27 CFR 19.703: Construction and equipment.

A proprietor must construct and arrange the buildings and enclosures where distilled spirits will be produced, processed, or stored so as to ensure adequate security and deter the diversion of spirits. Distilling equipment must be constructed to prevent unauthorized removal of spirits, from the point where distilled spirits come into existence until production is complete and the quantity of spirits has been determined. A proprietor also must equip tanks and other vessels so that they may be locked and must provide a method for determining the quantity of spirits in each vessel.