National Center For Construction Education & Research (NCCER) Plumbing Level 1 Practice Exam

When measuring cast-iron hub-and-spigot pipe, the total length required includes both the length of the pipe itself and the insertion length multiplied by the number of laying lengths. This is critical in ensuring that the entire system is measured accurately for installation. The run refers to the horizontal or vertical distance that the pipe needs to cover, while the insertion length accounts for the amount of pipe that fits into the hub of the fitting. Since several pipe lengths may be connected through these fittings, the insertion length is significant and must be factored in to determine how much of the pipe will actually be utilized in the installation. Thus, when calculating the total length required, you take into account not just the lengths of the pipes, but also how they join each other, ensuring a precise fit in the overall plumbing system. This thorough approach helps guarantee that there is enough material to complete the project without gaps or deficiencies.