Ask X3What does 49 CFR 173.309 (Fire extinguishers) require?
Generated guidance. Confirm the source and its applicability before you act. How we check sources.
As Ask X3, your fleet-compliance assistant, here is what 49 CFR 173.309 requires for transporting portable fire extinguishers, fire extinguishers for aircraft or suppression systems, and large fire extinguishers:
General Requirements:
* Extinguishing agents must be nonflammable, non-poisonous, and non-corrosive.
* Cylinders filled with compressed gas solely to expel a separately stored extinguishing agent cannot be transported under this section apart from the suppression system.
Specific Conditions by Cylinder Type:
* Specification 3A, 3AA, 3E, 3AL, 4B, 4BA, 4B240ET, or 4BW Cylinders: Must be charged with a nonflammable, non-poisonous dry gas (with a dew-point at or below -52 °F at 1 atmosphere, free of corroding components) up to no more than the cylinder's service pressure. They cannot contain more than 30% carbon dioxide by volume. Each must have an external corrosion-resisting coating. Specification 3E and 4BA cylinders must be packed in strong non-bulk outer packagings marked to show the inner packagings meet prescribed specifications.
* Specification 2P or 2Q Inner Non-Refillable Metal Packagings: The liquid portion (plus any additional liquid or solid) must not completely fill the packaging at 130 °F. Pressures at 130 °F cannot exceed 181 psig (use DOT 2P if pressure is between 141 and 160 psig; use DOT 2Q if it exceeds 160 psig). Packagings must withstand 1.5 times the equilibrium pressure at 130 °F without bursting. Each filled inner packaging must be heated to the equilibrium pressure at 130 °F with no leaks, distortion, or defects. They must be packed in strong non-bulk outer packagings marked to show the inner packagings meet prescribed specifications.
* Non-Specification Cylinders: Internal volume cannot exceed 18 L (1,100 cubic inches). For capacities under 900 mL (55 cubic inches), liquids/solids must not completely fill the container at 130 °F; capacities over 900 mL cannot contain liquefied compressed gas. Manufactured on/after January 1, 1976, they must have a burst pressure of at least six times the charged pressure at 70 °F. Before initial shipment, each must be tested to at least three times its charged pressure at 70 °F (not less than 120 psig) without failure, marked with the test year (within 90 days of the test date), and marked “MEETS DOT REQUIREMENTS.” They must be packed as inner packagings within a combination outer packaging (such as large cartons, racks, or cages), and subsequent shipments must comply with OSHA retest requirements (29 CFR 1910.157).
Limited Quantities:
* Fire extinguishers meeting paragraph (a), (b), or (c) and charged to no more than 241 psig at 70 °F are excepted from shipping papers (unless by aircraft or vessel), labeling (unless by aircraft), placarding, and specification packaging. They are eligible for § 173.156 exceptions and are not subject to parts 174 and 177 when moved by highway or rail, provided the extinguishing agents are nonflammable, non-poisonous, and non-corrosive, and packages are marked as specified in § 172.315.
**Large Fire Extinguishers (