These elements should be measured by length (meters/feet), diameter, and material.
In both scenarios, quantities must be segregated by diameter and material to ensure pricing accuracy.
Figure 17 - Illustration of the quantified length of round-shaped ducts.
Special Case (Insulation/Fire Protection): It is necessary to consider these as a distinct typology from regular ducts. Any specific characteristics in the composition should result in a new element type/class.