Description

Glass Fibre Filter Types

• A/E Glass Fibre
  • For gravimetric analysis of air pollutants and testing dissolved/suspended wastewater solids
  • High flow rates, wet strength, and dirt (solids) holding capacity
• A/B Glass Fibre
  • High dirt-holding capacity with thicker glass
  • Manufactured of the highest quality borosilicate glass microfibres

Pore Size Rating

Filter pore size ratings are based on liquid filtration ratings. Filters will retain much smaller particles from air (e.g. a 0.8 µm liquid rated filter will retain >50% of particles as small as 0.08 µm).

A nominal or approximate rating is usually applied to depth filters. Unlike membrane filters, depth filters do not contain a uniformly defined pore structure, but rather fibres or sintered particles that intertwine to create a torturous path of openings that allow air to pass through, but trap particles throughout the depth of the filter. Because of this structure, depth filters are usually tested for pore size by passing liquid containing particles of a certain size through the filter. If the filter traps an acceptable amount of the specific-sized particles (despite the openings in the filter being larger that the test particles), that particle size becomes the “liquid nominal” pore size rating for the filter. Nominal pore size ratings are typically stated as “Filter removes >xx% of particles ≥ µm”.