Visual quality of glass – Industry Standards

We hope you love your new windows, but we understand that sometimes there may be some imperfections as modern processed glass cannot be completely flawless. All glass suppliers follow industry standards for visual quality, outlined below.

Inspection Guidelines:

  • Stand at least 2 meters away from the sealed unit and look directly through the glass.
  • For toughened, laminated, or coated glass, stand at least 3 meters away.
  • If space is limited, position yourself as far back as possible.
  • Inspect in natural daylight, avoiding direct sunlight, and ensure the glass surface is dry.
  • Exclude a 50mm-wide band around the edges from your inspection.
  • View the glass at a 90° angle.

Acceptable Quality Criteria: Flat, transparent glass, including laminated, toughened, or coated types, is considered acceptable if the following are not clustered or overly noticeable:

  • Small bubbles or blisters
  • Fine scratches up to 25mm long
  • Tiny particles

The visibility of these minor imperfections is assessed by looking through the glass under natural light, not by examining its surface. Since processed glass is used in sealed units, some small blemishes are normal.

Units showing optical defects, such as smears, fingerprints, or dirt on the internal glass faces, may warrant further review.

Special Glass Considerations

  • Toughened Glass: Visual distortions may appear, especially when viewed with reflections in sealed units. This is a natural effect and not a defect.
  • Laminated Glass: Due to its multi-layered structure, laminated glass may display a few more blemishes than standard glass.
  • Low Emissivity Coatings: These coatings can create temporary visual effects. In certain lighting, the coating might appear as a transparent film or cause a slight haze, giving the surface a cloudy appearance. Light-colored items, such as sheer curtains placed near the glass, may appear somewhat darker.

Condensation

While sealed units typically reduce condensation, it can still occur under specific conditions.

Multiple Reflections

In certain lighting, multiple reflections can form within sealed units, potentially causing variations in appearance across different panes.

Rainbow Effect

Occasionally, light refraction through the glass may produce a slight, temporary rainbow effect. This phenomenon occurs when high-quality flat glass sheets are positioned parallel to one another.

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