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;
(iv) Except when offered or transported by air or vessel, 20 kg (44 pounds) or less of a Group A1 refrigerant specified in ANSI/ASHRAE Standard 15 (IBR, see § 171.7 of this subchapter); or
(v) 100 g (4 ounces) or less of a flammable, non-toxic liquefied gas.
(b) [Reserved]
[Amdt. 173-94, 41 FR 16081, Apr. 15, 1976, as amended by Amdt. 173-135, 45 FR 13090, Feb. 28, 1980; 65 FR 50462, Aug. 18, 2000; 68 FR 45038, July 31, 2003; 68 FR 75745, Dec. 31, 2003; 69 FR 76174, Dec. 20, 2004; 71 FR 14604, Mar. 22, 2006]