April 2018

Gasket Material for Natural Gas

Natural gas is widely used for heating and cooking and it’s the energy source for much of our electricity. Perhaps less well known, it’s also essential for fertilizers and plastics.

The systems that store and distribute natural gas need gaskets. Here we’ll discuss the materials most often used, but first, a short primer.

Hydrocarbon Origins and Uses

Like coal and oil, natural gas is formed from plant and animal remains. Decomposition produces methane, (CH4), and when trapped underground we call it natural gas. Natural gas is odorless, so a trace of mercaptan, (CH4S) is added to make it detectable.

Reacting natural gas with steam separates the hydrogen and a second reaction, this time with air, results in NH3, or ammonia. Chemists call this the Haber process and it’s the first step in producing fertilizers.

Like methane, plastics are also composed of carbon and hydrogen atoms. The difference is that the atoms are formed into long chains to create polyethylene, polypropylene and similar materials.

Storage and Distribution

When held above 200 bar (3,000 psi) natural gas is known as compressed natural gas (CNG). This makes it sufficiently dense for use as a vehicle fuel. When pipelines aren’t an option, for easier transportation cooling to below -184°F produces liquefied natural gas (LNG).

The Sealing Challenge

The biggest issues are permeability and flammability. Simply put, the very small methane molecules can find their way through some materials, and they burn readily. Fortunately, as it’s lighter than air, escaping natural gas tends to disperse quickly.

Sealing CNG and LNG presents additional challenges. Gasket materials must retain some flexibility at very low temperatures and should have the strength to resist extrusion through joint faces.

Materials for Natural Gas Gaskets

For most low pressure, ambient temperature applications nitrile and neoprene gasket materials are the first choice. In more challenging applications many engineers opt for more expensive Flexitallic spiral wound gaskets. PTFE and graphite are other options.

Every gasket application has some unique challenges. If you need material for natural gas gaskets, ask a product specialist at Hennig Gasket for advice.

Neoprene Gasket Applications

Neoprene is a synthetic polymer that resembles rubber, but as a derivative of chloroprene, it is far more durable in extreme temperatures, when exposed to oils and several chemicals, and it endures harsh weather conditions. But not all Neoprene gaskets are created equal—there are several variations or “grades” of neoprene. Each grade of neoprene gasket has its ideal application depending on factors such as temperature and pressure tolerances, the environment where it will be used, etc:

  • Commercial Grade Neoprene—15-50% Neoprene mixed with other elastomers; this blend is fine for general commercial gasket applications, but not in situations where high oil resistance is necessary.
  • Medium Grade Neoprene—51%+ Neoprene content; also suitable for many general manufacturing applications where a lower tensile strength will suffice.
  • High Grade Neoprene—100% Neoprene is extremely resilient in the harshest, most demanding environments while maintaining its resiliency, abrasion resistance and tensile strength.
  • FDA Neoprene—A mixture of Neoprene and other FDA-improved materials; gaskets made from this grade are used in the food industry, but also in many government-approved and military applications where oil resistance is key.
  • PSA Ready Neoprene—Available upon request, this Neoprene has one side with a matte finish and is designed to be used with pressure sensitive adhesives.
  • Nylon Cloth Inserted Neoprene—This grade is reinforced with one or two layers of nylon; good for improved creep reduction and stability.
  • Diaphragm Neoprene—Polyester insertions improve performance under high pressure applications requiring high levels of oil and petroleum resistance.
  • Flame Resistant Neoprene—Especially useful in potentially flammable, electric and high-heat applications, it passes the following flammability specifications: UL-94-HF-1, UL-94-HFB, MIL-R-6130C, FMVSS-302.

These grades vary in durometer ratings between 40, 50, 60, 70 and 80, can withstand temperatures between -20F to +180°F and come in sheets with several widths and thicknesses that can be cut (waterjet, flash and die cut) to exact specifications from your blueprints, or even reverse engineered.

Please contact Hennig Gasket & Seals if you have any questions about the different grades of neoprene that might best fit your application: 1-800-747-7661. We can custom manufacture any neoprene gasket you need to the most accurate specs possible.