The Health Ministry yesterday published guidelines issued by the Sri Lanka Standards Institution (SLSI) on non-medical reusable cloth face masks, with specific requirements for the design, materials, storage, performance, and testing methods.

According to the document consisting of the guidelines, the standard was approved by a special committee appointed for non-medical reusable cloth face masks and was authorised for adoption and publication as a Sri Lanka standard by the Council of the Sri Lanka Standards Institution on 22 July.

In terms of design, the face mask must fit closely over the nose, mouth, and chin of the wearer, even when typical head movements occur. According to the guidelines, the mask must ideally cover 50% of the length of the nose and extend 25 mm under the chin.

While the face mask should be made up of at least two layers of cloth, it must not have any decorative elements or embellishments that would interfere with the functions of the mask. “The cloth face mask should not incorporate any exhalation and/or inhalation valve(s),” the guidelines specify.

While several specifications were included about the material to be used, the SLSI specified that the material used must be able to withstand handling, washing and drying throughout the usable life of the cloth face mask. The innermost layer should have hydrophilic properties to give sufficient comfort to the wearer and the outermost layer should have hydrophobic properties which may limit external contamination of droplets from penetration through to the wearer’s nose and mouth.

“The cloth face mask is expected to act as a physical barrier to droplets typically more than five microns in size produced during talking, sneezing or coughing,” the performance requirements specify, adding that the cloth face masks should not cause difficulty in normal breathing.

The guidelines also include requirements on bacterial filtration efficiency (BEF) and differential pressure.

In terms of packaging, the SLSI specifies that the material should be sufficiently robust and of suitable waterproof material to withstand transportation, handling, and storage. “The packaging material shall be in accordance with regulations promulgated in terms of the National Environmental Act. 47 of 1980, as amended,” the guidelines state.

The guidelines also included marking specifications for both the master pack as well as the retail pack.

The document contained a warning that the “Use of the cloth face mask does not limit the spread of certain respiratory diseases unless other important protective measures such as physical distancing, proper hand hygiene, respiratory etiquette and disinfection of frequently touched surfaces are not adhered to”.

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