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Glass Breakage Investigation

Property type: Art Museum

Location:  Singapore

Client: The Museum

Incident description: The Museum opened in 2015 after an extensive remodeling which included bridging between and over two historic government buildings with cable supported curtainwalls and large water-covered skylights. Interior spaces widely utilized point supported all-glass curtainwalls and entrances. In 2018, Façade Consultants was engaged to investigate glass breakage at the curtainwalls and entrances, as well as a leak condition on the skylight.

Injuries: None

Documents reviewed by Façade Consultants (FC): Shop drawings for the various Façade elements.

Site investigation by Façade Consultants: The FC team spent a full week operating after hours, to avoid inconveniencing museum visitors. One of our teams spent the entire time scanning glass for the presence of gaseous and nickel sulfide inclusions. Our team leader performed fractographic examination on broken glass that was preserved for examination, and inspected the various curtainwall and entrance types for visible anomalies in construction. A polariscope was used to analyze stress concentrations in glass at hardware connections. The skylight was inspected and the source of leakage was located. Façade Consultants then issued a 39 page report of results and recommendations.

Opinion of Façade Consultants: A few instances of nickel sulfide inclusions were found, and these were the cause of some instances of spontaneous glass breakage. Many gaseous inclusions (bubbles) in the glass were found, but they were not determined to have caused glass breakage. The point-supported curtainwall and entrances had a deteriorating condition where connection washers were becoming misplaced, causing undue concentrations of stress, and some breakage in the glass. Connections at the point supported curtainwall were found to be coming loose, which brought about uneven stress concentrations in glass.

A wall of fixed glass and doors, all point supported
Workman used a specialized device to scan the glass for inclusions
One of the few instances of nickel sulfide inclusions found through scanning. This inclusion later broke the glass.
A broken door panel was preserved because it was laminated glass. The PVB interlayer held the glass together. The fracture origin could be found at one of the holes where the bottom door pivot was attached.
The bottom door pivot assembly
The design of the hole in the glass. Only one pane of the laminated glass panel receives load from the hardware
When the broken glass was replaced, we spotted an anomaly in the connection to the glass. A spring washer was falling out. The hardware was not fully tightened.
Using a polariscope, we could observe stress concentrations increase in the glass as the glass door was opened. This replacement door later broke during usage
Examination of the hardware revealed that critical washers that separate the glass from the metal penetrations were coming out and breaking off, leaving the glass undefended from the metal
Inspection of a cable-supported curtainwall
Detail of attachment of cables to glass, known as a “spider fitting”
The polariscope revealed varying amounts of stress in the glass at attachment points
The inspection also found a number of deficiencies at the spider fitting connections
Finally, façade Consultants’ founder Mark Meshulam had the unique experience of walking on top of a water-covered skylight at night, looking for a leak. He found it.

Disposition: Original contractors embarked upon corrective work based upon the recommendations of Façade Consultants.

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