One of the most prolific uses for glass in contact with water is in the construction of fish tanks. The hypnotic effect of watching fish swim, while the sun filters through the water, is a very beautiful and relaxing activity.
Various factors influence the glass used in these constructions. Unlike the load pressure of glass used in normal architectural projects, the load pressure of water is constant but not uniform. This lowers the glass’s ability to withstand the load pressure. We can calculate the load pressure of a liquid using either fresh or salt water (as these are the most common liquids used).
Another factor that causes non-uniform pressure of liquids in contact with the glass is anything disturbing the flow of the water (such as swimming fish). In smaller fish tanks this is not of crucial importance, but in larger tanks (eg. Aquarium tanks) this becomes very important.
The third factor is that the thermal stress of partially submerged glass is very different from other architectural projects. As the part receiving sunlight will be much warmer and the submerged part will be much colder. This can lead to higher thermal stress than in regular applications.
The best technical solution to the above mentioned is the use of toughened or laminated glass. These are stronger and can handle higher thermal stress as well as higher load pressure than normal annealed glass. But how do you build a tank strong enough to house dolphins or Orcas? By going overboard!
Large scale aquatic projects do not just require toughened or laminated glass, they require toughened laminated glass. This provides the best solution to all the unique problems mentioned, allowing for the possibility that if one pane breaks, the remaining glass will have sufficient strength to maintain its integrity.
In conclusion, next time visiting somewhere with these large aquatic tanks, spare a moment’s thought to the amazing ingenuity required in constructing a glass barrier between our world and the world beneath the water.