Hello, I'm seeing up a concrete tank with a viewing window for my cichlids. The dimensions are 96 inches x 28 inches x 34 inches. I would like to install a glass panel to the front 72 x 30 inches. What are your recommendations as to how thick the glass should be?
Glass viewing window, what thickness?
- Thread starter Clif Trini
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The thickness of glass would be determined by how tall the aquarium is. The depth of water creates pressure, not so much footprint.
for a tank 30” tall no less than 19mm
for a tank 30” tall no less than 19mm
You are absolutely correct in that "The depth of water creates pressure".
Although the length the glass is spanning (footprint) is also a consideration. Which is why on larger tanks the front glass is often thicker than the side panels.
The reason for this isn't that the pressure at the bottom is higher in the front than on the sides, as it's obviously the same. But a long span is more prone to bowing than a short span.
In this case, the viewing window will be braced on all four sides rather well. Much better than an glass box with an open top, even with glass braces much less a plastic frame.
I grabbed a random custom glass manufacturers site and checked it: https://www.customaquariums.com/glass-aquariums/all-aquarium-standard-sizes.html
They list a 72" long x 30" tall aquarium as having 0.625" front glass (and 0.5" on the sides). And remember this is the glass box with an open top, not something with bracing on all four sides.
Even the 48" tall x 48" long x 18" front-to-back uses 0.625" (which surprises me, I'd expect thicker).
First off, ensure that your glass' frame is solid and not flexible (which would be equally bad for the concrete). Then, if you are concerned that the front glass may be the weak point, consider adding a center vertical brace dividing the viewing window in half. It won't be as showy, but will be more structurally sound.
But all things considered, even without the extra brace I mentioned... my guess is you could 'get away with' 0.375" glass due to being firmly supported on all four sides. Though I'd go 0.5" to avoid cutting a corner too closely.
Although the length the glass is spanning (footprint) is also a consideration. Which is why on larger tanks the front glass is often thicker than the side panels.
The reason for this isn't that the pressure at the bottom is higher in the front than on the sides, as it's obviously the same. But a long span is more prone to bowing than a short span.
In this case, the viewing window will be braced on all four sides rather well. Much better than an glass box with an open top, even with glass braces much less a plastic frame.
I grabbed a random custom glass manufacturers site and checked it: https://www.customaquariums.com/glass-aquariums/all-aquarium-standard-sizes.html
They list a 72" long x 30" tall aquarium as having 0.625" front glass (and 0.5" on the sides). And remember this is the glass box with an open top, not something with bracing on all four sides.
Even the 48" tall x 48" long x 18" front-to-back uses 0.625" (which surprises me, I'd expect thicker).
First off, ensure that your glass' frame is solid and not flexible (which would be equally bad for the concrete). Then, if you are concerned that the front glass may be the weak point, consider adding a center vertical brace dividing the viewing window in half. It won't be as showy, but will be more structurally sound.
But all things considered, even without the extra brace I mentioned... my guess is you could 'get away with' 0.375" glass due to being firmly supported on all four sides. Though I'd go 0.5" to avoid cutting a corner too closely.
This question comes up very frequently both here and many other discussion sites. There are plenty of online calculators. It's unlikely any tank makers would respond and I would not be taking the free advice of hobbyists. Even if well intended.
There is a difference between tempered glass and float glass. Lamination and type of laminate are considerations. And setting the glass panel in a 4 sided steel frame, thickness of steel and having cross braces will influence structural design.
Additionally the safety factor you feel comfortable with needs to be understood so you can make the best decision. Where the tank will be and potential damage. Some glass bend may or may not be acceptable to you.
There is a difference between tempered glass and float glass. Lamination and type of laminate are considerations. And setting the glass panel in a 4 sided steel frame, thickness of steel and having cross braces will influence structural design.
Additionally the safety factor you feel comfortable with needs to be understood so you can make the best decision. Where the tank will be and potential damage. Some glass bend may or may not be acceptable to you.