The procedures are applicable to crude or refined products in the course of filling, or to products already contained in drums or in transportable or fixed tanks. Owing to the heterogeneity of the lots it is recommended to adopt the sampling during filling. Specifies particular precautions in view of the very hygroscopic nature of the product. The principle consists in samplings, at regular intervals, of equal quantities throughout filling. Mixing of these successive samples, homogenization and then taking the laboratory samples.