Illinois Plumbing Code Practice Exam 2025 – All-in-One Guide for Exam Success!

Under the Illinois Plumbing Code, the minimum size of a gas piping system is determined by the demand of the system and the specific application. The correct answer, indicating a minimum size of 1 inch in diameter, is appropriate for larger applications where higher gas volume is necessary, which is especially relevant for commercial and industrial settings.

This sizing helps to ensure adequate gas pressure, efficiency, and safety in the system. Smaller diameters, such as 1/2 inch or 3/4 inch, while suitable for residential or low-demand applications, do not meet the Code's requirements for larger installations.

It's important to assess the load calculations and ensure that the gas piping system is designed to deliver proper gas flow without causing pressure drop, allowing for safe and efficient operation of gas appliances. Therefore, the minimum diameter of 1 inch is appropriate in scenarios where higher capacity and demand are expected, conforming to the safety and performance standards of the Illinois Plumbing Code.