How to arrive the glass thickness ?

[rainbowrgb]

I have a glass which will act external water pressure of 10ATM and it is fully housed with the center opening(Consider wrist watch). What is the formula to get the required thickness. Say your diameter of the glass or area of the glass is fixed. And the formula required for different profiles say Round, Rectangular, Square, Oval, Tonneau and special profiles

 

[Simon Bridge]

Welcome to PF;
I take it English is not your first language?

Lets see if I understand you...
You want to use a small flat sheet of glass as the active component in a pressure gauge - is that correct?

 

[rainbowrgb]

Thanks for your reply and your understanding. I am explaining in details...

Basically i am looking a formula to arrive glass thickness and my input will be of Water resistance and the unit is in ATM. (Example 3ATM, 5 ATM and 10ATM). Configuration will be of fully supported and uniform distributed load and the load here can be of 5ATM. Glass shape will be of either round, Square, Rectangle with the supported are. Say Glass Dia is 40.00 mm and the unsupported area will be of Dia 33.00 mm. With the above details we need to arrive what should be the glass thickness should be designed ?. I am new to this forum. Is it possible to attach some JPG files here ? If so pleas confirm i can send the 3D image or 2D image

 

[Simon Bridge]

You can attach images to posts in this forum by using the advanced interface (see: "go advanced" below). You can also upload images to another site and link to them.

Now it sounds like you just want to make a small water-resistant window which can be rated to withstand different pressure-differences. In which case, your seal is more of a constraint than the thickness of the glass.

Still need to know what kind of glass - but if it is for an instrument you are constructing yourself then you should probably look at divers' supplies or scientific glassware notes like:
http://www.ilpi.com/glassblowing/techdata.html#nomogram
... which has a discussion of making glass to withstand pressure differences as well as a nomogram for cylinders. You should be able to find others or just look for a commercial gauge with similar dimensions to the one you want to make and make note of how thick the glass is.