HEPA/ULPA Filter Testing and Standards Analysis

High-Efficiency Particulate Air (HEPA) and Ultra-Low Penetration Air (ULPA) filters are widely used in various industries, especially in environments that require high levels of cleanliness, such as operating rooms, pharmaceutical manufacturing areas, and semiconductor fabrication plants. This article provides an in-depth analysis of HEPA and ULPA filter testing methods and related standards to help readers better understand and apply these filters.

 

Table of Contents

1. Introduction

2. Definition and Classification of HEPA/ULPA Filters

3. Testing Methods for HEPA/ULPA Filters

4. Standards for HEPA/ULPA Filters

    - EN 1822

    - ISO 29463

    - IEST-RP-CC001

5. Conclusion

 

Ⅰ. Introduction

Air quality directly impacts human health and the quality of industrial products. To effectively remove airborne particles, HEPA and ULPA filters have been developed. Understanding their testing methods and standards is essential for ensuring their performance and suitability.

 

Ⅱ. Definition and Classification of HEPA/ULPA Filters

 

HEPA Filters: Capture at least 99.97% of particles with a diameter of 0.3 microns. Commonly used in hospitals, pharmaceuticals, and food processing.

 

ULPA Filters: Capture at least 99.999% of particles with a diameter of 0.12 microns. Suitable for environments requiring extremely high air cleanliness, such as microelectronics manufacturing and biological laboratories.

 

Filters are classified based on performance and application into the following categories:

l   E10-E12: High-efficiency filters

l   H13-H14: Very high-efficiency filters

l   U15-U17: Ultra-low penetration filters

 

Ⅲ. Testing Methods for HEPA/ULPA Filters

 

Testing methods are crucial for ensuring the performance of filters. The main testing methods include:

 

1. DOP (Dispersed Oil Particulate) Test:

- Uses dioctyl phthalate (DOP) to generate uniform 0.3-micron particles.

- Tests the filter's efficiency in capturing these particles.

 

2. MPPS (Most Penetrating Particle Size) Test:

- Determines the filter's efficiency for the most penetrating particle size.

- Typically uses particles ranging from 0.1 to 0.3 microns.

 

3. Overall Leak Test:

- Checks for leaks in the filter to ensure its overall integrity.

 

4. Flow and Resistance Test:

- Measures the filter's air resistance at a specified flow rate to ensure its performance in actual use.

 

Ⅳ. Standards for HEPA/ULPA Filters

 

Several international and national bodies have established standards to regulate the performance and testing methods of HEPA and ULPA filters. The main standards include:

 

1.  EN 1822

 

EN 1822 is a European standard that covers the classification, testing, and identification of filters. It includes the following parts:

Part 1: Efficiency and Classification

  Defines the efficiency grades (E10 to U17) and their corresponding particle capture efficiencies.

Part 2: Aerosol Generation and Handling

  Describes the methods for generating aerosols used in testing.

Part 3: Efficiency Testing of Filter Elements by Particle Counting and Classification**  

  Details how to measure the efficiency of filter elements using particle counters.

Part 4: Filter Media Efficiency Testing

  Introduces methods for testing the efficiency of the filter media itself.

Part 5: Testing Filter Elements for Local Penetration

  Describes the procedures and requirements for overall filter leak testing.

 

2. ISO 29463

 

ISO 29463 is an international standard based on EN 1822, with additional details for global applicability. It comprises five parts:

Part 1: Classification, Performance Testing, and Marking  

  Describes the classification, performance testing methods, and marking requirements for HEPA and ULPA filters.

Part 2: Aerosol Production and Measuring Particle Size Distribution

  Details how to generate aerosols and measure their particle size distribution for testing.

Part 3: Testing Filter Media

  Introduces methods for testing the efficiency of filter media.

Part 4: Efficiency Testing of Filter Elements by Particle Counting

  Provides detailed methods for measuring filter efficiency using particle counters.

Part 5: Testing Filter Elements for Local Penetration and Efficiency Measurement

  Includes procedures for overall filter leak testing and efficiency measurement.

 

3. IEST-RP-CC001

 

IEST-RP-CC001 is published by the Institute of Environmental Sciences and Technology (IEST) in the United States and applies to the design and testing of HEPA and ULPA filters. Its main contents include:

Design and Manufacturing Requirements

  Specifies the design and manufacturing requirements for HEPA and ULPA filters.

Testing Methods

  Provides various testing methods, including the DOP test, and details how to conduct efficiency, flow, and resistance tests.

Quality Control and Acceptance Standards

  Specifies quality control requirements during production and acceptance standards for finished filters.

 

Ⅴ. Conclusion

 

HEPA and ULPA filters play a critical role in maintaining clean air. Understanding and adhering to relevant testing methods and standards ensure these filters' effectiveness and reliability in various applications. By following proper testing methods and standards, businesses and institutions can ensure the performance of their filters, providing high-quality air purification solutions.

 

We hope this analysis of HEPA/ULPA filter testing and standards provides valuable information, helping you make more informed decisions in practical applications.