Well, I'm not a materials scientist. I like to use silicone tubing for many purposes, including refrigerated circulators, e.g., for rotary evaporation applications. While I've never had any 'real' problems (I commonly use 5/16" ID x 11/16" OD), I do see some 'curious' questions when I calculate the burst pressure and compare it to the stated 'working pressure' for that product. (Generally, the 'working pressure' varies from 1/3rd to 1/5th of the burst pressure. The reported 'working pressure' for the above size tubing is usually stated to be 10 psi (or between 10 and 20 psi); so the maximal burst pressure based upon the 1/5th number and 20 psi would be 100 psi (10 psi is what you usually read; so you might say the burst pressure might be as low as 30 to 50 psi).

Now here is the problem I encounter: I used Barlow's Formula to calculate the burst pressure of the above tubing.

Burst Pressure = [Tensile Strength] [x^2 - y^2] / y^2 [1 + x^2/y^2]

The x and y above are squared.

X = OD/2

y = ID/2

The Tensile Strength for my tubing in psi is 1200.

So I end up with the equation [(1200)(0.094)] / [(0.024)(5.197)] = 794 psi being the burst pressure. That is a lot higher than one would assume based on what is advertised. I know that temperature and other factors can change these numbers but not to this degree. Burst pressure 30 to 100 psi? Or 794 psi?

Does anyone have any experience with these matters. Even empirical experience with the use of silicone tubing would be appreciated. The tubing I use is peroxide cured, so my real number would be even higher than 794 because the tensile strength I used in the above calculation was for platinum cured silicone tubing (1200 psi) which is lower than the 1595 psi for peroxide cured tubing.

You can have a look at https://www.tblplastics.com/how-to-determine-tubing-burst-pressure-and-working-pressure/

Thank You and Best Regards