Red Seal Gasfitter — Class B Practice Exam

What material is commonly used for gas piping in residential applications?

1. Typically black iron, steel, or flexible gas tubing

2. Plastic or PVC piping

3. Concrete or masonry materials

4. Aluminum or copper piping

The correct answer is: Typically black iron, steel, or flexible gas tubing

In residential applications, the most commonly used materials for gas piping include black iron, steel, and flexible gas tubing. These materials are specifically chosen for their strength and resistance to pressure, which are critical characteristics for safely conveying natural gas or propane from the supply source to appliances. Black iron pipe is a traditional choice for gas piping due to its durability and mechanical properties, making it effective in handling the pressures associated with gas systems. Steel pipes, similar to black iron but often galvanized to prevent rust, are also utilized in gas systems for their structural integrity. Flexible gas tubing, typically made from corrosion-resistant materials like stainless steel or another alloy, is increasingly popular because it simplifies installation in tight or complex building layouts. These flexible options can accommodate movement and are less prone to leaks compared to rigid materials when installed correctly. The other options are not suitable for gas piping; plastic or PVC cannot withstand the higher pressures and temperatures associated with gas. Concrete and masonry materials are too rigid and not suited for gas transport, while aluminum or copper does not have the necessary strength and sealing properties needed for gas systems, making them unsafe choices for gas piping in residential settings.