How does the pressure change on a side? You have 4 sides to a rectangular or square tank don't you? How does the water know the difference? That makes absolutely no sense.
As you know, the pressure changes with depth and not with horizontal measurments. At a specific depth, the pressure is the exact same in all 360 degrees.
The pressure, at a specific depth, say 2', is the same pressure on every piece of glass no matter the size. But its only at THAT depth, where the pressure, in this case, .865 PSI, is the same. At 2.5', you have a pressure of 1.082 PSI and at 1.5' there is a pressure of .649 PSI. This tells you that trying to get an "approx." pressure on the sides is impossible because the different in pressure can be drastically different then another depth.
So you could find the FORCE on the glass its self at that specific depth of 2' (.865psi). If you have a side glass that is 48" long, then considering we will be using PSI which is pounds per
sqaure inch. We will need to convert 48 linear inches into sqaure inches. Simple enough, 48" * 1" = 48 sq/in. lol. So you can perform the following, 48 sq/in * .865psi = 41.52 pounds of force on all side glass pieces that are 48" long.
Obveously you want to figure out what the maximum pressure will be so you want to take a measurment at the bottom of the tank to figure out what that pressure is.
You can think of it this way, you "could" use glass that was thicker at the bottom and got thinner to the top only because the higher you get, the less force is applied to the glass.
How far off would it be to say that?: At the 5' of depth the pressure would be 5 times what it is at 1'.
So you'd have to do:
pressure/^ft @ 1' x length
+
pressure/^ft @ 2' x length
+
pressure/^ft @ 3' x length
+
pressure/^ft @ 4' x length
+
pressure/^ft @ 5' x length
=
total pressure on any given tank surface
Would that work?
Ah, close, except for the last part in bold. Yes, 5' deep would be 5 times greater than at 1'. Adding all together would just give you the pressure at 5' and not the overall pressure on the glass since you
can't figure that out.
I think you know what you are talking about but possible wording it wrong. You should say something along the lines of, "= total pressure on all sides at the specific depth". Something like that anyways. Because pressure/ft^2 at 5' is drastically different than pressure/ft^2 at 1ft.
SO you really buying glass that can support the maximum pressure at the deepest part of the tank. There is a "safty factor" too, don't know how they come up with it, but lets throw a number out there saying 3 is good for the bottom. Well the safty factor is like 15 at 1ft depth which is out of this world good (atleast in this post).
I really don't care who is right. I just want to have a reliable, easy-to-use formula for this puzzling measurement that is fairly critical in building tanks. I think it's a huge factor in correctly determining what thickness of glass/acrylic to use and how much reinforcement you need.
I do believe you are making this harder than it should be considering you are trying to figure something out that cannot be done.
Just do
Pressure per ft^2 * Length Like you were doing. At specific depths.
I like being more accurate and using these forumlas.
Head Height (ft) / 2.31 = PSI
PSI * SQ/IN AREA = POUNDS IN FORCE
I think I said what I wanted but I have to go do something so i'll be back later.