If the temperature exceeds the limit on a fixed roof tank, what is the recommended action?

• A. Vent to atmosphere
• B. Blanket it with nitrogen
• C. Cool the tank with water spray
• D. Drain some product

Answer: (B)

When a fixed roof tank is hotter than its limit, the priority is to prevent flammable vapor formation and reduce ignition risk. Blanking the headspace with nitrogen creates an inert atmosphere, lowering the oxygen level and suppressing vapor concentrations, which helps prevent fires or explosions as the liquid temperature is controlled. Venting to atmosphere would release hydrocarbons and raise the danger, while cooling with water spray is more about active cooling during a fire or heat exposure rather than maintaining a safe inert environment, and draining product doesn’t address the vapor and ignition risks. So, nitrogen blanketing is the best way to manage the situation safely.