Weep holes provided in the plates of a distillation column

Facilitate draining out liquid from a tray when the unit is not in operation

Are normally located near the overflow weir so that any delivery of liquid during operation follows approximately the same path as the overflow fluid

Must be large enough (usually $${\frac{1}{4}}^{{}^{\prime \prime }}$$ to $${\frac{5}{8}}^{{}^{\prime \prime }}$$ dia) to prevent plugging but should not deliver excessive amount of fluid during operation