Pick out the wrong statement.

• In practical operation, distillation towers having diameter 3-6 metres equipped with bubble cap (round) size of 15 cms are used.
• Height of packing in a packed tower is about 3 times the column diameter for raschig rings and about 5 to 10 times the column diameter for saddle packing.
• In a seive tray, the minimum hole diameter is equal to the tray thickness.
• In a stainless steel seive tray, the minimum hole diameter is equal to 10 times the plate thickness.