That is of course if the tanks are built according to the rules for frangible roofs.
Frangible roof storage tank.
Frangible roofs are normally specified as a means of providing emergency relief venting in the situation when a tank is engulfed in fire or the adjacent tank is on fire causing rapid vaporisation of the stored product such that the normal venting system cannot cope and the pressure in the tank rises to a point where the roof to shell joint fails.
This paper presents the results of an investigation into the frangible joint behavior of tanks designed to api 650 rules.
The reasoning behind present api design formulas is reviewed.
See figures 7 and 8.
In fact the frangible roof design fulfills the venting requirements due to deflagrations inside tanks for most tank sizes greater than about 35 feet in diameter.
In the event of over pressurization the frangible roof to shell joint is designed to fail before the tank shell or the shell to bottom joint.