NATE Gas & Oil Heating Systems Practice Test 2025 – Complete Exam Prep

To determine the correct size for the main gas pipe from points "A" to "B," it's essential to understand the factors that influence gas pipe sizing, such as the volume of gas required, the length of the run, the number of fittings, and the pressure in the system.

A pipe with a diameter of 1.25 inches is commonly suitable for residential gas supply lines that require moderate gas flow while maintaining adequate pressure. This size can accommodate the needs of typical appliances and is often recommended by gas codes and standards to ensure safety and efficiency.

Choosing the correct size is critical because if the pipe is too small, it can restrict gas flow leading to insufficient gas supply for appliances, which may result in poor performance or shut-downs. Conversely, a pipe that is too large can also cause issues, such as increased costs for materials and installation without significant benefit.

Therefore, selecting 1.25 inches is based on established practices to ensure the safe and efficient operation of the gas system within a residential context, supporting equipment such as furnaces, water heaters, and other gas appliances effectively. Understanding the balance of these factors is crucial in making appropriate sizing decisions for gas delivery systems.