What is the difference between ISO 16890 and EN 779? How to choose the air filter grade?

1. What Is the Difference Between EN 779 and ISO 16890?

EN 779 classifies general ventilation air filters using G, M, and F grades:

EN 779:2012 evaluates medium- and high-efficiency filters mainly according to their filtration performance for particles of approximately 0.4 μm.

ISO 16890 evaluates filters according to different particulate-matter size ranges:

ISO 16890 therefore provides a more direct indication of a filter’s ability to control PM1, PM2.5, and PM10. This helps engineers select filters according to outdoor air quality and indoor cleanliness requirements.

2. Why Is ISO 16890 More Suitable for Engineering Procurement?

Two filters may both be classified as F7, but their actual PM1 efficiency may differ because of differences in filter media, structural design, and electrostatic filtration performance.

After ISO 16890 testing, the two filters may be classified as:

ISO ePM1 50%

and

ISO ePM1 60%

This allows purchasers to compare their fine-particle filtration performance more directly. ISO 16890 provides more specific performance information for hospitals, commercial buildings, data centers, pharmaceutical plants, electronics workshops, and fresh-air systems.

3. Can F7, F8, and F9 Be Directly Converted?

No fixed conversion relationship can be established. For example:

• F7 does not necessarily equal ISO ePM1 50%;

• F8 does not necessarily equal ISO ePM1 70%;

• F9 does not always correspond to ISO ePM1 80%.

Conversion tables can only be used as preliminary references and should not serve as formal procurement specifications. The two standards use different test particles, calculation methods, and classification rules.

Two filters classified as F7 under EN 779 may therefore receive different ePM classifications after ISO 16890 testing.

Purchasers should require the supplier to provide ISO 16890 test data or a test report for the specific filter model, rather than estimating the ePM class solely from the former EN 779 grade.

4. What Does ISO ePM1 60% Mean?

“ISO ePM1 60%” means that the filter achieves the corresponding overall filtration-efficiency classification for PM1 particles according to the testing and calculation methods specified in ISO 16890.

A procurement specification should not simply state, “An ePM1 filter is required.” It should specify the required percentage, such as:

• ISO ePM1 50%;

• ISO ePM1 60%;

• ISO ePM1 80%.

Different efficiency percentages may require different filter media configurations and may result in different initial pressure drops, energy consumption, and procurement costs.

5. Which ISO Class Corresponds to G4?

Traditional G4 filters are mainly used as the first filtration stage in AHUs and fresh-air systems. Under ISO 16890, these products may generally fall within the ISO Coarse classification.

However, G4 cannot be directly defined as a fixed ISO Coarse percentage. The actual ISO Coarse class must be determined by the test results of the specific filter.

When replacing G4 filters in an existing project, purchasers should first determine whether the original design objective was to capture large dust particles, protect downstream filters, or meet a specific PM10 requirement. A suitable ISO 16890 product can then be selected.

6. What Should Be Done When an Existing Project Specifies F7?

If the original AHU design specifies “G4 + F7,” the following selection procedure is recommended:

1. Confirm the original filter model and EN 779 grade;

2. Confirm the system design airflow and allowable pressure drop;

3. Request ISO 16890 test data for the proposed products;

4. Compare the ePM1, ePM2.5, and ePM10 efficiencies;

5. Compare the initial pressure drop at rated airflow;

6. Check the fan’s available static pressure and the installation dimensions.

This procedure prevents a higher filtration efficiency from causing excessive system resistance and reduced supply airflow.

7. How Should ePM1, ePM2.5, and ePM10 Be Selected?

General Pre-Filtration

If the main purpose is to capture larger particles and reduce the dust load, ISO Coarse or a suitable ePM10 class may be considered.

Commercial Buildings and General HVAC

If enhanced PM2.5 control is required, ePM2.5 should be evaluated according to the local outdoor air quality and the required efficiency percentage.

Hospitals, Clean Environments, and Precision Manufacturing

For projects focusing on fine-particle control, ePM1 performance should receive greater attention.

However, the highest efficiency is not necessarily suitable for every project. When increasing filtration efficiency, engineers must also evaluate initial pressure drop, fan capacity, operating energy consumption, dust-holding capacity, and replacement cost.

8. Does ISO 16890 Apply to H13 HEPA Filters?

ISO 16890 is mainly intended for general ventilation air filters. It is not the primary classification standard for H13 or H14 HEPA filters.

A typical filtration system may be configured as:

ISO Coarse → ISO ePM2.5/ePM1 → H13 HEPA

Primary and medium-efficiency filters are classified according to ISO 16890, while terminal H13/H14 filters are classified according to the applicable HEPA testing and classification standards.

An H13 filter should not be designated as “ISO ePM1 99.95%” because HEPA filters and ISO 16890 general ventilation filters belong to different testing and classification systems.

9. Which Parameters Should Be Provided During Procurement?

For international projects, an inquiry should not specify only “F7 Bag Filter.” It should include:

1. ISO 16890 class and efficiency percentage;

2. Filter dimensions;

3. Rated airflow;

4. Initial pressure drop at rated airflow;

5. Allowable final pressure drop;

6. Filter media and frame materials;

7. Operating temperature and humidity;

8. Third-party test-report requirements.

For an existing project, the inquiry may state:

Original Design Grade: EN 779 F7; the replacement filter must be supplied with ISO 16890 test data.

10. Boyang ISO 16890 Air-Filtration Solutions

Boyang supplies panel, bag, V-bank, and other medium- and high-efficiency air filters for AHUs, fresh-air systems, commercial buildings, hospitals, pharmaceutical plants, electronics manufacturing, and clean environments.

For traditional G4, F7, F8, and F9 projects, suitable products can be selected according to the original system’s filtration efficiency, design airflow, allowable pressure drop, and installation dimensions. Relevant ISO 16890 performance data can also be provided.

For new international projects, filter selection should follow this process:

Target Particulate Matter → ISO ePM Class → Efficiency Percentage → Rated Airflow → Initial Pressure Drop → Installation Dimensions

The transition from EN 779 to ISO 16890 is not simply a change in filter-grade names. Its purpose is to help purchasers understand the actual filtration performance for PM1, PM2.5, and PM10 and achieve a suitable balance among efficiency, resistance, energy consumption, and cost.