical care.”

Masks are used widely by the public in Asian countries and compulsory in some situations in China, yet recent advice in Western countries has played down the importance of mask use and instead rightly emphasised social distancing and hand washing. This has been partly led by the need to reserve PPE facemasks for healthcare workers and discourage stockpiling of all mask types by the public.

UK news stories

Shortages have already been reported in the Financial Times on March 19
This includes reference to Sir Simon Stevens, head of NHS England: “Sir Simon made clear, however, that further supplies would be needed to cope with an outbreak that would last months. In order to meet it, domestic production of the essential items would have to ramp up, he warned MPs.

Worldwide news stories including links to designs and materials

Parts of the US have found themselves poorly prepared and some doctors in the US are facing urgent shortages today and are begging for homemade cloth masks.

A clothing company in California called Hedley and Bennett are now producing their cotton ‘Wake up and Fight mask’ and cotton gowns in their 16,000 sq. ft factory in Los Angeles.

New York Governor Andrew Cuomo has accepted offers from fashion designers to make masks for New York hospitals.

Canadian Healthcare company Providence recently began asking volunteers to make them cloth facemasks. Within days local manufacturing companies stepped up to rapidly produce masks and face shields for them on a large scale.


In Washington State volunteers and small fabric companies are providing masks and gowns to hospitals, using a design and layers of woven and non-woven materials (similar to those used in surgical masks) chosen by Cindi Rang of, who is an ex health professional. Her videos are the most useful that I have seen so far and our prototype (next page) is almost identical. She issues a clear disclaimer that her mask offers no guarantee of protection comparable to established tested products.

Covid-19 Mask Prototype Instructions

Types of masks for Covid-19

Return to Covid-19 mask proposal