(a) Storerooms or compartments shall be so constructed and secured as to prevent unauthorized access and will be equipped for locking. These storage facilities shall be of sufficient capacity to hold the maximum quantity of tax-free alcohol which will be on hand at one time.

(b) Each stationary storage tank used to hold tax-free alcohol shall be equipped for locking in such a manner as to control access to the spirits. All stationary storage tanks shall be equipped with an accurate means of measuring the spirits.

(c) Storerooms and storage tanks shall be kept locked when unattended. A storage cabinet or locker kept inside a room which is locked when unattended is considered to be adequately secured.