Recorded at AIHce EXP 2023
The two most commonly used methods of quantitative respirator fit-testing are based on very different technologies. Controlled negative pressure (CNP) utilizes negative pressure as a direct measure of respirator leakage. Condensation nuclei counting (CNC) uses laser technology to measure aerosol concentrations inside and outside the respirator. While both technologies report a fit factor, the numbers are calculated in two distinct ways. CNP takes a modeled breathing rate that is associated with the and divides it by the measured leak rate. CNC samples the ambient environment and the mask environment and creates a ratio. The concentration of the particles outside the mask divided by the particle concentration inside the mask is the fit factor. Both technologies are accepted in national and international standards. It is important to understand the differences, benefits and limitations of the two methods. This session will cover: 1) the history of respirator fit-testing, 2) the current state, and 3) future innovations. The deepest dive into the two technologies will be the how, when, and where to use each type.
Upon completion of the session, the participant will be able to:
• Describe the technologies behind CNP and CNC respirator fit-testing.
• Recognize the benefits and limitations of each technology.
• Determine when to use which quantitative respirator fit-testing technology.
Donald Elswick, CIH, CSP, CHMM, CIT
Stephanie Lynch, PhD