[Code of Federal Regulations]

[Title 49, Volume 2]

[Revised as of October 1, 2005]

From the U.S. Government Printing Office via GPO Access

[CITE: 49CFR179.100-13]



[Page 1039-1040]

 

                        TITLE 49--TRANSPORTATION

 

   CHAPTER I--PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, 

                      DEPARTMENT OF TRANSPORTATION

 

PART 179_SPECIFICATIONS FOR TANK CARS--Table of Contents

 

 Subpart C_Specifications for Pressure Tank Car Tanks (Classes DOT-105, 

                         109, 112, 114 and 120)

 

Sec. 179.100-13  Venting, loading and unloading valves, measuring and 

sampling devices.



    (a) Venting, loading and unloading valves must be of approved 

design, made of metal not subject to rapid deterioration by the lading, 

and must withstand the tank test pressure without leakage. The valves 

shall be bolted to seatings on the manway cover, except as provided in 

Sec. 179.103. Valve outlets shall be closed with approved screw plugs 

or other closures fastened to prevent misplacement.

    (b) The interior pipes of the loading and unloading valves shall be 

anchored and, except as prescribed in Sec. Sec. 173.314(j), 179.102 or 

179.103, may be equipped with excess flow valves of approved design.

    (c) Gauging device, sampling valve and thermometer well are not 

specification requirements. When used, they shall be of approved design, 

made of metal not subject to rapid deterioration by the lading, and 

shall withstand the tank test pressure without leakage. Interior pipes 

of the gauging device and sampling valve, except as prescribed in 

Sec. Sec. 173.314(j), 179.102 or 179.103, may be equipped with excess 

flow valves of approved design. Interior pipe of the thermometer well 

shall be anchored in an approved manner to prevent breakage due to 

vibration. The thermometer well shall be closed by an approved valve 

attached close to the manway cover, or other approved location, and 

closed by a screw plug. Other approved arrangements that permit testing 

thermometer well for leaks without complete removal of the closure may 

be used.

    (d) An excess flow valve as referred to in this specification, is a 

device which closes automatically against the outward flow of the 

contents of the tank in case the external closure valve is broken off or 

removed during transit. Excess flow valves may be designed with a by-

pass to allow the equalization of pressures.



[[Page 1040]]



    (e) Bottom of tank shell may be equipped with a sump or siphon bowl, 

or both, welded or pressed into the shell. Such sumps or siphon bowls, 

if applied, are not limited in size and must be made of cast, forged or 

fabricated metal. Each sump or siphon bowl must be of good welding 

quality in conjunction with the metal of the tank shell. When the sump 

or siphon bowl is pressed in the bottom of the tank shell, the wall 

thickness of the pressed section must not be less than that specified 

for the shell. The section of a circular cross section tank to which a 

sump or siphon bowl is attached need not comply with the out-of-

roundness requirement specified in AAR Specifications for Tank Cars, 

appendix W, W14.06 (IBR, see Sec. 171.7 of this subchapter). Any 

portion of a sump or siphon bowl not forming a part of cylinder of 

revolution must have walls of such thickness and be so reinforced that 

the stresses in the walls caused by a given internal pressure are no 

greater than the circumferential stress that would exist under the same 

internal pressure in the wall of a tank of circular cross section 

designed in accordance with Sec. 179.100-6(a), but in no case shall the 

wall thickness be less than that specified in Sec. 179.101-1.



[29 FR 18995, Dec. 29, 1964. Redesignated at 32 FR 5606, Apr. 5, 1967, 

and amended by Amdt. 179-10, 36 FR 21345, Nov. 6, 1971; Amdt. 179-40, 52 

FR 13046, Apr. 20, 1987; Amdt. 179-42, 54 FR 38798, Sept. 20, 1989; 65 

FR 58632, Sept. 29, 2000; 68 FR 48571, Aug. 14, 2003; 68 FR 75760, Dec. 

31, 2003]