[Code of Federal Regulations]
[Title 49, Volume 2]
[Revised as of October 1, 2004]
From the U.S. Government Printing Office via GPO Access
[CITE: 49CFR177.837]

[Page 772]
 
                        TITLE 49--TRANSPORTATION
 
 CHAPTER I--RESEARCH AND SPECIAL PROGRAMS ADMINISTRATION, DEPARTMENT OF 
                             TRANSPORTATION
 
PART 177_CARRIAGE BY PUBLIC HIGHWAY--Table of Contents
 
                     Subpart B_Loading and Unloading
 
Sec. 177.837  Class 3 materials.

    (See also Sec. 177.834 (a) to (j).)
    (a) Engine stopped. Unless the engine of a cargo tank motor vehicle 
is to be used for the operation of a pump, Class 3 material may not be 
loaded into, or on, or unloaded from any cargo tank motor vehicle while 
the engine is running. The diesel engine of a cargo tank motor vehicle 
may be left running during the loading and unloading of a Class 3 
material if the ambient atmospheric temperature is at or below -12 
[deg]C (10 [deg]F).
    (b) Bonding and grounding containers other than cargo tanks prior to 
and during transfer of lading. For containers which are not in metallic 
contact with each other, either metallic bonds or ground conductors 
shall be provided for the neutralization of possible static charges 
prior to and during transfers of Class 3 (flammable liquid) materials 
between such containers. Such bonding shall be made by first connecting 
an electric conductor to the container to be filled and subsequently 
connecting the conductor to the container from which the liquid is to 
come, and not in any other order. To provide against ignition of vapors 
by discharge of static electricity, the latter connection shall be made 
at a point well removed from the opening from which the Class 3 
(flammable liquid) material is to be discharged.
    (c) Bonding and grounding cargo tanks before and during transfer of 
lading. (1) When a cargo tank is loaded through an open filling hole, 
one end of a bond wire shall be connected to the stationary system 
piping or integrally connected steel framing, and the other end to the 
shell of the cargo tank to provide a continuous electrical connection. 
(If bonding is to the framing, it is essential that piping and framing 
be electrically interconnected.) This connection must be made before any 
filling hole is opened, and must remain in place until after the last 
filling hole has been closed. Additional bond wires are not needed 
around All-Metal flexible or swivel joints, but are required for 
nonmetallic flexible connections in the stationary system piping. When a 
cargo tank is unloaded by a suction-piping system through an open 
filling hole of the cargo tank, electrical continuity shall be 
maintained from cargo tank to receiving tank.
    (2) When a cargo tank is loaded or unloaded through a vapor-tight 
(not open hole) top or bottom connection, so that there is no release of 
vapor at a point where a spark could occur, bonding or grounding is not 
required. Contact of the closed connection must be made before flow 
starts and must not be broken until after the flow is completed.
    (3) Bonding or grounding is not required when a cargo tank is 
unloaded through a nonvapor-tight connection into a stationary tank 
provided the metallic filling connection is maintained in contact with 
the filling hole.
    (d) Unloading combustible liquids. For a cargo tank unloading a 
material meeting the definition for combustible liquid in Sec. 
173.150(f) of this subchapter, the qualified person attending the 
unloading operation must remain within 45.72 meters (150 feet) of the 
cargo tank and 7.62 meters (25 feet) of the delivery hose and must 
observe both the cargo tank and the receiving container at least once 
every five minutes during unloading operations that take more than five 
minutes to complete.

[29 FR 18795, Dec. 29, 1964]

    Editorial Note: For Federal Register citations affecting Sec. 
177.837, see the List of CFR Sections Affected which appears in the 
Finding Aids section of the printed volume and on GPO Access.