Definition - What does Exfiltration mean?
Exfiltration is the gradual leakage of fluid through any industrial equipment, a membrane or a wall because of small opening. Exfiltration occurs when a small opening allows fluid to drain from within an assembly. The gradual deposition of leaking fluid can cause corrosion in metal structures such as boilers, heat exchangers, storage tanks and other types of equipment and machinery.
Exfiltration is also known as weep.
Corrosionpedia explains Exfiltration
Sometimes manufacturers provide small openings for exfiltration so that accumulated moisture can be drained off either via condensation or seepage. However, when a liquid accumulates at the storage points under the machinery, it can cause slow and gradual corrosion to the machine's outer structure. For example, the gaskets on heat exchanger plates have several small openings that cause the fluid to spill on the ground rather than going undetected inside the unit. These openings or weeps are in locations that do not see any flow unless a problem occurs.
Exfiltration points are generally located at the bottom of the machinery to allow for drainage. The weep hole must be large enough to overcome surface tension. The draining fluid should be cleaned regularly to avoid any damage to the equipment.