Rhode Island Journeyman Plumber Practice Exam 2026 - Free Journeyman Plumber Practice Questions and Study Guide

The formula to determine the length in feet for a plumbing capacity calculation is based on the relationship between the diameter of a pipe and its capacity. The correct formulation uses the diameter squared, which is a fundamental part of calculating the cross-sectional area of the pipe. By multiplying the diameter squared by a constant (0.0408) and then by the length, you’re effectively determining the volume or capacity of water that can flow through that specific length of pipe.

The constant 0.0408 is derived from the necessary conversions and calculations needed to accurately express capacity in terms of volume per length for plumbing systems. It accounts for the dimensions of the pipe and helps provide a standardized formula applicable to different pipe sizes.

In contrast, the other options either misrepresent the relationships involved or do not follow the correct order of operations to accurately reflect plumbing standards and practices. This highlights the importance of using the established formula correctly to ensure plumbing systems are designed and assessed effectively for their capacity needs.