What materials are commonly used for residential gas piping?

The correct choice highlights materials that are widely accepted and commonly used for residential gas piping. Black iron is a traditional and durable material known for its strength in handling natural gas and propane, and it is resistant to impact and pressure, making it a reliable option for gas installations. Flexible gas line, often referred to as Corrugated Stainless Steel Tubing (CSST), offers versatility in installation due to its flexibility, allowing for easier routing in complex structures. Polyethylene is often used for underground gas piping because it is highly resistant to corrosion and provides a secure, leak-proof installation.

In contrast, the other options include materials that are either unsuitable or not typically compliant with current gas piping codes. Plastics like PVC and materials such as glass do not have the necessary durability or resistance to high pressure and temperature variations required for handling gas. Tinned copper and aluminum might be compatible with certain gas applications, but they are not standard materials for residential gas piping due to concerns about corrosion and longevity in gas service. Finally, lead is not a safe or acceptable material for gas piping due to its toxic properties, and PVC should not be used for gas applications as it cannot withstand the conditions found in gas systems. Hence, the selected materials in the correct choice are crucial for ensuring