The International Society for Respiratory Protection

pdf Demystifying APFs for RPE: Attempting the impossible (Vol. 40, No. 2, 2023) Popular


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Demystifying APFs for RPE: Attempting the impossible


Samantha Connell1*, CIH, Stephanie Lynch, PhD, CSP2

1Global Health Programs Director, Indorama Ventures PCL, and President, International Occupational Hygiene Association

2Senior Technology and Research Manager at OHD LLLP, and Vice President, International Society of Respiratory Protection

* Corresponding author and email:



This commentary aims to share international perspectives on respiratory protective equipment (RPE) and the concept of assigned protection factors (APFs). APF is a numerical value established by an organization indicating the level of protection that should be expected for a majority of the population using that respiratory protective equipment (RPE), when used correctly. Different countries and organizations have different approaches to setting AFPs, which can lead to the same exact RPE having different APF values in different countries. After years of navigating multiple country specific rules (or lack thereof), the authors sought to establish which APFs should be applied for companies like theirs that operate globally. In this commentary, the authors do not come to a specific conclusion, rather they share the information they obtained along their journey and provide some discussion of the global situation. The authors are educated in the United States and have international work experience but do not claim to represent all countries' perspectives regarding APFs.


Keywords: respiratory protective equipment, assigned protection factor, nominal protection factor, international standards