ISO 16890: Air Filter Classification - Global Standard for Filter Performance

ISO 16890 is the international standard for testing and rating air filters for general ventilation, replacing the older EN 779 and ASHRAE 52.2 standards in many regions. This global standard provides a more realistic and practical approach to filter classification based on particulate matter (PM) efficiency, which directly relates to health impacts and real-world performance. Understanding ISO 16890 is essential for filter manufacturers, HVAC engineers, and building professionals worldwide.

ISO 16890 classifies filters based on their efficiency in removing PM₁, PM₂.₅, and PM₁₀ particles, which are directly related to health impacts and air quality standards. This approach provides more meaningful information for filter selection compared to traditional methods.

Introduction to ISO 16890

Scope and Application

Filters Covered:

• Air filters for general ventilation
• All filter media types
• All filter configurations
• Capacity range: All sizes

Applications:

• HVAC systems
• Air handling units
• Ventilation systems
• All air filtration applications

Key Objectives

Realistic Classification:

• PM-based efficiency
• Health-related metrics
• Real-world performance
• Global standardization

Performance Standardization:

• Consistent test procedures
• Accurate efficiency ratings
• Reliable test data
• Comparable results

Health Protection:

• PM₁, PM₂.₅, PM₁₀ efficiency
• Indoor air quality
• Occupant health
• Environmental protection

Filter Classification System

PM Efficiency Classes

ISO ePM₁ (PM₁ Efficiency):

• Particles ≤ 1.0 μm
• Ultrafine particles
• Health impact: High
• Classification: ePM₁ 50%, 65%, 80%, 90%

ISO ePM₂.₅ (PM₂.₅ Efficiency):

• Particles ≤ 2.5 μm
• Fine particles
• Health impact: Very high
• Classification: ePM₂.₅ 50%, 65%, 80%, 90%

ISO ePM₁₀ (PM₁₀ Efficiency):

• Particles ≤ 10 μm
• Coarse particles
• Health impact: Moderate
• Classification: ePM₁₀ 50%, 65%, 80%, 90%

ISO Coarse (Coarse Particle Efficiency):

• Particles > 10 μm
• Large particles
• Health impact: Low
• Classification: ISO Coarse 50%, 65%, 80%, 90%

Classification Naming

Format: ISO ePM₁ 80% or ISO ePM₂.₅ 65%

Example Classifications:

• ISO ePM₁ 90%: Very high efficiency for PM₁
• ISO ePM₂.₅ 80%: High efficiency for PM₂.₅
• ISO ePM₁₀ 65%: Medium efficiency for PM₁₀
• ISO Coarse 50%: Low efficiency for coarse particles

Performance Metrics

PM Efficiency

Definition:

Where:

• $M_{PM,in}$ = PM mass entering filter (μg)
• $M_{PM,out}$ = PM mass leaving filter (μg)

Test Procedure:

1. Generate test aerosol
2. Measure upstream PM concentration
3. Measure downstream PM concentration
4. Calculate efficiency
5. Classify filter

Minimum Efficiency

Minimum Efficiency Value (MEV):

• Lowest efficiency in test range
• Ensures minimum performance
• Quality assurance
• Performance guarantee

Classification Requirements:

• Must meet minimum efficiency
• All test points considered
• Performance consistency
• Quality verification

Arrestance

Arrestance (A):

Test Dust:

• ASHRAE test dust
• Standardized composition
• Reproducible results
• Realistic testing

Typical Values:

• Low efficiency: 20-40%
• Medium efficiency: 40-60%
• High efficiency: 60-90%
• Very high efficiency: 90-99%

Testing Procedures

Test Setup Requirements

Test Facilities:

• Calibrated test rig
• Aerosol generation
• Particle measurement
• Flow measurement
• Pressure measurement

Instrumentation:

• Particle counters
• Mass measurement
• Flow meters
• Pressure sensors
• Data acquisition

Test Procedure

Step 1: Initial Efficiency Test

1. Clean filter
2. Generate test aerosol
3. Measure PM concentrations
4. Calculate initial efficiency
5. Record data

Step 2: Loading Test

1. Load filter with test dust
2. Monitor pressure drop
3. Measure efficiency at intervals
4. Continue until final pressure
5. Record data

Step 3: Final Efficiency Test

1. Measure final efficiency
2. Calculate average efficiency
3. Determine classification
4. Verify requirements
5. Document results

Test Conditions

Standard Conditions:

• Face velocity: 0.944 m/s (standard)
• Test aerosol: DEHS or similar
• Test dust: ASHRAE test dust
• Temperature: 23°C ± 2°C
• Humidity: 50% ± 5% RH

Test Velocities:

• Standard: 0.944 m/s
• Low: 0.5 m/s
• High: 1.5 m/s
• Multiple velocities

Filter Performance

Efficiency vs. Particle Size

Typical Performance:

• Large particles (> 10 μm): High efficiency
• Medium particles (2.5-10 μm): Medium efficiency
• Small particles (1-2.5 μm): Lower efficiency
• Very small particles (< 1 μm): Lowest efficiency

Efficiency Curve:

• Minimum efficiency point (MEP)
• Most penetrating particle size (MPPS)
• Efficiency variation
• Performance characteristics

Pressure Drop

Initial Pressure Drop:

Typical Values:

• Low efficiency: 20-50 Pa
• Medium efficiency: 50-150 Pa
• High efficiency: 150-300 Pa
• Very high efficiency: 300-500 Pa

Final Pressure Drop:

Loading Capacity:

• Dust holding capacity
• Service life indicator
• Replacement schedule
• Cost consideration

Energy Consumption

Fan Energy:

Annual Energy:

Energy Cost:

Example:

• Airflow: 1.0 m³/s
• Pressure drop: 200 Pa
• Operating: 4,000 hours/year
• Energy: 1.0 × 200 / 0.6 × 4,000 = 1,333 kWh/year

Filter Selection

Selection Criteria

Application Requirements:

• Indoor air quality goals
• PM concentration levels
• Health requirements
• Energy considerations

Efficiency Selection:

• Minimum efficiency required
• PM type of concern
• Health protection level
• Cost-effectiveness

Performance Considerations:

• Efficiency vs. pressure drop
• Service life
• Replacement cost
• Energy consumption

Selection Guidelines

Residential:

• ISO ePM₂.₅ 50-65%: Standard
• ISO ePM₂.₅ 80%: High quality
• ISO ePM₂.₅ 90%: Premium

Commercial:

• ISO ePM₂.₅ 65-80%: Standard
• ISO ePM₂.₅ 80-90%: High quality
• ISO ePM₁ 80-90%: Premium

Healthcare:

• ISO ePM₁ 80-90%: Minimum
• ISO ePM₁ 90%+: Recommended
• HEPA filters: Critical areas

Industrial:

• ISO Coarse 50-80%: Pre-filters
• ISO ePM₁₀ 65-80%: Standard
• ISO ePM₂.₅ 80%+: High efficiency

Comparison with Other Standards

ISO 16890 vs. EN 779

EN 779 Classification:

• G1-G4: Coarse filters
• M5-M6: Medium efficiency
• F7-F9: Fine filters

ISO 16890 Advantages:

• PM-based efficiency
• Health-related metrics
• More realistic
• Global standard

Conversion:

• Approximate conversions available
• Not exact equivalence
• Performance-based selection
• ISO 16890 preferred

ISO 16890 vs. ASHRAE 52.2

ASHRAE 52.2:

• MERV ratings
• Particle size efficiency
• Different test method

ISO 16890 Advantages:

• PM mass efficiency
• Health-related
• Global standard
• More practical

Best Practices

Selection Best Practices

• Right efficiency for application
• Consider PM type
• Balance efficiency and pressure drop
• Life-cycle cost analysis
• Energy considerations

Installation Best Practices

• Proper installation
• Correct orientation
• Proper sealing
• Adequate access
• Commissioning

Operation Best Practices

• Regular monitoring
• Pressure drop tracking
• Replacement scheduling
• Performance verification
• Energy optimization

Maintenance Best Practices

• Regular inspection
• Timely replacement
• Proper disposal
• Performance tracking
• Documentation

Common Issues

Performance Issues

Low Efficiency:

• Causes: Wrong filter, damage, improper installation
• Solutions: Right filter, inspection, proper installation

High Pressure Drop:

• Causes: Dirty filter, wrong filter, high velocity
• Solutions: Replacement, right filter, optimize velocity

Short Service Life:

• Causes: High loading, wrong filter, poor maintenance
• Solutions: Pre-filters, right filter, regular maintenance

Conclusion

ISO 16890 provides a modern, health-focused approach to air filter classification. Key takeaways:

Classification System:

• PM-based efficiency
• Health-related metrics
• Realistic performance
• Global standardization

Performance Metrics:

• PM₁, PM₂.₅, PM₁₀ efficiency
• Arrestance
• Pressure drop
• Service life

Selection Guidelines:

• Application-based selection
• Health protection
• Energy efficiency
• Life-cycle cost

Best Practices:

• Proper selection
• Quality installation
• Regular maintenance
• Performance monitoring

Understanding and applying ISO 16890 ensures effective air filtration, improved indoor air quality, and occupant health protection. For HVAC professionals, compliance with this standard is essential for quality installations and optimal performance.

For detailed test procedures, classification methods, and selection guidelines, refer to the complete ISO 16890 standard document available from the International Organization for Standardization.