Eiropas standarts EPA, HEPA un ULPA filtriem
Procedure
- On a flat sheet of media, the MPPS is determined for the given media velocity. This can be done with a laser spectrometer or a combination of electrostatic classifier and CNC (Condensed Nucleus Counter).
- The filter is assembled with the specified media grade and amount of media to comply with the defined media velocity.
- The filter is challenged with an aerosol and at the MPPS both the local and overall efficiency are determined with either a CNC or laser spectrometer.
- Leaks are specified as maximum allowable local penetration at the MPPS and must not exceed 5 x the overall penetration.
- The filter is classified according to the test results in the range E10 - E12 for EPA, H13 - H14 for HEPA, U15 - U17 for ULPA.
Filter Classification
|
Efficiency (%) at the MPPS |
Penetration (%) at the MPPS |
Overall Value |
Local Value |
Overall Value |
Local Value |
E10 |
> 85 |
- |
15 |
- |
E11 |
> 95 |
- |
5 |
- |
E12 |
> 99,5 |
- |
0,5 |
- |
H13 |
> 99,95 |
99,75 |
0,05 |
0,25 |
H14 |
> 99,995 |
99,975 |
0,005 |
0,025 |
|
U15 |
> 99,9995 |
99,9975 |
0,0005 |
0,0025 |
U16 |
> 99,99995 |
99,99975 |
0,00005 |
0,00025 |
U17 |
> 99,999995 |
99,9999 |
0,000005 |
0,00001 |
Notes: • Filters in the class E10, E11 and E12 do not require verification of local penetration. • Filters in the classification H13 and H14 may, as an alternative, be verified with the visual oil-smoke test (previously known as DIN 24.184), which is accepted as equal or more searching than the specified local penetration. • U17 is an exception to the rule. In this case local penetration may not exceed 20 x the overall penetration value. |