American Society for Testing and Materials (ASTM)

ASTM International is a globally recognized leader in the development and delivery of voluntary consensus standards. Today, over 12,000 ASTM standards are used around the world to improve product quality, enhance health and safety, strengthen market access and trade, and build consumer confidence.

A respiratory fit test is used to verify that a selected make or model of N95 respirator properly fits, seals, and protects the employees or users required to wear the respirator for a specific task.

A fit test is not a general test, but a specific test administered for all brands and models of NIOSH-approved respirators to ensure that the wearer identifies the product that works best for them and their facial structure. Just like every individual’s facial structure is different, every make and model of an N95 respirator is shaped differently and therefore they do not fit all individual’s facial structures the same way.

The Occupational Safety and Health Administration (OSHA) outlines a protocol, as well as general requirements for fit testing, in Standard 1910.134 App. A. As part of the policy, employers must annually fit test employees who are required to wear a respirator to do their job.

Fit testing is not just an OSHA requirement for safer workplaces; it’s a matter of an employee’s livelihood. If you or your employees need to wear respiratory protection on the job to protect from dust, harmful chemicals, fumes, or gasses, you better make sure that it works. And the only way to do that is with a fit test.

Fit testing may seem like a nuisance to some, and because it can take time and expense to administer, companies may struggle to adhere to the annual OSHA requirements. But if your N95 respirator doesn’t fit properly, it will not protect you or do the job it is intended to do. If that’s the case, your level of protection may be no better than wearing no mask at all.

Employers and wearers have two options to conduct a fit test to determine the proper fit of an N95 respirator: quantitative fit testing and qualitative fit testing.

Fit Factor Score is the ratio of airborne particle count outside the respirator vs inside the respirator during a fit test procedure. NIOSH N95 approval calls for respirator samples to exceed a Fit Factor score of 100 or above.

Fit Capability Score is the percent of test panel subjects during ASTM RFC testing that achieved a Fit Factor Score above 100

A quantitative fit test uses a computerized precision instrument to measure the amount of leakage an N95 respirator may have when worn on a user’s face and then calculates the results. The result of the quantitative test is a Fit Factor score, which expresses how well that particular N95 fits the face of the test subject.

The measurement device, commonly known as a PortaCount® Respirator Fit Tester (by TSI Incorporated) determines how many airborne particles can break through the respirator’s seal while the wearer is simulating common body motions such as bending and head turns, as outlined in OSHA’s fit testing procedures.

Qualitative fit testing uses the body’s senses of taste and smell to detect a seal leak. Instead of using a machine to measure leakage, the tester drapes a loose testing hood over an individual wearing an N95. The hood is used to restrict ambient air from diffusing the airborne test solutions that are used to conduct the test. Qualitative fit testing can be conducted using strong sweet solutions, bitter solutions, or an irritant smoke.

The purpose of a respiratory program is to ensure that all employees required to wear respiratory protection as a condition of their employment are supplied with proper and well-fitting respirators and protected from respiratory hazards.

The operation and maintenance of a respiratory protection program is the responsibility of the employer.