[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: 49CFR179.100-4]

[Page 1069-1070]
 
                        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.  179.100-4  Insulation.

    (a) If insulation is applied, the tank shell and manway nozzle must 
be insulated with an approved material. The entire insulation must be 
covered with a metal jacket of a thickness not less than 11 gauge 
(0.1196 inch) nominal (Manufacturers' Standard Gauge) 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.
    (b) If insulation is a specification requirement, it shall be of 
sufficient thickness so that the thermal conductance at 60 [deg]F is not 
more than 0.075 Btu per hour, per square foot, per degree F temperature 
differential. If exterior heaters are attached to tank, the thickness of 
the insulation over each

[[Page 1070]]

heater element may be reduced to one-half that required for the shell.

[29 FR 18995, Dec. 29, 1964. Redesignated at 32 FR 5606, Apr. 5, 1967, 
and amended by Amdt. 179-10, 36 FR 21344, Nov. 6, 1971; Amdt. 179-50, 60 
FR 49077, Sept. 21, 1995]