Respirator Fit Testing

Last time I wrapped up our introduction to respiratory protection, and I closed with some comments on fit testing. Today I’m going to explore fit tests in greater detail, and introduce ten of our 3M products that are used in the process.


You remember the solutions that are used to test the security and quality of the respirators. We sell these solutions both as part of a larger kit (more on that later) and by themselves. There’s something a bit odd, however. There’s two kinds of solution, sweet and bitter. But then there are also two separate products with slightly different descriptions for use, even though their chemical makeup appears to be identical. There’s the FT-12 (sweet) and FT-32 (bitter) fit test solutions, along with FT-11 and FT-31, which are listed as “sensitivity solutions.” They contain the same amount of fluid (55 mL), so what’s the difference?


The sensitivity solutions appear to have drastically lower chemical-to-water ratios, but the data is confusing. For some reason, FT-12 has exact numbers: it’s 45% sodium saccharin and 55% water. But FT-11 says it’s <1% sodium saccharine and >99% water, and both values are marked as a trade secret. To use 3M’s words, “The specific chemical identity and/or exact percentage (concentration) of this composition has been withheld as a trade secret.” Then I checked the data for the bitter solutions. FT-32 is marked as 90-100% water, 3-10% sodium chloride, and 0-1% denatonium benzoate. F-31 has the exact same number ranges, but again marked as a “trade secret.” An instructional video shows that FT-11 and FT-31 are for measuring the user’s sensitivity to the substance, whether their taste buds are able to detect it at all at an extremely low concentration . The other two, obviously, are used for the fit test procedure itself. FT-12 must be extremely sweet, considering its percentages are so close compared to FT-32.


For a full fit testing kit, we offer two full qualitative fit test apparati, the FT-10 with sweet solution and the FT-30 with bitter solution. There’s also the FT-20 package, which includes all the items from FT-10 along with extensive training material (posters, brochures, videos, etc). What items are those?


To do the fit test, you’ll need three pieces of hardware: nebulizer, test hood, and collar. The hood (FT-14) is a rather funny-looking white bag with a clear face window and a valve in the middle. It is placed over the head for both the sensitivity and fit tests. It is held in place with the collar (FT-15), which fits over the shoulders and secures the hood over the head. The valve pops open to administer the test with the nebulizer (FT-13), which first administers the sensitivity test by squeezing into the mouth in sets of 10. If you can’t taste the agent after 30 squeezes, the other solution is used. The process is repeated, with the respirator on and using the fit test liquid. If you can’t taste it after 30 squeezes, the respirator has passed the test and is cleared for use in the field.


Fit testing is a crucial component of any respiratory protection program. Make sure you sanitize the inside of the hood and collar for each test subject. Stay safe.

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