The Basics of Respirator Fit Testing

In this blog, we break down when you should fit test respirators, the difference between qualitative and quantitative fit testing, as well as how to choose which test is right for your respirator. 

No matter how advanced a face respirator is, if it doesn’t fit right, it won’t protect the wearer. That’s why fit testing is essential.

In the US, the Occupational Safety and Health Administration (OSHA) requires fit testing before using a mandatory respirator for the first time and annually after that. The rules are similar in Canada. According to the Canadian Standards Association (CSA) and Ontario’s Occupational Health and Safety Act (OHSA), workers whose jobs require them to wear a respirator must complete fit testing before their first use.

Additionally, they must complete a fit test: 

- At least every two years, according to the CSA (Z94.9.1.6)

- After significant weight gain or loss, surgery, major dental work, or other physical changes that could affect a respirator’s fit

- When changing to a new respirator make or model

Qualitative vs. Quantitative fit testing

There are two types of fit testing: qualitative and quantitative. Qualitative fit testing is a subjective test that relies on the wearer's sense of taste or smell to determine if the respirator fits properly. This type of testing is a simple pass-or-fail method that does not measure the extent of leakage. OSHA accepts four methods for qualitative fit testing: isoamyl acetate (banana oil test), saccharin, Bitrex, and irritant smoke. 

Quantitative fit testing, on the other hand, is a more objective and precise method of testing the fit of a respirator. This type of testing uses specialized equipment to measure the amount of leakage around the respirator's seal. Quantitative fit testing requires a controlled environment and trained personnel to administer the test. The three OSHA-accepted methods for quantitative fit testing are generated aerosol, ambient aerosol, and controlled negative pressure. 

Should you use qualitative or quantitative fit testing?

Wondering which method of fit testing is best? The quick answer is: it depends.

Qualitative fit testing may be used for negative pressure respirators, such as N95 masks if they are being used in environments less than 10 times the permissible exposure limit (PEL). If contractors are using negative pressure respirators in environments above 10 times the PEL, they must use qualitative fit testing. 

For positive pressure respirators, either qualitative or quantitative testing will work. That is because positive pressure respirators supply their own air, and thus can overcome minor leaks. 

How to conduct qualitative fit testing

To perform qualitative fit testing, the wearer must put the respirator on and adjust it to fit their face. The test administrator will then instruct the wearer to perform a series of exercises, such as talking, nodding, and moving their head from side to side, simulating normal workplace movements.

During the test, the administrator will introduce an irritant to the environment, such as banana oil, Bitrex, saccharin, or smoke, and ask the wearer to indicate if they can taste or smell the test agent. The test administrator will also visually inspect the respirator for any leaks or gaps. If the wearer can taste or smell the test agent, or if there are visible leaks, the respirator does not fit properly and should be adjusted or replaced.

Qualitative fit testing is a simple and cost-effective way to determine if a respirator fits properly. However, it is not as precise as quantitative fit testing is more precise and may not detect all leaks or fit issues. 

How to perform quantitative fit testing

To perform quantitative fit testing, the wearer must properly put on the respirator and adjust it to fit their face. The test administrator will then use specialized equipment to measure leakage around the respirator's seal.

The equipment used for quantitative fit testing typically includes a probe placed against the wearer's face near the respirator's seal. The probe is attached to a special filter adapter, which then passes through the respirator to sample the air inside of the mask... As in qualitative testing, the wearer will be instructed to perform a series of exercises, such as talking, nodding, and moving their head from side to side to simulate workplace movements.

The test results are then compared to the manufacturer's fit factor, which measures the respirator's effectiveness. If the fit factor is within the acceptable range, the respirator fits properly. If the fit factor is outside of the acceptable range, the respirator does not fit properly and should be adjusted or replaced.

Quantitative fit testing is a more precise and accurate method of testing the fit of a respirator. However, it requires specialized equipment and trained personnel to administer the test. It is recommended that quantitative fit testing be performed whenever a new respirator is used, or when there are changes to the wearer's facial structure.

Get the most out of your respirator

Whether it’s qualitative or quantitative fit testing that you need, be sure to stay up to date with fit testing requirements for your respirator. Doing so not only ensures compliance but will help you stay safe amid a variety of work environments.

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