This standard is applicable for internally coated aluminium tubes, mainly used for the packing of pharmaceutical, cosmetic, hygiene, food or other household products. The internal coating is used as a barrier and should avoid any contact between aluminium and the product. This standard defines two alternative methods – copper sulphate and sodium chloride method – to detect the electrolyte conductivity as one criterion for the quality of the internal coating. NOTE The electrolyte conductivity of the internal coating is only one criterion for evaluation of the quality of an internal coating. It does not give any information on the quantity or size of any pores or uncoated areas, nor any hint on possible reactions between the aluminium tube and the product. The electrolyte conductivity should never be used as the sole criterion for quality evaluation of the internal coating, but always with other parameters e.g. film thickness, acetone and/or ammonia resistance and of course results of enhanced stability studies.