Expansion Joints and Pre-Compressed Sealants
BACKERSEAL Part of 3-yr Payback Plan for $550 Million Dollar Energy
Retrofit of Iconic Empire State Building (Retrofit 2008-2009)
New York City, NY--Setting
a new benchmark for large-scale, aggressive, energy retrofits of
existing structures, the Empire State Building's recent upgrade is
saving up to 40% and $3.8 million annually in energy costs, has earned
LEED Gold certification, and
has proved the economic viability of whole-building energy efficiency
retrofits in the
pursuit of sustainability.
BACKERSEAL by EMSEAL played a critical role in bridging the thermal
breaks between the window frames and the wall elements of the 6,514 windows.
The project team,
assisted by the Rocky Mountain Institute,
evaluated 70 ECM's (Energy Conservation Measures) by modeling them and
chose only eight--among them the building windows.
these eight measures are projected to result in a 38.4% decrease in
The sheer number of
windows means they are a huge percentage of the facade of the structure.
It became quickly
apparent that the windows themselves as well as the thermal breaks
between the window frames and the walls of the building had to be
"By changing the building envelope
insulation both through the windows and against the walls themselves, it
lowers both the heat and cold loads on the building,"commented Stephen
Doig, PhD, Program Director, Rocky Mountain Institute.
The existing failed sealant was a traditional backer rod and
polyurethane system that had aged, dried, stiffened and separated at the
bondline as the result of
(click images to
A survey of available depths
and widths was taken at various building elements.
Manufactured in a custom depth to suit the shallow joint profile, the
BACKERSEALwas installed behind liquid-applied silicone.
BACKERSEAL was supplied in a range of widths and replenished just in
time as consumed during installation.
BACKERSEAL self-expands after insertion into the joint and remains in
BACKERSEAL installed between window-frame and stainless steel facade
adornments. Supplied precompressed to less than joint size
Working from swing
stages, the window sealing was progressed on multiple elevations
simultaneously and tracked on wall-mounted facade elevation plans in the
Swing stages look
tiny against the massive facade of the Empire State Building as
crews work to reseal the 6,514 window perimeters using EMSEAL's
BACKERSEAL behind silicone liquid sealant.
Using integrated design
and whole systems thinking the cascading benefit effects of energy
conservation measures becomes
in isolation, upgrading and sealing of the windows would have yielded some
savings but would have a 20 year payback.
Looked at in respect to
the effect that upgrading and properly sealing the windows would have on
the reduction of load on the mechanical (heating and cooling) systems,
the results are altogether different.
"The way we as engineers like to
look at it is what we call interactive effects. What we think
about is, well, the windows will do some good, they'll save some energy,
but more importantly, they'll make our systems smaller. Our
heating system is smaller, our cooling system is smaller, that
optimization is much different than just 'what's the energy savings from
a better window?," remarked,
Peter Rumsey, P.E., Managing Director, Rumsey Engineers (now
In fact the building
owner had expected that they would have to add heating and cooling
capacity. Instead they ended up with excess capacity from the
existing systems because of reducing and managing the heat load better.
"There's massive innovation here, by
looking at an integrated approach,"
commented Malkin Holdings President, Tony Malkin.
Energy savings and
capital cost savings looked at in combination yield a far greater return
than looking just at the energy savings from projects in isolation.
A YouTube video of the
project from the Rocky Mountain Institute can be seen by
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