Copper tube installed underground is usually required to be 15" (400 mm) below the surface, or more than 24" (600 mm) under a commercial driveway or parking lot.

When copper tube passes through an exterior wall of concrete or masonry, it must be double wrapped, coated or sleeved, and then caulked on each side of the wall for a watertight seal, see Figure 8.


Figure 8: Copper tube through an exterior wall, such as "in" from a gas meter, or "out" to a barbecue.

The same requirement applies to an interior concrete or masonry wall, except that the caulking is not needed.

When installing copper natural gas lines indoors, several procedures are carried out to ensure their protection and safety. Some of the procedures are shown in Figure 9.


Figure 9: Copper Tube Installation and Protection

In general terms, it is good practice to install the lines close to other services, such as water distribution, conduit, and ductwork, and close to beams. At the same time, dissimilar metal contact should be avoided or prevented by double wrapping with tape or insulation, to avoid the risk of galvanic corrosion. It is also good practice when clips or hangers are required, to install them adjacent to fittings and connections, and immediately before and after bends. A copper gas line should never be used as a ground for an electrical system.

Copper tube running parallel to floor joists should be fastened to the centre of the vertical face of a joist, at least 1.75" (43 mm) from an exposed edge and with clips every 6 ft. (2 m) maximum. Copper or plastic clips should be used to avoid the risk of dissimilar metal corrosion. Tube at right angles or diagonal to joists may be installed through holes drilled in the joists. The holes should be at least 1-1/2 times as large as the outside diameter of the tube, and be more than 1.75" (43 mm) from an exposed edge. The tube may be fastened to the underside of joists, using clips at every second joist, but in such cases (or if the supporting holes are closer than 1.75" (43 mm) the tube should be protected with a 4" (100 mm) square of not less than 0.062" (1.59 mm) thick steel sheet. These squares are sometimes called "smash" plates, their main function being to provide protection against such items as nails and other fastenings.

In partition walls, copper tube passing vertically, parallel to the studs, need not be supported, but should be protected with a steel sleeve or steel "smash" plates where it passes through the upper and lower wall plates less than 1.75" (43 mm) from an exposed edge. The steel sleeves may be steel pipe or be made from 0.062" (1.59 mm) steel sheet, and should extend at least 1" (25 mm) above and below the plate as shown in Figure 9. The tube should be double wrapped with tape where it passes through the sleeve, to avoid dissimilar metal contact. When the tube is attached to a vertical stud, it should be at least 1.75" (43 mm) back from an exposed edge or be protected by a steel strip.

Any cutting, drilling or notching carried out to accommodate the tube, should not weaken the structure, and should be in accordance with local building codes.

Copper tube for natural gas lines in solid flooring, such as concrete, should be laid in a channel with a cover or, alternatively, encased in ventilated ducts with free air space around the tube of at least 1/2" (13mm). Vertical pipe chases also should have openings at the top and bottom for ventilation.


Copper tube clipped to the underside of joists.


Steel "smash" plates installed at a floor plate.


Copper tube installed through holes drilled in the joists. These holes are more than 1.75" (43 mm) from an exposed edge.