MECHANICAL SURFACE - DAMAGES
The different intensities and degrees of interference of scratches on glass surfaces
can be described as follows:

ANGEL HAIR
Angel hair - scratches are extremely fine. Surface scratches that is neither visible nor palpable under normal daylight conditions.

HAIR SCRATCHES
Hair scratches are fine, usually only visible against a dark background or glass scratches that can be seen on closer inspection and marking. Glass scratches that is visible but not palpable.

WEAK GLASS SCRATCHES
Weak glass scratches are usually easily visible scratches in diffuse daylight and against a dark background. Glass scratches that can be felt with the fingernail.

STRONG GLASS SCRATCHES
Strong glass scratches are highly visible damages. They are visible from any angle and against any background. Glass scratches clearly noticeable with the fingernail.

SCRAPINGS
Scrapings are extensive damages, which usually consist of a scratch coulter of weak to strong glass scratches.
CHEMICAL SURFACE - DAMAGES
The following materials can cause burns, changes or turbidity of the glass surface:
MATERIALS
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Strong alkaline facade cleaner
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Hydrofluoric acid and cleaning agents containing hydrofluoric acid
-
Cement mortar and concrete
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Mineral dyes
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Mineral plaster
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Acidic environmental influences etc.