§179.202-13. Retrofit standard requirements (DOT-117R). — Inbound Citations

(a) 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.

(1) 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.

(1) 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.