ISO 3601-3:2005规定了流体系统中使用的O形环的质量验收标准，其尺寸在ISO 3601-1、ISO 16031-1和ISO 16031-2中进行了标准化。 ISO 3601-3:20051还定义和分类了O形环上的表面缺陷，并规定了这些缺陷的最大可接受限值。 ISO 3601-3:2005也适用于航空航天结构中使用的O型环。

ISO 3601-3:2005 lays down the quality acceptance criteria of O-rings used in fluid systems, the dimensions of which are standardized in ISO 3601-1, ISO 16031-1 and ISO 16031-2. ISO 3601-3:20051 also defines and classifies surface imperfections on O-rings and specifies maximum acceptable limits for these imperfections. ISO 3601-3:2005 is also applicable to O-rings to be used in aerospace construction.