Face Fit - Qualitative V’s Quantitative Testing
There are two types of face fit testing, qualitative and quantitative. Both are valid and approved methods for face fit testing and each method has its uses and limitations.
Qualitative testing is suitable for disposable and re-usable half masks.
The test is carried out in two stages:
- Sensitivity test confirms that the wearer can detect the test agent (either smell or taste). The test agent is sprayed into a test hood (worn over the head and shoulders) so that the wearer’s sensitivity can be established.
- The fit test requires the wearer to don their face mask and the test hood. The tester sprays the test agent into the hood at intervals whilst the wearer is carrying out a series of exercises designed to simulate movement expected in the workplace (e.g. moving head side to side, up and down, and talking out loud). If the wearer can taste or smell the test agent at any time this indicates a fail – the mask does not fit.
The test takes around 20 minutes to complete.
Whilst the test can be subjective, the likelihood of a wearer being able to hide their reaction to the very bitter test agent is low.
A qualitative test can be used as a good training aid. Once the test is complete the tester will ask the wearer to reach inside the hood and gently lift the mask away from their face. The wearer will then immediately detect the test agent which highlights the protection the mask was affording to them.
Quantitative testing is suitable for all masks.
There are several methods of quantitative testing, the most commonly used is ‘particle counting’ using a machine called a TSI Portacount. This counts the number of microscopic dust particles in the ambient air and compares this to the number of dust particles inside the mask. The machine is connected to the mask with a plastic sample tube. During the test the wearer carries out a series of exercises designed to simulate movement expected in the workplace (e.g. moving head side to side, up and down, and talking out loud). The machine detects particles leaking into the mask and at the end of the test indicates whether the test is a pass or fail.
Quantitative testing is not affected by a person’s sense of taste or smell and is not subjective.
The table below shows what face fit testing method can be used with each type of mask.
CSTS provides a Fit2Fit accredited face fit test service for clients throughout the UK either at clients’ premises or their own training centres.