Recommended filters for controlling both air and water pollution. Made of 100 % borosilicate glass fibres with binders. Extremely low content in alkali-earth metals. Chemical stability: It keeps all its properties in contact with acid solutions (except hydrofluoric acid) and basic solutions at moderate concentrations. Usable as a pre-filter for membranes to prevent the membranes from silting up. Deposition of (radioactive) aerosols and monitoring of nuclear power plants. Gravimetrical analysis of organic and inorganic impurities in water and waste water according to DIN 38409 and EN 872 (suspended particles). Measurement of immission; measurement of dust in air and gases; monitoring of the efficiency of filtration and dedusting; monitoring the combustion air of power plants and of the steel and iron industry. Measurement of dust release in workplace and production processes and the purification of compartment air. Stability at high temperatures: It keeps its properties up to 500 °C. High flow speed and high permeability to air. Filtration time acc. to Gurley.