Fuel Gas: Copper

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Fuel gas systems convey natural gas or propane for laboratories, cooking, space heating, and...

 Copper is a long lasting, corrosion resistant, lightweight and strong material that...

Benefit of Material to Systems Application

While copper is a well-established material for many other applications, it is a relative newcomer to the world of fuel gas distribution, and is still not widely used for this application. However, it has been approved by major code bodies in the U.S.A. and Canada.

The advantages for using copper for fuel gas systems are flexibility (particularly in confined spaces), resistance to corrosion, easy joining, and availability in soft copper coils. When soft copper tubing is used, the number of connections is greatly reduced, which lowers labor costs and the potential for leaks. As a material lighter than the more common carbon steel pipe, copper can reduce injuries and labor costs.

The two classifications of fuel gas distribution systems that may be installed using copper tube are known as:
* Low pressure: Less than 14" wc (water column)
* Elevated pressure: 14" wc to 5 psig.

Currently in the United States, 2 psig tends to be the most commonly used elevated pressure system for residential and light commercial installations. However, 2 psig is not the only pressure at which gas can be delivered, and the system pressure selected must be compatible with available delivery pressures and other system requirements. The system designer should consult with the gas company regarding available pressure and metering requirements for each installation.

Possible disadvantages of copper usage include: copper pipe fittings may not be allowed by some utility codes for natural gas, copper can be easily confused with water piping, some gas can prove corrosive to copper, and more piping supports are needed for copper than with steel.

System Application and Material Usage

The use of copper tube and copper alloy fittings for interior fuel gas distribution systems are incorporated in the National Fuel Gas Code (ANSI Z223.1/NFPA 54). Similar provision is made in the Canadian document CAN/CGA-B149.1, Natural Gas Installation Code.

A copper gas line should never be used as a ground for an electrical system.

Several types of copper can be used for fuel gas, including ASTM B 88, TYPE L; ASTM B 280, Type ACR; or ASTM B 837, Type GAS copper.  Joints can be brazed or flared.

For copper natural gas systems joined with flared tube connections, flared brass fittings of a single 45° flare type are used. Note however that flared joints should not be used in concealed locations.

When copper fuel gas systems are brazed, brazed joints utilizing ASME/ANSI B16.22 wrought copper fittings should be used.  BAg Series brazing filler with a melting point above 1,000° F and a phosphorus content of less than 0.05% should be used.

Connections to steel pipe are made with an NPS threaded-to-flared copper adapter. Compression fittings in a gas piping system are not permitted unless allowed by the authority having jurisdiction.

All tube fittings for natural gas installations are rated at more than 125 psig, but should not be used at pressures beyond those allowed by local codes.

Gas installation regulations aim to avoid joints within walls or other inaccessible places where undetected leakage might cause an accumulation of gas. However, joints in these locations may sometimes be unavoidable. Since mechanical joints are prohibited in inaccessible locations, brazed joints should be used, provided they are approved by the authority having jurisdiction. These joints should be inspected and tested prior to enclosure to ensure a leak-free system. Minimization of joints, especially in inaccessible areas, can be easily accomplished using long, flexible lengths of copper tube.

For additional information, reference the Copper Development Association (CDA) website.

Manufacturers and Suppliers Participating in OPUS

F.W. Webb Company

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Galloup Company

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Jomar Valve

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MORSCO is a leading U.S. distributor of commercial and residential plumbing, HVAC, and PVF, with......
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Mueller Industries, Inc.

Mueller Industries, Inc. is the leading U.S. manufacturer of copper tube, copper fittings and......
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The Commonwealth Group

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Weldbend Corporation

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Applicable Joining Methods


Brazing is a joining process that produces coalescence of metals by heating the components to a...
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Used for ductile iron pipe, the mechanical joining method consists of a number of components...
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