Air Filter Standard ISO 16890 – The step in the right direction

6 questions and 6 answers

At the end of the year 2016, the filter standard ISO 16890 came into force for the test and evaluation of air filters for ventilation and air conditioning technology. Since then, publications have dealt mainly with the technical problems. At this point, the general meaning of this standard should be made clear by means of questions and answers.

1. The last amendment of EN 779 took place in 2012. – Why introduce a new standard now?

EN 779 is binding in European member countries, e.g. as DIN EN 779 in Germany. Outside of the EU other significantly-deviating standards exist, e.g. the U.S. Standard ASHRAE 52.2. For the international community, it is important to have standards available which are binding world-wide, such as ISO 16890. Furthermore, the transferability of the test results from EN 779 to real applications is always problematic, and the informative value with respect to the generated air quality is limited. This will be significantly improved by ISO 16890.

2. What is the time schedule planned for the introduction of ISO 16890?

A comprehensive, and also juridical, difference exists in the ratification of an initially non-binding ISO standard and the binding fixed-stipulation in writing as DIN EN ISO 16890 as a new German standard. These formalities will probably be concluded by June 2017. Then, in a transitional period to June 30, 2018, both air filter standards DIN EN ISO 16890 and DIN EN 779 will exist in parallel. From the 3rd quarter of 2018, air filters are to be tested and evaluated exclusively according to DIN EN ISO 16890.

3. Why was the transitional period of 18 months provided?

For putting into effect as DIN EN ISO 16890, 2 significant technical prerequisites are to be met, which require a transition period. On the one hand, while ISO 16890 does include a valuation procedure for air filters, e.g. ISO ePM2.5 60% however, there is no classification process in which the test results are classified. Within the group of the ISO ePM Coarse, no differentiation into individual classes currently exists at all. In DIN EN 779 e.g. filters which indicate medium efficiencies between 80-90% are classified into the Filter Class F7. Such filter classes must be formed and arranged for the ISO in the months following. It is currently not decided whether their classes should be formed in every country or a common international classification should be formed.

In addition, all regulatory specifications, which are presently based on EN 779 or DIN EN 779, must be adapted to ISO. VDI 6022, as an important binding regulatory specification, presently prescribes the employment of certain filter classes, e.g. F7/EN779. These classes must be replaced by ISO equivalents. On the other hand, it is scarcely conceivable that all adaptations will be settled by 2018 and that the binding DIN EN 779 validity can be withdrawn by then. Every filter user should therefore wait for the work of the specialists. This creates a breathing space in which to examine the meaning and possibilities of ISO 16890.

4. What is the technical progress of ISO 16890 compared to DIN EN 779?

ISO 16890 evaluates in future the particle separation characteristics of air filters with a view of the fine dust fractions PM10, PM2.5and PM1. PM (Particulate Matter) values are used by WHO and the environmental-protection authorities as a measure for the evaluation of air quality.

PM valueFine dust fraction
PM100-10 µm
PM2,50-2,5 µm
PM10-1,0 µm
Table 1: Definition of the fine dust fractions

Since the fine fractions are considered particularly hazardous to health, limit values for particles in ambient air have been stipulated with the EU Directive 1999/30/EG. The Federal Office for Environmental Protection determines PM10 and PM2.5 values at approx. 300 measuring points in Germany and publishes these regularly.

While the present DIN EN 779 evaluates the separation characteristics with respect to an individual particle size (0.4 µm), ISO 16890 subdivides air filters into 4 ISO groups, dependent on their separation characteristics with respect to the PM particle collectives.

ISO groupParticle collective Minimum efficiency
ISO ePM Coarse0,3-10,0 µm< 50 %
ISO ePM100,3-10,0 µm> 50 %
ISO ePM2,50,3-2,5 µm> 50 %
ISO ePM10,3-1,0 µm> 50 %
Table 2: ISO groups with corresponding particle collectives

A filter is taken into the appropriate group if the corresponding minimum efficiency is exceeded. Accordingly, if a filter separates out the particle collective of 0.3-2.5 µm to 70%, it is evaluated as ISO ePM2.5 70%. With this evaluation and the knowledge of the PM values of the ambient air, clean air quality can be predetermined better in the future, influenced by appropriate filter selection and the filter characteristics can be estimated

5. What do filter manufacturers and filter users have to consider in 2017 – 2018?

The test standard ISO 16890 evaluates air filters according to criteria different to usually encountered in practice with DIN EN 779. The assignment into the new group must be evaluated for the individual case and depends individually on the technical design of the air filter. Thus e.g. F7 filters are evaluated according to ISO and assigned to the groups ISO ePM2.5 or ISO PM1. In this case technical questions have to be solved, particularly with regard to the unification of the test sequence. The filter laboratories of the filter manufacturers, as well as independent testing institutes, will carry out many series of experiments to develop those routines, which are necessary for the secure handling of the new standard. Furthermore, executive authorities and specialist committees will have to prepare regulations for the air quality targeted in the future.

In the meantime, DIN EN 779 represents a further valid test- and classification specification, which is to be employed in ventilation and air conditioning until the date of its withdrawal on June 30, 2018. When all work has been completed with the introduction as DIN EN ISO 16890,   we will be pleased to be able to make an important step to improved room-air quality.

Prüfstand EN 779

Test rig EN 779

6. How does the test procedure of ISO 16890 deviate from ISO 16890 in detail?

ISO 16890EN 779
Test objective
Assignment to an ISO ePM groupClassification into Filter Classes G, M and F
Coarse dust filter:
ISO ePM Coarse
Coarse dust filter:
G1 – G4
Medium dust filter:
Medium dust filter:
G3 – M6
Fine dust filter:
ISO ePM2,5
Fine dust filter:
M5 – F8
Fine dust filter:
Fine dust filter:
F7 – F9
Relevant filter characteristic
Coarse dust filter:
Initial gravimetric arrestance with respect to A2 dust
Coarse dust filter:
Average gravimetric arrestance with respect to ASHRAE dust
Fine dust filter:
Fractional efficiency with respect to ePMx
Fine dust filter:
Average efficiency with respect to 0.4 µm particles
Used test aerosols
DEHS and KCl aerosolDEHS aerosol
Assessed filter status
Initial condition;Initial and dust-loaded condition;
Initial condition after IPA treatmentInitial condition after IPA treatment
IPA treatment process
Filter elementFilter medium sample
Vapour-treatment with IPAImmersion into liquid IPA
Utilisation of an IPA vapour-treatment chamberIPA shell
Pressure drop
Pressure drop on the filter element in % of the nominal airflowPressure drop on the filter element in % of the nominal airflow
Dust-holding capability
Dust application with A2 test dust (quartz dust)Dust application with filter test dust ASHRAE (quartz dust, soot flakes, cotton fibres)
Pressure drop, end
ePM Coarse: 200 PaG1 – G4: 250 Pa
ePM1 – 10: 300 PaM5 – F9: 450 Pa
Energy classification
Manufacturer-related label processManufacturer-related label process
Table 3: Test procedure of ISO 16890 compared to DIN EN 779


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