Mask Permeability Test
Masks are protective accessories that are generally made of cloth, fabric, leather or plastic and used by attaching to the face to protect them from viruses and external effects. It can be named differently as a result of the application of tests such as mask permeability tests. Various tests are applied to both surgical face masks and medical masks suitable for general use in advanced laboratory environments. These mask permeability tests are required and used to determine the performance of masks and to classify them. It is of great importance that hospital personnel continue their professions appropriately and that we need to protect ourselves due to the epidemic today.
Mask permeability tests can be performed according to many variables. According to these variables, masks are divided into two groups as surgical masks and respiratory system protective masks. Medical masks, also called medical masks, are produced in accordance with TS EN 14683 standards. It must meet all the conditions in terms of appearance and structure. Most of the time, the masks preferred by many companies that employ workers and personnel are called respiratory protective masks.
Mask permeability tests are carried out in special devices by simulating the human face in accordance with the specified articles of the relevant standards, providing a certain pressure and air flow. Mask permeability tests are performed with certain aerosols and dusts to measure bacterial filtration and viral filtration efficiency. It is not made with a real bacteria or virus. By simulating the size, virus or bacterial transmission can be calculated. In addition, in mask permeability tests, the controls of the permeability of blood, liquids and chemicals from the mask surface to the other side are simulated with various hydrostatic test devices. The breathability of the mask is also tested with air permeability tests. Here, too, air permeability test cabinets are used. For reusable masks, measurements of microbial activity that may occur on masks that have been washed several times are provided. In addition to protective masks, non-flammability and face compatibility tests are also performed.
Let´s talk about mask permeability tests:
Various organizations that develop standards both in Europe and the USA are conducting various studies to determine the properties and test methods of these masks. For example, the full name of the F2100 standard developed by the American Society for Testing and Materials (ASTM): ASTM F2100 - 19 Standard specification developed for the performance of materials used in medical face masks.
Various tests applied by the standard in line with the mask permeability test:
• Bacterial or viral filtration efficiency test
• Differential pressure test (Delta P test)
• Flammability test
• Particle filtration efficiency (latex particle difficulty)
• Synthetic blood fluid penetration resistance testing for face masks
What is a Bacterial or Viral Filtration Efficiency Test?
It is a test method that helps to determine the resistance of the respiratory material to penetration by bacteria. The results of the applied test are published as the efficiency ratio. This result is related to the ability of the fabric used to make the mask to resist a bacterial penetration. As a result of the high test, it is concluded that the barrier efficiency is good. Features such as the fiber type of the yarn, weaving properties, general quality properties, and basis weight affect the bacterial filtration efficiency of the mask.
This test method has been used unchanged for many years and provides a standard reference for the filtration materials compared. The test is usually performed together with the differential pressure test (Delta P Test).
What is Differential Pressure Test (Delta P Test)?
It is a test method in which the ease of passage of air from one side to the other in the mask is evaluated. Its results indicate how easily the wearer breathes while wearing the mask.
A high Delta P value, or in other words a high differential pressure value, indicates that it is difficult for air to pass through the mask. The result of the condition is the blowing effect. Air may escape or the person´s face may be exposed to contamination from the edges of an unsuitable mask. This is due to the low level of the mask or misuse. While lacking in comfort, the higher Delta P value provides better filtration.
One of the performance requirements of medical face masks in the ASTM F2100 standard designed by ASTM is the Delta P pressure difference. The higher the value, the harder it is for the wearer to breathe. Masks with a Delta P value of less than 2.0 are considered suitable.
What is Flammability Test for Masks?
There are gases and oxygen sources used for anesthesia, especially in the operating rooms of hospitals.