What are common types of gas connections for residential furnaces?

The appropriate choice for common types of gas connections for residential furnaces is 3/4-inch black iron or copper piping. This type of piping is widely used in gas supply systems due to its strength and durability, which are crucial for safely transporting natural gas or propane to residential heating equipment.

Black iron piping is particularly favored because it has a high resistance to corrosion and is designed to handle the pressures of gas delivery systems. Copper piping is also acceptable because it is flexible and resistant to various types of corrosion, but it is generally used in specific applications and must adhere to local building codes.

In contrast, 1-inch PVC piping is primarily used for venting or drainage in plumbing systems and is not appropriate for gas supply due to its inability to withstand the necessary pressures and its flammability. Flexible rubber hoses, while sometimes used for gas connections, are typically limited to specific and temporary applications and do not meet the necessary safety standards for permanent installations in residential settings. Galvanized steel piping, although used in some applications, is less common for gas supply connections due to its susceptibility to rust and corrosion over time. Thus, 3/4-inch black iron or copper piping is the most reliable and compliant choice for gas connections in residential furnaces.