How thick is the Glazing?
Acrylic windows under hydrostatic pressure have to retain the massive water load of the water column in the tanks. In public and private tanks the safety of the viewer but also of the marine life should be considered as vital. The design engineer therefore has to limit the material's tension and the maximal deflection of the window in order to maintain safety regulations.
The choice of acrylic panel thickness or the definition of the permissible water pressure is based on theoretical calculations and confirmed by practical tests. Our calculation of the required sheet thickness under hydrostatic pressure (according to Girkmann / Czerny) allows evaluation according to the maximum material stress and maximum deflection.
The basis for this calculation are:
elastic modulus = 3300 MPa
Poisson's ratio mb = 0.37
safety stress permiss. water side = 3 MPa
safety stress permiss. air side = 5 MPa
Detailed calculations by a structural engineer are required to precisely determine the actual material stress at a given location. The joints bonded call for special certification. In this case, the maximum safety stress should be less than or equal to 3 MPa.