Surgical masks are designed to be used by doctors and other healthcare workers. They are generally used in an operating room and other non-toxic environments.
Their primary purpose is to prevent germs and other harmful contaminants from the mouth of the wearer to the patient. These masks are not designed to filter out dangerous viruses like the COVID-19.
They are not efficient in filtering out such small viruses. The different key aspects of surgical masks are discussed below:
How are Surgical Masks Made
Surgical masks are made from non-woven fabric.
This fabric has improved bacteria filtration and air permeability properties. They are also less slippery compared to woven cloth. Surgical masks are generally made from polypropylene that has a density of 20-25 GSM.
In most cases, 20 GMS masks are made using a spun bound process. The 25 GMS masks are made using meltdown technology.
These masks have two filter layers that can filter bacteria above 1 micron. The filtration efficiency of surgical masks depends on the fiber used and its cross-sectional shape.
Surgical Mask Tests
Once manufactured, surgical masks are subject to the following tests:
Bacteria Filtration Efficiency (BFE)
This test measures the efficiency of the mask in catching bacteria. Aerosol along with staphylococcus aureus is shot at the mask at 28.3 liters per minute.
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The test assesses the efficiency of the mask in catching the percentage of bacteria that it’s supposed to.
Particle Filtration Efficiency
In this test, an aerosol of polystyrene microspheres is shot at the mask. This test is done to check the efficiency of the mask in filtering particle sizes.
The purpose of conducting this test is to ensure that the mask will retain its shape and provide proper ventilation when you breathe. An airflow is shot at the mask and the difference in air pressure on both sides of the mask is taken.
In the splash resistance test, surgical masks are shot at by liquids that are simulated like human blood. The force of this simulated liquid is like human blood pressure.
This test checks the effectiveness of surgical masks in ensuring the liquid does not penetrate it.
Surgical masks are used in an operation theatre that has many flammable substances. Surgical masks are tested for flammability. They are set on fire to measure how slowly they catch fire and the time taken for the material to burn.