27 C.F.R. § 19.192 – Security.

(a) General. The proprietor of a distilled spirits plant must provide adequate security measures at the plant in order to protect the revenue.
(b) Buildings. The buildings, rooms, and partitions must be constructed of substantial materials. Doors, windows, or any other openings to the building must be secured or fastened during times when distilled spirits plant operations are not being conducted.
(c) Outdoor tanks. Outdoor tanks containing spirits, denatured spirits, or wine must be individually locked or locked within an enclosure when they are not in use.
(d) Indoor tanks. Indoor tanks containing spirits, denatured spirits, or wines, or the rooms or buildings in which such tanks are housed, must be equipped so that they may be secured.
(e) Approved locks. Locks meeting the specifications prescribed in paragraph (f) of this section must be used to secure:
1. (1) Outdoor tanks used to store spirits, or an enclosure around such tanks;
2. (2) Indoor tanks used to store spirits, or the door from which access may be gained from the outside to the rooms or buildings in which such tanks are housed; and
3. (3) Any doors from which access may be gained from the outside to rooms or buildings containing spirits stored in portable bulk containers.
(f) Specifications for locks. Locks meeting the specifications in this section or other locks that have been approved for use by the appropriate TTB officer are approved locks for the purpose of 26 U.S.C. 5682.
1. (1) General. The following are the specifications for approved locks:
  1. (i) A corresponding serial number on the lock and on the key, except for master key locking systems;
  2. (ii) A case hardened shackle at least one-fourth inch in diameter, with heel and toe locking;
  3. (iii) A body width of at least 2 inches;
  4. (iv) A captured key feature (the key may not be removed while the shackle is unlocked);
  5. (v) A tumbler with at least 5 pins; and
  6. (vi) A lock and key containing no bitting data.
2. (2) Other approved locks. If the proprietor wishes to use locks of an unusual design, which do not meet the specifications in paragraph (f)(1) of this section, the proprietor must submit an example or prototype of the lock to the appropriate TTB officer, with a request that the lock be approved for use. The appropriate TTB officer will evaluate the lock and determine whether the lock should be approved for use.
3. (3) Master key systems. Master key locking systems using approved locks may be used at the option of the proprietor.
(g) Additional security. Whenever the appropriate TTB officer finds that construction, arrangement, equipment, or protection is inadequate, additional security (such as fences, flood lights, alarm systems, and guard services) must be provided or changes in construction, arrangement, or equipment must be made to the extent necessary to protect the revenue.
(26 U.S.C. 5178, 5202)