General fabric masks with breathing valves and fabric neck buffs
Fabric face masks for general public use with valves or vents permit air to be exhaled through an opening in the material, which can result in expelled respiratory droplets that can reach others – potentially enabling the spread of Covid-19.
General public fabric face masks with breathing valves/vents does not have the necessary barrier efficiency required.
It is therefore NOT recommended for the general public to use fabric face masks with breathing valves or vents. These breathing vent/valve masks defeat the purpose and it is recommended that these types of masks not be worn or sold in the Republic of South
Africa.
Fabric neck buffs, are generally a tube of fabric worn around the neck, are made of thin, stretchy material and offer little to no prevention for respiratory droplets from being expelled by the wearer
and reaching others. It is NOT recommended that these neck buffs be worn as a preventative mechanism against the Covid-19 pandemic.
Fabric Selection for Masks
Tests have shown that at least two layers of fabric is sufficient for balancing performance and comfort. An increase in the number of layers will improve the barrier efficiency, but have the opposite effect on breathability.
Using three layers, selecting a non-woven fabric with strong filtering capability as the middle layer is recommended.
Ideally this middle layer should be inserted into the mask (or removed) via an envelope style design to allow for improved cleaning and easy replacement filters when worn out.
It is recommended that the pocket into which it fits be at least 120mm by 100mm to ensure compatibility between multiple masks and filters in production domestically. Clear markings or design options must be used to distinguish between the outside of the mask and the inside of the mask.