All canopy glazing must be subject to professional calculation on the basis of accurate snow and wind loads.
Laminated Toughened Glass
Special hard nylon fixings should be employed to prevent compression of the laminating interlayer and excessive localised stress around the fixings.
Toughened / Heat-strengthened Laminated Glass
The toughened glass is designed to withstand the imposed loads and has Laminated to it a 6mm thick heat strengthened “carrier glass” intended to maintain integrity in the event of breakage. Such systems require specially designed fixings that fully clamp only on the toughened glass.
All types of glass panes that have centre fixings must be subject to finite element analysis based on the provision of accurate wind and snow loads. This is due to the high local stress induced by the effects of hogging and sagging. glass subject to such effects is specially toughened to 120 N/mm² whereas the normal design stress limit is 59 N/mm².