Fit Testing & Seal Checking Your Respirators

If you’re worried about COVID-19, and you have sent your clinicians and staff into battle with N95 respirators, I hope you’ve fit tested everyone.

While OSHA has temporarily suspended the annual fit test requirement for now, they still take seriously every health care worker’s need for respirator fit testing:

Perform initial fit tests for each HCP with the same model, style, and size respirator that the worker will be required to wear for protection against COVID-19 (initial fit testing is essential to determine if the respirator properly fits the worker and is capable of providing the expected level of protection).

Also, each of your staff should be seal-checking their respirators, each time they put them on. Staff may be embarrassed to admit they don’t know how to do this. A failed seal test means the respirator is not providing adequate protection.

Sending a worker out with an ill-fitting N95 respirator is in some ways worse than sending them out with a plain surgical mask, in that it gives them a false sense of protection and wastes an N95.

The Fit Test - Before You Wear It, Then Once A Year

This sounds complicated, like you need an expert. But any conscientious clinical staff member can manage and oversee this program for your practice. Here’s a good outline of the fit testing process and the required documentation. In brief:

  1. You need a qualitative fit testing kit. You can buy one from a supplier, or sometimes you can borrow one from an obliging local hospital or colleague. The three main components in the kit are a testing agent (usually saccharine), a testing hood, and a nebulizer with bulb.

  2. First, you need a baseline test (“sensitivity”) to ensure that the employee can taste the challenge agent (saccharine). Have an employee don the hood, WITHOUT their N95 mask on. Fill the nebulizer cup with the sensitivity solution, add the atomizer pin, and connect the bulb to the bottom of the cup, where you would normally put the nebulizer tubing. Squeeze the bulb until they can taste the saccharine solution and record the number of squeezes (<10, 20, or 30).

  3. Once you’re certain that they can taste the saccharine, have them rinse their mouth out, then repeat the test, this time wearing their respirator. Have them don their respirator and achieve a good seal, then redon the testing hood over the respirator. Fill the nebulizer cup with the testing solution. Repeat the testing challenge to see if the employee can taste the saccharine.

  4. If the employee cannot taste the saccharine, proceed with the seven phases of testing. The employee should spend one minute each of: breathing normally, breathing heavily, moving their head side to side, moving their head up and down, talking continuously, bending forward at the waist, and again breathing quietly. If these movements and activities do not dislodge the respirator, and the seal stays firm, then the employee should still be unable to taste the saccharine even by the end of the 7 minutes.

YouTube video reference from 3M

The Seal Test - Every Time You Put It On
After putting the respirator on your face, cover the respirator with both hands, trying to occlude as much of the surface area as possible. While holding your hands against the respirator, exhale quickly into the respirator. You should feel the mask press out against your hands. You should not hear or feel air leakage.

Lots of demos on YouTube from US Ag Safety, the University of Nebraska, and 3M (for FFR and elastomeric respirators)

If you are reusing N95 respirators, remember that the external surface of the respirator is contaminated. Wear gloves to touch the external surface of the respirator.

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