HEPA - Wikipedia
2019-6-25 · HEPA filters are composed of a mat of randomly arranged fibres. The fibers are typically composed of fiberglass and possess diameters between 0.5 and 2.0 micrometers.Key factors affecting its functions are fiber diameter, filter thickness, and face velocity.The air space between HEPA filter fibers is typically much greater than 0.3 μm.