This post is a follow-up to our recent webinar for dentists, dental hygienists and other dental professionals about face masks and fit tests.
We encourage you to watch the webinar first for some background information.
Truth be told anyone who wants to learn more about fit testing, face mask standards and the difference between a face mask and a respirator will find useful information in this post.
We created this post to provide general guidelines about fit testing, face masks and respirators.
Given the evolving situation with COVID-19, dental professionals in Canada should consult the dental association of their province or territory for guidance.
Here’s an index of what we’re going to look at:
- What are disposable respirators?
- What’s the difference between respirators and masks?
- What is an N95 made of?
- Should I wear a surgical mask over my N95 to make it last longer?
- Are there performance standards for respirators?
- Are the KN95 and the N95 equivalent?
- How does quantitative and qualitative fit testing differ?
- Are there standards for surgical masks?
- In what order should I don and remove PPE?
- How Levitt-Safety can help you
What are disposable respirators?
You might hear disposable respirators referred to as filtering facepiece respirators, but they are the same thing. People use disposable respirators to protect themselves from inhaling particulate contaminants.
In general use, these respirators protect you from small particles like sawdust, pollen or dust.
Disposable respirators, like the N95, are in high demand because they can also protect from airborne viruses, if properly fit tested.
Healthcare workers wear disposable masks when concerned about aerosolized droplets. For instance, interacting with a patient on a ventilator.
In dentistry, “aerosol is created when high-powered devices need compressed air and water to work effectively” according to the National Center for Biotechnology Information.
We’ll explore how N95s and other filtering facepiece respirators work more in other sections of this post.
What’s the difference between respirators and masks?
The terms respirator and mask are used interchangeably, but they do different jobs. The table below illustrates those differences.
|Overview||Fit tightly over the wearer's face and create a seal between the face and respirator when properly fit tested.||Fit loosely over the face and leave gaps between the mask and the wearer's face.|
|Standards||The National Institute for Occupational Safety and Health (NIOSH) provides testing, approval and certification for respirators.|
A NIOSH approved respirator will have the following printed on it:
|Health Canada follows the recommendations of the Food and Drug Administration (FDA) in the US.
The FDA does not test or certify surgical masks. They review the manufacturer's test data to decide if the mask meets the claims.
|Purpose||Respirators reduce a person's exposure to airborne contaminants ranging from dust to airborne viruses.||Surgical masks are a physical barrier to protect the wearer from large droplets or splashes body fluids.|
|Do they require a fit test?||Yes, a respirator must have a tight seal against a person's face. |
It is pertinent that a person is fit tested to ensure they are using the right model and size of respirator for their face.
|No, surgical masks are not tight fitting and cannot be fit tested.|
|Filtration||Respirators are named after the particle amount they filter, for instance: |
An N95 filters 95% of airborne particles. A P100 filters 99.97% of airborne particles.
|Surgical masks are not designed or certified to prevent the inhalation of small airborne contaminants.|
What’s in a mask?
Not all masks are the same. In the table above we explained the physical and technical differences between a respirator and face mask. In the chart below we look at filtration effectiveness.
What is an N95 respirator made of?
N is the Respirator Rating Letter Class. N stands for ‘Non-Oil’ meaning that you can wear it in situations without oil-based particles. There are also R (resistant to oil) and P (oil proof) classes of masks.
95 indicates this respirator has a 95% efficiency for filtering particulates that are 0.3 microns or more in size.
The mask material varies by manufacturer. N95 masks typically contain many layers of filter media and non-woven fabrics like polypropylene and cellulose.
Can you wear an expired N95 mask?
Should I wear a surgical mask over my N95 to make it last longer?
We don’t recommend it and it’s not something done under normal circumstances.
Placing the surgical mask over top of the N95 increases breathing resistance. This makes it hotter and harder to breathe through.
This also wouldn’t prolong the life of the N95 respirator and for most people wouldn’t be worth the added discomfort. In a healthcare setting it’s generally your breath from inside the N95 that clogs the respirator, not the outside contaminates.
Are there performance standards for respirators?
Performance standards for respirators differ around the world. The United States, China, Australia, Korea, Japan and Europe all have their own standards for testing respirators.
In Canada we follow the American NIOSH standard for applicable regulations and CSA Z94.4-18: Selection, Uses and Care of Respirators. Therefore, we use NIOSH-approved respirators.
|Country||Type of respirator|
|United States||N-series masks (N95, N99 N100)
R-series masks (R95, R99, R100)
P-series masks (P95, P99, P100)
|Europe||FFP1, FFP2, FFP3|
|Korea||Korea 1st Class|
N95 masks are hard to get at this point, which means more people are turning to KN95s.
Are the KN95 and the N95 equivalent?
We are asked this question a lot.
In a whitepaper 3M released in January, the respirator manufacturer offered a comparison chart of respirators from the countries listed above. In the whitepaper, the company stated:
Based on this comparison, it is reasonable to consider China KN95, AS/NZ P2, Korea 1st Class, and Japan DS FFRs as “equivalent” to US NIOSH N95 and European FFP2 respirators, for filtering non-oil-based particles such as those resulting from… bioaerosols (e.g. viruses). However, prior to selecting a respirator, users should consult their local respiratory protection regulations and requirements or check with their local public health authorities for selection guidance.
Admittedly, reading it’s “reasonable to consider” KN95s as equivalent to N95s does not inspire much hope. However, N95s and KN95s are both rated to capture 95% of particles.
If KN95s are the only style of respirator available, the best thing to do is have them fit tested.
A quantitative fit test (we’ll talk more about that in the next section) measures the actual amount of leakage into the facepiece.
A note about fit testing KN95 masks: As part of our fit testing protocol, Levitt-Safety has decided that we will issue a fit test card and report for KN95 masks tested to pass the CSA protocol. The report and card show a fit factor at an acceptable level but not a certificate.
How does quantitative and qualitative fit testing differ?
We wrote about the difference between qualitative and quantitative fit testing in our post “What is fit testing and why should I care?”
There are 2 types of respirator fit tests:
- Qualitative fit testing: This method uses your sense of smell and taste or your reaction to an irritant to determine if the seal is good. If the person can smell or taste the challenge agent, the mask isn’t the right fit.
- Quantitative fit testing: This method uses a machine to count microscopic particles inside and outside the respirator to determine a fit factor based on the ratio of these two values.
A demonstration of quantitative fit testing.
Both tests require the user to perform a series of moving, breathing and talking exercises designed to simulate the same movements made in the field.
Since quantitative fit testing is a numbers-driven test, it’s a more accurate representation of how effective your mask’s seal would be in the real world.
Qualitative fit testing is also an allowable method to fit test, however physical distancing is not as easily maintained as quantitative. A hood is worn by the person being fit tested but it is also recommended that the fit tester wear proper respiratory and face protection too.
Are there standards for surgical masks?
The American Society for Testing and Materials (ASTM) sets the standards for surgical masks. ASTM F2100 is the standard used for the performance of materials used in medical face masks.
There are 3 classifications for surgical masks:
- Level 1 (low) – venous pressure splash
- Level 2 (moderate) – arterial pressure splash
- Level 3 (high) – high-velocity procedures, orthopedic surgery
In what order should I don and remove PPE?
There are important steps to take when donning and removing PPE to limit contamination. We created this poster with the steps which you can download and print here.
The order in which you don and remove PPE is critical to preventing contamination or infection.
For a more in-depth explanation, watch this explainer video from Alberta Health Services.
How Levitt-Safety can help you:
Since the first case of COVID-19 was reported in Canada on January 25, we have put our effort into protecting workers across Canada. We do this not only by the products and service we regularly offer, but also through the blogs we post and pivoting our business model to source emergency supplies from overseas.
It is critical that dental professionals in Canada follow the guidelines set out by the regulatory body of their province or territory.
For our part, Levitt-Safety will continue to publish helpful resources on our website and through our social media channels. Our number 1 goal, regardless of circumstance, is to keep workers safe.
We offer the following products, services and training:
- Rental equipment for air quality, air sampling and sound level meters
- Consulting options for risk assessments and safety program reviews
- Respiratory protection
- Hand hygiene for healthcare
- Workplace violence awareness for health care services
Have a question?
Our team of safety specialists is here to help answer any questions you might have. Fill out the form below to learn more about this topic or get recommendations on equipment, services or training.