Johns Manville’s VVSD Spiracoustic Plus is a duct liner with kerfs engineered specifically to fit ducts with diameters ranging between 6” and 8” in size.
Spiral ducts are a popular choice for commercial applications for a variety of reasons, ranging from preferred aesthetic appeal to longer duct runs resulting in lower potential for duct leakage. Despite this, spiral ducts have presented somewhat of a challenge when it comes to using a duct liner insulation.
Unlike rectangular ducts, that offer a flat surface that the insulation can be pinned to, spiral ducts require the duct liner to conform to the shape of a circle inside the duct. As anyone who has ever tried to wrap a circular object with wrapping paper knows, this can be difficult.