Which of the following can be used for gas piping when the gas is not corrosive?

The choice of using copper and brass for gas piping when the gas is not corrosive is appropriate due to their excellent resistance to corrosion and ability to withstand high pressure. Copper is widely recognized in plumbing for its durability and reliability, while brass, which is an alloy of copper and zinc, provides further strength and stability. Both materials can maintain the integrity of the gas piping system, ensuring safe and efficient transport of gas without the risk of leaks often associated with more reactive or weaker materials.

In contrast, while polyethylene is commonly used for underground gas installations because it is flexible and resistant to moisture, it may not always be suitable for above-ground applications or high-pressure situations. Ceramic materials, though they can be strong and resistant to certain chemicals, are generally not used for plumbing applications due to brittleness and lack of flexibility. Galvanized steel can be used in some scenarios but is less desirable due to its propensity to rust and corrode over time, particularly in an environment where moisture may be present. Thus, copper and brass stand out as the ideal materials for non-corrosive gas applications, making this choice the most suitable.