Absolute Filtration
Definition
A filtration rating stating that a defined percentage — typically 99.9 % (beta 1000) — of particles at or above the rated micron size is removed in a single pass.
An absolute micron rating is a measured, repeatable value derived from standardized multi-pass testing (e.g. ISO 16889). A "1 µm absolute" element removes at least 99.9 % of 1 µm particles, giving predictable, reproducible effluent quality.
Absolute-rated media are essential where downstream equipment or product quality demands tight, guaranteed particle control — for example membrane pre-filtration, amine polishing, or final filtration before a critical process step.
Relevance for high-flow filtration
R+F high-flow elements are available with absolute-rated glass-fiber and graded-density media from 1 to 100 µm, giving 98–99.9 % efficiency at the rated micron size.
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Related terms
A filtration rating indicating an approximate particle-removal efficiency — commonly 50–90 % — at the stated micron size, without a guaranteed single-pass value.
Beta Ratio (β)A dimensionless number expressing filtration efficiency: the ratio of particles of a given size upstream to those downstream of the filter.
Micron RatingThe nominal particle size, in micrometers (µm), that a filter is designed to remove — stated as either an absolute or a nominal value.
Glass Fiber (GF) Filter MediaA high-efficiency, absolute-rated pleated medium made from fine borosilicate glass microfibers, used for demanding fine filtration.
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