Fire Protection in Floating Roof Tanks

Around the world, there are over 4,800 oil terminals responsible for storing nearly a billion cubic meters of crude oil and other combustible or flammable petroleum products (source: www.tankterminals.com). Many of these terminals use floating roof tanks (FRTs). Though FRTs are considered safer than traditional fixed-roof and open-top storage tanks, they still afford the possibility of gas or vapor leaks that can ignite due to lightning or other causes.

An FRT is an aboveground tank in which a metal deck or pan (the roof) floats directly on the surface of the liquid.

The roof is flush with the wall of the tank and moves up and down with the level of the liquid, much like a piston in a cylinder. The purpose of the system is to minimize the volume of vapor present in the tank, as well as to reduce the emission of vapors from the tank thanks to a rim seal between product fluid and the environment. When a failure occurs on a rim seal, there is the potential for flammable vapors or product to escape.