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Toughened and heat-strengthened glasses

When Thermobel Stopray is toughened or heat-strength- ened, certain deformation or optical phenomena (leopard spots caused by anisotropy) are sometimes visible in the reflection. These are considered inherent to the toughening process.Toughened glasses can break spontaneously due to the presence of NiS inclusions within the glass itself. To avoid breakage it is advisable:• to request a heat soak test: this must be requested specifi-cally by the customer in each order;• to specify thermobel Stopray heat-strengthened glass instead of Thermobel Stopray toughened glass. The heat strengthening process is only appropriate if heat treatment is required for reasons linked to the risk of thermal stress and not safety, since heat-strengthened glass is not, by definition, a safety glass.NB: For Thermobel Stopray facades using toughened or heat-strengthened glass, it is necessary to state the dimen- sions on the purchase order in the following order: base x height (the base being the measurement running parallel to the ground), for reasons having to do with the general appearance of the building.

Guarantee

Thermobel Stopray is covered by the same guarantee appli-cable to all other Glaverbel insulating glasses.The text of the guarantee is available upon request.

Description for the specifications

Insulating glazing

Thermobel Stopray solar control sealed unit from Glaverbel, type……….* consists of two sheets of Planibel glass, one of which has a fine coating of noble metal deposited under vacuum by the cathode sputtering process. This coating is located on one of the inside faces of the insulating double glazed unit.The two Planibel panes are separated by a spacer tube filled with desiccant. The entire structure is sealed by a double elastic joint which ensures cohesion of the unit and keeps it permanently sealed. The space between the Planibel panes is filled with dry, thermally insulating gas**.The principle light and energy characteristics of this unit are as follows :LT : …………….. % SF : ……………... %LR : …………….. % U : …………W/(m The air or gas in the cavity is liable to expand or contract due to variations in temperature and atmospheric pressure.This phenomenon may be more pronounced if the space between the panes is large and if the inside pane is thicker than the outside one. Note also that the pressure exerted by frame clamping may produce optical distortions when viewed in reflection.

Appearance

For customers seeking the right combination of vision glazing and spandrels, or a vision glazing alone, Glaverbel recommends first carrying out an on-site examination using prototypes. The type of environment, orientation, position of the observer and reflection level of the glazing can all have a significant impact on the general appearance of a facade.When receiving an order, Glaverbel will assume that the above-mentioned examination has been carried out and that prior agreement has been obtained from the various parties involved (building architect, contractor, facade specialist and any other party involved in the decision-making process).
2 .K)The percentages concerning the light and thermal proper-ties are nominal values subject to variations due to the pro- duction process.The tolerances on the measurements of glass properties can also be source of difference regarding the mentioned values.
* e.g. Thermobel Stopray, type Silver.** to be replaced by words «dry air» if this is specifically requested. Otherwise, Thermobel Stopray insulating units are supplied as standard with dry, ther- mally insulating gas.