Airborne assurance: A guide to N, R, and P respiratory masks
Choosing between an N95, R95, or P95 respiratory mask can be challenging in itself. Add to that having to determine when to conduct fit testing and medical evaluations can leave many people scratching their heads. We’ll help clarify each of these masks and what OSHA expects for compliance.
Is a dust mask a “respirator?”
Yes, OSHA considers a dust mask as a type of filtering facepiece respirator. They are designed to filter air contaminants thereby substantially lowering the risk of breathing in toxic or hazardous substances like chemicals, toxins, pollutants, viruses, and bacteria.
What is meant by “filtering face mask?”
Filtering face masks are no different than a “filtering facepiece respirator” as defined by OSHA at 1910.134(b). Filtering facepiece respirators are negative pressure particulate respirators with a filter incorporated into the facepiece, or that has a facepiece that is made entirely of filtering medium.
What does “negative pressure” mean?
Negative pressure means the air pressure inside the facepiece is negative during inhalation compared to the outside, ambient air pressure. This simply means the user is required to breathe air in through the filter, creating a negative pressure, so contaminants are forced through the filtering medium instead of the lungs.
What’s the difference between N95, R95, and P95 masks?
Understanding which mask is best for a particular task is critical for effective protection. Each of the N95, R95, and P95 masks are classified to filter at least 95% of airborne particles, hence the “95.” However, the major difference between them is their resistance to oil-based particulate.
The National Institute for Occupational Safety and Health (NIOSH) classifies these as:
- N = resistant to particles that do NOT contain oils. Think “no” help with oils.
- R = resistant to oily particles. Think “resistant” to oils.
- P = strongly resistant to oily particles. Think “protects” against oils.
When are fit testing and medical surveillance required?
OSHA's Respiratory Protection standard (1910.134) requires fit testing for all employees using tight-fitting respirators, including filtering facepiece respirators like disposable N95, R95, and P95 masks. The fit test must be performed before the respirator is used in the workplace and be repeated at least annually, whenever a different type of respirator is used, or there is a change in the employee's physical condition that could affect the fit. (NOTE: The user must also perform a seal check each time they don the respirator to ensure a tight fit.)
In any workplace where respirators are necessary for worker protection, employers must implement a written respiratory protection program with worksite-specific procedures, . This includes offering medical evaluations at no cost to employees per 1910.134(c)(1)(ii) even for wearers of an N95, R95, or P95 filtering facepiece respirator (mask).
What if masks are only being used voluntarily?
If an employer has determined that voluntary use of filtering facepiece respirators will not itself create a hazard, the employer's only further obligation under the Respiratory Protection standard is to provide a copy of Appendix D to employee voluntarily using a filtering facepiece mask.
OSHA does not require ft testing if filtering face masks are being worn voluntarily. However, it is still recommended to ensure a proper fit and seal and to help maximize the effectiveness of the mask.
Though voluntary use of a filtering facepiece respirator does not require medical evaluation, paragraph (c)(2)(ii) of the standard also requires employers to ensure that any employee using a respirator voluntarily is medically able to do so, and that the respirator is cleaned, maintained, and stored in a manner that protects the user against any health hazard.
Key to remember: Understanding the differences in masks and associated responsibilities with each type can help assure your employees are protected from airborne contaminants.