This European Standard describes three methods of determining the fineness of cement. The sieving method serves only to demonstrate the presence of coarse cement particles. This method is primarily suited to checking and controlling the production process. The air-jet sieving method measures the retention on sieving being suitable for particles which substantially pass a 2,0 mm test sieve and can be used to determine the particle size distribution of agglomerates of very fine particles. This method uses test sieves with aperture sizes of 0,06 mm and 0,09 mm. The air permeability method (Blaine) measures the specific surface (mass related surface) by comparison with a reference cement sample. The determination of the specific surface serves primarily to check the consistency of the grinding process of one and the same plant. This method only enables a limited assessment to be made of the properties of the cement in use.1 ) The methods are applicable to all the cements defined in EN 197.