Why not to use Glass for Underwater Windows
Float glass - even tempered glass - is not meant to bear weight loads. Acrylic panels on the other hand can be used as structural elements in building architecture. Once installed acrylic has proven to retain its stability over several decennia.
The pictures shows the two best reasons why not to use float glass for underwater windows:
- The window is supposed to be transparent. Instead it is green like a water bottle. Note that float glazing needs to be very thick to withstand the water pressure. The transparency of float glas is lower than that of acrylic glazing, giving the window a greenish color
- See the cracks on the bottom of the window? Float glas is not meant to be used under pressure. It is not flexible. It shatters. People might tell you that this is true for normal float glass, but not for their "special" float glass. From my long experience with pressurized glazing, this is not true.
This is why Hydrosight use float glass only in rare cases. Hydrosight mostly uses cast acrylic glazing.