OUR MASK
What makes our mask unique?
Here are some frequently asked technical questions about the Community Mask.
Behind the mask.
Here are some frequently asked technical questions about the Community Mask.
N95 masks are certified by the National Institute of Occupational Safety and Health (NIOSH) and are designed to filter very fine particles with an efficacy of at least 95%, hence the name. Proper use of an N95 mask requires a fit-test, where a professional checks for air leakage around the perimeter of the mask and the performance criteria are very strict. These masks are used in industrial settings as well as by medical professionals, and should be reserved for such uses.
Medical masks, sometimes referred to as surgical or procedure masks, are also designed for very high efficacy in filtration, blocking at least 95% of fine particles and bacteria, and blocking body fluids. Contrary to N95 masks however, they are not fitted tightly around the face and some air can leak around the sides of the mask. In North America, medical masks must meet standards of performance set by the American Society for Testing and Materials (ASTM) through the standard F2100.
You can find a good article on N95 and surgical masks here: https://blogs.cdc.gov/niosh-science-blog/2009/10/14/n95/
Cloth masks or DIY face coverings for use by the general public (as recommended by the CDC) are not required to be tested in any way, and are not required to meet any standards of performance. However, they are still very useful as suggested by epidemiological research. One such study was conducted by scientists from the University of Cambridge in the aftermath of the 2009 H1N1 flu pandemic. It concluded that while cloth masks captured fewer particles than an N95 mask, they still were able to capture 69% of 1-micron particles (the size of a piece of dust). This would suggest that wearing a cloth face mask and adhering to social distancing guidelines, is still more effective in slowing the spread of viruses than by not wearing any face mask at all.
BFE is a measure of the efficiency (%) of a material to block the passage of bacteria under controlled laboratory conditions. Since not all bacteria are the same size and all bacteria are larger than viruses, this is used as an indication of performance only and not an absolute value for all types of microorganisms.
It is still a useful data point when evaluating different masks against each other for protection, as a higher percentage of bacterial filtration offers more protection. Cotton or linen masks offer almost no protection against bacteria. Spera Community masks have been tested by an independent accredited lab and offer a BFE of 99.9%.
Surgical and N95 masks have a minimum BFE of 95%-99% depending on the exact type. The Spera Community face mask has the same level of performance against bacteria with a rating of at 99.9%.
Represents the mask’s resistance to penetration by synthetic blood under pressure (mmHg). It measures the ability of a mask’s material construction to minimize fluids from traveling through the material and potentially coming into contact with the wearer. High resistance to fluid penetration is useful in a personal use mask to prevent airborne droplets from a cough or a sneeze to pass through the mask and potentially contaminate surrounding surfaces or people.
Spera Community face mask – Pass at 120 mmHg (same as Surgical Mask level 2)
Represents the percentage of blocked bacteria with a size of 3 microns. It is used as an indication of performance only and not as an absolute value for all types of microorganisms.
Spera Community face mask – Tested Result: 99.9%
Represents the percentage of blocked particles with a size of 0.3 microns. Viruses are not exactly at that size and much smaller than bacteria, but they are in this size range. It is used as an indication of performance only and not as an absolute value for all types of microorganisms. The average cotton or linen face mask filters such fine particles with an efficiency of less than 10%.
Spera Community face mask – Tested Result: 77.9%
Represents the pressure drop across the mask, or resistance to air flow measured in Pa/cm2. The higher the value, the more difficult it is to breathe through the mask. determines breathing resistance. As a comparison, some types of surgical masks have a maximum ΔP of 49 Pa/cm2.
Spera Community face mask – Tested Result: 48.3 Pa/cm2
A measurement of a material’s propensity to burn rapidly and spread flames. The purpose of this standard is to evaluate the flammability of textiles and textile products for clothing use. Class 1 textiles exhibit normal flammability and are acceptable for use in clothing.
Spera Community face mask adheres to: Class 1
The short answer is, yes.
Microns are small, measuring 1 millionth of a meter. A nanoparticle is a particle smaller than a 0.1 micron, roughly 600 times smaller than the width of an average human hair. Particles in that size range are particularly difficult to capture in a filter, an unfortunately it happens to be the size range of the average virus particles. SARS-COV-2 virions, that cause COVID-19, have a diameter of approximately 0.06-0.14 microns, and ranges in size up to 1.4 microns.
The Spera Community face mask relies on the filtration mechanics of straining, impaction and interception to capture particles. Larger particules are strained, i.e. they simply cannot fit through the holes in the ePTFE membrane and are mechanically blocked. A large portion of the particles smaller than the hole size of the membrane end up impacting or ‘getting stuck’ to the material of the filtration membrane as they travel through its maze. A small portion of the finer particles end up passing through.
Disposable N95 and surgical masks have an additional trick up their sleeve. They rely on electrically charged fibers to ‘attract’ very fine particles that also have a slight electric charge. They end up capturing more of the nanoparticles this way. However, washing such disposable filter material negates the electric charge in the fibers and the masks’ efficiency drops significantly. Hence the ‘disposable’ property of these masks.
The Spera Community face mask can also provide high level filtration against pollen and dust, and against smoke and ash inhalation from wildfires and forest fires.
The Spera Community face mask was designed in Quebec, Canada following recommendations of the IRSST – Institut de recherché Robert Sauvé en santé et en sécurité du travail (Robert Sauvé Research Institute on Workplace Health and Safety). The Institute recommends, for all personal-use masks worn in a community setting, a minimum Particle Filtration Efficiency (PFE) of 60%, a maximum Differential Pressure of 108 Pa/cm2 and a resistance to penetration by body fluids, a test adapted from the ASTM F1862 method.
The Spera Community face mask – Tested results:
In following the standard set by IRSST for all community style protective face masks for Quebec, Spera Community Face Masks underwent the following tests.
When we breathe, talk, cough or sneeze, we emit particles through the mouth and nose. A community type barrier mask must offer a certain resistance to the spraying of these droplets. The external surface of a barrier mask should not contain any trace of liquids emanating from the wearer during the period of use. The spray test is used to assess the extent to which the liquid passes through the material when subjected to consecutive sprays. At least 15 out of 20 samples tested must resist the passage of fluids completely for the mask to pass the test.
Spera Community face mask – Tested Result: Pass
The filtration test is used to determine the capacity of a medium (material) to retain particles. Filtration performance is quantified in terms of percentage of blocked airborne particles with sizes varying from 20 nanometers (nm) to 2 micrometers (µm). The filtration efficiency of textiles for making barrier masks is tested for all particle diameters.
Spera Community face mask – Tested Result: >60% minimum filtration efficiency
Breathability is an important characteristic when selecting or making a community type barrier mask. It determines both the ability of a material to let air pass when we breathe, and the condensation that forms inside the mask. When we breathe, the friction of the air which moves through the material generates a pressure loss (pressure drop) which must be compensated by an effort to breathe. The desired breathability value is less than 108 Pa/cm2.
Spera Community face mask – Tested Result: 48.3 Pa/cm2
A micron is the measurement used for particles one millionth of a meter, most often used to describe particle size. This chart demonstrates the efficacy of different masks and blocking airborne contaminates relative to their size.
