This part of ISO 3601 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.
This part of ISO 3601 also defines and classifies surface imperfections on O-rings and specifies maximum acceptable limits for these imperfections.
This part of ISO 3601 is also applicable to O-rings to be used in aerospace construction.