Online Learning > COVID-19 Resources > COVID-19 Web Series FAQs > Personal Protective Equipment (PPE)

ACMT COVID-19 Web Series FAQs

Personal Protective Equipment (PPE)

Personal Protective Equipment (PPE) has been an area of great concern and evolving guidelines as the COVID-19 pandemic has progressed. A portion of the shifting guidelines is attributable to the recognition that many individuals carrying SARS-CoV-2 may be infectious, but not symptomatic. That led to recommendations for face coverings in April 2020 when social distancing was not possible, while such was not recommended earlier in the epidemic in the U.S.A. 

A general lack of understanding of the importance of a range of administrative and engineering controls and work practice changes, as well as significant supply and pipeline deficits for N-95 respirators added further to the confusion generated about appropriate use of “respirators" and “masks.” Early in March 2020, the FDA extended emergency use authorization (EUA) for industrial respirators, but these are not synonymous in all settings to medical N95 respirators. To add yet more to the confusion, the designations N (or R or P) and the particle exclusion (e.g., 95%, 99%, or 99.7% of particles larger than 0.3micrometers) doesn’t adequately describe the good ability of these respirators’ filtering properties for mucous/aerosol-carried viral particles.

We hope that the following over-riding principles and comments will help dispel some of the confusion and mis-information on this very important topic. Because of the rapid changes in response and differences across the country in institutional response and federal guidance, please also consult your local industrial hygiene and occupational health resources. The active webpages from the FDA and CDC are noted below. Please also view the recorded webinar presented on April 8, 2020 and the follow-up town hall held on April 24, 2020. The virtual town hall in particular addressed a number of very practical issues related to appropriate mask use and conservation. The FAQs to the left summarize this material as well.



  1. A face covering protects others from the wearer’s coughs and sneezes
    1. Face coverings do not have seals around your breathing space
    2. Face coverings block the collections of liquid and particles (droplets) breathed, sneezed or coughed out by someone else
    3. The more compact the fabric material (no light shining through), the better the barrier 
  2. A “respirator” requires a good face seal or filtered air into a protective hood (positive pressure)
    1. Respirators protect the individual from inhaled droplets and aerosols containing particulate material
    2. An N95 (or P100, etc.) is a “negative pressure” setup – you inhale against the filtering resistance of the material
    3. A PAPR with HEPA (or other appropriate) filter is a “positive pressure” setup – the air is filtered and pumped into your breathing space
  3. Respirators are coded for durability and particle size exclusion
    1. The letter designation (N, R, P) indicates whether the material will stand up to an oily mist or paint, or degrade faster (N=not oil resistant, R=oil resistant, P=oil proof)
    2. The number designation (95, 99, 100) indicates the ability to exclude that percentage of particles smaller than 0.3micrometer (300nm) when tested against a standard chemical
    3. Viral particles are smaller than 300nm, but are excluded by traversing overlapping grids of adsorbent material
      1. ~100 nanometer particle slowing moving across/through millimeters of fabric (“a journey of more than 1000 times its size”)
      2. Direct impact
      3. Electrostatic forces (“clumping”)
    4. Increased resistance to chemical degradation and greater particle exclusion means increased work of breathing, decreased production throughput, and increased cost
  4. Respirator use after Medical Approval to use a respirator under the guidance of proper fit testing for the brand/size/style redone on an annual basis is the “ideal” for those whose jobs routinely require “respirator fit testing” and use
    1. All direct acute patient care medical providers should have been participating in a “fit testing” program already, although adherence has proven not to be universal
    2. If no changes to physical condition (e.g., >20 pound weight gain/loss) or facial features (e.g., beard, facial reconstructive surgery), OSHA has waived annual fit testing updates during this time
    3. Contact your occupational health provider and industrial hygienist for new hire (never before tested) or expanded scope use of respirators
    4. There is a hierarchy of PPE use and incorporation into exposure reduction practice that may help in time of scarcity
      1. Use Administrative Controls to decrease exposure (limit number of personnel providing direct care)
      2. Use Engineering Controls like a shield, fan, ion generators, negative pressure room, etc. to decrease exposure
      3. Good (in-date) Respirator (N-95) with fit testing in past for size/style/brand and no physical changes
      4. Respirators from other countries with fit testing
      5. Expired N-95 respirator with fit testing
      6. Respirator without a formal fit test (qualitative seal demonstrated by exhaling against gloved hand)
      7. Respirators from other countries without a fit test
      8. Expired respirators from other countries without a fit test
      9. Surgical masks
      10. Home Made devices (e.g., scarves)
      11. Back to Administrative and Engineering Controls
  5. Many aspects of care decrease your risk of exposure
    1. Appropriate PPE is not the only exposure protection
    2. During this pandemic in different areas and at different times, “ideal” and “good enough” will differ
    3. Shielding (e.g., barriers) and Distancing (e.g., “3 or 6 foot rule”) are very important general guidelines
    4. Fans, frequent air exchanges, or negative pressure rooms are very important engineering controls for high-risk areas that significantly decrease viral presence
    5. Avoiding touching face (especially fingers to mask to face – mucous membrane surfaces) and hand hygiene are very important “work practice” changes
    6. Reserve highest level of PPE protection (e.g., PAPR with HEPA filters) for those with highest risk of exposure (e.g., for pulmonologist performing bronchoscopy on COVID-19 patient in ICU)



U.S. Centers for Disease Control and Prevention: Coronavirus Disease 2019 (COVID-19): N95 Respirators. Accessed April 28, 2020 at:

U.S. Food and Drug Administration: N95 Respirators and Surgical Masks (Face Masks). Accessed April 28, 2020 at:

Lynch JB, Davitkov P, Anderson DJ, Bhimraj A, Cheng V C-C, et al. Infectious Diseases Society of America Guidelines on Infection Prevention in Patients with Suspected or Known COVID-19; 4/27/2020. Accessed May 3, 2020 at:


FAQs- Personal Protective Equipment (PPE)

Last updated: May 13, 2020
 What is the difference between a respirator and a face covering or mask? posted on 7:07 PM, May 12, 2020
 How does data on virus viability on surfaces apply to re-use of masks, storage conditions and timeframe? posted on 7:25 PM, May 12, 2020
 Can surgical masks be cleaned/disinfected and re-used? posted on 7:26 PM, May 12, 2020
 What are reasonable cleaning/disinfection/sterilization methods for N95 respirators? posted on 7:27 PM, May 12, 2020
 Can other PPE (gowns, face shields, goggles) be cleaned and re-used? posted on 7:28 PM, May 12, 2020
 What do the designations “N”, “R”, and “P” mean when talking about fitted masks? posted on 7:08 PM, May 12, 2020
 What do the particulate exclusion ratings mean for protection against viruses? posted on 7:10 PM, May 12, 2020
 What is appropriate PPE for treating COVID-19 patients posted on 7:11 PM, May 12, 2020
 What is a reasonable hierarchy of allotment or use of available PPE in time of scarcity? posted on 7:19 PM, May 12, 2020
 At the current time, for those who have been fit-tested previously, what is the minimum required testing? posted on 7:20 PM, May 12, 2020
 At the current time, for those who have never been fit tested previously, what is the minimum required testing protocol? What about workers who have asthma or who are pregnant? posted on 7:21 PM, May 12, 2020
 How long can an individual continue to use a single N95 or other fitted respirator? posted on 7:23 PM, May 12, 2020
 What is reasonable re-use criteria for N95 (or P100, etc.) respirators? posted on 7:24 PM, May 12, 2020
RSS rss