General. All tanks on wine premises used for wine operations or for other operations as are authorized in this part will be suitable for the intended purpose. Each tank used for wine operations will be located, constructed, and equipped as to permit ready examination and a means of accurately determining the contents. Any tank used for wine operations not enclosed within a building or room will be enclosed within a secure fence unless the premises where the tank is located are enclosed by a fence or wall, or all tank openings are equipped for locking and are locked when used for wine operations and there is no proprietor's representative on the wine premises, or the appropriate TTB officer has approved some other adequate means of revenue protection. All open tanks will be under a roof or other suitable covering.

Other requirements. Each tank used for the taxpayment of wine, storage of spirits, or spirits additions will be constructed and equipped as follows:

An accurate means of measuring the contents of each tank will be provided by the proprietor. When a means of measuring is not a permanent fixture of the tank, the tank will be equipped with a fixed device to allow the approximate contents to be determined readily;

Safe access to all parts of a tank will be provided by the proprietor;

Tanks may not be used until they are accurately calibrated and a statement of certification of accurate calibration is on file at the premises;

If a tank or its means of measuring is changed as to location or position subsequent to original calibration, the tank may not be used until recalibrated; and

All openings in tanks used for the storage, weighing, or measuring of spirits, or for the addition of spirits to wine, will be equipped for locking or have a similar means of revenue protection. Any vents, flame arrestors, foam devices, or other safety devices affixed to a spirits tank will be constructed to prevent extraction of the contents of the tank.