Frequently Asked Questions
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Glass Fiber Filters FAQ
Do you need a Chemical Compatibility Chart?
We have a Chemical Compatibility Chart that you can use for reference.
I have noticed that the glass fiber disk filters have a subtle texture difference between the sides - one side is somewhat rougher than the other. Does the orientation of the filters in the holder affect filtration performance?
As a result of the manufacturing process, one side of the glass fiber filters is indeed slightly rougher than the other side. This difference does not affect performance and users need not be concerned with filter orientation. The filters will exhibit similar retention and throughput regardless of which surface is facing upstream.
What is the pore size rating of the quartz fiber filters?
You can find the current specifications for the Advantec quartz fiber filters at https://www.sterlitech.com/quartz-fiber-filters.html. Click the "Application/Specification" tab near the middle of the page and scroll down as necessary. The QR-100 grade is shown to have a collection efficiency of 99.99% when challenged with 0.3µm dioctyl phthalate (DOP) aerosol particles. Similarly, the QR-200 grade is shown to have collection efficiency of 99.90%. It can be reasoned from these results that either grade has an effective absolute pore size rating of 0.3µm when used to filter air or gases. It should be noted that filtration efficiency, and consequently pore size rating, would be significantly different if used to filter water or liquids.
Do glass fiber filters shed?
To some extent, all glass fiber filters have the potential to shed some fibers. Acrylic resin bonded glass fiber filters typically shed much lower amounts of fibers compared to binderless glass fiber filters. The amounts of shed fibers not only depend on the grades of glass fiber media used but are also influenced by the application conditions. Shed fibers are not typically a concern in applications where the glass fiber filters are used as a prefilters for subsequent membrane filters.
I noticed that the listed equivalent glass fiber filters have different specifications. What is the reason for this?
Glass Fiber Filters have nominal pore size ratings. These ratings are not necessarily consistent between different manufacturers. Consequently, it is possible for glass fiber filters from different manufacturers to have equivalent retention characteristics while having different nominal pore size ratings.
What is the smallest pore size rating available for the glass fiber filters?
The smallest available pore size rating for the glass fiber filters is 0.3µm, as featured by the Advantec Grade GF75 and Sterlitech Grade A glass fiber filters. It is important to note that the glass fiber filters are nominally rated and it should be expected that some amount particles ≥0.3µm will pass through these filters.
What is DOP?
DOP is an abbreviation for dioctyl phthalate. Aerosol particles made with DOP have a very uniform size of 0.3µm and are used to characterize air filter retention. For example, DOP particles are used in ASTM D2986-95a, Standard Practice for
Evaluation of Air Assay Media by the Monodisperse DOP (Dioctyl Phthalate) Smoke
Test.
What is the function of the binder in the glass fiber filters?
The acrylic (PMA) resin binder significantly improves the wet strength of the glass fiber filters. Resin bonded glass fiber filters are easier to handle and are resistant to fiber shedding. When evaluating application compatibility, it is important to consider the acrylic (PMA) resin.
What are the advantages of glass fiber filters?
Glass Fiber Filters are exhibit high operating temperatures and are particularly economical for use as a pre-filter.