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Why Is Respirator Fit Test Important?

“It’s critical to understand the ultimate reason why you wear respirator. It is to protect yourself from harmful gas, chemicals and other airborne elements. However, just putting on a respirator does not necessarily protect yourself from respiratory related ailment. Hazardous elements could easily get through into your respiratory system if the mask of the respirator does not fit you.” Edward Chow, VP & GM of Asia Pacific, TSI Instruments.

“How do you know whether a particular respirator fits you or not?  You will need to do a FIT TESTING to ascertain how well a particular respirator fits your unique facial contour. FIT TESTING is similar to testing how well a scuba diving masks seal to your face in an underwater test. However, in this case, you don’t need to get wet in a FIT TESTING.”

“I believe this article will provide you with a better understanding on how to protect yourself against harmful elements by using FIT TESTING to select an optimal model of respirator.”

“Maintaining occupational health and safety is our principal concern.”


As a Health & Safety professional, we know that in some of the healthcare, industrial and manufacturing sectors, workers are constantly exposed to airborne contaminant. These airborne contaminants are often invisible because of their small size or ubiquitous nature. You are not able to see, feel or even smell them.

These airborne contaminants can be in many forms such as chemical, biological, dusts, mists or fumes. Years and years of breathing these can caused respiratory problem in the long run, some of the contaminants are so toxic that can even cause cancer.  Implementing and maintaining a proper respiratory protection program not only keeps workers safe, it helps your organization comply with the various national standards or directives.

 The purpose of this article is to understand how the importance of FIT TESTING. 


In any of these hazardous environment settings, workers are susceptible to airborne contaminants. The primary reason to fit test an individual is to verify that he or she has been trained to wear a respirator and has in fact learned how to don the respirator correctly. Respirator sizing is certainly important, but secondary. If a person does not know how to use the equipment, the protection level afforded will be compromised regardless of whether or not the respirator is the right size.

A good respiratory protection program includes respirator-specific training for individuals who must wear a respirator. Some organizations hold day-long classes and others may spend a shorter time, but without exception, the employees are taught the why and wherefore of respirator usage, and are given a chance to work with the respirators.

A fit test should be thought of as a final examination. Students go through a training course that includes classroom instruction and hands-on practice, and then take an exam to determine if they really learned the material. At the same time, assuming they don the respirator correctly, they find out which size respirator is right for them.

Proper implementation of an organization– wide Respiratory Protection Program (RPP) is a huge undertaking but 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 meet compliance of strict National standards and industry directives (i.e., OSHA Respiratory Protection Standards 29 CFR 1910.134, CSN EN 592-2005 Respiratory Protective Devices, Centers for Disease Control & Prevention (CDC) and The National Institute for Occupational Safety and Health (NIOSH)) and instill trust in workers that their respirators work.


Fit testing of the N95 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 can only be detected if the respirator leaks unacceptably. QNFT is an objective test that involves the use of an instrument to measure how well the respirator fits by actual measurements taken during the fit test, and not being dependent upon a person’s voluntary response.


QLFT is a low cost, subjective pass/fail test that exposes the respirator wearer to a chemical stimulant (while donning a test hood) that can only be detected if the respirator leaks. Multiple challenges exist for QLFT, including operator error and fatigue as well as deceitful responses from the person being fit tested, not to mention the book keeping challenges it presents.


QNFT method measures an aerosol challenge agent on the outside of the respirator (Cout) as well as on the inside of the respirator (Cin) as the wearer performs a series of exercises that approximate conditions of use, while the results are recorded. The ratio of the two measurements (Cout/Cin) is called a fit factor.


A N95 or half-faced respirator requires having a fit factor of at least 100 to pass the fit test. This means that the air inside of a properly donned respirator must be at least 100 times cleaner than the air outside of the respirator.

For a full-faced respirator, different standards dictate fit or protection factor. OSHA and National Fire Protection Association (NFPA) require a protection factor of at least 500 for full-face respirators; American National Standards Institute (ANSI) requires 1000. UK Government HSE website, provide a document on ‘Respiratory protective equipment at work’, that state a fit factor of 2000 for full-faced respirator. 

QNFT method have a technological advantage in that they use computers and specially designed software to conduct and adhere to the fit test protocol, maintain records and facilitate printing of fit test certification cards that individual worker can carry. It’s virtually impossible to make mistakes and eliminates negative tendencies those plague QLFT. Being more simple and portable, the Ambient Aerosol method of QNFT is the most economical and the industry preferred method. 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.


Ambient aerosol fit test instruments were first introduced by TSI more than 20 years ago. Today, TSI offers the industry-proven PortaCount® Respirator Fit Tester, the best OSHA-accepted fit test method. Only the PortaCount Fit Tester can:

+ Enable real-time fit optimization

+ Facilitate training on proper donning procedures

+ Speed up testing time using real-time fit factor technology

+ Eliminate errors with automated step-by-step guidance

+ Ease of managing reports and record keeping

+ Go above and beyond regulatory compliance

+ Test all types of N95 half-face and full-face respirators


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 the National Institute of Occupational Safety and Health (NIOSH) in 2007, the title “Simulated Workplace Protection Factors for Half-Facepiece Respiratory Protective Devices” was published by the Journal of Occupational and Environmental Hygiene Vol 4, No 6. Pp420-431, June 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. The results show that any fit test method significantly improves respirator protection and QNFT is particularly beneficial, showing the respirator with QNFT provides the wearer the optimum protection.

All too often companies, and manufacturing facilities alike, 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 the respirator 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 optimum protection.

 contact us to demonstrate how QNFT works for you.

Singapore : +65 6595 6388

India : +91 80 67877200

China : +86 10 82197688

Published: 16-12-14

Click here for more information: http://www.tsi.com/Landing-Pages/PortaCount-Pro--8038-Landing-Page.aspx


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