FAQs- Personal Protective Equipment (PPE) > What do the designations “N”, “R”, and “P” mean when talking about fitted masks?

What do the designations “N”, “R”, and “P” mean when talking about fitted masks?

Respirators/Masks/Facial Covering: Definitions and Differences
posted on 7:08 PM, May 12, 2020

A “fitted mask” is a respirator (filtering facepiece respirator). The letter designations indicate the durability of the mask filtering material and are primarily important for industrial use where workers may be using oily paints (e.g., auto body repair painting shops) or exposed to an oily mist (e.g., drill press operators exposed to cutting oils and lubricating oils). CDC/NIOSH (National Institute for Occupational Health and Safety) approves various manufacturer’s respirators as: Not resistant to oil, Resistant to oil, or oil-Proof.

For the purposes of healthcare workers responding to the COVID-19 pandemic, the durability of the mask construction means that an “R” or “P” respirator will stand up to decontamination and cleaning longer than an “N” respirator. Traditionally, “N” respirators are single use, “R” were for an 8 hour shift use, and “P” is 30 days use. Under “extended use and limited re-use” situations such as this pandemic, any respirator may continue to be used as long as it still fits, the elastics and seal are adequate as determined by a qualitative check of breathing seal (inhale/exhale against your gloved hand), and work of breathing is OK (indicating the filtering fabric is not clogged). When re-using respirators, avoid touching the inside aspect of the mask. For practical purposes, use of facial cosmetics should be minimized while using the masks and the filtering area should not be written on (identification can be maintained on the exterior of a paper bag used for storage or by an ID on one of the elastic bands).


NIOSH-Approved Particulate Respirators. The National Personal Protective Technology Laboratory (NPPTL). CDC/NIOSH. Accessed on May 6, 2020 at:  


Recommended guidance for extended use and limited reuse of N95 filtering facepiece respirators in healthcare settings. CDC/NIOSH. Accessed on May 6, 2020 at: