TOUGHENED GLASS SPECIFICATIONS

1. STANDARDS COMPLIANCE 2. STAMP (TOUGHENED GLASS IDENTIFICATION & STANDARDS LOGO) 3. SIZE LIMITATIONS 4. DIMENSIONAL TOLERANCES 5. FLATNESS TOLERANCE (BOW) 6. EDGE QUALITY

7. SURFACE QUALITY 8. ROLLER WAVE DISTORTION 9. WORKING OF TOUGHENED GLASS 10. HOLES 11. SLOTTED HOLES 12. FINGER GRIPS

13. NOTCHES 14. CUTOUTS 15. HEAT SOAKING 16. HANDLING & STORAGE 17. OTHER

1. STANDARDS COMPLIANCE

Chevron Toughened Glass is supplied to conform to the following Australian Standards.
AS/NZS 2208: 2006 - "Safety Glazing Materials in Buildings"
AS/NZS 2080: 2006 - "Safety Glass for Land Vehicles"
AS 1288: 2006 - "Glass in Buildings-Selection & Installation"
AS/NZS 4667: 2000 - "Quality requirements for cut-to-size and processed glass"

2. STAMP

All Chevron toughened glass will be supplied with a Chevron stamp (or logo). This stamp verifies manufacture by Chevron Glass, our licence number, glass type and thickness and conformity to AS/NZS 2208 or AS/NZS 2080 standards certification where applicable. If glass is required without the stamp, this must be indicated in writing at the time of ordering and a removable sticker will be applied instead.

3. SIZE LIMITATIONS

Limitations on sizes are:

4. DIMENSIONAL TOLERANCES

All dimensions + / – 2.0mm
 

5. FLATNESS TOLERANCE

Toughened glass is not always flat like annealed glass. Generally the deviation is slight, depending on size and thickness.
Overall bow can be checked at the point of maximum gap on the long edge using a straight edge with the panel standing within 5° of vertical.
The following standards for bow are in accordance with AS/NZS 2208.

 

Maximum Aspect Ratio
To minimise distortion, the ratio of length to width of rectangles should not exceed 15: 1 ratio.

6. EDGE QUALITY

Toughened glass cannot be supplied with "clean cut" edges. Chevron toughened glass is supplied with a minimum of an arrissed edge.
Other types of edge treatment are available on request.
Shells are acceptable that have been arrissed provided they extend no more than 5mm from the edge.
Shells are not acceptable on flat polished, flat smoothed, beveled or mitred edges.

7. SURFACE QUALITY

The standard for toughened glass is based on faults not being readily visible at 1 metre when viewed perpendicular to the surface and as the glass would normally be viewed.

Furnace pick-up should not exceed 3.0mm in diameter. More than 3 pick-up markings between 1.0 and 3.0 mm in diameter per piece is unacceptable. Any number of pick-up markings below 1.0mm in diameter is allowable.

Heat markings are acceptable if not visible from 3 metres when viewed between an angle normal for the glass and 45° to the glass.

8. ROLLER WAVE DISTORTION

An inherent consequence of the heat treatment process is roller wave which is caused by the heated, slightly softened glass being in continual contact with the oscillating ceramic rollers. This distortion is more noticeable in reflective or dark tinted glasses and if applicable, the direction of roller wave should be specified.
Evaluation of the level of distortion that is caused by the furnacing process is a subjective judgement. The use of a Rollerwave Gauge to measure the surface profile of the glass will give a good indication of the level of visual distortion in the glass. The standards for visual distortion are based on a surface profile that will result in an acceptable level of visual distortion. The rollerwave is measured from peak to trough and maximum standards are as follows:

9. WORKING OF TOUGHENED GLASS

All necessary processing must be carried out before the glass is toughened. No work can be carried out after toughening due to the risk of breakage. Therefore accurate dimensions must be submitted at the time of ordering.

10. HOLES

Holes must be drilled in glass before toughening.
Unusual hole configurations or large hole sizes should be referred for consideration before ordering.

10.1 HOLE SIZE

Minimum Dimension
Hole diameters cannot be less than the thickness of the glass.

Maximum Dimension
The maximum dimension of any large circular or non-circular hole should not exceed 1/2 of the minimum width of the panel.

10.2 EDGE FINISH

Holes will normally have a ground finish.
Holes can be countersunk at 45° with ground edges on request.
Countersunk depth should not exceed 75% of glass thickness.

10.3 TOLERANCES

10.4 POSITION OF HOLES FROM EDGE

For holes less than 50mm diameter the distance between the edge of any hole and the edge of the glass must never be less than 1.5 times the thickness of the glass for glass up to 10mm thickness, and two times the thickness for 12 to 19mm thick panels.

 

 

10.5 POSITION OF HOLES FROM CORNER

The distance from the edge of hole to the corner of glass must be a minimum four times the glass thickness.

10.6 SPACING OF HOLES

The minimum distance between the edges of adjacent holes cannot be less than three times the glass thickness. Where there are more than four holes in a group the minimum distance cannot be less than six times the glass thickness.

10.7 HOLES OTHER THAN CIRCULAR

All non-circular holes must have radius corners with the internal radius not less than the thickness of the glass. Refer to section 13 on Notches.

11. SLOTTED HOLES

The diameter of slotted holes must not be less than the thickness of the glass (t).
The width of the slot (S) must be at least equal to half of the thickness of the glass (t).

12. FINGER GRIPS

Standard finger grips are available in glass of 5mm thickness or greater.

13. NOTCHES

The inside of notches must have radius corners at least equal to the thickness of the glass.

13.1 EDGE FINISH

Edges will have a flat smooth (ground) finish with arris. Polished notches are available on request. Limitations apply.

13.2 DIMENSIONS

The height / width of a notch must be greater than the thickness of the glass. The depth of a notch cannot be greater than half the width of the glass.

13.3 TOLERANCES

The tolerance on notch location in relation to the edge of the glass is ±2.0mm.

13.4 CORNER NOTCHES

Defined as having maximum dimensions of 200mm x 200mm. Must have an internal radius corner (R) at least equal to the glass thickness. Notches are generally supplied with a flat smooth edge.

13.5 SIDE NOTCHES

Defined as having maximum dimensions of 200mm x 200mm. The minimum distance from a corner should be 75mm. External corners on notches must be rounded. Notches are generally supplied with a flat smooth edge.

13.6 CENTRE NOTCHES

All centre notches must have radius comers equal to or greater than the glass thickness. The distance between the edge of the centre notch and the glass edge must be at least four times the glass thickness, with a minimum of 25mm for 4-6mm glass and 100mm for 8-19mm glass. The interior width of a centre notch must be equal to or greater than the glass thickness. The distance between centre notches must be at least four times the glass thickness. The notch height and width must be less than 50% of the glass height / width. Centre notches are generally processed by Waterjet Cutter then arrissed.

14. CUT OUTS

Defined as having any one dimension greater than 200mm. Cutouts are processed by Waterjet Cutter and supplied with flat ground and arrissed edges.

15. HEAT SOAKING

Heat soaking involves heating toughened glass in an oven for a period of time to induce breakage that may be caused by any inclusions or contaminants in the glass. The process substantially reduces the likelihood of breakage after installation. The process is strongly recommended for balustrades, pool surrounds and toughened glass assemblies.
In most circumstances, where glass is to be glazed vertically 5.0 metres above ground or floor level, and in the case of sloped overhead glazing 3.0 metres above ground or floor level, it is mandatory for the glass to be heat soaked.

16. HANDLING & STORAGE

The edges of toughened glass must be treated with care to avoid chipping or shelling. A chipped edge is a source of weakness which may cause subsequent failure.
Toughened glass should always be stored on edge on suitable soft blocking. It should not be stacked horizontally.

17. OTHER

Any toughened glass requirement not covered by these specifications should be referred to our Production staff for approval prior to processing. Chevron Glass may reject any order due to OH & S considerations.