Fit Testing Industry Professionals Can Trust

At minimum, OSHA requires that respirator fit testing occurs on an annual basis. However, fit testing must occur in other notable instances, as well.

• By Molly Doran, John Morton
• Nov 01, 2014

As an industry professional:

• Do you work in an environment where the air is unfit to breathe?
• Does your workplace have a plan for and provide you with the assurance you'll be safe while at work?
• What can you do to ensure you're protected from lung damage or occupational disease?

These are important questions to ask to safeguard your occupational safety and health. Respiratory protection use can be the most important step in the protection from occupationally induced cancers, lung impairment, diseases, or even death--but only if your respirator fits properly.

General industry can encompass a broad range of workplace settings with different levels of occupational exposure to harmful dusts, fogs, smokes, mists, gases, vapors, and sprays. These settings include:

• Confined or enclosed spaces
• Oxygen-deficient environments
• Toxic substance environments

What Are Respirators?
There are two basic types of respirators:

• Air Purifying Respirators (APRs) that filter contaminants from the air
• Supplied Air Respirators (SARs) that supply clean air from an external source (i.e., a compressor or high-pressure cylinder)

Supplied Air Respirators are available in loose- or tight-fitting styles, while Air Purifying Respirators are typically tight-fitting masks. Loose-fitting respirators are basically hoods that cover the worker's head, with the fit not dependent upon facial features. Tight-fitting respirators are designed to form a seal to a person’s face, requiring the fit to be accommodating to individual facial features. This means that each individual wearing this type of respirator needs to be fit tested to confirm proper donning and fit, ensuring maximum protection while on the job.

Why Fit Test?
Working in any of the industry settings described above, workers are susceptible to aerosolized particles that contain impurities or hazardous compounds; many remain suspended in the air for extended periods of time. Many times, these particles are generated when a worker performs his assigned job responsibilities, exposing him to respiratory hazards—including, but not limited to, toxic dust from cutting cement or mining, metal fumes from welding, solvent vapors from adhesives and paints, chemical hazards from petroleum refining, and chemical contaminants during pharmaceutical production. Transmission or spread occurs when these aerosols are inhaled and/or come into direct contact with the surface of the hands, eyes, nose, or mouth.

Proper implementation of an organization-wide Respiratory Protection Program (RPP) is a huge undertaking, but it is the most important factor in keeping workers safe while on the job. Worth the effort, an effective Respiratory Protection Program is essential in order to comply with strict federal OSHA and state OSHA respiratory protection standards, as well as to instill trust in industry workers that their respirators work.

Because each workplace is different, it is essential that employers have robust programs that reflect their specific workplaces.

Know You're Protected
Respirators come in various types, shapes, and sizes. Most important, a respirator must be selected to provide the best face fit and seal. A proper seal inhibits the flow of air between the user's face and respirator's sealing surface, in turn ensuring that the air inhaled either passes through the filter media or originates from the supplied-air system, maximizing worker protection. To safeguard a proper seal, it is very important that the wearer knows how to properly don (put on) and wear the respirator. Employing a respirator fit test is the only way to determine whether it is being worn correctly and providing optimal fit and the rated level of respiratory protection.

At minimum, OSHA requires that respirator fit testing occurs on an annual basis. However, fit testing must occur in other notable instances, as well. This includes when an organization changes to a different respirator model or the worker experiences facial changes of any kind, possibly due to significant weight loss or gain, etc.

The style of respirators used in industry settings can vary from half- to full-face masks, with each offering different levels of protection. Each will vary with the utilization of different types of filters, cartridges, or canisters, depending upon the type and amount of airborne contaminant in the workplace and the atmospheric characteristics. In addition, the scheduling of maintenance or replacement of the above noted components is a very important consideration in the optimal functioning of the mask.

When a respirator is required, employers must provide NIOSH-certified respirators to workers as required per industry regulations. The National Institute for Occupational Safety and Health, in a lab setting, is responsible for testing different respirator models to ensure they meet certain minimum performance standards. This includes filter efficiency testing of the filter media used with a respirator to determine its suitability for a particular use. All are designed to keep you safe from your particular workplace hazards.

Fit Testing Methods
OSHA-approved fit testing of respirators can be done using two different methods: Qualitative Fit Testing (QLFT) or Quantitative Fit Testing (QNFT). QLFT is a low-cost, subjective pass/fail test that manually exposes the respirator wearer to a chemical stimulant that is assumed to be detected only if the respirator leaks unacceptably. QNFT is an objective test that involves the use of testing instrumentation to numerically measure how well the respirator fits. Because the QNFT method uses actual measurements taken during the fit test, it is not dependent upon a person’s voluntary response.

Qualitative Fit Testing (QLFT)
There are four types of QLFT methods currently accepted by OSHA: Isoamyl Acetate (banana tasting), Saccharin Solution Aerosol (sweet tasting), Bitrex® Solution Aerosol (bitter tasting), or Irritant Smoke. All too often, QLFT methods are compromised by well-meaning test operators who skip some of the important steps and thereby unknowingly invalidate the fit test. This temptation exists when the same test operator rushes to fit test many people in a limited amount of time, day after day, or when the fit test protocol is prone to problems. There is also the potential for deceitful responses from the person being fit tested in an attempt to hurry the test process along.

Quantitative Fit Testing (QNFT)
There are two aerosol-based, OSHA-accepted QNFT methods: Generated Aerosol (complex and lacks portability) or Ambient Aerosol (simple and portable). Both methods measure an aerosol challenge agent outside of the respirator (C_out) as well as from inside of the respirator (C_in), as the wearer performs a series of exercises that approximate conditions of use while the results are recorded. The ratio of the two measurements (C_out/C_in) is called a fit factor. OSHA requires full-face respirators to have a fit factor of at least 500 to pass the fit test. This means that the air inside of a properly donned respirator must be at least 500 times cleaner than the air outside of the respirator.

QNFT methods have a technological advantage in that they can use computers with software specially designed to conduct and adhere to the fit test protocol, maintain records, and facilitate printing of fit test certification cards that individual workers can carry. It's virtually impossible to make mistakes or erroneously pass a fit test and eliminates negative tendencies that plague QLFT.

Being simpler to operate and portable, the Ambient Aerosol method of QNFT is the most economical QNFT method and is industry preferred. The challenge agent used is the ambient microscopic particles that are present at all times in the air we breathe. These particles can't penetrate the respirator filter, so any particles measured inside the respirator are attributed to a face seal leak.

Conclusion
Without a fit test, there is absolutely no way to know that a worker's respirator is providing the expected/maximum protection. Studies show that respirator wearers who undergo respirator fit testing achieve far greater protection than those who have not. This was confirmed by a study performed by NIOSH in 2007. The study compared the protection offered to wearers by N95 respirators with and without fit testing being performed, according to each of the fit test methods used. It concluded that any fit test method significantly improves respirator protection, and that QNFT is particularly beneficial.

All too often, companies look at fit testing as just another annual requirement that must be "checked off" an already long regulatory "to do" list. Yet study after study has shown that taking the time to do respirator fit testing properly ensures the respirator users are getting the expected protection from their respirators because they know how to use it and they know it fits. A formal Respiratory Protection Program, along with a verifiable fit testing method, is the only way to achieve this optimal protection.

This article originally appeared in the November 2014 issue of Occupational Health & Safety.