Working in a hazardous workplace comes with a lot of consequences. But that’s where safety guidelines come in. The safety guidelines by Occupational Safety and Health Administration (OSHA) require you to wear respirators if you work in a hazardous workplace that involves toxic dust, gases, or other substances. A proper respirator fitting shields the wearer from dangerous environments, allowing them to inhale less poisonous substances. However, an employee must undergo a medical assessment and a respirator fit test before using a respirator. Because if your respirator does not suit your face, it will not protect you. And contaminated air can flow into your respirator facepiece if it doesn’t fit your face correctly, exposing you to hazardous compounds. 

So, what exactly is a respiratory fit test? It is a process of ensuring that respirators worn by workers fit perfect for each particular user, performs according to the manufacturer’s requirements and that it offers the amount of protection desired. 

Types of respiratory Fit testing 

The respirator fit testing is divided into two methods:  

1) Qualitative fit testing is a process that detects leakage into the respirator by using your sense of taste, smell or your reaction to a toxin. It does not determine the amount of leakage that has occurred. Qualitative fit testing is commonly used for people who wear respirators that cover their nose and mouth or half-mask respirators. The four qualitative fit test methods accepted by OSHA are Isoamyl acetate, which smells like bananas; Saccharin, which leaves natural sweetness in your tongue; Bitrex, which leaves bitterness in your mouth; and irritant smoke, which can trigger coughing.  

2) Quantitative fit testingmeasures the actual quantity of leaking into the respirator rather than depending on your taste buds, smell, or irritation to determine leakage.  

OSHA has approved three procedures: 

Any tight-fitting respirator can be put through a quantitative fit test (QNDT) to ensure a good seal to increase security and prevent illnesses. 

Process of respirator fit testing 

A respirator’s face to facepiece seal can be tested in various ways. And qualitative fit testing and quantitative fit testing are the two broad categories that consist of all the procedures involved. When quantitative fit testing is not possible, such as when equipment fails or needs repairing or when access to a computer and software is unavailable, qualitative fit testing procedures will be performed. 

Qualitative Fit Testing 

Only negative pressure air-purifying respirators with a fit factor of 100 or less are subjected to qualitative fit testing procedures. The following are the processes for doing qualitative fit testing: 

1. Negative User Seal Check: The wearer gently inhales and holds while the intake ports are blocked. On the wearer’s face, the respirator should be somewhat compressed.  

While sustaining a negative pressure inside the respirator for several seconds, there must be no leakage around the face seal. 

2. Positive User Seal Check: The wearer slowly exhales to generate a modest positive pressure within the facepiece with the exhaust ports covered. There should be no leakage outside around the seal. 

3. If somehow the wearer cannot achieve a suitable facial fit during the negative or positive user seal checks, the head straps should be modified and the operation repeated. To obtain an appropriate facial seal, extreme or painful tightening of the respirator straps is forbidden. 

4. If the straps on a respirator cannot be adjusted to fit, an alternative type and size should be tried. 

Another type of Qualitative Fit Testing is Irritating Smoke Test.                                                      

Once the negative and positive user seal checks have yielded a suitable fit, the quality of the face seal is tested using an irritant smoke. 

The following are the steps to take during the testing process: 

1. Explain the significance and process for irritating smoke testing to the employee. 

2. Tell the employee to take out their lens, if any.  

If the individual wears eyeglasses, they will be equipped with a half-mask respirator to wear while wearing their glasses. But eyeglasses must be removed if a complete facepiece respirator is worn. 

3. Before donning the respirator, a weak concentration of irritating smoke is released towards the individual to see if they can sense it. 

4. After confirming irritating smoke sensitivity, have the test employee put on their respirator and execute the proper user seal checks. 

5. The employees must be instructed to close their eyes tightly and take a deep breath. 

6. If the wearer does not suffer irritation, irritant smoke is released around the entire face and cartridge seal, slowly at first and then increasing the quantity. Throughout the exercises, smoke is continually added to the employee. 

7. The face fit testing is finished if there is no pain from the smoke.  

If coughing, vomiting, or discomfort develops, adjust the respirator straps or switch models, then do negative and positive user seal tests again. 

Quantitative Fit Test 

Each employee shall be fit tested with their respirator once in a while. Depending on the respirator, a particular pre-probed filter or mask will be needed. The processes for quantitative fit testing are outlined below. 

Preliminary Processes include: 

1. Switch on and set up Porta Count, then let it run through the “Daily Checks” self-diagnosis process. 

2. Check for faults and hygienic conditions in all test respirators. 


1. Explain the Porta Count fit test procedures to the individual and make it easier.  

2. Tell the subject to put on the respirator and modify it until it is a comfortable fit. 

3. Install a set of P100 HEPA filters in the respirator. Carry out positive and negative user seal checks on the probed breathing port. Connect the Porta Count sampling line to the probed filter or probed mask. 

4. Ask the participant employee to complete the exercises that the Fit Test Plus software displays. All of the 60-second exercises required to establish the overall assessed fit factor will be performed. Some of the exercises performed by the worker eligible for the face fit testing are: normal breathing with no head movement, deep breathing with no head movement, turning the head slowly sideways while breathing and taking breaths for a minimum of two breaths before changing direction, moving the head up and down while breathing with breaks before changing directions, speaking loudly while breathing normally, distort face to challenge mask seal for just 30 seconds.  

5. After the Porta Count fit test, the subject disconnects the sample line and removes the respirator fitting. Thereafter, the general convenience and tolerability of the respirator are questioned, and any pressure sites are noted. Fit factors are calculated by the Fit Test Plus program for each activity. 

6. Each test result should be recorded to identify the test by number, time, person, kind of respirator, exercise protection factors, and overall test fit aspect. The total measured fit factor, not the individual exams, will determine whether or not a candidate passed the test.  

7. To provide adequate protection, half-mask air-purifying negative pressure respirators must have an overall fit factor of at least 100. And full-face air-purifying negative pressure respirators must have an overall fit factor of at least 500. 

8. Beyond all, the user’s comfort must be the deciding factor.  

 Why is respiratory fit testing necessary? 

Before any respirator is used in the workplace, it must be fit tested on the user’s face. This ensures that workers receive the required level of safety by checking that the seal is tight. A properly fitted respirator will seal against the face, reducing the amount of pollutant leakage. The best-suited respirator’s model type, design, and size are assessed during fit testing. 

As per the guidelines by OSHA, fit testing must be carried out once every year. Apart from that, it is important to conduct fit tests for new employees and during the change of brand of the desired respirator. Furthermore, it is critical to conduct fit tests when employee reports change or when supervisors, doctors, or other certified health care professionals observe physical changes in the employee that could affect the respirator fitting. 

Who requires respirator fit testing (RFT)? 

According to OSHA, respirator fit testing services should be performed on every worker at risk of being exposed to airborne workplace hazards.  

How can Compound Services help you? 

We at Compound Services know respirator fit testing services are essential to prevent accidents and illnesses. But how can you be sure that your respiratory fit testing is accurate? Compound Services can help you with that. Compound Services Australia conducts fit testing in line with AS/NZS 1715:2009, covering the selection, use, and maintenance of respiratory protection equipment. Our aim is to conduct respirator fit test to ensure workplace safety and health. 

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