The Ins & Outs of Respiratory Protection

Learn the ins and outs of respiratory protection, what the respiratory factors are, how to select a respirator, and more.


Respiratory Protection Factors

Respirators are rated for the level of protection they provide to the person wearing them. These ratings are called Assigned Protection Factors (APF). The APF represents the protection multiplied by the Permissible Exposure Level (PEL) set by OSHA. The one assumption is that the respirator fits properly and no air leaks in or around the seal to the face (this is why we document a “fit test”). Below we’ve outlined general guidelines for the APFs of different types of respirators*:

  • Dust masks and half face dual cartridge respirators, APF of 10
  • Full face dual cartridge respirators, APF of 50
  • Powered air purifying respirators (PAPR) to a hood, APF of 25
  • Full face airline supplied respirators, APF of 1,000
  • Full face airline supplied respirators with escape bottle, APF of 10,000
  • Full face continuous flow airline respirators, APF of 1,000
  • Self-contained breathing apparatus (SCBA), APF of 10,000

*These are general guidelines; APF is dependent upon the type of facepiece used; loose-fitting, helmet, hood, or full facepiece. Unless you have sampled the air and know the PEL, you may not know what level of protection you need. Unless you do fit testing, you won’t know if the respirator is properly sealing to your face. Our Safety Services Team can assist you with fit testing and providing the information you need on respirator usage.


Learn More About Conney Fit Testing

Select a Respirator in 4 Simple Steps

Identify the Contaminants You’re Dealing With

1. The primary source of information on a chemical’s state and physical form is the Safety Data Sheet (SDS). The SDS may also make recommendations for what type of respirator may be needed to work safely with the product. Once the potential contaminants are identified, air sampling should be done to determine how much of the contaminant is likely to be present in a work shift.


Test Your Environment

2. Air sampling can be performed by a consulting firm, through an OSHA consultation, or even by yourself. We encourage you to contact our Safety Services Team to determine the best option for you. This evaluation should include a reasonable estimate of employee exposures to respiratory hazards and an identification of the contaminant’s chemical state and physical form.

Once the contaminant level is established, you should investigate effective hazard control methods, such as engineering and administrative controls, before resorting to a respirator. If you do need a respirator, our trained staff can help you make the appropriate choice.

If the employer cannot identify or reasonably estimate the employee exposure, the employer shall consider the atmosphere to be IDLH (Immediately Dangerous to Life and Health).



Choose a Level of Protection

3. Select a filter that is designed to remove airborne particulates which may be harmful to the lungs in your workplace. Particulates which may be blocked by a filter include dust, fumes (metal particles from welding), fibers, and mists. Dry particulates can be removed with an N95, N99, or N100 filter. Dry or oily particulates can be removed with an R95, R99, P95, P99, or P100 filter.

Note: The “N” in these values refers to “no oil,” the “R” refers to “oil resistant,” and the “P” stands for “oil proof.” The number after the letters has to do with efficiency (note that some particulates do require the highest rated filter at P100).

You may even need a cartridge and a filter, depending on the nature of your work. Cartridges contain either activated charcoal or other sorbent media which can be chemically treated to remove various gases and vapors. We have several types of cartridges to choose from. Certain chemicals will not be blocked by the cartridges and you may need to consider a supplied air system.


Size Your Respirator

4. A mask must fit properly and be fit tested to ensure complete protection. It should have a tight seal around the nose and mouth to prevent leakage. We offer fit testing services to help assist you with this process. Remember that all persons who wear respirators for a chemical hazard must conform to OSHA requirements, which includes fit testing and medical evaluations.

You can learn more about our available services, including fit testing and medical evaluations, through our Inspection & Facility Services page. If you have any additional questions, our Safety Services Team is here to help. You can contact us today at 800-462-1947 or

For more technical guidelines about Air Purifying Respirators and Disposable Respirators, check out the respective Ready Reference documents below.


Download Air Purifying Respirators Reader Reference


Download Disposable Respirators Ready Reference


Related: Learn more about the 3M Secure Click full face respirator and how it could help your workers stay safe.


Silica Standard Whitepaper

The Respirable Crystalline Silica Standard remains a hot topic in the safety industry, as it affects respiratory protection enforcement in a variety of work environments. Gain an in-depth understanding of this standard by downloading our FREE Silica Standard Whitepaper today!

Download Respirable Silica Whitepaper


Respiratory Protection Training

Employees are required to wear respirators whenever engineering and work practice control measures are not adequate to prevent atmospheric contamination at the worksite. When employees must work in environments with insufficient oxygen or where harmful dusts, smokes, mists, fumes, gases, vapors, or sprays are present, they need respirators.

Training is essential for correct respirator use. Employers must teach supervisors and workers how to properly select, use, and maintain respirators—and we can help with this!

Contact us today at 800-462-1947 or to learn more about our training offerings or visit our Safety Training page.


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