Long-lasting, fibre-free duct lining solution for world's most famous building

The Empire State Building (ESB) is soaring to new heights in sustainability. A $20 million renovation, guided by a partnership between the Clinton Climate Initiative (CCI), Johnson Controls Inc. (JCI), Jones Lang LaSalle (JLL), and Rocky Mountain Institute is expected to deliver a 40% energy savings and earn the world’s most famous skyscraper LEED® Gold certification for Existing Buildings: Operation & Maintenance. Renovations include everything from triple glazed windows to occupancy sensors. 

But not everything will change. The duct lining remains the same: AP/ArmaFlex* has been the fiber-free duct liner of choice – an all-in-one solution for insulation, condensate control, and noise attenuation.

“AP/ArmaFlex self-adhering duct liner was written into the Empire State Building’s specifications several years ago—without any substitution,” said Bob Dizel, Northeast Sales & Market Manager for Armacell. “It remains the perfect choice because, like the Empire State Building, ArmaFlex is constructed to last. Properly installed, ArmaFlex should last as long as the duct itself," said Dizel.

The duct liner’s smooth, closed–cell structure does not absorb moisture, which can cause other insulation materials to deteriorate or fall victim to mold growth. It is easily cleaned and need not be replaced even if mold is detected within the ductwork. In contrast, fiberglass duct liners must be removed and thrown away if they become wet or contaminated with mold.

Little, if anything, will compromise the performance of the material, including cuts and punctures. Because of its closed-cell structure, it remains unaffected by the corrosive velocities of an air delivery system. It even stands up to rough handling by installers.

Allure of Fresh, Clean Air

One thing that has always been on the mind of ESB owners and property management is tenant occupancy. These days, property management firms frequently leverage improved indoor air quality to lure tenants. Certainly this factored into the decision to implement demand-controlled ventilation into ESB office spaces. As a fibre-free, non-particulating material, AP/ArmaFlex does not release unwanted fibers into the air stream. It is also made with EPA- registered Microban® antimicrobial treatment which provides a higher level of protection for facilities seeking to reduce their risks for mold on their insulation materials. Finally, ArmaFlex has been certified by the GREENGUARD Environmental Institute to meet the stringent indoor air quality requirements of GREENGUARD Children and Schools. This particular GREENGUARD certification verifies that the product meets strict emissions limits for formaldehyde, phthalates, fine respirable particles and other volatile organic compounds or VOCs.

Quieter, More Productive Office Spaces

Tenants who care about worker productivity are also legitimately concerned with intrusive noise from a building’s mechanical system. Of course, sheet metal ductwork is notorious for transferring unwanted vibration and noise from the mechanical system into occupied spaces. Fortunately, AP/ArmaFlex does an excellent job minimising mechanical noise. It has a sound absorption rating of NRC 0.50 and a sound transmission value of Class 25 when applied to sheet metal duct. Elastomeric foam material provides superior HVAC duct noise dampening compared to fiberglass duct liner.

*AP/ArmaFlex was used in this project and is sold in the United States of America. Consider ArmaFlex Airduct, ArmaFlex Class 0 or ArmaFlex Class 1 for your projects in Japan.

Our solutions

ArmaFlex Airduct


For long service lifetime

ArmaFlex Class 0


For reliability and better indoor air quality

ArmaFlex Class 1


Engineered to prevent condensation

ArmaFlex Accessories


Complementary accessories for a professional finish

ArmaFlex 520 adhesive


Complete your insulation system with ArmaFlex adhesive. Install it. Trust it.