Weep holes provided in the plates of a distillation column

• A. facilitate draining out liquid from a tray when the unit is not in operation.
• B. are normally located near the overflow weir so that any delivery of liquid during operation follows approximately the same path as the overflow fluid.
• C. must be large enough (usually 1/4" to 5/8" dia) to prevent plugging but should not deliver excessive amount of fluid during operation.
• D. all (a), (b) and (c).