Gas fittings are specifically designed for use with gases, such as flammable propane or hazardous phosgene. These types of fittings have a reverse thread; meaning, the threads are cut in the reverse direction from all other fittings so that gas lines cannot be connected to air lines, water lines, or vent lines. Common applications for gas fittings include gas mains, residential gas lines, propane tanks, medical use, hazardous gas applications, and explosives.   

Fitting Types   

Gas fittings come in a variety for styles, depending on the application. Common styles for gas fittings include adapter, coupling, cross or 4-way, 45° or 90° elbow fittings, and quick couplers.

When choosing gas fittings, connection selection is an important consideration that should be made based on the application.

For more information on types of fittings and connections, visit the Pipe Fittings Learn More page.

Material Types

    
Gas fitting materials are often selected with consideration of piping materials. Selection depends on factors such as cost, flexibility, media, environmental conditions, and required pressure ratings. Material choices include different types of plastic or metal. 

For a detailed description of material types and benefits of each, visit the Tube Fitting Learn More page.

Features

    
Features should be selected based on the desired application. Examples of gas fitting features include:

• Gas bulkhead fittings are designed to be mounted in a wall or bulkhead to allow tube connections on either side of the barrier.
• Bullhead fittings are in a T-shape, in which the branch port is larger than the run ports.
• Expansion joints and couplings connection sections of tube allow for movement due to service load, shock, or thermal cycling.

Specialty Fittings

   
Insulated, lined, and plated gas fittings are also available. Insulated fittings contain insulated materials and jacket construction. Lined fittings are common in applications where cleanliness is important. The lining in these fittings are often made from engineered polymers. Plated fittings are available with nickel or chrome — for appearance or corrosion resistance purposes. 

Gas fittings may also be reducing, side outlet, swivel, or underground rated. Size-reducing fittings can collapse in size. Side outlet fittings have more than two connections, that are often placed on the side of the main component. Swivel gas fittings allow one or more fitting ends to rotate or swivel. Underground rated gas fittings are designed and constructed for underground applications. 

Related Standards

Gas fittings must adhere to several standards to ensure proper design and functionality. For example, ASTM C1541 + REDLINE is the standard specification for shielded transition couplings using flexible polyvinyl chloride (PVC) gaskets to connect dissimilar DWV pipe and fittings, ASTM F2817 is the standard specification for PVC gas pressure pipe and fittings for maintenance or repair, and BS EN 10301 discusses steel tubes and fittings for on and offshore pipelines.

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Beswick Engineering Co., Inc. | TEAM Industrial Services | WIKA Instrument, LP