Apprentice question
Verify first
Verify before you commit. Cheap to catch now.
A tight pleated elbow can create system effect and turbulence on high-velocity duct. Use an approved smoother/longer-radius fitting or revised route where the system needs it.
['Short-radius or light-duty pleated elbows can work in the wrong place, especially near fans, VAV inlets, or high-velocity runs. The air can separate through the turn and create noise, pressure drop, and bad readings.', 'Replace the restriction with a smoother approved elbow, longer-radius fitting, or revised offset path that fits the pressure class and equipment requirement. Verify the fitting type before assuming any 45° elbow is acceptable.']