49 CFR § 173.307 - Exceptions for compressed gases.
(a) The following materials are not subject to the requirements of this subchapter:
(1) Carbonated beverages.
(2) Tires when inflated to pressures not greater than their rated inflation pressures. For transportation by air, tires and tire assemblies must meet the conditions in § 175.8(b)(4) of this subchapter.
(3) Balls used for sports.
(4) Refrigerating machines, including dehumidifiers and air conditioners, and components thereof, such as precharged tubing containing:
(i) 12 kg (25 pounds) or less of a non-flammable, non-toxic gas;
(ii) 12 L (3 gallons) or less of ammonia solution (UN2672);
(iii) Except when offered or transported by air, 12 kg (25 pounds) or less of a flammable, non-toxic gas;
(v) 100 g (4 ounces) or less of a flammable, non-toxic liquefied gas.
(5) Manufactured articles or apparatuses, other than light bulbs each containing not more than 100 mg (0.0035 ounce) of inert gas and packaged so that the quantity of inert gas per package does not exceed 1 g (0.35 ounce).
(6) Light bulbs (lamps) conforming to the requirements of § 173.11.