When will glass stop falling from Austin sky-rises?

Glass panels have plummeted from the tops of two of Austin’s most iconic high-rises on five occasions since 2011, tumbling through the air and crashing onto downtown streets and sidewalks.

Luckily, the falling glass has not caused any fatalities. And while the city has quietly moved to make glass balconies safer, most buildings still feature balcony guardrails made of glass that has a history of shattering onto the ground below.

The most recent event occurred last week when a balcony panel fell from the city’s tallest building, the Austonian, raining shards onto Congress Avenue.

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Austin fire fighters clean up glass along Congress Ave. on Thursday, August 11, 2016 where glass fell into the street and sidewalk from the 48th floor of the Austonian, Austin’ tallest building. No reported injuries from the broken glass. RICARDO B. BRAZZIELL/AMERICAN-STATESMAN

At least four of the five incidents involved what is called tempered glass — panes that have been heated and quickly cooled in an effort to strengthen them. Such glass, which “pebbles” up when it breaks as opposed to falling in in sharp shards, makes up the vast majority of balcony railings throughout the country.

But tempered glass has another, more unwelcome property: in rare, but often highly publicized cases, it can spontaneously shatter, raining the cube-shaped shards onto the ground below. Tempered glass also weakens at its edges. At least one glass failure at the W Hotel was blamed on something — possibly a chunk of falling grout striking the exposed edge of a glass railing.

Safety reforms were made in the aftermath of the W Hotel’s incidents. The building’s free-floating guardrail design was replaced with sturdier rail coverings. In 2013, the City of Austin also amended its building code to require the stronger, and more expensive, laminated glass in railings above streets, pools and courtyards.

Laminated glass, traditionally used in windshields, is made of glass panes sandwiched around a film of polyvinyl resin that make spontaneous shattering highly unlikely (After the W Hotel incidents, the China-built tempered glass in the hotel’s balconies was replaced with laminated panels.).

Last year, a similar requirement was included in the latest version of the International Building Code, which provides the basis for many municipal building codes.

Industry experts say the change is driving increased interest nationally in laminated glass. “We do see more who are moving toward laminated glass in anticipation of adoption of this code,” industry official Valerie Block told the USGlass News Network last month.

Austin’s amendment won’t affect the Austonian and other buildings constructed or permitted before the 2013 change. But as Austin’s skyline continues to transform with sleek downtown high-rises, many of them condominiums with balconies, officials hope it will reduce the amount of glass spilling onto the ground.

 

 

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