# Thickness of shells under external pressure for Hemispherical Heads

## Values for calculation

$T$ $\mathrm{°C}$
$P$ $\mathrm{MPa}$
$R_o$ $\mathrm{mm}$
$t_s$ $\mathrm{mm}$
$B$ $\mathrm{MPa}$

## Calculation

### Factor $A$

$$A=\cfrac{0.125}{\left(R_o/t_s\right)}$$

### Calculated value of maximum allowable external working pressure for the assumed value of $t_s$

$$P_a=\cfrac{B}{\left(R_o/t_s\right)}$$$$P\le P_a$$