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.

Find our respirators here. 

The Top 4 Considerations When Evaluating Portable Air Scrubbers

Airflow ratings can be very misleading: The cheapest units are often the most costly

When purchasing portable air scrubbers for use on restoration and/or mold remediation projects, there are many factors that should be considered in selecting the proper piece of equipment. Too many times airflow (or claimed airflow) and price are the only issues considered before a purchase.  All too often the contractor finds that the equipment does not meet their expectations or needs when it arrives. 

1. Ease of transport

This is one of the most important, yet most overlooked, aspects of portable air scrubbers. Scrubbers must constantly be moved from job to job and from location to location during a project. Some units are designed for one-person operation; others may require two people to move. Weight is very important, but so is weight distribution. Scrubbers that include a transport system for easy movement by one operator are safer and more cost-effective to operate. A stair climber is also a valuable feature when stairs are a factor. Size and weight should also be considered when thinking about transport and vehicle requirements.

2. Air scrubber filtration system

The filtration system is the heart of a portable air scrubber. Poorly designed filtration can add hundreds or even thousands of dollars in annual operating costs. Filters must provide a substantial dirt-holding capacity and long filter life without significant airflow loss. A well-designed filtration system requires three stages of filters to progressively filter all particle sizes. If odors and particulates are to be removed simultaneously, a fourth stage of gas/odor filtration may also be needed.

Easy “no tools” access is important when inspecting and replacing dirty filters. The filter module should not have to be removed to change or inspect filters. This is time consuming and can also cause debris to be spilled onto the HEPA and the surrounding area.

HEPA filters must be individually tested by the filter manufacturer and certified to a minimum efficiency of 99.97% at 0.3 microns. It is not enough to simply assemble a filter using HEPA media. A true HEPA filter must be constructed to the exact manufacturing practices necessary to ensure that the finished filter does not leak through the filter media or around the frame or seams. If debris can bypass the HEPA media, the filter will not pass DOP testing required in many abatement specifications. Insist that the HEPA filter itself be certified to HEPA standards, with a certification label affixed to the frame of the HEPA filter.

3. Blower type

Air scrubbers are required to trap large quantities of debris. Debris buildup on the filters hinders the airflow and causes what is technically known as static resistance. Specific blowers are much better suited than others for overcoming this resistance. There are many types of air moving blowers available, each with specific characteristics for certain applications. 

For example, forward-inclined “squirrel cage” blowers are designed to move large volumes of relatively clean air and low static resistance. These inexpensive blowers may be suitable for applications such as use in a furnace or even in an asbestos negative air machine; they are not, however, a very good selection for use in an air scrubber.

Backward-inclined or airfoil type blowers are a much better choice since they are engineered with the capacity to overcome the pressure drop of dirty filters. The use of this type of blower will not only increase filter life but will also produce higher airflow as the filters begin to accumulate debris. This generally means significantly better performance (airflow) over the life of the filters and much lower replacement filter expenses than a scrubber or negative air machine that is equipped with a forward inclined blower with a comparable peak airflow rating.

4. Materials and construction methods

Most negative air machines position the blower at the outlet of the cabinet, and pull air through the cabinet. This keeps the entire cabinet – including the section downstream from the HEPA filter - under lower (negative) pressure compared to the air in the surrounding area. With this design, the machine must be perfectly sealed to prevent contaminated air from being sucked into the cabinet and exhausted without ever passing through the HEPA.

This is a big concern when the unit is used as a negative air machine and exhausts air into another part of the facility, especially if that area is occupied. Any such leaks will negate the effectiveness of the HEPA filter and will more than likely cause contamination of the area and failure of any air testing required by the job specification. This should be an important liability concern of any mold abatement contractor.

Generally, the use of  gaskets and solid rivets produce the most leak free cabinets. Beware of any cabinet that uses fasteners such as hollow pop rivets, or threaded fasteners such as sheet metal screws or nuts and bolts. These devices do not afford the airtight seal necessary to keep small particles from infiltrating a negative pressure cabinet.

Fun fact: It has been found that sub-micron particles can actually travel along the threads of a screw or bolt!

Lastly, make certain that any hardware, instruments, or transport system components that penetrate into the cabinet are sealed in such a way as to prevent any leakage or bypass. For more information on evaluating portable air scrubbers contact us!

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