HVAC Journeyman Practice Exam 2025 - Free HVAC Practice Questions and Study Guide

The requirement for supporting round horizontal ducts that are 10 inches in diameter or less is based on industry standards for proper installation and safety. Using 1 inch wide galvanized straps or No. 18 gauge wire spaced 10 feet apart ensures that the ductwork is adequately supported while allowing for the necessary structural integrity and flexibility.

Galvanized straps or wire are preferred materials because they are resistant to corrosion, which is particularly important in HVAC applications where moisture may be present. The specified spacing of 10 feet provides sufficient support to prevent sagging or excessive movement of the ducts, which can lead to disconnections or inefficiencies in the system.

This combination offers a balance between support and practicality, as closer spacing may unnecessarily increase material usage and labor costs without providing significant benefits for ducts of this size. Thus, adhering to these specifications is essential for ensuring effective ductwork installation and function.