Step 1: Is there enough oxygen?
Filters clean the ambient air, they do not supply oxygen. That is why this question comes first. In tanks, pits, shafts and confined spaces, or if the oxygen content is not certain to be sufficient, no filtering respirator may be used. DGUV Rule 112-190 requires at least 17 % by volume, the instructions for use of the AirGuard Pro products 19.5 % by volume.
Step 2: Which substance is present?
The safety data sheet names the substance and its properties, the risk assessment sets the concentration. The filter type follows from this:
| Kind of substance | Examples | Filter type |
|---|---|---|
| Dust, smoke, mist | Grinding dust, rust particles, paint mist | P (particle filter, P3 in the range) |
| Organic vapours, boiling point above 65 °C | Solvents such as toluene or xylene | A |
| Inorganic gases | Chlorine, hydrogen sulphide | B |
| Acid gases | Hydrogen chloride, sulphur dioxide | E |
| Ammonia and amines | Stable air, refrigerants | K |
| Gas and dust together | Painting, grinding with vapours | Combination filter, e.g. A1E1P3 or A1B1E1K1P3 |
If the substance is unknown, there is no reasoned filter choice. The AirGuard Pro range has no filters against carbon monoxide, nitrous gases, mercury and organic substances with a boiling point up to 65 °C.
Step 3: How high is the concentration?
| Class | Maximum | AirGuard Pro |
|---|---|---|
| Class 1 | 0.1 % by volume (1,000 ml/m³) | AGA1E1, AGABEKK1, AGABEKK1P3 (bayonet) |
| Class 2 | 0.5 % by volume (5,000 ml/m³) | AGA2E2, AGABEK2, AGABEK2P3 (RD40) |
| Class 3 | 1.0 % by volume (10,000 ml/m³) | not in the range |
For particles the multiple of the workplace exposure limit counts, for gases also the gas concentration in % by volume. Both limit which filter and which mask are permitted.
Step 4: Half mask or full-face mask?
| Device | Up to | In the AirGuard Pro range |
|---|---|---|
| Filtering half mask FFP1Disposable respirator 6100 | 4 × limit value | Disposable respirator 6100 |
| Filtering half mask FFP2Disposable respirators 6201, 6203 | 10 × limit value | Disposable respirators 6201, 6203 |
| Filtering half mask FFP3Disposable respirators 6311, 6311C, 6312 | 30 × limit value | Disposable respirators 6311, 6311C, 6312 |
| Half mask with particle filter P1Alternative: AG360 with AGP3R1 or AGP3R2 (P3, up to 30 × limit value) | 4 × limit value | Alternative: AG360 with AGP3R1 or AGP3R2 (P3, up to 30 × limit value) |
| Half mask with particle filter P2Alternative: AG360 with AGP3R1 or AGP3R2 (P3, up to 30 × limit value) | 10 × limit value | Alternative: AG360 with AGP3R1 or AGP3R2 (P3, up to 30 × limit value) |
| Half mask with particle filter P3AG360 with AGP3R1 or AGP3R2 | 30 × limit value | AG360 with AGP3R1 or AGP3R2 |
| Full-face mask with particle filter P1Alternative: AG700 with AGP3R1, AGP3R2 or AGP3R (P3, up to 400 × limit value) | 4 × limit value | Alternative: AG700 with AGP3R1, AGP3R2 or AGP3R (P3, up to 400 × limit value) |
| Full-face mask with particle filter P2Alternative: AG700 with AGP3R1, AGP3R2 or AGP3R (P3, up to 400 × limit value) | 15 × limit value | Alternative: AG700 with AGP3R1, AGP3R2 or AGP3R (P3, up to 400 × limit value) |
| Full-face mask with particle filter P3AG700 with AGP3R1, AGP3R2 or AGP3R | 400 × limit value | AG700 with AGP3R1, AGP3R2 or AGP3R |
| Half mask with gas filterAG360 with gas or combination filter (bayonet) | 30 × limit value | AG360 with gas or combination filter (bayonet) |
| Full-face mask with gas filterAG700 with gas or combination filter | 400 × limit value | AG700 with gas or combination filter |
If 30 times is enough, the half mask AG360 or AG360W is sufficient. If the concentration is higher, or eyes and face are to be protected, the full-face mask AG700 is needed. More under Half mask or full-face mask.
Step 5: Does the connection fit?
Bayonet filters sit in pairs at the sides of half and full-face masks. Filters with an RD40 thread fit singly and centrally only on the full-face mask AG700. Both at once is not permitted. The overview is under Bayonet or RD40.
| Filter | Half mask AG360, AG360WBayonet, two filters | Full-face mask AG700Bayonet, two filters | Full-face mask AG700RD40, one filter |
|---|---|---|---|
| Particle filter P3 RAGP3R1 | fits | fits | does not fit |
| Particle filter P3, glass fibreAGP3R2 | fits | fits | does not fit |
| Particle filter P3, RD40AGP3R | does not fit | does not fit | fits |
| Combination filter A1E1P3 R DAGA1E1 | fits | fits | does not fit |
| Gas filter A1B1E1K1AGABEKK1 | fits | fits | does not fit |
| Combination filter A1B1E1K1P3 R DAGABEKK1P3 | fits | fits | does not fit |
| Combination filter A2E2P3AGA2E2 | does not fit | does not fit | fits |
| Gas filter A2B2E2K2AGABEK2 | does not fit | does not fit | fits |
| Combination filter A2B2E2K2P3AGABEK2P3 | does not fit | does not fit | fits |
Three examples
- Grinding metal: dust only, up to 30 times. Half mask AG360 or AG360W with particle filter AGP3R1 or AGP3R2.
- Spraying solvent paint: organic vapours and paint mist. Half mask with combination filter AGA1E1 (A1E1P3 R D) or AGABEKK1P3.
- Ammonia in refrigeration at a higher but known concentration: full-face mask AG700 with RD40 filter AGABEK2 or AGABEK2P3, class 2.
More examples with notes on limits are under Application examples. The respirator finder works out the combination for your workplace.
Frequently asked questions
Which filter is the right one?
That depends on the substance: P for dust, A for organic vapours, B for inorganic gases, E for acid gases, K for ammonia. Add the concentration (class 1 or 2) and the mask. The respirator finder guides you through the selection.
Is a combination filter enough for everything?
No. A combination filter only covers the types printed on it. It does not help against carbon monoxide, nitrous gases or mercury.
Can I use a particle filter against vapours?
No. Particle filters retain dust, smoke and mist, but not gases and vapours.
Who decides the filter choice?
The employer, based on the risk assessment, usually together with the occupational safety specialist. The selection aid on this website does not replace it.
