Which materials are unsuitable for use in gas piping systems?

Plastic materials are unsuitable for use in gas piping systems primarily due to their flammability and lower structural integrity compared to other materials. Gas lines must be capable of withstanding high pressures, temperature variations, as well as potential physical damage. Plastic lacks the durability required for long-term service in these environments. Additionally, certain types of gas can deteriorate plastics over time, leading to leaks and failure of the gas piping system.

On the other hand, metal alloys, copper tubes, and cast iron are commonly used in gas piping systems due to their strength, durability, and resistance to corrosion. These materials provide a reliable method for safely transporting gas and can withstand the pressures typically found in gas systems, making them suitable choices for this application.