March 2018

Gasket Material Selection

It’s said that what comes out of the joint is what goes back into the joint, but sometimes we’re asked if there’s a better material to use. That’s because the expense of replacing a gasket often far outweighs the cost of the part. When that’s the case a little extra spent on better gasket material might save a lot.

Unfortunately, there’s no easy answer to the material question. All we can say is, “It depends.” Here’s why, along with some guidance on selecting the best gasket material.

Four Key Criteria

It’s impossible to determine an appropriate material without knowing the temperature, environment, media and pressure the gasket will experience. It’s also important to determine the actual range of every parameter and every operating condition. Cleaning with caustic agents, for example, creates very different gasket challenges than handling a benign fluid like milk.


This refers to the temperature of the media. Many elastomers harden when cold, making them less able to resist pressure and reducing their ability to flex as the joint changes size. Neoprene, for example, has a lower limit of -40°F while high-performance fluoroelastomer (FKM) only goes to -10°F.


Temperature is one factor, sunlight another. A gasket used outdoors in a midwestern winter could see low temperatures while one exposed to the desert sun will get extremely hot. In addition, UV light damages some common gasket materials. NBR, for example, has poor UV resistance while EPDM holds up much better.


Some gasket materials suffer swelling when exposed to oils and other will oxidize rapidly. Brake fluid is incompatible with nitrile rubber and FKM while silicone and EPDM are a poor match for gasoline.


The pressure inside a pipe or enclosure can force gasket material to extrude out sideways. Harder materials generally hold up better but require higher clamping forces. In extreme cases, it may be necessary to consider PTFE, spiral-wound or metal gaskets.

Seek Advice

Every gasket application is different and it’s never easy to say which is the best material to use. Start by determining the four criteria listed above, then consult a material specialist.

Oxygen Compatible Materials

Many industries use oxygen. It’s one of the most reactive elements, which makes it useful in processes from steelmaking to paper production as well as healthcare and waste treatment. This reactivity, (a willingness to form chemical bonds with other elements,) also creates sealing problems. Here’s an overview of the challenges posed by oxygen and a discussion of the best gasket materials to use.

The Air We Breathe

Oxygen is one of the most plentiful elements and makes up some 20% of the air we breathe. It’s also locked into the oceans as water. At temperatures above -297°F (183°C) it’s a gas. Oxygen has a strong affinity for electrons, which is what lets it bond readily with many other chemicals. Rust and oxidation are the common results, although fire and explosions are always possible.

Oxygen Production

Oxygen is produced by cryogenic distillation or pressure swing adsorption (PSA). As the name implies, the cryogenic process entails cooling air until it becomes liquid, allowing the oxygen to boil off. This produces a very high purity gas.

PSA involves pushing air through aluminosilicate minerals. These take up the nitrogen, leaving just oxygen, but at a lower purity than the cryogenic process.

Keeping Oxygen Systems Clean

Given that oxygen is highly reactive, it’s essential that any surface it touches is clean. Some industries have special requirements for oxygen-clean surfaces. The standards applicable to your industry will specify the type and degree of cleaning needed.

Materials for Gaskets in Contact with Oxygen

Liquid oxygen can only be sealed by materials capable of withstanding very low temperatures. PTFE gaskets are a good choice as is FFKM (perfluoroelastomers) gasket material.

Good gasket materials for gaseous oxygen include neoprene, EPDM, silicone, butyl and Viton® (a DuPont brand name for FKM.) Rubber materials such as SBR and natural rubber should be avoided because of their tendency to react with oxygen.

Ask an Expert

Always consider temperature, pressure and the environment along with the media being sealed. For this reason, it’s prudent to consult with a materials specialist before ordering gaskets or gasket material.