New Polyester Duct Liner Insulation Less Expensive & Reduces Installation Time
Schreiber Foods is constructing a new corporate headquarters and global technology center in downtown Green Bay, Wisconsin. Founded in Green Bay in 1945, it is the world’s largest employee-owned dairy company. Its $50 million headquarters building spans 235,000 sq ft and reaches five stories high, featuring primarily office space. When completed, it will employ approximately 550 people in the greater Green Bay area.
The firm Hammel, Green and Abrahamson (HGA, Inc.) is an integrated architecture, engineering, and planning company responsible for designing the HVAC system, along with other mechanical systems, for the Schreiber Foods Project. HGA Senior Mechanical Engineer and Vice President Kevin Pope is the Engineer of Record on the project.
“For most ducting projects of this type, we typically specify a polyimide foam liner for the supply ducting and a fiberglass liner for the return,” Pope said. “The reason for this is any fibers coming off the fiberglass liner are captured in the air handling filtration system before it reenters the supply air. It’s also a way to keep costs down since fiberglass is less expensive and offers reasonable sound attenuation.”
The polyimide foam is typically coated with an acrylic-type polymer when used as a duct liner. The coating provides a protective barrier against dust and moisture from collecting in the duct. However, one of the drawbacks of polyimide foam is that it can be more expensive than other materials.
F. Ahern Co. is the mechanical contractor for the project, responsible for the sheet metal and other mechanical systems. J.F. Ahern Project Manager Shaun Neubauer has he need to control project costs as one of his primary functions.
“It’s part of my job to control project costs, so I begin immediately looking for alternative material choices,” Neubauer said. “We noticed immediately that the polyimide foam cost was coming in rather high, and we began investigating alternative duct liner material. We had an opportunity to meet with Ductmate Industries to compare their new PolyArmor polyester-based liner material.”
PolyArmor is new to the market, having been introduced only one and a half years ago. It is a polyester duct liner insulation used in forced-air heating, ventilation, and air conditioning systems. It is engineered to provide industry-leading R-values, with excellent noise reduction and superior indoor air quality.
The polyester material is webbed into a thermal blanket, which is then bonded with an FSK facing to resist damage during system installation and operation. It also provides excellent durability in the airstream.
Neubauer said the PolyArmor met the specification requirements, and he was pleasantly surprised with the cost estimate. Since the polyimide was specified, he submitted the PolyArmor cost saving and specifications to Pope and requested a substitution, which was approved.
F. Ahern and Neubauer have a long history working with Ductmate. Quite often, they specify other Ductmate products, such as access doors, connectors, and vane systems. Their relationship was a key factor in their decision to install the new PolyArmor liner material.
More emphasis was placed on noise reduction than on insulation values, although both were important. The PolyArmor proved excellent for sound attenuation, achieving a .65 NRC rating, while also delivering an R5 insulation value in one-inch material thickness.
Duct sizes vary, with dimensions up to 6’ by 3’, and they can handle an airflow of up to 80,000 CFM. The specifications called for the PolyArmor to be installed approximately 20’ downstream from each VAV discharge connection.
J.F. Ahern Shop Manager Chris Elwing was impressed with the installation performance of PolyArmor. With over 31 years of experience in the sheet metal industry, 13 of those with J.F. Ahern, he has seen his share of duct insulation.
“We install all duct liners at the shop and have had to use an elastomeric-type product for many of our installations,” Elwing said. “Elastomeric material is tough to work with because it’s hard to cut and shape into place. We had never used the PolyArmor liner before and discovered that it installs much faster and is easy to pin; it greatly reduced our man hours on the project.”
Elwing estimated that they installed 25,000 sq ft of the liner material, all of which was installed by hand using no coil machine. Even with the additional labor time required, he cut his installation time by 30% or more!
PolyArmor liner is installed on the duct surface using water-based adhesives. This eliminates the need for solvent-based bonding agents that emit VOCs for many years after installation. The polyester base material does not promote or support the growth of mold or mildew, making it very desirable for a healthy environment and occupant safety.
The net result was even better than expected.
“Not only did we reduce costs for the liner material, we saved another 30% on installation time, which is significant,” Neubauer commented.
Both companies agree they will use PolyArmor on future projects.
