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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.

Frequently Asked Questions About Heat-Soaked Glass Products

What is Heat Soaked Glass?

Heat-soaked glass is tempered safety glass that has been exposed to temperatures exceeding 450°C (842°F) for a sustained period of time. This process has proven to be highly effective at eliminating the risk of spontaneous breakage due to nickel sulfide inclusion stones NiS, which can cause the glass to break without warning.

Heat soaking helps to reveal any existing NiS flaws in the glass and make them visible so they can be identified and addressed before installation. As such, heat-soaked glass is a valuable tool for improving safety standards in any application where tempered glass is used. Its use is especially important for applications involving high temperatures or high levels of stress on the glass, as these conditions can increase the likelihood of spontaneous breakage from nickel sulfide inclusion stones. By using heat-soaked glass in these high-risk applications, safety risks can be significantly reduced.

Where is Heat-Soaked Glass Used?

Heat-soaked glass is an optimal choice where the risk of nickel sulfide induced or other inclusion failure needs to be minimized along with a requirement for safety from glass fallout. The additional processing involved makes it more expensive than ordinary tempered safety glass, however its use can help ensure safe and secure environments in areas where access to replacement panes may prove difficult. Heat soaking does not guarantee breakage-free conditions after glazing but serves as a precautionary measure by lessening potential risks associated with traditional methods.

Some of the areas where heat-soaked glass can add the most value are:

  • Projects where a crane is required to install glass
  • Buildings with a complicated or intricate glass designs
  • Glass installations where one glass is used as a building material to support other elements.
  • Oversized or specialized glass units
  • Balconies or mezzanine floors that use either frameless or infill glass balustrades.
  • Storefront entrances
  • Overheard glazing
  • Structural walls
  • Spandrel areas
  • Commercial windows

What are the Advantages of Heat-Soaked Glass?

Heat soaking is a valuable process used to detect NiS inclusions within tempered glass before it reaches its eventual destination. This thorough screening procedure ensures the highest quality, safety-tested glass products for our customers and is a recognized, effective solution for preventing the costly consequences of nickel sulfide inclusions, protecting your legal liability and ensuring that occupants remain safe.

Is Heat-Soaked Glass Safer Than Tempered Glass?

Heat-soaked glass has already been tempered. The heat soaking process forces the occurrence of spontaneous breakage to occur in a controlled environment rather than after construction has been completed.

This means that heat soaking can minimize the risk of failure due to NiS and, in turn, reduce the legal liability and associated replacement, maintenance, and disruption costs.

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