Why the seal decides
According to DGUV Rule 112-190 a respirator with a sealing face piece only gives effective protection if the face piece fits the wearer. If it does not, air flows past the sealing line unfiltered. This applies to disposable masks, half masks and full-face masks.
Fit check: the requirement
The rule provides that the fit is checked before first use under the guidance of a trained person. In the workplace qualified persons for fit checks do this. When changing model or size or after changes to the face, for example through scars or strong weight change, it should be repeated.
Qualitative or quantitative
| Method | How it works | Note |
|---|---|---|
| Qualitative | The person notices a test substance by smell or taste if the mask leaks. What is assessed is whether they notice the substance. | Simple, no instrument. Requires that the person can perceive the test substance. |
| Quantitative | An instrument determines the fit factor, the ratio of particle count outside to inside. | Measurable and documentable. For fire services the DGUV treats quantitative testing of full-face masks as an additional measure, for example with repeated leaks. |
For quantitative tests to ISO 16975-3 a compilation by BGN names required fit factors: 100 for half masks, 2,000 for full-face masks.
What you do yourself every time you put on the mask
- Put on the mask according to the instructions for use, straps firm but not painful.
- With disposable masks shape the nose clip to the nose. See Putting on an FFP mask.
- Carry out the seal check as described in the instructions for use and put the mask on again if it leaks.
- Beard, sideburns and glasses frames must not interfere with the sealing line. See Face seal and beards.
Fit with the masks
The full-face mask AG700 and the half mask AG360 are available for different faces according to the instructions for use. With disposable masks such as 6201 and 6311 you check the fit every time you put the mask on. If you are not sure which model fits, the respirator finder helps.
Frequently asked questions
Must the seal be checked?
DGUV Rule 112-190 provides for a check of the fit before first use by a trained person. In addition the seal check when putting on, as described in the instructions for use, belongs to use.
What is a fit test?
A method that checks whether a mask fits the shape of the face. There are qualitative methods by smell or taste and quantitative ones with an instrument.
How often must the fit test be repeated?
The rule does not state a flat deadline. When changing model or size and with changes to the face it makes sense again. Set it in the risk assessment.
Does a beard work with an FFP mask?
No. A beard or sideburns in the sealing area prevent a tight fit. See Face seal and beards.
