Train The Trainer

What do I do if a face fit test fails?

If the subject tastes the ‘leak-detector’ at any point during the test then a fail is to be recorded. Equally, if the subject doesn’t taste the solution at the end of the test when we ask them to break the seal a fail must also be recorded (was there ever enough in there for them to have tasted it).

In all cases of a fail being recorded, a period of 30 minutes should be waited before starting the test again from the sensitivity test. There will be additional requirements too which we’ll cover on a case by case basis in the rest of this article.

Let us try and break down now some of the common reasons for a face fit test to fail, firstly, we’ll look fails for reasons other than the mask not working along with what should be done.

A leading cause of failure not down to the mask not working would be coughing, sneezing or laughing during the test. These ‘special events’ are not ones we expect a mask to work through and so a test can be repeated on the same mask. They are, however, very easy to miss when doing a test.

Why? Well, typically our subject won’t taste the solution at the time of the cough, sneeze or giggle. It will be 3-5 seconds after which means unless we are paying close attention it’s easy to miss the root cause. Always listen out for these events and quietly log them, if nothing is mentioned carry on with the test.

Fails owing to other causes can occur at any point of the test but generally, failures tend to be within the first few exercises and it’s down to the tester to determine the cause, apply the necessary corrective action and retest. A methodical approach to rooting out the cause of failure is best applied:

1) Are we happy the failure wasn’t caused by a laugh, cough or sneeze or other non-standard facial movement?

2) Remove the hood and now check fitment of the mask. Are straps secured and located right, is the nose-bridge adjusted correctly and is it located on the face correctly?

3) Check the mask for faults and defects. Are the filters installed properly? Is the exhaust valve obstructed? Is there a tear in the mask? Does the mask have a particulate filter attached rather than a vapour filter?

Typically if all the above is ok then it is time to try a different mask as in all likelihood the one initially used isn’t suitable for this subject. Generally it is accepted that a single retest is permitted on a mask.

If the test goes well but the subject cannot taste the solution when they break the seal between the mask and face at 7 minutes then we also have some investigating to do:

What was their sensitivity result? Whilst they may have tasted the solution in 1-10 sprays, someone who required >7 sprays has a very different susceptibility to that of someone requiring <3 sprays. It maybe that while they tasted the solution we weren’t really in the ‘sweet-spot’ of their taste.

A repeated sensitivity test may yield a higher number of sprays for a strong reaction meaning that upon repeating their face fit test more of the test solution is used.

It’s also possible we either picked up the wrong nebuliser or topped up the right nebuliser with the wrong liquid. Equally the nebuliser may be blocked and/or our squeezing of the bulb may have been below that required for a proper delivery into the hood.

Taking apart both nebulisers and washing them thoroughly before refilling is a minimum requirement before retesting anybody in this circumstance.