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Heat Soaked Glass Products

PFG Glass is certified to process heat soak testing tempered glass to the European Standard EN 14179-1: 2016-TC.

What is heat soaking?

Heat soaking is the process of exposing tempered safety glass to heat for several hours in a specifically designed oven. While the glass is in the oven, it goes through a heating phase in which the glass starts at an ambient temperature and finishes when the surface temperature of the glass reaches 290 degrees Celsius. This temperature is then kept for a minimum of 2 hours, known as the holding phase.

Glass being heat treated in a chamber
heat treated tempered glass in a chamber

Why heat soak glass?

The heat soaking process works to reduce the potential for the glass to break spontaneously due to nickel sulfide inclusion—undissolved particles formed in the manufacturing of float glass that can cause imperfections smaller than the human eye can detect. While these inclusions are rare, they are an ever-present possibility that can expand over time, causing the glass to break spontaneously.

Since tempered safety glass is often installed in locations where guardrail load is a factor, spontaneous breakage caused by nickel sulfide inclusions can lead to exposed areas like balcony railings or floor-to-ceiling windows where there is a risk of falling that can lead to injury or even death.

While heat soaking tempered safety glass does not eliminate the potential for spontaneous breakage, heat soaking is a value-added service that minimizes the chances that the glass will break and provides customers with a greater degree of assurance.

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