I get this question occasionally. It usually comes with a half smirk and a “they won’t fit any different next year.”
I assume most of them are joking (or at least I hope they are). I often mention that a person’s face changes slightly each year and that can affect how a respirator fits. NIOSH has a recently released a study verifying that point (especially those wearing N95s), which gives me something I can now point to.
So what did they want to do with the study?
NIOSH initiated it to address three primary questions:
- Does respirator fit change over time?
- Does weight change cause respirator fit change?
- Is annual fit testing necessary?
A CDC blog summed up the study and results nicely:
Researchers focused on FFRs (filtering facepiece respirators) because they are the most commonly-worn respirator used in the healthcare industry and the necessity of annual fit testing for these types of respirators is often debated. The study included seven different sizes and models of N95 FFRs, all of which were purchased for the CDC Strategic National Stockpile at the time the study was initiated.
The researchers were interested in measuring the fit factor, which tells the researcher whether a respirator fits the subject properly or not. Subjects qualified for the study by demonstrating acceptable fit for one of the N95 FFR models in the study. They then used samples from that same FFR model for the remainder of the study. Fit factors from nine donnings (putting on the respirator) were measured and physical characteristics of the subjects were captured approximately every 6 months for a 3 year period.
The study found that the longer workers went without being fit tested, the greater the chance of exposure.
The estimated percent of workers whose respirator did not fit them increased with increasing length of time between fit tests, from 10% at Year 1 to 20% at Year 2, doubling those at risk for exposure if not fit tested, and to 26% at Year 3. This exceeds the 7% threshold used by OSHA in 1998 during rulemaking. Additionally, twenty-four percent of subjects who lost more than 20 pounds no longer maintained an acceptable fit.
So, basically to answer the three questions: yes, yes and yes.
Learn more about respirator fit testing
- Read theOSHA 1910.134 specification
- TSI PortaCount Pro series quantitative respirator fit test systems
- Other posts about respirator fit testing
RAECO-LIC LLC is the authorized TSI representative in the Midwest United States.