Key Things to Consider when Choosing O-Rings

January 31, 2023 – by Eastern Seals

PTFE coated o-rings

The importance of choosing O-rings in sealing applications cannot be emphasised enough. Ask any O-ring supplier across the UK and you will know that choosing the right O-ring is integral to engineering.

In this post, we look at some key factors to consider when choosing O-rings.


O-rings are manufactured from different materials including rubber, thermoplastic and polyethylene. If the materials in the application are incompatible with the O-ring material, it can degrade.

The O-ring may swell if the wrong compound causes fluids to build up. The easiest solution is to choose a material that does not corrode during the application.


O-rings are generally designed to hold pressures of up to 1500psi. However, it’s important to know the amount of pressure the O-ring will be subjected to during the application. This can have a direct impact on the choice of hardware geometry, durometer and elastomer type.

Some compounds have been designed specifically to handle extremely high pressure, extremely low pressure and rapid change in pressure. When choosing an O-ring for your application, be sure to check it can handle the pressure you want to subject it to. This will help prevent leaks.


With the improvement in chemical processes and efficiency of products like engines and electronics, there has been an overall rise in operating temperatures that O-rings are subjected to. The need to operate these devices in excessively cold environments has also gone up.

Different O-ring materials have been specifically designed to work across an array of temperature ranges. Identifying the temperature range of the prospective application will help you choose the right O-ring.


O-rings are available in an array of sizes. In fact, there are more than 400 sizes in standard AS568A inch measure and many more in metric sizes.

Using a standard O-ring size for your application can help save a lot of time and money on customisation, tooling, lead time and more.


When it comes to choosing O-rings, the load is usually ignored. For the perfect seal, an O-ring must compress into the seal groove. The O-ring should efficiently push across both sides of the groove, just like a spring does when decompressed.

The compression rate of O-rings varies between 19% to 30%. This deformation is measured using a durometer. Low pressure applications will typically need lower durometer compounds whereas higher pressure applications will need higher durometer compounds.

Contact Eastern Seals for Quality O-rings

If you are looking for high-quality o-rings, contact Eastern Seals today. With years of industry experience, we offer a range of high-quality O-rings for an array of industries. Contact us today to find out more.

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We are one of the largest suppliers of British Standard, Metric series O-rings and sealing solutions.

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Eastern Seals (UK) Ltd
Unit 3 Sovereign Business Park
Jubilee Industrial Estate
Ashington | Northumberland
NE63 8UG

+44 (0) 1670 840529
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