sulphide inclusions and remediation of
Spontaneous fracture of toughened glass can be a significant problem in
curtain wall and other flat glass installations, and it is a problem
that is difficult to solve. It is well known and has been well
documented that spontaneous fracture in toughened glass is caused by
nickel sulphide (NiS) inclusions formed during manufacture. This
topic was covered in some detail in a 22 Sept 2001 article in New
Scientist, and the action
of nickel sulphide in toughened glass is explained in a recent article
in GlassOnWeb (PDF file, 510kB).
Dr John Barry of PicaMS has carried out two major projects on the
glass facades which suffer spontaneous fracture.
Work done in conjunction with Resolve Engineering
(Brisbane) which involved the development of the patented Photoglass
method for on-site detection of nickel sulphide inclusions in glass
windows ("detection of defects in glass", J.C. Barry, Australian patent
- 732132; US patent - 6236734). The Photoglass method was applied
in a major Brisbane building and resulted in removal of more than 200
suspect windows. An important outcome of the work was that the
rate of window breakage dropped from 2 failures per month to 1 failure
Scanning of windows in the main grandstand of a
Melbourne Racecourse. This project involved manual scanning
of windows in a (1400 sq metre) glass curtain wall. This detailed
study of inclusions in the windows helped racecourse operators to
improve viewing conditions in the main grandstand.
There are many cases worldwide where the spontaneous fracture of glass
in building facades poses a safety risk, and in these cases our
technology is especially useful.
The story of the
nickel sulphide inclusion told in pictures
The result of
- a characteristic fracture pattern.