Leading Glass Expert Performs a Failure Analysis on Failed
Tempered Glass Doors
Numerous tempered glass doors recently installed in a new high rise failed
"spontaneously". Glass Expert was commissioned to determine the root cause of the
failure.
The failed doors remained intact; therefore contractor was able to preserve the
failure origins. He located the center of the "crack pattern", and he
preserved a 12
inch square around this center with tape. The tape held the glass in place, and this
contiguous piece of the glass could be removed. This preserved the area of the
origin was sent to the glass expert for
glass failure analysis.
Figure #1: Photograph of origin (arrow) preserved by taping the opposite side.
The arrow shows the origin that was examined for glass failure analysis.
The origin area was opened up to make the fracture surfaces visible for the root
cause failure analysis. The
fracture origin was located by tracing the Wallner lines backwards (Figure #2).
In addition a glass expert examined the glass fracture with a scanning electron microscope (SEM)
and energy dispersive spectroscopy (EDS) (Figure #3). EDS showed that the
elements present were nickel (Ni) and Sulfur (S).
Thus the root cause of the door failures was the presence of NiS particles
(nickel sulfide particles).
Figure #2: Photomicrograph of the failure origin on the fracture surface. One
can see the Wallner lines spreading from the nickel sulfide particle origin .
Failure analysis shows that the failure was caused by a NiS
particle(Magnification 40X).
Figure #3: Scanning Electron Photomicrograph of the particle at the failure origin.
The diameter of this particle is 180 microns (Magnification 400X).
Figure #4: Energy Dispersive Spectroscopy of the particle at the origin. The two
elements that compose the particle are nickel (Ni) and sulfur (S). The root
cause of the failure is a nickel sulfide particle.
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