[Code of Federal Regulations]
[Title 49, Volume 2]
[Revised as of October 1, 2007]
From the U.S. Government Printing Office via GPO Access
[CITE: 49CFR179.100-13]

[Page 1072]
 
                        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.
    (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]