Testing and classification method for filters with MPPS <0.1 um (e.g. membrane medium filters)——Understanding ISO 29463 and Testing Requirements

The fibrous structure of membrane filter media presents unique challenges in the realm of particle detection and filtration efficiency. With a Most Penetrating Particle Size (MPPS) around 0.07 μm, membrane filter media have significantly smaller fibers compared to micro fiberglass media, which have an MPPS ranging from 0.1 to 0.25 μm.

Testing Requirements

Accurately testing these filters necessitates the detection of particles as small as 0.05 μm. This requirement exceeds the capabilities of standard laser particle counters, which are not sensitive enough to detect such small particles. Consequently, Condensation Particle Counters (CPCs) are needed for testing membrane filter media. CPCs can detect much smaller particles, ensuring accurate measurement of filtration efficiency.

ISO 29463 Classification

Classifying filters based on MPPS values according to ISO 29463 becomes infeasible when using laser particle counters due to their detection limitations. However, ISO 29463 provides an alternative procedure to address this challenge. By employing a correlation factor F, the standard allows for the calculation of MPPS filtration efficiency through the testing of 0.14 μm penetration efficiency. This method provides a practical solution for assessing filter performance without requiring equipment capable of detecting the smallest particles.

SC-FT-1406DU: An Ideal Tester

For filter media MPPS testing needs, the SC-FT-1406DU is an excellent tester. With a maximum efficiency range of 99.999999% at 0.1 μm, it meets the stringent requirements of MPPS testing according to ISO 29463 standards. This tester ensures that even the most challenging filtration efficiency measurements can be accurately and reliably obtained.

Conclusion

In light of these considerations, a 0.1 μm particle counter is generally sufficient for most industrial applications. While it may not detect the smallest particles required for precise MPPS measurement in membrane filters, the alternative procedure outlined in ISO 29463 ensures that accurate and reliable filtration efficiency can still be determined. The SC-FT-1406DU, with its high efficiency range, further supports these testing needs, balancing the need for practical solutions with the technical limitations of available particle detection technology.