The procedure includes drying a sufficient quantity of the sample by heating, allowing to cool to room temperature, adding distilled or deionized water to the cleaned, dried and weighed pyknometer containing 10 g of the dried sample until it is completely filled, displacing air adhering to the test portion, drying the outside of the pyknometer, reweighing the pyknometer and its contents, emptying the pyknometer, refilling with distilled or deionized water, drying the outside and weighing again. Annex A gives information on the international standards series for non-metallic blast-cleaning abrasives ISO 11126 and ISO 11127.