Quantitative Fit Testing

Today's article will be all about quantitative fit testing.  What is this exactly?  Well, you know when you see pictures or videos of people working in labs with masks on?  Those masks that those people are wearing need to be tested to make sure that they fit and function properly.  So, there are two types of tests that can be done.  The first is qualitative fit testing.  According to the site https://www.osha.gov/video/respiratory_protection/fittesting_transcript.html , this testing is done by your reaction to smell, taste and irritation.  It is a pass fail test and uses four tests to determine if a mask fits properly.  These four ways include irritant smoke, which will cause you to cough, Bitrex which will leave a bitter taste in your mouth, isoamel acetyl which will smell like bananas and Saccharin which leaves a sweet taste in your mouth.  If any of these symptoms are experienced, then the test fails.  The other type of testing is called quantitative fit testing.  This test uses a hose that is connected to a machine that calculates the leakage of the mask.  If employees need to wear any sort of PPE while on the job, then they need to wear this same PPE during the testing because it may interfere with the respirator.  This testing takes about 15-20 minutes and must be done annually.  Basically, this tests the masks for leaks while the person talks, and moves around while the machine is running.  At the end of the test, the machine gives you the results if the mask is okay to wear.  You should fit test an employee when they are required to wear a respirator while on the job.  This is for safety precautions.  Wearing a respirator protects you from hazards in the workplace.  You may hear the terms fit factor and assigned protection factors, or APF.  These are the numbers assigned to a respirator after a mask has been tested to see if it is acceptable to wear by the employee.  According to the site https://ohsonline.com/Articles/2004/05/Respirator-Fit-Testing-Requirements-and-Procedures.aspx?Page=2 , the fit factor must have a rating of at least 100.  However, the APF only goes up to 50, and incorporates a safety factor of 10.  So, if you want a mask tested by the fit factor to be the same as a 50 APF rated mask then a fit factor of 500 would need to be achieved because the APF has that multiplier of 10.  500 divided by 10 gives you the 50 rating.  So, how does the machine come up with the concentrations to let the user know if the respirator is acceptable or not?  Well, according to the site http://www.moldex.com/healthcare/non-product/fit-instructions/respiratory/fit-testing/qualitative-quantitative.php , the machine takes the concentration of the ambient air outside, and also take the concentration of the particles inside the respirator that may have leaked in.  This ratio of concentrations is what the fit factor is.  So just for a quick recap of fit testing.  Qualitative uses a persons senses to determine if the fit test is successful or not, whereas quantitative fit testing uses the machine to record concentrations of air and compares them to each other in order to find out if the mask is acceptable to wear.  I hope this article was helpful in providing to you some useful information about what fit testing is and how it is done.