N95 Mask Fit Testing for Dental Clinics in Vaughan

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COVID-19 has reached pandemic proportions and the potential for a second wave of the outbreak this fall proves that complacency has no role in the control of new and potentially fatal respiratory diseases.

The leading health organizations all recommend the use of N95 tight-fitting, air-purifying respirators. N95s reduce the exposure to viruses and are also effective when exposed to tuberculosis and other infectious diseases. The prefix ‘N’ refers to not oil resistant, and the respirator will remove 95 per cent of all particles that are at least 0.3 microns in diameter.

The Canadian Standards Association’s Z94.4 standard and provincial regulations for health-care and residential facilities, industrial establishments, and construction sites requires that all workers pass a fit test before wearing a respirator for the first time. Users of tight-fitting respirators require fit testing every two years or sooner.

A corporate respirator protection program must clarify protections available, should another wave of COVID-19 or another infectious disease strike.

Fit-testing program elements

Any comprehensive respirator protection program requires a number of specific elements. Procedures should be available for selecting respirators appropriate for the work being done, for proper use of respirators, for fit testing, and roles and responsibilities of workplace parties.

Additional elements of a program include the following:

  • lists of departments and jobs requiring respirators, as well as a profile and list of respirators required
  • procedures and schedules for storing, inspecting, cleaning, disinfecting and maintaining respirators
  • education of employees regarding potential hazards during routine and emergency situations
  • training of employees on how to properly use, wear, remove and dispose of respirators, as well as the limitations of respirators
  • employee respirator user screening and health surveillance form
  • record keeping — which includes an employee’s name, department, pass or fail of test, brand, model and size of respirator successfully fitted for, date of test and name of tester
  • program effectiveness evaluation procedures.

Protections offered by a comprehensive respirator protection program include properly fit testing for every employee who needs a respirator.

The ‘taste’ test

Upon beginning a fit test, test hoods are placed over employees’ heads. Wearing gloves, the ‘fit tester’ pumps 10 puffs of an aerosolized sensitivity test solution — a dilute version of the fit-test solution (often denatonium benzoate) — into the hood.

Detectable at one part per 20 million, the world’s most bitter substance is a useful tool to stop children from sucking their thumbs or drinking household cleaners.

Because the test is qualitative, the employee will indicate when he tastes the solution. In some cases, workers will tear off their test hoods immediately following the test while others will display a look of disgust. Some do not taste the substance until sufficient concentrations are reached.

The test is given to ensure that employees being fit tested can taste the solution at very low levels, and to determine the concentration of test solution to be maintained during the actual fit test.

Once properly fitted with a respirator, there should be no leaks and, in turn, no taste detected during the fit test.

Employees with compromised respiratory systems (asthma or emphysema) or with chronic heart disease must check with a physician before wearing a respirator. The respirator user screening form provides the opportunity for the user to identify that a prior medical condition exists that may hamper the use of a respirator.

Those employees who have no prior conditions and are able to wear a respirator are administered a bitter test solution or sweet saccharin.

Neither the sweet nor the bitter solution has an odour, so employees are asked to breathe through their mouths for both tests. If an employee doesn’t taste the solution after a maximum of 30 sprays inside the hood, they will require quantitative testing using a calibrated machine.

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