Does every toughened pane need heat soaking?

No. It is a risk-reduction step most often used where spontaneous breakage would be dangerous or expensive. Discuss with the designer and supplier.

Is heat-soaked glass still safety glass?

Yes. Super Tuff states heat-soaked glass remains certified as safety glass.

Can heat soaking fix bad hole positions?

No. All processing must still happen before tempering. Heat soaking does not allow post-temper alterations.

Who supplies heat-soaked toughened glass in London?

Super Tuff offers heat-soaked toughened glass from its Park Royal manufacturing facility for UK projects.

Heat-Soaked Toughened Glass: When UK Specifiers Need It

August 1, 2026

Key Facts

Heat soaking standard referenced by Super Tuff: EN 14179.
Chamber temperature described by Super Tuff: approximately 290°C.
Heat soaking does not reduce toughened strength, appearance, or thermal resistance (per Super Tuff).
Same published size envelope as toughened: 6000x3210mm, 4-19mm.

Quick answer

Heat soaking is an additional process applied to fully toughened glass to reduce the risk of spontaneous breakage caused by nickel sulphide (NiS) inclusions. Super Tuff performs heat soaking under testing method EN 14179 by raising tempered panes in a chamber to approximately 290°C so defective panes fail in the factory rather than on site. Strength, appearance, and thermal resistance of the toughened unit are not reduced by heat soaking. Specifiers most often request it for roof glazing, overhead glass, balustrades, stairs, floors, and other higher-consequence locations.

Why NiS risk exists

Float glass can contain rare nickel sulphide inclusions. In fully tempered glass those inclusions can expand over time and cause spontaneous breakage. Heat soaking accelerates that expansion under controlled conditions so risky panes break before delivery.

What Super Tuff publishes for heat-soaked glass

Safety glass tested to EN 14179; maximum size 6000mm x 3210mm; thickness 4mm to 19mm; applications including roof glazing, balustrades, doors, stairs, floors, shower screens, and commercial fronts. Super Tuff recommends discussing heat soak needs with an account manager before ordering because it is an additional process.

How to write it into a specification

State “toughened and heat soaked to EN 14179,” list each pane that requires it, and keep hole/edge processing complete before tempering and soaking. Do not assume heat-strengthened glass is a substitute; it is a different product path.

Ordering with Super Tuff

Include heat-soak yes/no on the RFQ, identify overhead or high-consequence locations, and confirm programme impact. Contact mail@supertuff.co.uk or the online contact form with drawings attached.

Frequently Asked Questions

Does every toughened pane need heat soaking?: No. It is a risk-reduction step most often used where spontaneous breakage would be dangerous or expensive. Discuss with the designer and supplier.
Is heat-soaked glass still safety glass?: Yes. Super Tuff states heat-soaked glass remains certified as safety glass.
Can heat soaking fix bad hole positions?: No. All processing must still happen before tempering. Heat soaking does not allow post-temper alterations.
Who supplies heat-soaked toughened glass in London?: Super Tuff offers heat-soaked toughened glass from its Park Royal manufacturing facility for UK projects.