Testing Our Face Masks

When we started making our face masks in March, little was known about Covid-19 and the benefits of fabric face masks in non-medical settings – there has been much controversy surrounding whether these should be introduced in public settings. For us, this conversation included research into which construction and materials would be best and how much protection would a well-made fabric mask offer.

We have been developing bespoke fabrics for 26 years and we used this experience plus all the information we found on the internet to come up with our mask designs. We knew that they were well made, but we wanted to be able to measure their benefit in comparison to the disposable surgical masks.

Appropriate tests are done by a few specialist facilities and we sent our masks to be tested by Nelson Labs in Salt Lake City, USA, a leading global provider of laboratory testing and expert advisory services for MedTech and pharmaceutical companies. We waited five weeks, and on the 27th of May, we at last got the results of our tests and we are delighted to share them.

PDF of official test results from Nelson Labs here

To assist you to understand these results, here are a few links with further information:

What did we test: The filtration efficiencies of our masks as a function of stopping aerosol particles from penetrating the mask. This test method has been specifically designed for measuring bacterial filtration efficiency of medical face masks.

How did we test it: Our tests were performed to ASTM F2101 – 19 and BS EN 14683:2019 standard, which specifies the construction, design, performance requirements and test methods for medical face masks intended to limit the transmission of infective agents from staff to patients during surgical procedures and other medical settings with similar requirements.

The testing was performed with the inside of the medical face mask being in contact with the bacterial challenge. With the aerosol challenge directed through either the face side or liner side of the test specimen, thereby, allowing evaluation of filtration efficiencies which relate to both patient-generated aerosols and wearer-generated aerosols.

This is a high-level medical test. 5 masks were compared, so that an average result could be achieved, and the testing could ensure consistency of performance of all our masks.

What are the results: The results indicate that our masks are 77% effective, which is at the top end of the fabric face masks performance, surgical masks start at 70%, and N95 masks offering 95% - 99% protection.

About the fit: One of the reasons that fabric face masks cannot offer the same high level of protection as full medical masks, is the level of fit. We have designed our masks ensuring that they are comfortable to wear in a working environment. They are not meant as medical devices or to be worn in high-risk environments, but we believe they are of benefit in managing the risk of infection in spa or hospitality settings. The tests suggest that they will offer a good level of protection and assist to protect both staff and guests. Cloth masks offer additional sustainability benefits through re-use, thus limiting costs and reducing environmental waste.

Our fabric face masks are made of high-quality fabric and are guaranteed for a minimum of 30 washes. They consist of three layers of fabric, one being a non-woven layer of interlining for filtration.

Here are some recent medical publications about the studies on fabric face masks and their construction. These also indicate why our mixed fibre fabrics seem to yield the best result:

Aerosol Filtration Efficiency of Common Fabrics Used in Respiratory Cloth Masks

Face Masks Against COVID-19: An Evidence Review