Page 34 - OHS, July/August 2021

PPE: RESPIRATORY PROTECTION
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IBY GREG BOOTHE
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n my experience, respiratory protection is one of the more common forms of PPE used by employers in the United States. In many cases, employers
may decide to use respiratory protection to reduce employee exposures to health hazards without trying to reduce personal exposures using more effective engineering or administrative controls. Because the consequences of being exposed to high concentrations of some chemicals can result in severe health effects or death, it is very important that respirators are properly chosen and worn in the workplace.
OSHA published a respiratory protection standard, 29 CFR 1910.134 in 1998.1 The respiratory protection standard is designed to help employers establish and maintain a highly effective respirator program when respirators are required to be used in a workplace. To discuss all of the requirements of the standard would take more space than we have in this article. Therefore, I will focus on fit testing, the use of assigned protection factors (APFs) and the calculation and use of maximum use concentrations (MUCs). These are the areas where I see employers struggle the most with with comprehension and implementation.
Respirator Fit Testing
The respiratory protection standard includes a requirement for a medical clearance for required use of tight- fitting respirators and for some specific respirators even with voluntary use. The medical evaluation is designed to determine if an individual has any medical conditions that might preclude them from being able to safely wear a respirator in the workplace. You would not want an individual donning a respirator and having a heart attack because of the respirator use.
Another requirement of the standard is to perform a fit test prior to the original use of a respirator and annually thereafter. The fit test is designed to determine which type, model and size of respirator will properly fit each individual. An employee
using a respirator that does not fit properly can have little to no protection from the hazardous environment present in the workplace. You do not want an individual to don a respirator and think that adequate protection is provided only to have the worker experience a severe health reaction because the respirator is not providing the protection that it was supposed to.
There are two basic methods that OSHA has approved for determining if a respirator fits properly. These methods are referred to as quantitative fit testing (QNFT) and qualitative fit testing (QLFT). The names tell you that the QNFT method provides a quantitative result while the QLFT provides a qualitative result. Basically, the QNFT provides you with a numerical fit factor indicating quantitatively how the respirator fits the individual while the QLFT just ask if the respirator fits. Of the two methods, my experience has been that a majority of employers utilize the QLFT because it carries a lower initial investment and is easier to perform. OSHA has published the instructions for performing fit tests for the QNFT and QLFT methods in Appendix A to the regulation.
Assigned Protection Factors
OSHA developed the assigned protection factors (APFs) to assist you with the determination of maximum protection for different respirators. The APFs are listed in Table 1 of 29 CFR 1910.134.
When using one of the QNFT methods the respirator is attached to the machine and the result is displayed as a number called the fit factor. Positive pressure respirator facepieces must be converted and tested in the negative pressure mode. The fit factor and the APF are related by a factor of 10. The fit factor must be 10 times higher than the APF to correspond with the APF. Therefore, the fit factor must be at least 500 for all full-facepiece respirators and at least 100 for all quarter- and half- mask respirators in order to pass the fit test. When using the QLFT methods, the individual just has to indicate they do not detect the challenge agent in order to pass the fit test and use the designated APF. The obvious question is: when can I use the QLFT method and when do I have to use the QNFT method?
First, we must look at the different types of respirators that could be used in a hazardous environment. There are two
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30 Occupational Health & Safety | JULY/AUGUST 2021
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