Pneumatic Fittings: Specifications and Materials

Pneumatic fittings are used to connect sections of pipe, tube and hose in pressurized gas systems. Compared to hydraulic fittings, pneumatic fittings are generally characterized by tighter seals and lower pressure requirements. They are often utilized in pneumatic logic control systems and instrumentation.

Specifications of Pneumatic Fittings from Bryan Hose & Gasket


Once you have determined the type of fitting required, proper sizing can be addressed. Proper sizing is crucial to successful fitting selection, as oversized or undersized parts will either be completely incompatible or will seal or connect inadequately.

A pneumatic fitting size is defined by the size of vessels it connects to. Tubes, hoses and pipes are sized based on inside diameter (ID) and outside diameter (OD), measured in inches (in) or millimeters (mm). Fittings that are designed to connect to a tube with a 2″ OD are rated as a 2″ OD fitting. While inside diameter measures the diameter of the empty portion of the cylinder, outside diameter diameter involves the thickness of the tubing wall.


Pneumatic fittings are usually rated for specific temperature and pressure ranges based on what they are designed to handle.

The working range of pressures or the pressure ratings at which the fitting was designed to operate is the operating pressure range. It is generally measured in pounds per square inch (psi). Operating above or below this rating can result in the fitting failing (i.e. break, leak, lose its seal).

The working range of temperatures or the temperature ratings at which the fitting was designed to operate is the operating temperature range. It is measured in degrees Fahrenheit (°F) or degrees Celsius (°C).

Materials Used for Pneumatic Fittings from Bryan Hose & Gasket

Fitting material is critical for determining a variety of physical properties of the part as well as gas compatibility. Material options include metals, plastics and composites.



Aluminum is lightweight and corrosion resistant. It has low tensile strength and is utilized in low pressure applications for its corrosion resistance and low density. To improve its strength and hardness, aluminum is alloyed with zinc, copper, silicon, manganese and/or other metals.


Brass is strong, durable and corrosion resistant. It has high temperature ductility and good conductivity, and is is an alloy of copper and zinc. Because of its machinability and its excellent performance properties, brass is a commonly used metal for smaller compression and threaded fitting typical of pneumatic systems.


Steel is durable and strong with high heat resistance. It is an alloy of iron and carbon, and is generally alloyed with other metals to improve its resistance to corrosion. For added rust protection and chemical resistance, galvanized steel is coated with zinc.

Stainless Steel

Stainless steel is strong with a great resistance to chemicals and corrosion. It is an alloy of steel that contains over 10.5 percent chromium. This metal has the strength and durability of steel while also providing excellent resistance to corrosion.



Fluororesins such as polytetrafluroroethylene (PTFE) and polyvinylidene fluoride (PVDF) are fluorcarbon-based polymers generally utilized for temperature requirements above 500°F (250°C). This plastic exhibits extremely good chemical resistance and dielectric properties.


This thermoplastic material is commonly used for pneumatic fittings because of its price, broad material compatibility and durability. It exhibits great cold flow, bi-axial strength and yield elongation properties. This material can be utilized in exposed applications because of its UV, weathering and ozone resistance.


Composite fittings consist of those made from combinations of materials, such as carbon, fiberglass and graphite. They have high melting points and are utilized as fittings for applications that require high temperature durability and chemical resistance. These materials also exhibit low electrical and thermal conductivity.


Don’t hesitate to contact Bryan Hose & Gasket with the link below for more information or to purchase your pneumatic fittings today!

Leave a Reply

Your email address will not be published. Required fields are marked *