A clear winner: Why quantitative testing is the best choice for respirator testing

July 24, 2023
By Amanda Winstead | Full list of stories

Fit testing respirators is essential to ensure employees maintain an adequate fit and seal to protect their health. Respirator fit testing is also a requirement as specified by the Occupational Safety and Health Administration (OSHA).
 
That said, there are currently two types of approved testing by OSHA: qualitative and quantitative. While OSHA states when each type of test should be used, there is much debate over whether one is always the better choice.
 
Let’s analyze the difference between the two types of testing and look at reasons for why quantitative testing is the clear winner and should be prioritized above qualitative testing. This is meant to help employers hoping to develop a better respirator testing program for employees. It can also guide employees so they can make informed decisions to protect their own health and well-being.
​

Qualitative vs. quantitative testing for respirators 

Before diving into the science of it all, the basic difference between a Qualitative fit test (QLFT) and a Quantitative fit test (QNFT) is this:
​

• Qualitative: A basic pass/fail test to assess the general adequacy of respirator fit.
• Quantitative: A numerical measure of the actual leakage into the respirator.

 
Simply using this information, you could come to the conclusion that QLFT might work in situations where the worker is less at risk and needs to wear a simpler mask, like an N95. This is because you only need to measure whether the mask fits or not.
 
In contrast, if a worker is at higher risk of being exposed to much more deadly fumes, gasses, or other particles, and requires half- or full-face respirators, then QNFT makes more sense. This is because quantitative testing will actually measure whether any of those hazardous particles are getting through and – if they are – how much. 

Qualitative fit testing

Qualitative testing is performed to determine whether the worker can taste or smell an irritant or substance through the mask being tested. This type of test is performed as follows:
​

• Test Solutions: An aerosol, such as denatonium benzoate, sodium saccharin, or stannic chloride, or a vapor from isoamyl acetate is used in this testing process. In each case, the chemical compounds used are known to be bitter.
• Test Exercise: The subject performs each of the following for one minute: normal breathing, deep breathing, moving the head up and down, turning the head side to side, speaking, and bending over (or jogging).
• Subject Participation: The subject (worker) must indicate whether or not they can smell or taste the testing solution being used.
• Pass/Fail Criteria: It is a pass if the subject does not detect anything and a fail if they do.

Again, this type of testing simply determines whether or not the worker can smell or taste anything. It’s a simple yes or no — pass or fail. 
​

Quantitative fit testing

Quantitative fit testing determines the measure of leakage, meaning it’s not a simple pass or fail but instead is meant to actually quantify how many particles are getting through the mask, if any.
 

• Test Solutions: An aerosol, such as sodium chloride, corn oil, etc. or CNP (air) is used to administer the test.
• Test Exercise: The same exercises are used as QLFT but with the addition of having the subject grimace. An alternate regime is also allowed for Controlled Negative Pressure (CNP).
• Subject Participation: Instead of simply having the subject verify whether they smell or taste anything, a machine calculates the amount of leakage.
• Pass/Fail Criteria: For a half-face respirator, the minimum fit factor results must be 100. And for full facepieces, the minimum fit factor results must be 500.

So, the difference with QNFT is that a machine is used to calculate the amount of leakage, whereas, with QLFT, the test relies on the individual to simply state whether they do or do not detect the solution.
​

When is one test required over the other?

With most classes of tight-fitting respirators, including disposable filtering facepieces, either QLFT or QNFT may be used. As specified by OSHA, qualitative fit testing may be used for negative-pressure air-purifying respirators, but only if they will be used in atmospheres ten times the permissible exposure limit (PEL). For greater concentrations, QNFT must be used. Additional exceptions for when QNFT is required are as follows:
 

• If an assigned protection factor (APF) of 50 is needed with cartridges or filters while using a full facepiece;
• If a supplied air respirator (SAR) or self-contained breathing apparatus (SCBA) is being used in demand mode;
• If an SCBA facepiece is being used for structural firefighting. 
  ​

Why quantitative fit testing is ideal

So long as all guidelines are being followed, you can use QNFT or QLFT. However, QNFT is arguably the better choice because it relies on real data that shows whether there is actually any leakage in the respirator and how much.
 
With QLFT, you are relying on the subject to be able to adequately determine whether they smell or taste anything, but this leaves room for human error. Because everyone’s senses are different, it’s possible they may not detect anything even if the particles are, in fact, getting through.
 
With QNFT, however, the test relies on verifiable data. A person may not be able to detect anything, but a machine can, and it provides measurable results so you will know the exact amount of leakage. In other words, quantitative testing is more efficient and accurate.
 
There are situations where knowing the exact leakage is not necessary. And in those cases, QLFT may be fine. But when a worker is wearing half- or full-face respirators because they are being exposed to highly dangerous and toxic substances – where even the smallest of leakages could threaten their health – then QNFT is the better choice. 
​

​Protecting workers is top-priority

The health and well-being of all employees should be a number one priority, but it is especially crucial when it comes to high-risk workers. Furthermore, certain high-risk workers have rights per federal regulations.
 
High-risk workers, such as those in construction, manufacturing, agriculture, oil rigging, and maritime operations, face a number of dangers, including exposure to hazardous substances. As such, OSHA and the National Institute for Occupational Safety & Health (NIOSH) have established guidelines to protect workers’ rights, which include ensuring adequate fit testing for respirators.
 
In addition to following federal regulations, it’s also helpful to note that if employees are not adequately protected, it can affect workplace productivity. Stress can negatively impact the workplace and cause safety concerns. For instance, workers who are stressed about being exposed to life-threatening substances may struggle to focus and complete their work, which is both dangerous and can negatively impact productivity outcomes. At its worst, stress can also increase the risk of accidents and injuries.
 
Even OSHA warns that stress can cause problems in the workplace. Therefore, it is imperative that employers do what they can to reduce instances of stress, including ensuring their workers feel safe and protected by using adequate PPE and conducting thorough respirator fit testing.
​ 

Next steps

To protect employee health and well-being, employers must develop a better PPE protocol. This includes choosing the right respirator protection as well as testing for adequate fit.
 
If you aren’t sure which respiratory protection your employees need, you can check OSHA’s guidelines and ask certain questions, such as — “What hazards do your employees face?” And “Have your employees been medically evaluated before wearing a respirator?”
 
You can also use the help of professional safety specialists to ensure your respirator protection program is compliant with federal standards. 

Vertical Divider

Like what you're seeing here? Subscribe to the Blue Print for FREE and get the magazine sent right to your address.

Subscribe

​Got feedback? Email us at
[email protected]