A duct loses capacity in two ways: heat gain through the wall and leakage at the joints. We insulate and seal both, using duct wrap or closed-cell sheet depending on whether the run is internal, exposed or outdoors, and taping the system so the vapour barrier is genuinely continuous.
We also line ducts acoustically where the run passes over occupied space, insulate AHU casings and chilled water headers in the plant room, and supply flexible ducting and the tapes, pins and adhesives that go with the job.
