How frequently must external duct insulation be identified with manufacturer details?

The requirement for external duct insulation to be identified with manufacturer details at specific intervals is critical for ensuring safety and compliance in mechanical systems. The correct answer indicates that this identification must occur every 36 inches along the ductwork.

This practice serves several purposes: it allows for easy identification of the duct insulation material, which is important for maintenance and safety inspections. Knowing the manufacturer and the specifications ensures that any work done on the ducts adheres to manufacturer recommendations and relevant codes. Additionally, proper labeling helps in recognizing the type of insulation used, which can affect the system's energy efficiency and performance.

The 36-inch interval is established within the guidelines to promote sufficient visibility and accessibility to the information. This distance strikes a balance between practicality and ensuring adequate identification along the length of the duct, which aids technicians and inspectors in quickly evaluating the insulated ductwork without excessive disruption or delays.