Frangible Roof Storage Tank

See figures 7 and 8.

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. 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. That is of course if the tanks are built according to the rules for frangible roofs. 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.

A frangible roof joint forming a flexible gastight connection between a tank shell and a roof comprising an annular link mechanism sealingly secured at or adjacent a first edge thereof to a rim of the tank and sealingly secured at or adjacent a second edge thereof to the periphery of the roof. A frangible roof joint forming a flexible gastight connection between a tank shell and a roof comprising an annular link mechanism sealingly secured at or adjacent a first edge thereof to a rim of.