Remediating ductwork from the inside was the only option. When Cool Zone Inc., Naples, FL, an HVAC contractor and a Carlisle HVAC Products, Wylie, TX, factory-trained authorized applicator, was contacted to clean and remediate the ductwork of a 27,000-sq.-ft. facility in South Florida, they knew the task wouldn’t be simple. The building’s dual-wall spiral ductwork was painted purple and exposed to the interior of the building for aesthetic reasons.