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.

To solve this problem, Johns Manville introduced Spiracoustic Plus to the market over a decade ago. Spiracoustic Plus is a duct liner with factory-cut kerfs that allow it to be rolled easily into a circular shape.

Once the seam is taped, the material can be flexed into a heart shape, slid into the duct, and released into place. The material will rebound out of the heart shape into a circle that fits snugly against the interior of the spiral duct, and in most diameters, it does not require adhesive or mechanical fastening.

Spiracoustic Plus has been an excellent solution for lining most spiral duct applications, but it has had one noticeable shortcoming: the kerfs aren’t sufficiently spaced for VVSD (very, very small diameter) 6”– 8” ducts. To remedy this, many fabricating shops must spend time customizing the kerfs in the insulation to ensure that the insulation can fit in VVSD duct sizes. This customization, however, is time consuming and creates inefficiencies in the duct lining process.

This is why Johns Manville released VVSD Spiracoustic Plus, a spiral duct liner with kerfs engineered specifically to fit ducts with diameters ranging between 6” and 8” in size. As the first pre-kerfed, spiral duct liner engineered for VVSD ducts, Spiracoustic Plus can help save fabrication shops significant amounts of time when working with 6-8” duct sizes.

During product development, JM sent a small sample of VVSD Spiracoustic Plus to different contractors for their feedback regarding how the material handled and installed in a fabrication shop. Kevin Gurklies, general manager of Omni Duct, was one of the first fabrication shops to demo JM’s new VVSD product. He explained that VVSD ducts make up a large portion of the spiral ducts they insulate.

Customizing Spiracoustic Plus to fit these duct sizes, “was a labor killer,” for their shop. “There was a lot of additional labor trying to install VSD Spiracoustic Plus into 6-8” ducts. In order to be competitive in the market, we need to be efficient in the shop.  VVSD Spiracoustic helps with that,” he said.

This sentiment was seconded by Matt Iten, floor supervisor from Hercules Industries. “When you start looking at grooving VSD Spiracoustic plus to fit 100+ feet of 6-8” ducts, you’re talking about hours to days of additional work for a single project. The VVSD Spiracoustic Plus fits and rolls very nicely in the VVSD ducts just like standard Spiracoustic Plus does for the larger sizes,” he said.

Mike DeRammelaere, branch manager for Hercules Industries further expanded, “VVSD is so much more effective for 6-8” ducts, that we made the decision to wait until the product was released rather than committing more time to grooving more VSD Spiracoustic Plus.”

As contractors and fabrication shops strive to optimize their processes, products like VVSD Spriacoustic Plus can be an integral component to maximizing efficiencies.

This article originally appeared in the January 2021 issue of SNIPS magazine.