Heat Soaking

On some rare occasions it has been known for toughened glass to break once installed for no apparent reason.

This can be caused by a variety of reasons including damage, impact or inclusions within the glass. One particular type of inclusion, nickel sulphide, has attracted publicity and it is important that specifiers understand its characteristics and the risk of breakage in service.

Nickel sulfide (NiS) is formed naturally within the glass making process but is of concern only in glass that is subsequently toughened. The inclusions are too small to be visually detected by the glass manufacturers and when heated in the toughening process undergo a phase change that reduces their size. Cooling of the glass is far too rapid to allow reversal and this takes place over a period of time. If an inclusion is sufficiently large and is located within the centre of the glass it can cause spontaneous breakage.

It is vital to stress that the risk is very small. Glass manufacturers estimate the incidence at less than 1 in 13,000kg.

© ESG Group Limited 2016. All rights reserved | Privacy Policy | Terms & Conditions
Company Registration Number: 9927672 | VAT Registration number: 233 0173 53
Website designed and spun by Twist

Signup to our Newsletter

* Your Email Address:
First Name:
Last Name:
* Preferred Format:
* Enter the security code shown:


Get in touch