Exploding Glass? What You Need To Know

If you’re installing a glass balustrade, pool fence, or shower screen, you may wonder about the risk of breakage. The spontaneous explosion of toughened glass is not uncommon, and it’s important to be aware of the potential causes and how they can be prevented.



To help explain further, we’ve put together this helpful blog with all you need to know about exploding glass.

Common causes

Exploding glass is commonly caused by installation defects or damage, binding in the frame, internal defects and inclusions, thermal stresses, and inadequate glass thickness.

Installation damage

If glass is chipped or nicked during transport and installation, it can spontaneously explode. While these small areas of damage might not cause instantaneous breakage, over time stress concentration can develop as the glass expands. If you’re using tempered glass, it’s often the case that the entire unit will break. 

Binding in the frame

As temperatures change, glass naturally expands and contracts. As a result, glass is placed on resilient blocks, and space is allowed for expansion around the sides and at the top. The gaskets keeping the glass within the frame usually protect the glass against wind buffering. If there isn’t any space left around the glass, it will end up binding against the frame. Stresses will then develop in the glass which will overtake its strength and thus lead to breakage. 

Internal defects and inclusions in the glass

Glass can sometimes include nickel sulphide, or “stones”, which is the result of using stainless-steel machinery in the manufacture and handling of the glass. Over time, these stones change their structure and grow, leading to internal stresses. If these stresses exceed the glass’s strength, it will break. Tempered glass is particularly susceptible to this kind of breakage, which can be identified through the appearance of a characteristic “figure-eight” shape.

Additionally, small pieces of brick may be eroded from the internal walls of the furnace used during processing and become lodged in the final product. These pieces are also known as “stones” and may result in breakage when the glass is heated. 

Thermal stresses

Larger pieces of sealed insulating glass coated with a reflective heat-absorbing surface are susceptible to breakage caused by thermal stress. This particular coating is generally applied to the inner face of the outside lite. As the coating converts solar radiant heat into sensible heat, it causes the outside lite to heat up more quickly than the inside lite. As the outside lite heats and expands, it causes the entire glass unit to bend. If the two lites form a rigid connection, undue stress may result which is greater than the strength of the glass, thus causing breakage. 

Inadequate glass thickness

If the glass hasn’t been properly manufactured to cope with wind, or if it’s too large or thin, it can be broken by wind strength.