Sieving of the sand base is carried out on a rotational-shaking installation that provides 300±5 turns of the eccentric and 180±10 strokes of the drummer per minute or on a vibration-acting installation that provides vibration of sieves with an oscillation amplitude of 0.1-1.0 mm and a frequency of 50 vibrations/s. Climatic version U, accommodation category 4 according to GOST 15150-69.