A new report from the UK’s Office for Product Safety and Standards (OPSS) has revealed significant compliance failures across manufacturers of heat-soaked thermally toughened glass, raising concerns throughout the glass and glazing supply chain.

Published on 5 March 2026, the findings show that every heat-soaked insulated glass unit (IGU) assessed during OPSS inspections failed compliance checks. The regulator also reported widespread shortcomings in documentation, labelling and conformity marking.

Only 50% of the companies inspected were able to produce a Declaration of Performance (DoP) at the time of inspection – a mandatory requirement under Construction Products Regulations. Meanwhile, 93% failed to meet labelling requirements, and 86% could not demonstrate compliance with marking standards.

According to Kevin Jones, Head of Technical at the Glass and Glazing Federation (GGF), the results should serve as a wake-up call for the industry.

While the findings do not necessarily indicate that the glass products themselves are unsafe, Jones stressed that many companies have failed to maintain the documentation needed to prove compliance. In several cases, manufacturers lacked evidence of initial type testing, factory production control records or up-to-date technical documentation.

Established following the Grenfell Inquiry, OPSS has the authority to stop products from entering the market where compliance cannot be demonstrated.

The report is available here.