MCC-NH Gas Fitters Practice Exam

Where is plastic gas piping allowed to be used?

1. Only abovegrade indoors

2. Aboveground and below grade

3. Underground only

4. Only in commercial buildings

The correct answer is: Underground only

The use of plastic gas piping is subject to specific regulations and guidelines. Primarily, it is allowed underground, as this placement helps to protect the piping from physical damage, UV exposure, and other environmental factors present above ground. Installing gas piping underground limits the potential for leaks due to environmental conditions while providing a safe and unobtrusive way to transport gas. Plastic piping is not typically permitted for use above ground in most residential applications because of its vulnerability to damage from external influences such as sunlight, heat, and mechanical forces, which are more prevalent in above-grade installations. Furthermore, certain building codes and regulations restrict its use in commercial buildings, particularly when installed above ground, due to concerns regarding safety and durability. Therefore, the most accurate situation in which plastic gas piping can be installed is underground, aligning with safety practices and code requirements.