PPE fit testing - what's it all about?

Fit testing masks

This week I’ve been out fit testing FFP3 masks on some of our front line staff, to ensure that their protective masks will work in protecting them and their patients from the spread of Coronavirus. This is new to most of us, so I thought it might be helpful to share with you what happens.

For information on when to use the FFP3 masks, and other Personal Protective Equipment (PPE), please refer to the full guidance on the Gov.uk website. Masks are worn as part of a suite of PPE - please follow the Public Health England guidelines on what to wear, and how to safely put this on (don) and take it off/dispose of it (doff). 

What does FFP3 mean?

'FFP' stands for Filtering Face Piece, and the 3 stands for the level of protection (3 being the highest). These masks are designed to filter out dust, particles or aerosols and they provide protection against transmission of viruses and bacteria via coughing and sneezing, or procedures that cause air movement (for instance a dental drill). These masks are only recommended for use where there are aerosol generating procedures - please refer to the guidelines for further information.

Why do they need fit testing?

It is really important that the FFP3 masks fit, and provide an adequate seal to protect from airborne transmission of the virus. Everyone has a different shaped face, and so there are some people who will find that certain makes of mask won’t fit them properly. It is important that even if you’ve been fit tested for one make, you carry out a repeat test for different ones.

What happens during the fit test?

Step 1: How to wear the mask

The first thing is to learn how to put the mask on and off, whilst making sure to follow social distancing, so staying at least two metres apart from each other. The Health and Safety Executive have put together a helpful poster that shows the basic principles of this process, including what to do if you have facial hair. Take a look at the poster>

Fit testing FFP3 masks

Step 2: Sensitivity testing

Once everyone is comfortable with how to correctly put on the mask, we work one at a time to test the fit.

A ‘vapour’ is used to check the fit of the mask, but before this can be done we need to establish each person’s sensitivity to the vapour. You don’t wear the mask for this part, instead, we ask you to put on a very loose-fitting hood that has a window in the front.

One of two different sprays are then dispensed in to the hood in sets of five puffs. One of the sprays tastes bitter and the other tastes sweet, and as soon as you can taste the vapour we stop. We will spray up to 30 puffs of each spray in order to find a solution you are sensitive to. We do this in order determine your level of sensitivity, and tells us how much to administer in the full test.

Sarah Williams fit testing masks

Step 3: The fit test

The final step is to test the mask. We ask you to put on your FFP3 mask follow by the hood, and start to puff the solution in again (the number of times depends on your sensitivity, i.e. how quickly you tasted it in Step 2). We ask you to do seven things whilst we do this:

  1. breathe normally,
  2. breathe deeply,
  3. move your head from side to side,
  4. nod your head up and down,
  5. lean forward,
  6. talk,
  7. breathe normally again.

The hood and the vapour dispenser are cleaned in between each person.

How do I know that the mask fits properly?

If the mask fits properly, you will not have been able to taste the solutions during the test, and you can now use these masks as per the PPE guidelines.

What if it doesn’t fit?

If you are able to taste the solution when wearing the mask, then it doesn’t fit your face properly. We can try some adjustments, but unless you pass the fit test, you won’t be able to work in situations that require one of these masks. For anyone that finds themselves in this situation don’t worry, there are plenty of other things that you can do, and it’s most important that you are safe.

How long does the test take?

It isn’t the same for everyone, but on average it takes about 10 to15 minutes per person. It sounds a lot worse than it is, with talk of hoods and puffs of liquid solution, but it is not at all stressful and we’ve had a lot of fun doing this over the last week. Maybe we will see you soon.

About the author

I am the Associate Director for Research & Improvement, and lead the Academy, its core team and the clinical academic programme for Solent NHS Trust. I also work nationally and across Wessex on a number of areas, such as quality improvement, research strategy, patient and community partnership working and workforce development.