We are regularly asked about specific filters in combination with a powered respiratory system (PAPR) and what the possibilities are. This also applies to AX and AXP3 filters in combination with the T-Air blower filter system. Below, we therefore describe why an AX(P) filter cannot be used in combination with an RSG T-AIR PAPR.
EN12941 & EN12942 explained
- EN 12941: deals with Powered Filtering Devices Incorporating Helmets or Hoods
- EN 12942: is about powered breathing systems with a full face mask, half mask or mouthpiece (Powered Filtering Devices Incorporating Full Face Masks, Half Masks or Quarter Masks).
So: 12941 = helmet/hood, 12942 = mask.
Why not an AX(P) filter in combination with a T-Air PAPR?
1. Features of AX filters:
- a. An AX filter is specifically intended for organic gases and vapours with a boiling point below 65 °C (i.e. volatile substances).
- b. The adsorption material becomes saturated very quickly and the breakthrough time is short.
- c. AX filters are therefore, in practice, always disposable and should not be reused.
2. Constraints in combination with PAPRs:
- a. A PAPR works with continuous airflow, which makes an AX filter saturate even faster. This makes protection unpredictable.
- b. The system cannot signal when breakthrough occurs – the user would imperceptibly inhale toxic fumes.
- c. EN 12941 only requires filters that are sufficiently reliable and predictable within the system. AX filters do not meet this requirement because their performance depends on concentration, temperature, humidity and, above all, airflow.
3. Normative exclusion in EN 12941:
- a. The standard explicitly states AX filters are not compatible with powered air systems.
- b. Only filters of types P (particulates), A (organic vapours >65 °C), B (inorganic gases), E (acid gases), K (ammonia and amines) and combinations thereof are permitted.
4. The difference from EN 12942 (masks):
This standard does include AX filters as a filter type, but with strict restrictions:
- Only in systems where airflow is dependent on breathing (on demand).
- For single use only.
- No reuse, as adsorption saturates quickly and there is a risk of desorption.
- Typically used in situations where a mask needs to provide immediate and short-term protection against volatile organic vapours (< 65 °C boiling point).
In a nutshell
An AX filter should not be used on a PAPR system according to EN12941 and EN12942 with a constant air flow because the adsorption material becomes saturated far too quickly under the continuous air flow, making breakthrough unpredictable. This makes the use unsafe and therefore the standard explicitly excludes AX filters.
Conclusion
Even though EN 12942 mentions AX filters, in a PAPR system with constant air flow (i.e. powered air), the situation is identical to EN 12941:
- The filter becomes saturated too quickly.
- There is no breakthrough alarm.
- Use is practically and normatively excluded.
AX filters are therefore only used in practice in non-powered masks (EN 14387 context), where the air flow is dependent on breathing rate.
Selection table:
In the selection table below, we list the possible respiratory protection solutions that can be deployed.
| Situation | AX filter (mask, EN 14387) | Supplied air (airline or SCBA) |
| Short duration (a few minutes, limited task) | ✅ Possible with half/full face mask + AX filter ⚠️ Only single-use, no reuse, and only at known, low concentrations | Optional, but safer if concentration is unknown or fluctuating |
| Medium duration (tens of minutes, repeated use) | ❌ Not suitable – AX saturates too quickly, unreliable protection | ✅ Recommended: SCBA or airline respirator (T-AirLine) |
| Long duration (hours, production/maintenance work) | ❌ Absolutely unsuitable | ✅ Required: supplied air (T-AirLine) or SCBA |
| High concentrations / possible exceedance of explosive or IDLH limits | ❌ Unsafe – breakthrough may occur almost immediately | ✅ Mandatory: SCBA or airline respirator with backup |
| Unknown concentration / unpredictable situation | ❌ Unsafe – no reliable service life can be determined | ✅ Always use supplied air (SCBA or airline (T-AirLine) respirator) |
*SCBA = Self-Contained Breathing Apparatus
Still unsure about what to use? Feel free to contact us! sales@rsgsafety.com.
