ISO 1833-7:2017规定了一种使用甲酸测定聚酰胺纤维在去除非纤维物质之后的质量百分比的方法， - 聚酰胺 同 - 棉，粘胶，铜绿，模态，莱赛尔，聚酯，聚丙烯，氯仿，丙烯酸，玻璃纤维，弹性成型机，弹性烯和三聚氰胺，或 - 羊毛（如果羊毛含量小于或等于25％）或动物毛发纤维。 当羊毛含量超过25％时，ISO 1833-7:2017不适用;适用ISO 1833-4。

ISO 1833-7:2017 specifies a method, using formic acid, to determine the mass percentage of polyamide fibre, after removal of non-fibrous matter, in textiles made of mixtures of - polyamide with - cotton, viscose, cupro, modal, lyocell, polyester, polypropylene, chlorofibre, acrylic, glass fibre, elastomultiester, elastolefin and melamine, or - wool (if the wool content is less than or equal to 25 %), or animal hair fibres. ISO 1833-7:2017 does not apply when the wool content exceeds 25 %; ISO 1833-4 applies.