ISO 29461-1 is the latest international test standard for reporting the efficiency and dust holding capacity for the entire range of air intake filters for gas turbines, compressors, and other turbomachinery applications.
The ISO 29461-1 presents a uniform method for testing filters that enables turbomachinery operators to more easily compare and select air inlet filters.
Gas turbines and other turbomachinery are sensitive equipment that require protection against harmful particulates that could diminish life and performance. Air inlet filters are the most cost-effective way to protect your assets since they can prevent contaminants from reaching your turbomachinery.
Operators currently use filters with a wide range of particle capture efficiencies, from coarse pre-filters to ultra-fine final filters designed to keep engines clean and running at peak performance. There are currently multiple standards used in the industry to help select filters; most prevalent are the EN779, ASHRAE 52.2, and ISO 16890 for lower efficiency filters and ISO 29463/ EN1822 for higher efficiency filters. The ISO 29461-1 has been designed to replace these four standards and as such is the first filter classification that can be applied to the entire range of filters in a single uniform standard that is more relevant to real-world performance.
The ISO 29461-1:2021 classification system shown in the table categorizes filters in groups and classes using test protocols from ISO 16890 and ISO 29463:
| Class | Group | MPPS efficiency | ePM1, min | ePM2,5, min | ePM10 | Initial gravimetric arrestance A100 |
|---|---|---|---|---|---|---|
| ISO T1 | Coarse |
20% < A100 < 50% | ||||
| ISO T2 | ≥ 50 % | |||||
| ISO T3 | ≥ 70 % | |||||
| ISO T4 | ≥ 85 % | |||||
| ISO T5 | ePM10 | ≥ 50 % | ||||
| ISO T6 | ePM2,5 | ≥ 50 % | ||||
| ISO T7 | ePM1 | ≥ 50 % | ||||
| ISO T8 | ≥ 70 % | |||||
| ISO T9 | ≥ 85 % | |||||
| ISO T10 | EPA | ≥ 85 % | ||||
| ISO T11 | ≥ 95 % | |||||
| ISO T12 | ≥ 99,5 % | |||||
| ISO T13 | HEPA | ≥ 99,95 % |
| Filter Categories | ISO 29461-1 |
|---|---|
| Bag | T4 - T9 |
| Panel | T2 - T6 |
| Compact | T7 - T13 |
| Cartridge | T5 - T10, T12 |
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