How to Select the Right O-Ring Material for Any Application

From preventing leakage in transit to keeping a tight seal on a junction long-term, O-rings are an important item for sealing equipment in machinery of all kinds. Depending on what application you need them for, it is crucial that you choose the right material for your O-ring to suit whatever fluid or gas is being contained. In this blog, we will discuss the various options of materials available for O-rings, as well as give several key factors on how to choose the right O-ring distributor fit for your operations.

What Is an O-Ring?

An O-ring is a loop of material which can be placed around the interference point between two parts, such as a container and its lid. O-rings are specially designed to trap in fluid or gas that might otherwise leak between these points. Some O-rings may be made of an elastic substance and able to stretch and contract onto a groove, whereas other O-rings can be made of a solid material to provide extra durability.

Rubber O-Ring Types

Rubber materials are cost effective and excellent at maintaining their shape which makes them a popular choice for sealing applications. The following is a list of some rubber O-ring types along with several of their characteristics.

Silicone O-Rings: Silicone resists fatigue and damage from wear and high temperatures. It can also stand ozone and UV radiation for outdoor applications.

EPDM O-Rings: Ethylene propylene diene monomer (EPDM) O-rings are a cost-effective option which can resist damage from chemicals, acids, and steam. They are commonly used in water systems and automobiles, as well as in the manufacturing of food, dairy, and pharmaceuticals.

Neoprene O-Rings: These O-rings are great for outdoor applications because they resist damage from water, oxidation and UV radiation. They can also withstand exposure to coolants and ammonia, making them a popular choice for refrigeration systems.

Viton O-Rings: These hard rubber O-rings are capable of maintaining their shape in a temperature range from -20? to 400?. In addition, they are also able to resist physical damage, as well as that from chemicals, fire, water, and oil.

Nitrile O-Rings: Nitrile O-rings are oil and fuel resistant, making them a reliable option for fuel systems and machinery. They also comply with many military material standards. Note however, that nitrile-O-rings can become inflexible at low temperatures.

Clear O-Rings: Clear O-rings are made of transparent silicone compounds and commonly used for assemblies that are highly visible or require a high level of cleanliness. Clear O-rings are also non-toxic, chemically inert, and odorless, making them a common choice in the manufacturing of consumables.

Factors to Consider When Choosing O-Ring Material

Consider these factors when choosing O-ring material:

Temperature: It is important to consider the temperatures that an O-ring will need to operate within. Nitrile-based O-rings are commonly used for high-temperature applications, whereas different silicone materials may operate within a wider range.

Flexibility: The inner diameter of an O-ring must be smaller than that of the groove it is meant to fit over, and they must be able to stretch to fill that groove. This characteristic is important because it ensures a tight seal.

Pressure: It would also be helpful to consider what pressure the O-ring will need to withstand, either from the contents inside a component or the surrounding environment. Higher pressure applications will require an O-ring with higher shore hardness, that is the measure of a material’s resistance to indentation.

Size: It is essential to make sure to know the dimensions of the component an O-ring will cover before making your material selection. The material should be able to stretch enough to be positioned over the widest part of a component, but still able to contract tightly at the intended groove to form a seal. Some materials will be more capable of stretching than others, affecting what sizes can be used.

Surface Finish: It is important that an O-ring is smooth enough on its surface to minimize the risk of excessive friction or accelerated wear. They should exhibit a tight surface roughness range between 5-16 µ inch RMS to be within the optimal range.

Other Properties: The type of material you choose may have a long or short lifespan, may require different production techniques, and can cost more or less in comparison with similar materials. These are all important properties to consider depending on your budget and application.

Choosing the Right O-Ring Distributor

A good distributor should meet all your material and production requirements, operate within your timeline and budget, and provide reliable delivery. At Emergent Purchasing, we understand the importance of these factors as well as maintaining items with a high standard of quality. As a part of the ASAP Semiconductor family of websites, we have access to a widespread distribution network which allows us to ensure rapid lead times and cost-friendly options for all our customers. Browse our robust inventory of aircraft parts and other industrial components with ease or use the search tool provided on our website. If an item piques your interest, you may send us an Instant RFQ form to get a custom response tailored to your needs in 15 minutes or less! 


Semiconductor's Certifications and Memberships
The only independent
distributor with a
  • All orders are fulfilled in the USA.
  • All shipments must comply with U.S.A export laws.
  • No exceptions.
Fallen Heroes Fund

“We Proudly Support Intrepid Fallen Heroes Fund that serves United States Military Personal experiencing the Invisible Wounds of War : Traumatic Brain Injury (TBI) and Post Traumatic Stress (PTS). Please visit website ( and help in their valiant effort”.

Thank You for Visiting.

We Hope that You Will Visit Us Again the Next Time You Need NSN Parts and Make Us Your Strategic Purchasing Partner.

Request for Quote

We use cookies to ensure that we give you a great experience on our website. If you continue to use this site we will assume that you are happy with it.