Glass/Acrylic Thickness Calculations

[robr0924]

nice calculator, Day dreaming here but I want to build a bigger tank, 12'x4'x30" (so I can get through a door way if necessary. calc has me at 30mm that's pretty thick.

And moving after the build would be a *****!
some thing to think about.

 

[Pirocop]

Great contribution. I liked.

 

[Japonicus]

nice, thanks for the info

 

[David K. Bradley]

Acrylic Thickness:

SD Plastics Acrylic Calculator

Pharaoh:

I have tried to access the SD Plastics Acrylic Calculator web site to access the use of this calculator and have been unsuccessful. My computer will not allow this access.

I am in the R & D stage of a DIY PLYWOOD BUILD for a tank volume of roughly 1,436.25 US gal. A water volume area of 144 inches X 48 inches X 48 inches. I have read the entire thread on the Pro's and Con's of Glass vs. Acrylic. I will either use Acrylic or Starphire Glass for my viewing window or windows.

The size of my viewing window will be 132 inches X 36 inches . At the moment, I am planning to have an added 2 inch border around the viewing window which would make the final dimmensions 136 inches X 40 inches. This calculates to 5,280 sq. inches or 34,066.56 sq. centimeters.

My questions to everyone are:

[1] What simplified mathmetical formula would I use to calculate the water volume pressure against the tank viewing window?

[2] What simplified mathematical formula I may use for calculating the thicknesses for:
(a.) Starphire Glass; and
(b.) Acrylic

[3] In calculating these parameters for my viewing window, is there a safety factor involved and if this is so, how would this be calculated as well?
NOTE: I do realize and fully understand that MFK nor any MFK member can not guarantee the validity of a manufacturer's product.
So knowing this and keeping this in mind, is a safety factor calculation still a do-able thing?

 

[David K. Bradley]

BUMP

 

[Pharaoh]

OK, I do have to make one assumption here. That the 2" border that is around the tank will also account for water. So, that would make the dimensions 136 x 38.

Starphire Glass (Same as regular plate glass)- Coming up with 1" on this one.

With glass, there is an industry standard safety factor of 3.8, which is what I used int he calculation above. Of course. this can be changed as well. For example a 2.0 safety factor would give you roughly 3/4" glass. This is all a matter of how comfortable you feel with using a lower safety factor. Some tank manufacturers have done this for years, some haven't.

Acrylic- 1.5" on this one.

There's not really a safety factor with acrylic per se, but you can change the beta within the equation and modify the results. From experience, manufacturers have also built acrylic tanks with thinner acrylic with acceptable results. The acrylic calculation is based on deflection. The thickness listed above will allow minimal deflection(bowing) of the acrylic.

 

[David K. Bradley]

OK, I do have to make one assumption here. That the 2" border that is around the tank will also account for water. So, that would make the dimensions 136 x 38.

Starphire Glass (Same as regular plate glass)- Coming up with 1" on this one.

With glass, there is an industry standard safety factor of 3.8, which is what I used int he calculation above. Of course. this can be changed as well. For example a 2.0 safety factor would give you roughly 3/4" glass. This is all a matter of how comfortable you feel with using a lower safety factor. Some tank manufacturers have done this for years, some haven't.

Acrylic- 1.5" on this one.

There's not really a safety factor with acrylic per se, but you can change the beta within the equation and modify the results. From experience, manufacturers have also built acrylic tanks with thinner acrylic with acceptable results. The acrylic calculation is based on deflection. The thickness listed above will allow minimal deflection(bowing) of the acrylic.

Thank you your feed back on this Pharaoh.

I'm not sure if I made it clear on the viewing window dimmensions. The 132 inches x 36 inches will be exposed as the viewing portion of the window. The 2 inch border will not be seen. It will be hidden behind the plywood. It would then make the dimmensions 138" x 40" not 136" x 38" as you mentioned in your response above, in your 1st paragraph. So knowing this, would it have any direct effect on your calculations as you have mentioned earlier using the standard safety factor of 3.8 with the glass?

Additionally, how much weight will this produce using acrylic @ 1.5" x 136" x 40" or starphire glass @ 1" x 136" x 40"?

 

[Pharaoh]

Thank you your feed back on this Pharaoh.

I'm not sure if I made it clear on the viewing window dimmensions. The 132 inches x 36 inches will be exposed as the viewing portion of the window. The 2 inch border will not be seen. It will be hidden behind the plywood. It would then make the dimmensions 138" x 40" not 136" x 38" as you mentioned in your response above, in your 1st paragraph. So knowing this, would it have any direct effect on your calculations as you have mentioned earlier using the standard safety factor of 3.8 with the glass?

Additionally, how much weight will this produce using acrylic @ 1.5" x 136" x 40" or starphire glass @ 1" x 136" x 40"?

Just saw this today. I recalculated based on what you had mentioned. It gives you a bit more room for play, but doesn,t change much.

With a SF of 3.8, I come up with 0.905" glass.

With a SF of 2.6, I come up with 0.748" glass.

For your last question, Are you referring to the weight of each? If so, then here you go:

1.5" Acrylic (136 x40) - 331.5 lbs

1.0" Glass (136 x 40) - 509 lbs

 

[Gervahlt]

Quick question for you, Pharaoh if you don't mind. I'm still playing around with pricing on the aquarium I want to build. I have the glass calculator directly from the Federation of New Zealand Aquatic Societies (not sure if this is the same one you're using). The glass tank I'm wanting to construct is 96"L x 30"W x 24"H. Using those dimensions, how thick does the bottom plate need to be, and does it need to be tempered?

Thank you in advance!

 

[Pharaoh]

I'm coming up with anywhere between 1/2" to 3/4", depending on the safety factor that you want to use. 5/8" would put you right in the middle.