Product category:
Air handling: Dust + Fume extraction
News Release from: Hosokawa Micron | Subject: HEPA filters
Edited by the Processingtalk Editorial
Team on 24 October 2007
When were your HEPA filters last
checked?
Hosokawa Micron are now able to offer HEPA Filter Integrity Tests either as a specific task or as part of a planned maintenance programme
Industry recommends that HEPA filters be checked at 14 month intervals or less, or immediately after filter change This is because where high efficiency filters are fitted, it is important that the filter housing/sealing device does not allow particulate material to pass and therefore compromise the classification of the controlled environment installation that is being served
This article was originally published on Processingtalk on 13 Nov 2003 at 8.00am (UK)
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The Filter Integrity Test is commonly referred to as a DOP test because the original smoke used in the test was generated using Di-Octyl Phthalate.
This chemical was found to have carcinogenic properties and was subsequently substituted by a mineral oil, Shell Ondina EL.
The smoke generated from this has identical characteristics and the term DOP testing remains, although it is now understood to mean 'Dispersed Oil Particulate'.
During the test the HEPA filter is challenged on the upstream side with a pre-determined volume of smoke created by an aerosol smoke generator, which is referred to, for calculation purposes, as 100%.
The amount of smoke that passes the HEPA filter is measured on the downstream side using a digital aerosol photometer.
A reading less than 0.001% means the HEPA Filter has passed its integrity test.
A higher reading means there is a problem with how the filter is seated or with the seal itself, this would need to be checked /refitted and retested.
When the HEPA Filter has passed its test Hosokawa Micron will issue a certificate verifying that the test has been completed to current standards, BS/EN/ISO 14644 part 3, BS5295:1989,PD6609.
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