Definitions of Quality

Quality requirements for hardened glass manufactured by Lumon Oy

1. General

Lumon Oy uses glass that conforms to the standard quality level of building glass, which is regulated with strict quality standards. The currently applied quality assurance instructions are prepared in accordance with standard EN 572-2. The instructions also take into account standard EN 572-8 for cut glass (Supplied and final cut sizes). Lumon manufactures tempered glass according to standard EN 12150-1.

2. Inspection

These instructions are for toughened or laminated glass delivered by Lumon Oy. Unless otherwise specified, the quality of glass is inspected from a distance of two meters in normal daylight, against a homogeneous background, and perpendicularly. Normal daylight refers to sunlight, however, not direct sunlight to the glass. The glass must be inspected when it’s dry. Misted glass may show amorphous patterns because of surface tension.

3. Assessment of Quality

3.1 Optical Distortion

When examined in close range, slight optical distortion characteristically occurs in toughened glass. Especially distortion in the fringe areas is allowable.

3.2 Point Defects

Point defects with diameter less than 0.5mm are innate properties of glass.Two defects with diameter of 0.5-1.0 mm are allowable in any parts of the glass provided that their relative distance is not less than 500 mm. Point defects measuring over 1.0 mm in diameter are not allowable anywhere in the glass.

3.3 Scratches

Transparent scratches up to 150 mm are allowable, but not closer than within relative distance of 500 mm.Deep scratches detectable from a 2 meter distance under the specified conditions shall not be wider than 0.5 mm and/or 5 mm long. One deep scratch per glass is allowable. Scratches that are smaller than the above measurements can be characteristic to glass and therefore allowable.

3.4 Edge Finishing

Rectangular glasses have flat ground edges, other shaped glasses have seamed glass edges. Clearly detectable cracks totaling over 50 mm on each edge are not allowable.

3.5 Overall and Local Bow

Toughened glass has a slight innate bow. Standard EN 12150-1 allows overall bow not exceeding ± 3 mm/m. Local bow of ± 0.5 mm can occur over length of 300 mm. Local bow is measured by using a straight 300 mm metal ruler placed on the surface of the glass. Overall bow can be determined similarlyby placing a straight ruler over the entire surface of the glass.

Lumon Oy has specified even stricter total dimensional tolerances for balcony glazing, which is measured at the manufacturing plant. Tempered glass delivered by Lumon Oy must have an overall bow of less than ± 2 mm/m.

3.6 Other Defects in Surface

Dimness of glass due to alkali-silicate on the surface is not allowable. Such glass has lost its polish and it is less transparent. So called anisotropy phenomenon may occur in toughened glass. This is a normal property of glass and therefore allowable. The phenomenon becomes Svisible in certain conditions as “leopard spots” caused by stress in the glass. Dirt and stranding are normal, but they should not be visible in a correctly cleaned glass from a distance over 2 meters. If the dirt cannot be removed, the manufacturing plant should be contacted for reference of a suitable detergent. Misting may show patterns that result from different surface tensions over the glass.

3.7 Tolerance Limits for Dimensions

The dimensional tolerance of the glass panes is determined according to standard EN 572-8:

Length of Edge Glass Pane Thickness 3-6mm Glass Pane Thickness 8-12mm
≤ 1,5 m ±1,0 mm ±1,5 mm
1,5≤ 3,0 m ±1,5 mm ±2,0 mm

Lumon Oy has determined the following dimensional tolerances for glass panes applied in glazing system: glass pane thickness 6 mm: ±1.0 mm and glass pane thickness 8-10 mm: ±1.5 mm. Cross-dimensional tolerances for individual panes are: Glass pane thickness 6 mm: ± 2.0 mm and glass pane thickness 8-10 mm: ± 3.0 mm.

Quality Specifications for Laminated Glass Manufactured by Lumon Oy

1. General

These specifications apply to finished laminated glass panes and the defects on their see-through area.

2. Definitions

Point defects including dull spots, seeds and foreign particles, hairline defects include scratches in glass and film. Other defects include creases, stripes or contract of laminating film.

3. Defects in the See-trough Area

Point defects < 0.5 mm in laminated glass are not observed. Defects >3.0 mm are not allowable. The number of defects < 1.0 mm is not restricted provided that their relative distance is > 400 mm. One point defect measuring 1.0-3.0 mm is allowable per square meter. Hairline defects (i.e. scratches) measuring >30 mm are not allowable. Hairline defects measuring < 30 mm are allowable provided that their relative distance is not shorter than 200 mm. Any foreign particles such as hairs are not allowable in laminated glass.

4. Defects in the Fringe Area

n laminated glass to be framed, 15 mm from the edge of the glass is deemed the fringe area. Point defects of 5 mm are allowable in the fringe area or around holes. Laminated glass panes not intended for framing must have finished (arised edge with blank spots or ground edge with blank spots), polished, or faceted edges according to standard EN ISO 12543-5. Thus seeds, blemishes and contract of laminating film etc. are allowable, if they are not detectable when an upright glass pane is inspected from a distance of two meters, against a pale matte-finished wall in daylight (not in direct sunlight).

5. Overall Bow in Laminated Glass

The tolerance for overall bow in laminated glass is ± 4 mm/m.

Quality Specifications for Building Boards

Quality specifications for building board panes are based on standard EN 438-6. Panes are inspected within distance of 1.5 m. The size of an individual defect shall not exceed 2 mm²/m². The allowable total number of surface defects is 20 mm/m², and the allowable cracks on edges totals 3 mm.

Quality Requirements for Aluminium Profiles Used in Lumon Oy’s Products

1. Surface Quality

Profiles must not show obtrusive surface defects when inspected from a distance of 5 m. Visible surfaces of the profile at end product must not show obtrusive defects when inspected from an arm’s length (60 cm). According to GSB specifications, the thickness of paint coating shall be 60 - 120 μm.

Inspection distances for finished products are:

- 1 m indoors

- 5 m outdoors.

2. Dimensional and Shape Tolerances of Aluminium Profiles

Straightness and shape tolerances for the special profiles used in the products are presented in the profile product cards. In standard profiles (L-shaped corners, rectangular profiles etc.) the overall straightness tolerance is ±1,5mm/m, and locally not more than 0,6 mm/ 300 mm. Tolerances for convexity and concavity of profiles are determined according to the shape and width of the profile. The allowable values for open profiles are presented in the last column of the table below. In closed profiles, another factor contributing to tolerance values in addition to profile width is the thickness of the profile bevel (t). Tolerances for closed profiles are presented in the middle column of the table below. W represents the width of the profile bevel.

3. Tolerances for sawing and tooling, dimensional tolerances for a finished product

Tolerance in sawing and tooling aluminium profiles is ± 0,5 mm.

4. Overall dimensional tolerances of finished Lumon products are:

- Lumon balustrade ± 5 mm

- Terrace door pane ± 1 mm.