---
title: "Why can’t you use an AXP filter on a PAPR according to EN12941 & EN12942?"
url: "https://www.rsgsafety.com/why-cant-you-use-an-axp-filter-on-a-papr-according-to-en12941-en12942/"
type: "post"
published: "2025-09-29T12:40:43+00:00"
modified: "2025-09-29T12:40:45+00:00"
author: "RSGsafety2023"
---

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 s**hould 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).

1.

## 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](mailto:sales@rsgsafety.com).

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