If a respirator doesn’t fit your face properly, it won’t protect against exposure to dust or chemicals. But how do you as an employer determine which test will best determine if your worker’s respirator is protecting them against these airborne hazards? The price of the test is sometimes a deciding factor, but it shouldn’t be. Though less expensive, the qualitative respirator fit test may not be the most legally defensible method for certain respirators. And using the wrong fit test could expose your worker to a higher risk of contracting a disease or illness and open your company up to higher workers’ compensation costs.
In this post we offer some insight into how to determine which respirator fit test will best evaluate the effectiveness of the respirators your workers use to protect themselves. We thought it would be helpful to provide you with a definition of each type of testing before we get into the most appropriate testing method for your respirators.
Quantitative vs. qualitative: what’s the difference?
Quantitative respirator fit testing is a robust testing procedure that produces an objective numerical measurement of the ‘fit factor’ of a particular respirator. A particle counting device (such as a TSI Portacount Plus) measures the concentration of microscopic particles that exist in ambient air to measure the ‘fit factor’ directly. The measurement is made while the person performs dynamic movements and/or breathing exercises resembling those experienced in the workplace in order to stress the respirator seal.
The qualitative fit testing is simple and subjective in nature, but can be effective for certain respirators. One common method requires the employee to wear the mask and then attempt to detect a bitter or sweet taste. A solution is injected into a test booth or hood while the employee is wearing his/her mask and if he/she can’t detect it, the test is considered a pass. Of course, this relies on the individual’s sense of smell, which is what makes the test more subjective than quantitative testing.
When to use quantitative fit testing
The quantitative test can be performed on all types of masks and provides an objective, numerical fit factor.
When to use qualitative fit testing
Qualitative fit testing can be used on all half-face masks. However, for full-face respirators, some manufacturers suggest the qualitative method cannot adequately determine whether or not a worker is achieving the high level of fit required for these types of masks. Alberta Health Services recommends following CSA Standards, which state that qualitative fit testing can be used for the following types of full-face piece respirators:
- a) Powered air-purifying respirators, as well airline, continuous-flow or pressure-demand respirators (must be tested in a negative-pressure mode, i.e. without the blower activated).
- b) Negative-pressure air-purifying respirators where the hazard ratio is less than or equal to 10.
The hazard ratio is a value that rates the level of employee protection needed, based on a workplace exposure evaluation by an industrial hygienist. This value is obtained by dividing the concentration of an airborne contaminant by the occupational exposure limit (OEL). So if results from an industrial hygiene audit suggest your company’s brick layers are exposed to 0.105 mg/m(3) per cubic metre of crystalline silica and the exposure limit is 0.025 mg/m(3), the hazard ratio would be:
In this example a qualitative respirator fit test could be used to evaluate the effectiveness of the negative-pressure respirator because the hazard ratio is less than 10.
If your company doesn’t know the hazard ratio and is unable to obtain this value, we recommend performing quantitative respirator fit testing on all full face respirators used by your workers. Without knowing if the qualitative fit test is capable of evaluating the effectiveness of a respirator, you can’t be certain your employees are protected from airborne hazards and your company is protected from costly workers’ compensation claims.
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