Surface pressure break I

Mechanic surface load – long-term – dynamic / static
Type of glass

Polished glass, rolled sheet glass, laminated glass, figured (ornamental) glass; very often glass pack.

Examples

Too big load due to the temperature, air pressure, and/or height differences between the glass packs production and installment places;

Aquarium glass of too small measurements fastened from 4 sides.

Beginning

Edge crack angle in all directions, not upright;

Not visible centre of fragmentation;

Transition angle not upright;

There are no curvilinear cracks by the glass edge.

Lines of process

From edge to edge, of S and arc form;

Parallel to the longer edge, often furcating;

Direct, bent, but not angular break lines.

End

From the mid of the glass always till the angle or near the glass angle.

Other features

Surface curvilinear fragmentations: in the convex pieces of glass (usually the sub atmospheric pressure in the gap) - external curvilinear cracks, in the convex pieces of glass (overpressure in the gap) in the side of the gap, thus it is possible to recognize whether the break occurred due to the overpressure or due to the sub atmospheric pressure;

In the single glass curvilinear cracks in the load side;

With the increasing load, the number of fragmentations also increases.