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Glass Breakage and Fatal Fall from Heights, Hotel

Property type: Hotel
Location: Atlanta, GA
Client: Attorney for Plaintiff (Family of Deceased)
Incident description: 30 year old female hotel guest was hosting a small birthday party in her 10th floor hotel room. She and a friend were crouching near the room’s floor-to-ceiling windows. The pair leaned against the glass, which suddenly and unexpectedly broke, allowing both women to fall backward through the window.

Broken window glass after two hotel guests fell through
This photo, taken soon after the accident, shows how the glass broke, leaving an opening through which the two women fell from the 10th floor window

The female landed on a skylight 5 floors below and died:

Skylight glass where both women landed after falling from window
The glass skylight, eight floors below the incident hotel room, was seriously damaged after the two women crashed onto it

The friend rolled down the skylight, then fell an additional distance to the sidewalk. She survived with permanent injuries. The window glass was approximately 45″ wide x 37″ tall x .190″ thick. The floor level glass was not tempered or laminated.

Injuries: Death from multiple blunt traumas

Documents reviewed by Façade Consultants(FC): Depositions of witnesses, Property Manager, Building Engineer, construction documents, site photos, CPSC-16 CFR Part 1201, Safety Standard for Architectural Glazing Materials.

First Site Investigation by Façade Consultants: FC visited incident the hotel room. The entire exterior wall of the room was floor to ceiling window wall with a horizontal mullion at 39.5″ height from the floor. Most noticeable were three factors: a) the interior glazing gaskets were shrunk back and clearly not providing much support to the glass, b) The outside of the glass was “cap beaded”, which means the glass was caulked around the edges to the frame and c) there was another pane of glass in the same room that had a crack.

The hotel windows and glass were found in a state of poor maintenance that weakened the glass
The hotel windows and glass were found in a state of poor maintenance that weakened the glass. The glass was poorly supported and there was even a crack in one of the other panes of glass in the same room

Shrunken glazing gaskets were prevalent in the incident hotel room. This indicates that glass is poorly supported and maintenance is poor

Dangerous, poorly suppirted glass contributed to the glass breakage and window fall
Dangerous, poorly suppirted glass contributed to the glass breakage and window fall. Evidence of previous repair attempts show that a problem already existed (probably leakage)

Two layers of outside glazing sealant, called a “cap bead” indicates multiple attempts to fix a glazing leak

Crack in adjacent hotel glass indicates surprisingly lax maintenance
Crack in adjacent hotel glass (at top) indicates surprisingly lax maintenance giving rise to the suspicion that the incident glass (at bottom) was also weakened

Police photo of broken incident window taken from the inside. Above right: Crack in glass found during inspection following incident. The crack was dirty, indicating it had been there, unrepaired, for years, suggesting poor maintenance. Cracks in glass are known to weaken glass. Did the incident glass give way too easily because of pre-existing damage?

Second Site Investigation by Façade Consultants: FC attended a forensic exercise in which the glass with the 3″ long crack was removed. A chips at the edge of the glass that propagated into a crack was from original construction, decades before the incident.

Fragment Examination and Attempted Reassembly: FC created a scaled, full size template of the broken glass shards that were recovered from the incident. Some crack edges were extended and three possible crack convergence points were found:

Full scale template was created to allow glass shards to be reassembled and analyzed
Facade Consultants created a full scale template of the broken window glass to allow shards to be reassembled and analyzed

This template was used for an attempted reassembly of the shards. The purpose was to determine if fractographic evidence could reveal whether there was pre-existing damage to the glass. We were not able to positively locate crack origins, but it was worth a try:

Meshulam assembles glass shards in the search for more information on the glass breakage
Meshulam assembles the incident glass shards in the search for more information on the glass breakage leading to the fatal fall

A tin-side detector was used to place the shards in the proper up/down orientation:

Assistant uses a tin-side detector to determine orientation of the glass
Window glass has a “tin side” which is the side that was floated on a bed of molten tin during the float glass process. Here a detector is used to determine the tin side in order to assist in reassembling the glass puzzle

All glass fragments were catalogued:

Shards of broken glass were each carefully photographed and documented
Each shard of broken glass was carefully photographed and documented during the process of analyzing the cause of the breakage

Glass Impact Testing: FC designed a test protocol to measure the ability of glass to act as a barrier against human fall-through. The CPSC-16 CFR Part 1201, Safety Standard for Architectural Glazing Materials was used to the greatest extent possible in order to avoid reinventing the wheel. In this test, a 100 lb punching bag is swung against the face of a glass pane in order to evaluate the glass behavior from various heights:

Impact device used to test safety glass according to Federal Standard 16CFR1201 and glass industry standard ANSI Z96.1
Impact device used to test safety glass according to Federal Standard 16CFR1201 and glass industry standard ANSI Z96.1. It involves dropping a 100 pound ball (impactor) at the glass from different heights, and observing the results

The vertical component of the swinging bag determines the impact force in foot-lbs. For instance, a “drop height” of 1 foot provides 100 foot-lbs of impact (100 lb bag x 1 foot drop). In the 16 CFR 1201, only 18″ and 48″ drop heights are used (150 and 400 foot-lbs respectively). FC’s first modification to the protocol was to start with smaller drop heights, then ramp up with repeated impacts. The other modification was how the breakage was evaluated. We were interested in the point at which the glass ceased to act as a barrier against human falls. We called this point “break-through”.

Results of laboratory impact test on annealed (not laminated or heat treated) glass showing resultant dagger-like shards
Results of laboratory impact test on annealed (not laminated or heat treated) glass showing resultant dagger-like shards. This breakage pattern is the reason safety glass is used instead in areas where human contact is likely

When annealed glass breaks, it breaks into large, dagger-like shards and evacuates the opening readily. Once broken, if offers no resistance to a person falling through, except for cutting the person on the way with the daggers that remain in the frame, like this:

Police photo showing dangerous glass shards remaining in the frame after the window fall with blood present
Police photo showing dangerous glass shards remaining in the frame after the window fall. Presence of blood indicates that at least one of the victims was immediately and seriously cut at the moment they fell through the window

Actual police photo soon after the incident. Sharp triangular shaped shards of annealed glass remain in the frame, adding injury to what soon became tragedy.

Laboratory impact test of tempered glass showing the small particles commonly seen when tempered glass breaks and the large opening in the middle, where people can easily fall through the glass after breakage
Laboratory impact test of tempered glass showing the small particles commonly seen when tempered glass breaks, and the large opening in the middle, where people can easily fall through the glass after breakage

Tempered glass is far stronger against blunt impact than is annealed glass. Our small study suggested it is twice as strong. When tempered glass breaks, it breaks into hundreds of tiny cubes by design. The cubes cut you less severely than do the large shards, but they easily leave the opening, providing no resistance to a person falling out.

Laboratory impact test of laminated glass showing how the shards tend to stay together after breakage due to their being bonded to a PVB (plastic-like) interlayer
Laboratory impact test of laminated glass showing how the shards tend to stay together after breakage due to their being bonded to a PVB (plastic-like) interlayer. Laminated glass is one type of officially recognized safety glazing. The other is tempered glass.

The laminated glass we used (1/4″ thick with 2 thicknesses of 1/8″ glass) actually cracked under impact quite readily, but because of the PVB (polyvinyl butyral – a plastic sheet), the pieces held together and did provide a greater resistance to falling through than any other glass type.

Glass taken from the building was tested along with new annealed, tempered and laminated glass in order to best understand the results. Unfortunately, of the two glass panes taken from the building, only one survived the shipping to the lab.

Laboratory impact test results. Old, weathered annealed glass was very weak. New annealed glass performed six times better than than old glass. Tempered and laminated glass performed far better in terms of keeping a person from falling through the glass.
Laboratory impact test results. Old, weathered annealed glass was very weak. New annealed glass performed six times better than than old glass. Tempered and laminated glass performed far better in terms of indow fall prevention.

Results of glass impact test. Annealed glass from the hotel broke at the very first impact with only a 3″ drop height (25 foot-lbs). Even new annealed glass performed six times better than that. Tempered and laminated glass performed far better in terms of keeping a person from falling through the glass.

Why did the Hotel glass break more easily than the new annealed glass?
Glass “weathers” over time. Exposure to the elements actually makes the glass weaker over time. Glass engineers add a weathering factor to their calculations, wherein a 20 year life span is contemplated. The problem here, and in many other older buildings, is that the Hotel glass was 37 years old at the time of the incident, nearly double the age considered by any glass strength calculation. Consider these facts:

Review of relevant building codes and wind load requirements. At original construction in 1973, safety glass should have been used but it was not
Review of relevant building codes and wind load requirements. At original construction in 1973, safety glass should have been used but it was not. During a 2006 renovation, safety glass should have been used, but it was not

Although the glass met wind load requirements, it did not meet safety glazing requirements in either the original construction or a later renovation including compliance with the 2006 International Building Code. Most telling, there was an ongoing history of glass breakage in the building in the years prior to the incident.

Opinion of Façade Consultants: The building ownership and management failed in their duty to provide a safe place for guests to reside. They not only allowed the windows to remain in poor repair, but they also failed to recognize or warn guests that the glass was weakened and breaking. Safety glass should have been used in the floor level application. These failures are proximal causes for the tragic death and injury that took place.

Disposition: Monetary settlement and the Hotel committed to adding safety film to floor-level glass.

Similar incident: Glass facade shatters, woman dies after 25-foot fall from restaurant in Kolkata

Another  investigation of hotel glass breakage 

Another investigation of hotel glass breakage with injury

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