Several procedures should be followed to ensure the protection and safety of copper natural gas lines installed indoors. Some of these are shown in Figure 13. In general, it is good practice to install the lines close to beams and close to other services, such as water distribution, conduit and ductwork.
A COPPER GAS LINE SHOULD NEVER BE USED AS A GROUND FOR AN ELECTRICAL SYSTEM.
In areas where excessive moisture is anticipated, dissimilar metal contact should be avoided or prevented by wrapping with an approved tape to avoid the effect of galvanic corrosion on steel hangers or studs.
Copper tube running parallel to the floor joists should be fastened to the center of the vertical face of the joist with clips not more than 6 feet apart. Tube at right angles, or diagonal to the joists, may be installed through holes drilled through the center of the joists. These holes should be at least 1 times the O.D. of the tube. If the holes are closer than 1.75" to the exposed edge of the joist, the tube should be protected with a steel striker plate 0.0508" thick, minimum. The main function of striker plates is to protect against such items as nails and other fasteners.
The tube may be also fastened to the underside of the joists, using clips every second joist. In such cases, special care must be taken to prevent damage to the tubing.
In partition walls, copper tube passing vertically, i.e., parallel to the studs, does not need to be supported, but it should be protected from puncture with a steel sleeve or steel striker plate where it passes through an upper or lower wall plate. In walls of larger than 2" x 4" construction, protection is only required if the tube is less than 1.75" from an exposed edge.
Steel sleeves may be either steel pipe or made from galvanized sheet steel at least 0.0508" thick and should extend at least 4" above and below the wall plates as shown in Figure 13. The tube should be wrapped with an approved tape where it passes through the sleeve to avoid abrasion.
Copper tube for natural gas distribution lines in solid flooring, such as concrete, should be laid in a channel with a cover or encased in ventilated ducts with a free air space around the tube of at least 0.5". Vertical pipe chases also should have openings at the top and the bottom for ventilation.
When copper tube passes through an exterior wall of concrete or masonry, it should be protected by wrapping with an approved tape, installing through a plastic or steel sleeve, and then caulking on each side of the wall for a watertight seal, Figure 14. The same requirements apply to similar, interior concrete or masonry walls; caulking is required per applicable building codes.
According to the National Fuel Gas Code, underground piping must be installed with at least 18 inches of cover. This may be reduced to 12 inches if external damage to the pipe is not likely to result. If this minimum of cover cannot be maintained, piping must be installed in a conduit or it must be bridged. In addition, excessive stressing of the pipe must be prevented where there is heavy vehicular traffic or where soil conditions are unstable and settling of piping or foundation walls could occur. Piping passing through flower beds and other cultivated areas should also be protected. Also, to avoid corrosion, copper tube should never be laid in contact with cinders or soils containing cinders.