#### § 180.503 Definitions.

The following definitions and those contained in §§ 171.8 and 179.2 of this subchapter apply:

*Coating/lining owner* means the person with the financial responsibility for purchasing and maintaining the integrity of the interior coating or lining.

*Corrosive to the tank or service equipment* means a material identified in Appendix D of this part or a material when in contact with the inner shell of the tank or service equipment has a corrosion rate on steel greater than 2.5 milli-inch per year (mpy) (0.0025 inch per year).

*Defects* mean abrasions; corrosion; cracks; dents; flaws in welds; distortions; erosion; missing, damaged, leaking or loose components and fasteners; and other conditions or imperfections that may make a tank car unsafe for transportation and/or require it to be removed from service.

*Design level of reliability and safety* means the level of reliability and safety built into the tank car and, therefore, inherent in its specification, design, and manufacture.

*Inspection and test* means a careful and critical examination of a tank car and its appurtenances performed by qualified personnel following the owner's qualified procedures.

*Interior heater system* means a piping system located within the tank shell that uses a fluid medium to heat the lading for the purposes of unloading.

*Maintenance* means upkeep, or preservation, including repairs necessary and proper to ensure an in-operation tank car's specification until its next qualification.

*Modification* means any change to a tank car that affects the certificate of construction prescribed in § 179.5, including an alteration prescribed in § 179.6, or conversion.

*Objectively reasonable and articulable belief* means a belief based on particularized and identifiable facts that provide an objective basis to believe or suspect that a tank car or a class or design of tank cars may be in an unsafe operating condition.

*Qualification,* as relevant to a tank car, means the car and its components conforms to the specification to which it was designed, manufactured, or modified to the requirements of this subpart, to the applicable requirements of the AAR Specifications for Tank Cars (IBR, see § 171.7 of this subchapter), and to the owner's acceptance criteria. Qualification is accomplished by careful and critical examination that verifies conformance using inspections and tests based on a written program approved by the tank car owner followed by a written representation of that conformance. A tank car that passes the appropriate tests for its specification, has a signed test report, is marked to denote this passage, and is considered qualified for hazardous materials transportation under this subchapter.

| Qualification of | Tests and inspections | § 180.509(*) |
| --- | --- | --- |
| Tank | Visual Inspection | d |
| | Structural Integrity Inspection | e |
| | Thickness Test: Note 1 | f |
| | Safety System Inspection | h |
| Service Equipment | Service Equipment | k |
| Coating/lining | Internal Coatings and Linings | i |

Note 1:

Subparagraph (f)(2) may require thickness tests at an interval different from the other items for qualification of the tank.

*Railworthy, Railworthiness* for a tank car means that the tank, service equipment, safety systems, and all other components covered by this subchapter conform to the HMR, and are otherwise suitable for continued service and capable of performing their intended function until their next qualification.

*Reactive to the tank or service equipment* means a material that, in contact with the inner shell of the tank, or with the service equipment, may react to produce heat, gases, and/or pressure which could substantially reduce the effectiveness of the packaging or the safety of its use.

*Reinforced tank shell butt weld* means the portion of a butt weld covered by a reinforcing pad.

*Reinforcing pad* means an attachment welded directly to the tank supporting major structural components for the purpose of preventing damage to the tank through fatigue, overstressing, denting, puncturing, or tearing.

*Reliability* means the quantified ability of an item or structure to operate without failure for the specified period of its design life or until its next qualification.

*Representation* means attesting through documenting, in writing or by marking on the tank (or jacket), that a tank car is qualified and railworthy. See also §§ 180.511 and 180.517(b).

*Safety system* means one or more of the following: Thermal protection systems, insulation systems, tank head puncture resistance systems, coupler vertical restraint systems, and systems used to protect discontinuities (e.g., skid protection and protective housings) as required under this subchapter.

*Service equipment* means equipment used for loading and unloading (including an interior heating system), sampling, venting, vacuum relief, pressure relief, and measuring the amount of lading or the lading temperature.

*Service equipment owner* means the party responsible for bearing the cost of the maintenance of the service equipment.

*Tank car owner* means the person to whom a rail car's reporting marks are assigned, as listed in the Universal Machine Language Equipment Register (UMLER).

*Tank car tank* means the shell, heads, tank shell and head weld joints, attachment welds, sumps, nozzles, flanges, and all other components welded thereto that are either in contact with the lading or contain the lading.

[77 FR 37986, June 25, 2012, as amended at 81 FR 35546, June 2, 2016; 89 FR 52994, June 24, 2024]