Empire State Building in New York City Empire State Building at night


The year 1954 marked a significant milestone in thermal insulation history. Armstrong’s R&D Project Number 54013, developed by three innovators, evolved into ArmaFlex, the world's first flexible, closed-cell elastomeric foam for equipment insulation. This product revolutionised the insulation industry. Today, 70 years later, ArmaFlex continues to be warmly welcomed by customers. The secret of its enduring strength? Reliability and longevity. The Empire State Building iconic project is proof that when properly installed and maintained, ArmaFlex can last the life of the system – in this case performing for three decades.


An icon like New York’s Empire State Building moves with the times too. An extensive LEED® Gold certification procedure in 2009 involved all areas of the structure being carefully benchmarked to identify energy-saving potential. Renovation upgrades included efficient windows, a chiller plant retrofit, updated building controls, and new tenant energy management systems. ArmaFlex insulation was written into the specification without substitution and used on the chiller, chilled water piping, condensate lines, and ducts. Its closed-cell structure, flexible nature, and ability to fit into tight spaces, made it the ideal choice. Plus, it meets all the thermal conductivity requirements to save energy and control condensation, especially on below ambient temperature equipment.

Interestingly, a unique issue for skyscrapers is the stack effect. This occurs in tall buildings when the outside temperature is much colder than the indoor temperature. Warmer air inside rises looking for a way to escape, creating negative air pressure at lower levels, and pulling the cold air inside. This creates a challenge for maintaining temperatures throughout the building and is another reason why it’s important to insulate piping on exterior walls. The low thermal conductivity of ArmaFlex was a great choice to prevent freezing.

Additionally, ArmaFlex met indoor air quality expectations. It’s fibre-free and non-particulating, meaning no fibres would be introduced into the airstream, especially important in a duct liner application – and because it’s manufactured with Microban® anti-microbial product protection, it inhibits the growth of mould and mildew in the insulation. Plus, it’s GREENGUARD Gold certified assuring low volatile organic compound (VOC) emissions, which benefit building occupants.


The Empire State Building achieved LEED Gold, exceeding the one-year goal by five percent, saving $2.4 million in the first year. Powered by the successes of their own renovation, Dana Robbins Schneider, the SVP & Director of Energy, Sustainability and ESG, established the ‘Empire Building Playbook: An Owner’s Guide to Low Carbon Retrofits’ – a step-by-step guide to meet sustainability goals and make smart investments.


To assess product performance and the achievement of energy goals, Armacell spoke with Timothy Dailey, Director of Engineering at the Empire State Realty Trust (ESRT) which holds a portfolio of New York City properties including the Empire State Building. Dailey, who has more than 40 years of expertise, said: “We’re on track for our goals and improving every year.” In reference to using ArmaFlex he commented: “ArmaFlex is a no-brainer. It doesn’t fail, it performs great, and it looks good […] when installed properly, ArmaFlex is clean and tight.”  Although our AP/ArmaFlex Duct Liner had been installed years before, it did not require replacement as the fibre-free insulation was (and still is) delivering energy efficiency, indoor air quality protection and noise attenuation. ESRT engineers continue to specify ArmaFlex for the Empire State Building, and for all its other buildings in the trust.

At 93-years-old, the award-winning Empire State Building is now one of the most energy efficient buildings (of any age) in the world – achieved by making ambitious decisions that drive admirable sustainability goals that pay back dividends year-on-year. And the ESRT is on track to be Net Zero by 2035.

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Microban® is a trademark of Microban Products Company and is used herein with permission. USGBC® and the related logo are trademarks owned by the U.S. Green Building Council® is used herein with permission. LEED® stands for Leadership in Energy and Environmental Design. LEED®, and its related logo, is a trademark owned by the U.S. Green Building Council® is used herein with permission.