-13 Retrofit standard requirements (DOT-117R).

(a)Applicability. Each tank retrofit under these specifications must conform to the general requirements of § 179.200 and the prescriptive standards in § 179.202-13, or the performance standard requirements of § 179.202-12.#

(b)Approval to operate at 286,000 gross rail load (GRL). A tank car may be loaded to a gross weight on rail of up to 286,000 pounds (129,727 kg) upon approval by the Associate Administrator for Safety, Federal Railroad Administration (FRA). See § 179.13.#

(c)Thickness of plates. The wall thickness after forming of the tank shell and heads must be, at a minimum, 7/16 of an inch, and constructed with steel authorized by the HMR at the time of construction.#

(d)Tank head puncture resistance system. The DOT-117R specification tank car must have a tank head puncture resistance system in conformance with § 179.16(c). The full height head shields must have a minimum thickness of 1/2 inch.#

(e)Thermal protection system. (1) The DOT Specification 117R tank car must have a thermal protection system. The thermal protection system must conform to § 179.18 of this part and include a reclosing pressure relief device in accordance with § 173.31 of this subchapter.#

(2)A non-jacketed tank car modified to the DOT Specification 117R must be equipped with a thermal protection blanket with at least 1/2-inch-thick material that meets § 179.18(c) of this part.#

(f)Jackets. The entire thermal protection system must be covered with a metal jacket of a thickness not less than 11 gauge A1011 steel or equivalent; and flashed around all openings so as to be weather tight. The exterior surface of a carbon steel tank and the inside surface of a carbon steel jacket must be given a protective coating.#

(g)Bottom outlets. If the tank car is equipped with a bottom outlet, the handle must be removed prior to train movement or be designed with protection safety system(s) to prevent unintended actuation during train accident scenarios.#

(h)Top fittings protection—(1) Protective housing. Except as provided in §§ 179.202-13(h)(2) and (3) of this paragraph, top fittings on DOT Specification 117R tank cars must be located inside a protective housing not less than 1/2-inch in thickness and constructed of a material having a tensile strength not less than 65 kpsi and must conform to all of the following conditions:#

(i)The protective housing must have a height exceeding the tallest valve or fitting which requires protection and the height of a valve or fitting within the protective housing must be kept to the minimum size compatible to allow for proper operation.#

(ii)The protective housing or cover may not reduce the flow capacity of a pressure relief device below the minimum required.#

(iii)The protective housing must provide a means of drainage with a minimum flow area equivalent to six (6) 1-inch diameter weep holes.#

(iv)When connected to the nozzle or fitting cover plate, and subject to a horizontal force applied perpendicular to and uniformly over the projected plane of the protective housing, the tensile connection strength of the protective housing must be designed to be—#

(A)no greater than 70 percent of the nozzle to tank tensile connection strength;#

(B)no greater than 70 percent of the cover plate to nozzle connection strength; and#

(C)no less than either 40 percent of the nozzle to tank tensile connection strength or the shear strength of twenty (20) 12-inch bolts.#

(2)Pressure relief devices. (i) The pressure relief device(s) must be located inside the protective housing, unless space does not allow for placement within a housing. If multiple pressure relief devices are installed, no more than one (1) may be located outside of a protective housing.#

(ii)The height of a pressure relief device located outside of a protective housing in accordance with paragraph (h)(2)(i) of this section may not exceed the tank car jacket by more than 12 inches.#

(iii)The highest point of a closure of any unused pressure relief device nozzle may not exceed the tank car jacket by more than six (6) inches.#

(3)Alternative. As an alternative to the protective housing requirements in paragraph (h)(1) of this section, the tank car may be equipped with a system that prevents the release of contents from any top fitting under accident conditions where any top fitting may be sheared off.#