New Zealand media outlets have reported broken glass falling from buildings posing potentially very serious risks to public safety. Over recent years there have been a number of such instances and some links to the articles are provided herein.
In many cases the breakage issue relates to toughened glass in buildings which when it breaks, breaks completely into small fragments and these can fall onto the street below posing a high risk of injury. The most common cause of these panes to suddenly explode and fall out of the frame without warning is attributed to Nickle Sulphide (NiS) inclusions in the glass. These particle inclusions are not visible to the human eye and exist in many panes of glass in buildings today. Often their presence in the glass does not lead to a breakage but sometimes tiny cracks can propagate from the inclusion overtime and eventually unbalance the forces in the toughened glass pane causing the whole pane to explode into fragments. Often following a pane explosion the fragments will fall from the window ‘clumped’ together so if falling from height onto a passer-by below then serious injury or worse is the risk. Glass manufacturers cannot avoid these particle inclusions during manufacturing and they cannot detect them without cost prohibitive examination so the result is millions of panes of glass with a potential spontaneous failure trigger.
On a particular high profile project in Australia, the window film manufacturer Saint-Gobain Solar Gard has been recently involved. In this instance a number of glass panes exploded in a high rise apartment building in Sydney over a period of 2 years from 2010 to 2012 inclusive. These panes of broken glass then fell many stories. Fortunately no one was hit by the falling glass but the risk of injury was deemed severe.
A remedial action involved Saint-Gobain Solar Gard working with engineers to design a method that included Solar Gard security film being applied to the glass combined with other retention methods that met the criteria set by the relevant insurance company for the building.
For such toughened glass breakage mitigation projects the product / technical solution involves two aspects:
1. Applying a clear security film onto the glass to hold the broken glass fragments together
2. Securing the security film to the window frame to hold the glass + film against falling (retention)
The Saint Gobain Solar Gard technical response team are experts in designing unique and custom designed film and retention solutions against spontaneous glass breakage risks in buildings.
As mentioned, over recent years there have been a number of media reports over New Zealand where glass has spontaneously broken. In the first three articles below the post breakage fracture pattern proves the pane was toughened glass. In the Dunedin Mall article there is no picture and the article mentions the pane breaking into two pieces which would not be toughened glass however this article still helps to highlight the dangers of overhead glass and if security film had been fitted this glass is unlikely to have fallen out;
1 - Central Wellington Apartment building 12th May 2016
2 - Christchurch Public Hospital February 2016
3 - Willis Street Escalators September 2015
4- Dunedin mall March 2015
In the absence of the post breakage analysis for the above reports assuming that there has been analysis has even been carried out it cannot be categorically said that nickel sulphide inclusion is the cause of these failures however regardless of failure mode they all highlight the significant danger to the public and property from unsecured glass breaking and falling from height.
Retrofit to any glass, security film from Solar Gard can greatly improves the safety of existing buildings while being visually unobtrusive, quick and cost effective versus any other glass safety measure.
Distributed in New Zealand by:-
Specialty Window Films
3D/89 Ellice Road
Tel (09) 441 0040
Contact:- Ross Eathorne
A Solar Gard release - Wednesday 28 September 2016