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N95 Respirator: Filtration, Fit & Proper usage

The COVID-19 Pandemic has put tremendous pressure on our front line Corona Warriors like doctors, nursing staff, medical assistance, law enforcement etc. Despite using the best quality N95 respirators it is found that a large number of these front line warriors have been infected by COVID-19 themselves. This gives birth to some natural questions:

1. Are the N95 respirators being used are providing adequate filtration?

2. Are the N95 respirators being used fit properly to the face of users?

3. Are the N95 respirators being used properly and what kind of training is imparted to the Corona warriors before using the N95 respirators?


Most N95 Respirators are designed to reduce the user’s exposure to airborne particulate hazards like aerosol, industrial particulate and diseases such as COVID-19, SARS and influenza etc. The “N” is N-95 means that respirator is “Not resistant to Oils” and “95” means that it is designed to offer 95% or more filtration efficiency.

To ensure this the filter media is tested to ensure that it is offering at least 95% filtration efficiency against the non-oily particles.

Fit Test:

The N-95 fit test is a critical test to ensure that the respirator fits snugly on the face of user and there are no gaps between the user skin and respirator forming a good seal.

No matter how efficient is the filtration efficiency if the fit is not proper then the N95 respirator cannot give you required protection. It is highly recommended that if the N-95 respirator doesn’t fit the face type of user properly they should use a different model or different manufacturer for proper safety against the COVID-19.

To ensure the above regulatory authorities strongly recommend that a “Fit Test” should be performed to ensure a proper Fit. The Accufit 9000 Fit Tester from Accutech IHS is a quantitative fit tester compliant with OSHA, HSE & CSA Protocols. This device can be used to test full masks, half masks and most disposable masks for fit factor.

For more details of this Fit Tester you may watch the DEMO VIDEO of write us

Proper Usage:

Using the N95 respirator is as important as the above two points. If a respirator is having very good filtration efficiency and fit factor but it is used in a wrong way it will still result in exposure to the aerosol or bio aerosol causing significant risk to the safety of user. Putting on the N-95 Mask (donning) involves user seal check. The user seal check is different from the fit test and must be performed each time you wear the N95 respirator. The steps involved in user seal check are as below:

- Inspect the respirator including the strap for tears or damage. If you find any damage use the new N95 Mask.

- Use one hand to put the respirator on your face and finger tips on the nose piece.

- The nosepiece should span and cover the bridge of your nose and the respirator cup should cover your chin.

- Pull the top strap over your head resting it high at the back of your head.

- Pull the bottom strap over your head and position it above your neck and below your ears. Do not crisscross the straps.

- Make sure that your mouth and nose are covered by the respirator.

- If the nose piece has a metal strip use both hand to mold it so that it conforms to the shape of your nose.

- Conduct a user seal check by inhaling and exhaling as per manufacturer’s instructions and ensure that there is no air leakage.

- If there is a leakage then don’t use the respirator and try a different model/ manufacturer.

If you need any clarifications or have any feedback regarding this article contact the author

Thanks for your time!

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