Point-Supported Glass Calculator

Because glass only comes in standard thicknesses (6, 8, 10, 12, 15, 19, 22, 25mm), and the calculator always rounds the calculated minimum thickness UP to the next available standard step -- so the selected thickness usually has more capacity than the bare minimum required, leaving Stress Utilization comfortably below 100% rather than landing exactly at it. That is only true when a standard size big enough actually exists, though: for a large panel under heavy wind load, the required thickness can exceed even 25mm (the largest standard size), in which case Selected Thickness is stuck at 25mm, Stress Utilization reads OVER 100% (up to roughly 5x in the most extreme declared-range cases), and Thickness Infeasible flags 1 to make clear that 25mm is not actually an adequate answer here.

Only how the load reaches the fittings, not the glass sizing itself. Load Per Fitting drops as the same total wind-plus-dead load is shared across more spider arms, which is the whole point of adding points on a large or heavy panel. But Actual Stress, Stress Utilization, and Deflection stay exactly the same no matter how many fittings you pick from the 2-6 range -- those are plate-bending properties of the span between supports, the panel's aspect ratio, and its thickness, none of which Support Points touches.

No, not always -- despite tempered glass having roughly double the allowable design stress of heat-strengthened glass (93 MPa versus 45 MPa), the relationship is not strictly monotonic because both glass types round UP to their own nearest standard thickness independently. At a 1500x2000mm panel and 6,700 Pa wind load, for example, Glass Type 1 (heat-strengthened) needs enough thickness that it steps up to a 22mm standard pane, while Type 2 (tempered) only needs to step up to 15mm -- and that smaller thickness jump leaves Type 2 with LESS spare margin than Type 1 got from its larger jump, so Type 2's Stress Utilization can land higher than Type 1's even though its allowable stress is larger. Tempered glass is still required for bolt-hole drilling regardless (it breaks into small, less hazardous fragments), but its stress-utilization number isn't guaranteed to read lower.

Min. Thickness and Selected Thickness, yes -- both rise (or at worst plateau at the same standard size) monotonically across Design Wind Load's full 200-8,000 Pa declared range, since higher pressure directly raises the bending moment the plate formula solves for. Actual Stress and Deflection are NOT always monotonic in wind load, though: right at the point where a load increase pushes Selected Thickness up to the next standard size, the thicker glass can drop Actual Stress and Deflection noticeably below what they were at a slightly lower load and the previous (thinner) standard size -- a step up in glass thickness outweighs the extra wind pressure at that crossover.

Minimum Edge Distance is the larger of 60mm or 2.5 times the selected glass thickness -- so for the thinnest standard panels (6-10mm) it is fixed at the 60mm floor, but once selected thickness exceeds 24mm the 2.5x-thickness rule takes over and edge distance grows directly with glass thickness.