Glass max height in plywood tank building

[nolapete]

Does the max height of the glass relate to the max water depth or just the max height of the piece of glass.

In example:

If I have a 48" long x 30" tall piece of glass, can I

a) have a tank only 34-36" tall allowing for framing for the glass

or

b) have a tank 72" tall with a 48" x 30" viewing glass?

 

[eh1421]

as long as the glass is mounted at the top of the tank within the first 36" whats below it will have no bearing on glass thickness

mike

 

[Skeeter]

Water pressure gets greater the deeper you go (the more water above a certain point, the more weight, in essense, is pushing on that point).

So it's not so much the size of the glass as it is how much water is above it. A 30" sheet of glass placed 48" deep should be treated as a 48" sheet of glass as far as thickness is concerned because of the extra pressure at that depth.

 

[nolapete]

ok got it, I was under the impression that the more water a tank contained the greater the pressure.

I still find it hard to believe that a 30" deep 30000 gallon tank could be contained by a 1/2" thick 48"x30" piece of glass, but of course I'm no engineer.

 

[Skeeter]

....I still find it hard to believe that a 30" deep 30000 gallon tank could be contained by a 1/2" thick 48"x30" piece of glass, but of course I'm no engineer.

I am an engineer and even I sometimes have a hard time explaining why this is. This link does a pretty good job of explaining things without getting too awfully technical:

http://scubageek.com/articles/wwwparad.html

 

[nolapete]

That's awesome. Thanks!

 

[maxumis]

Rent the movie Poseidon on DVD, watch the extras...
They have something like 90 000 gallons of water held back by 1/2" tempered glass. They actually had to blow the glass with remote fuses... Was very cool to watch. The movie is not so great.