Why is free boarding important in fire tank design?

Free boarding is crucial in fire tank design primarily to avoid spills during the filling process. When a tank is filled with water or other fire suppression agents, the liquid can expand or surge due to turbulence, causing the level of the liquid to rise. If the tank does not have an adequate amount of free board—the space between the maximum liquid level and the top of the tank—excess liquid can overflow, leading to potential environmental hazards, loss of valuable resources, and safety risks.

Having proper free board ensures that there is sufficient room to accommodate these variations without risking spillage. It is part of a well-thought-out design consideration in preventing overflow, which is particularly important in emergency situations where the tank may be filled rapidly to respond to a fire.