Heat Soak Testing for Tempered Glass: When and How to Specify It
Heat soak testing is an additional process used for selected tempered glass to reduce the risk of spontaneous breakage associated with certain inclusions, particularly nickel sulphide. It does not eliminate every possible cause of breakage and should be specified with the correct standard and documentation.
Understand what the process can and cannot do
During a controlled heat cycle, tempered panes containing critical inclusions are more likely to break in the test chamber before shipment. The process reduces residual risk but cannot guarantee that no pane will ever break.
Thermal stress, edge damage, impact, installation contact and structural overload are separate risks that require proper design and handling.
Decide when testing is appropriate
Heat soak testing is often considered for façades, overhead glazing, balustrades, high-level panels or locations where replacement is difficult or breakage consequences are elevated. The project designer should make the risk decision.
Local regulations, client requirements and insurer or façade-consultant specifications may also govern its use.
Cite the applicable standard and scope
State the required heat soak test standard, furnace cycle, calibration, load traceability, acceptance and marking. Specify whether every tempered pane in the scope is tested.
Review the tempered glass page, standards and certifications and tempered glass specification guide.
Request useful records
Documentation requirements should be agreed before production. Depending on the project, records may include furnace identification, cycle data, batch traceability, breakage log and compliance statement.
- Project standard and edition
- Glass types and quantities in scope
- Test and marking requirements
- Batch and pane traceability
- Required reports or certificates
- Replacement and site-breakage protocol
Prepare a project enquiry
For a project-specific review, send drawings, panel schedules, dimensions, quantities, required standards, destination and programme through the Archivitro contact page. You can also browse our technical data hub and architectural glass projects.