ABEK respiratory filters – meaning, filter classes and correct selection

The BartelsRieger guide to using ABEK respiratory filters

ABEK respiratory filters are multi-type gas filters for certain organic and inorganic gases and vapours, acid gases, ammonia and organic ammonia derivatives. The letters identify the gas filter types. An ABEK-P3 combined filter adds a particle filter of a specific classification. The suitability of a respiratory filter depends on the contaminants, exposure, temperature, humidity and the facepiece used. It must be noted that filtering respiratory protective devices do not protect against oxygen deficiency. They must not be used where the ambient atmosphere contains less than 17 vol.-% oxygen (in some countries not less than 19 vol-% oxygen). 

When maintaining plant or cleaning components, you need to assess whether the available respiratory protection is suitable for the intended work. The marking “ABEK” alone does not answer this question. 

Here you will learn how to interpret the marking, which limitations of use must be observed and what information enables you to select a suitable filter.

What does ABEK mean in respiratory protection?

ABEK combines four gas filter types. Each letter is assigned a colour code. 

This system provides an initial guide. It does not replace an assessment of the specific substance and conditions of use.

For maintenance and cleaning work, you should therefore consider the agents used and any potential process residues. An enquiry such as “We need respiratory filters for plant cleaning” is easier to answer if the relevant substances and working conditions have already been described and material safety data sheets (MSDS) are available.

ABEK1, ABEK2 and A2B2E2K1: what do the numbers mean?

The gas filter class describes the capacity

Gas filters are divided into three classes according to their capacity:

• Class 1: low capacity
• Class 2: medium capacity
• Class 3: high capacity

A higher number indicates greater capacity, not lower filter penetration. If the other conditions of use remain the same, a respiratory filter with a higher capacity may remain usable for a longer duration.

The marking therefore does not specify a duration: “ABEK2”, for example, cannot be used to determine a fixed number of hours of use.

Read each number individually

A2B2E2K1 indicates class 2 for A, B and E, and class 1 for K. With A2B2E2K2, also referred to as ABEK2, all four types are assigned to class 2.

When comparing or reordering respiratory filters, provide the full marking and, wherever possible, the article number. This ensures that differences between models with similar designations remain apparent.

What role does DIN EN 14387 play?

DIN EN 14387 specifies the requirements that gas filters and combined filters must meet, how they are tested and marked. Refer to the documentation for the specific product to identify the applicable edition of the standard.

However, the standard designation on a product does not replace selection for the intended application. Follow the documentation for the respective respiratory filter and facepiece.

ABEK or ABEK-P3 – what is the difference?

An ABEK gas filter alone does not provide protection against particles. An ABEK-P3 combined filter combines the gas filter types with a class P3 particle filtration stage.

Particle filters are divided into the following particle filter classes according to their particle filtration efficiency:

• P1 (low filtration efficiency)
• P2 (medium filtration efficiency)
• P3 (high filtration efficiency)

Particulate contaminants include solid or liquid aerosols, such as smoke, dust and mist, and airborne biological agents, such as mould, fungi, spores, viruses and bacteria.

The working method also matters when selecting a filter. For example, describe whether a cleaning agent is applied, sprayed or used in another process. This information helps to assess potential exposure.

An additional P2 or P3 stage does not turn a gas filter into universally suitable respiratory protection. With combined filters, the limitations of use of the complete device (filter and facepiece) must also be observed.

When is an ABEK respiratory filter insufficient?

Oxygen deficiency and unknown atmospheres

A respiratory filter does not supply additional oxygen. Filtering respiratory protection is therefore unsuitable where oxygen is deficient. The German DGUV Rule 112-190 also excludes its use under unknown ambient conditions. If adequate protection cannot be ensured with filtering devices, self-contained breathing apparatus independent of the ambient atmosphere must be used.(Source: DGUV Rule 112-190, 2021)

For work planning, this means that missing information about the atmosphere cannot be compensated for by selecting a filter with an extensive marking.

Particularly for maintenance work, it should therefore be established at an early stage what information is available about the place of use and who will carry out the necessary assessment.

The employer may only permit work involving hazardous substances or biological agents to begin once a risk assessment has been carried out in accordance with e.g. section 6 of the German Hazardous Substances Ordinance (GefStoffV) or section 4 of the German Biological Agents Ordinance (BioStoffV), respectively. The risk assessment must be reviewed at regular intervals and whenever circumstances require, and updated where necessary.(Source: DGUV Rule 112-190, 2021)

Specific substances and mixtures

The ABEK marking does not indicate protection against carbon monoxide. Low-boiling organic compounds also require a separate filter selection assessment; type A applies to boiling points above 65 °C. Special gas filters marked AX, also colour-coded brown, are available for low-boiling organic compounds with a boiling point ≤ 65 °C.

You should therefore avoid general orders such as “respiratory filters for solvents”. Specify the substance or mixture used. Have the material safety data sheet available and describe the intended task.

How do you select a suitable ABEK respiratory filter? 

Start with the working conditions. Product selection follows from the risk assessment. This should cover the nature and extent of the risk, its duration and its likelihood for employees.

Preparation checklist

Use these items to gather the information needed for your selection decision. Make the decision itself on the basis of the workplace risk assessment.

Example: preparing for plant cleaning

Hypothetical example: a maintenance team is to treat components with a cleaning agent. Full face masks and ABEK respiratory filters are already available.

The task and cleaning agent are documented for the enquiry. This is supplemented by the available exposure information and the exact mask and filter designations. Unresolved questions are explicitly identified.

This allows an assessment of whether the existing equipment can continue to be used or whether a different solution is required. The mere availability of an ABEK filter does not constitute authorisation to use it.

Which respiratory protective mask is compatible with the ABEK respiratory filter? 

Observe the connection requirements and manufacturer’s information 

Among other products, BartelsRieger offers screw-in filters with a standard thread connection in accordance with EN 148-1. 

Do not simply check whether a respiratory filter can be mechanically connected. The manufacturer’s information on the intended combination and the requirements of the application are decisive. 

Half face mask or full face mask? 

A general statement covering all ABEK respiratory filters is insufficient. For example, the data sheet for the BartelsRieger BR ABEK specifies use with full face masks with a standard thread connection. This use is also described for the BR A2B2E2K2 P3. 

Filters weighing more than 300 g must not be connected directly to mouthpiece assemblies, half face masks or quarter masks. Filters weighing more than 500 g must not be connected directly to class 2 and class 3 full face masks. (Source: DGUV Rule 112-190, 2021) 

The facepiece must also fit the wearer. With tight-fitting masks, for example, a beard or other interruptions to the face seal may affect suitability. Assessing the fit by means of fit testing should therefore be an essential part of ensuring the effectiveness of a respiratory protective device. 

If you wish to continue using existing masks, specify the exact model in your enquiry. This makes it easier to check against the product documentation. 

How long can ABEK respiratory filters be used? 

Distinguish between three time periods 

Three different aspects are relevant when considering how long a filter lasts:

For the BR ABEK filters, the data sheet specifies a shelf life of six years from the date of manufacture under the stated conditions. According to this document, opened respiratory filters must be replaced after six months at the latest (special documentation required). This period is not a guaranteed duration of protection.

Plan filter replacement to suit the application

How quickly a respiratory filter becomes exhausted depends on exposure and working conditions. These include the substances present and their concentrations, the breathing volume of air required, temperature and humidity. If the wearer of the filtering respiratory protective device cannot detect filter breakthrough (by smell and/or taste), selection requires specific workplace rules for use (operating instructions); otherwise, breathing apparatus must be used. (Source: BG RCI – Respiratory Protection Guide)

A fixed operational replacement schedule can make organisation easier. However, it must be derived, from a technical perspective, from the operating conditions and the manufacturer’s specifications. A general replacement interval without this basis is insufficient.

With a combined filter, both filter components must remain suitable for use. If either the gas filter component or the particle filter component reaches its limit of use, the respiratory filter must no longer be used.

Store opened respiratory filters correctly

Store respiratory filters outside the contaminated work area. Protect them from dirt, moisture, extreme temperatures and other damaging influences. The storage requirements for the respective product remain decisive.

Keep a traceable record of the opening date, contaminant(s) and duration of use. This allows filter management to be integrated into workplace procedures.

ABEK respiratory filters from BartelsRieger

The following overview provides an introduction to the range. The product pages contain further information and documentation to support the selection assessment.

The overview shows selected models. Variants with Hg markings and special connection configurations are also available or listed. 

The screw filters and positive pressure filters categories provide a broad overview