Tolerances for Toughened & Laminated Glass

The glazing industry works to a universal standard for the quality of glass. However, there is a certain amount of tolerance within the industry for glass panels. This is due to the nature of glass processing, and the understanding that modern processed glass is not going to be 100% flawless. The levels of acceptable tolerances are regulated by the Glass and Glazing Federation (GGF).

What is the acceptable standard?

The GGF’s standards state that flat transparent glass, including laminated, toughened or coated glass is acceptable if the following are neither obtrusive nor bunched:

  • Bubbles or blisters
  • Fine scratches not more than 25mm long
  • Minute particles

White Metal Acceptable Standards of Toughened & Laminated Glass Tolerances

When inspecting the glass, please ensure the following:

  1. When viewing the glass, stand a minimum of 3 metres away, facing the glass. This is because under normal everyday situations, looking through the glass is usually done at a distance, and not with your nose a few inches from the surface.
  2. Look through the glass and not at it. This is expected as normal as the glass is there to enable a view beyond the balustrade, and not there to be inspected.
  3. Ensure the glass is clean and dry, inside and out. It is impossible to check glass that has rain, dust or condensation on it.

A good test of criteria is whether you can get a photo of the imperfection on your phone. Scratches or imperfections that are an issue will generally be picked up by the camera on your phone. If you cannot get a picture which shows the imperfection, it is likely that the imperfection falls into the ‘acceptable tolerances’ of glass.

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