If your company uses tight-fitting respiratory protective equipment (RPE) then a fit test is a legal requirement. The fit test functions to ensure the mask correctly fits the wearer’s face. Therefore it is able to provide its stated respiratory protection. Ill-fitting masks will not have the required tight seal and are leaky and vulnerable to bypass by contaminants. Faces come in all shapes and sizes so it’s not realistic to expect one mask to fit everyone.
Mask types that require a fit test are:
- Disposable respirators (Qualitative or Quantitative test)
- Re-useable half face masks (Qualitative or Quantitative test)
- Re-useable full face masks (Quantitative test only)
Fit testing should be repeated if there is a reason for the mask to no longer fit adequately, such as weight loss or gain. Fit testing is to be carried out by competent person. Although there is no set qualification that deems a person competent, they must be trained and qualified with the knowledge to carry out the testing. The Fit2Fit accreditation scheme run by BSIF has a database of their accredited trainers and this is a great resource to use, to ensure your fit tester is appropriately trained. They also run training courses so someone in your company could become a qualified fit tester, if this is deemed necessary.
Fit testing and facial hair
The seal on tight fitting RPE will be compromised if you have facial hair and stubble you cannot carry out a fit test. However if you must keep your facial fair, non-tight fitting RPE alternatives are available which do not rely on the tight facial seal.
What’s the difference between a fit test and a fit check?
A fit test is the responsibility of employer. It should be completed before any work is carried out in the hazardous environment, therefore ensuring tight fitting RPE fits the wearer correctly. This differs from a fit check which should be carried out every time the respirator is put on and is the responsibility of the wearer. The wearer uses positive and negative pressure techniques to judge the fit of the mask and whilst not required by law it is good working practise to carry out every time before use.
Manufacturers provide their own instructions on how to perform the fit check, but generally once you have put the mask on and moulded the nose piece to your nose if necessary, for a valved respirator you cover the front of the mask with the palms of both hands and inhale sharply. The respirator should collapse slightly on to your face. For an unvalved respirator, cover the front with your palms and exhale sharply, the mask should expand slightly and you should not be able to feel leaks at the seals. If the fit check does not pass, you can adjust the nose piece and the position of the mask slightly. However if you re-perform the fit check and you cannot achieve the sufficient fit, you should not wear the mask for work, as its protection will be compromised.
How to perform a fit test
A complete fit test is performed in two parts called the sensitivity test and the fit test and will use two types of solutions:
- Sensitivity solution for the sensitivity test. You put the test hood on the subject. Then count the number of squeezes of the nebuliser it takes for them to taste the sensitivity solution without their mask on. This informs the tester of how sensitive the subject will be to the test solution.
- Test solution for the fit test. Get the subject to put on their mask and then put the test hood on the. Add the initial dose (based on the sensitivty test) of test solution. This is then topped up with subsequent doses, again based on the results from the sensitivity test. The subject carries out a number of exercises to see if they can taste the test solution. If they fail, the test can be repeated once. If failure is still recorded, stop the test and try an alternative mask.
Read full fit test guide here.
Ampoules vs bottles
The fit test and sensitivity solutions are provided in two main formats – a bottle of liquid or in smaller ampoules. There are pros and cons to both and selection really just depends on user preference. Purchasing your solutions in the larger bottles is more economical. Because fit test solutions do not have published expiry dates, they are okay to use, even if it has been opened before. However having your solution in a smaller ampoule will give that piece of mind that it is fresh. Saccharin solutions may start to crystallise which could block the nebuliser, this is less likely to happen with ampoules. If crystallisation does occur, leave the bottle in warm water for it to dissole before use. Depending of end user sensitivity, 5ml of the 3m solutions is enough for about 10 tests. Each 2.5ml Alpha solway ampoule is enough for around 3-4 tests.
Where to buy?
At Camlab we are able to supply fit testing kits from leading manufacturers 3M and Alpha Solway. Whilst the general method and function of the tests are the same, the difference with products supplied by each are 3M provide their solutions in 55ml bottles, whereas Alpha Solway provide theirs as smaller 2.5ml ampoules (they supply these as packs of 6).
Where can I find out more information?
The official HSE website has a wealth of information about fit testing masks and also respirators and PPE in general. Find out more here.