ISO 3601 standard
#1 What is ISO 3601 and why is it so important?
ISO 3601 is by far the most important and recognized standard in the world of O-rings. It is the international basis for dimensional tolerances, quality acceptance criteria and size charts.
As an illustration: The manufacture and evaluation of O-rings is to be evaluated so naturally in accordance with the specifications of ISO 3601 that it is hardly mentioned in any article texts or
data sheets. It is internationally accepted that ISO 3601 counts.
Important note: The international ISO 3601 standard has replaced the German standard DIN 3771 since 2010. DIN 3771 is therefore no longer valid.
#2 What exactly does ISO 3601 regulate?
Section 1: Dimensions and tolerances (ISO 3601-1)
1. class A: industry or aviation applications
2. class B: Classic O-rings
In the first section you will also find information on size charts. Here are some O-ring dimensions that have been established as a standard by ISO 3601 and are used internationally in applications.
Section 2: Design and installation spaces (ISO 3601-2)
Here you will find all the information and guide values you need for the optimum design of an O-ring.
Section 3: Quality acceptance criteria (ISO 3601-3)
The quality assessment is also divided into 3 groups:
Class N: Classic O-rings
Class S: Industrial or aviation applications
Class CS: Critical industrial or aviation applications
Section 4: Back-up rings (ISO 3601-4)
Section 4 defines a total of 5 types of back-up rings. You will also find information on the design of support rings.
Section 5: Materials (ISO3601-5)
Section 5 deals with the various O-ring materials (NBR, EPDM, FKM, etc.). Here, for example, material properties such as compression set, temperature resistance, media resistance and the like are defined.
Technical article on the ISO 3601 standard | Sealing Academy | Click here >>