[Code of Federal Regulations]
[Title 49, Volume 2]
[Revised as of October 1, 2003]
From the U.S. Government Printing Office via GPO Access
[CITE: 49CFR177.840]

[Page 752-755]
 
                        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.  177.840  Class 2 (gases) materials.

    (See also Sec.  177.834 (a) to (j).)
    (a) Floors or platforms essentially flat. Cylinders containing Class 
2 (gases) materials shall not be loaded onto any part of the floor or 
platform of any motor vehicle which is not essentially flat; cylinders 
containing Class 2 (gases) materials may be loaded onto any motor 
vehicle not having a floor or platform only if such motor vehicle be 
equipped with suitable racks having adequate means for securing such 
cylinders in place therein. Nothing contained in this section shall be 
so construed as to prohibit the loading of such cylinders on any motor 
vehicle having a floor or platform and racks as hereinbefore described.
    (1) Cylinders. Cylinders containing Class 2 gases must be securely 
restrained in an upright or horizontal position, loaded in racks, or 
packed in boxes or crates to prevent the cylinders from being shifted, 
overturned or ejected from the motor vehicle under normal transportation 
conditions. However, after December 31, 2003, a pressure relief device, 
when installed, must be in communication with the vapor space of a 
cylinder containing a Division 2.1 (flammable gas) material.
    (2) Cylinders for hydrogen, cryogenic liquid. A Specification DOT-4L 
cylinder containing hydrogen, cryogenic liquid may only be transported 
on a motor vehicle as follows:
    (i) The vehicle must have an open body equipped with a suitable rack 
or support having a means to hold the cylinder upright when subjected to 
an acceleration of 2 ``g'' in any horizontal direction;
    (ii) The combined total of the hydrogen venting rates, as marked, on 
the cylinders transported on one motor vehicle may not exceed 60 SCF per 
hour;
    (iii) The vehicle may not enter a tunnel; and
    (iv) Highway transportation is limited to private and contract 
carriage and to direct movement from point of origin to destination.
    (b) Portable tank containers containing Class 2 (gases) materials 
shall be loaded on motor vehicles only as follows:
    (1) Onto a flat floor or platform of a motor vehicle.
    (2) Onto a suitable frame of a motor vehicle.
    (3) In either such case, such containers shall be safely and 
securely blocked or held down to prevent movement relative to each other 
or to the supporting structure when in transit, particularly during 
sudden starts and stops and changes of direction of the vehicle.
    (4) Requirements of paragraphs (1) and (2) of this paragraph (b) 
shall not be construed as prohibiting stacking of containers provided 
the provisions of paragraph (3) of this paragraph (b) are fully complied 
with.
    (c) [Reserved]
    (d) Engine to be stopped in cargo tank motor vehicles, except for 
transfer pump. No Division 2.1 (flammable gas) material shall be loaded 
into or on or unloaded from any cargo tank motor vehicles with the 
engine running unless the engine is used for the operation of the 
transfer pump of the vehicle. Unless the delivery hose is equipped with 
a shut-off valve at its discharge end, the engine of the motor vehicle 
shall be stopped at the finish of such loading or unloading operation 
while the filling or discharge connections are disconnected.
    (e) Chlorine cargo tank motor vehicles shall be shipped only when 
equipped:
    (1) With a gas mask of a type approved by the The National Institute 
of Occupational Safety and Health (NIOSH) Pittsburgh Research Center, 
U.S. Department of Health and Human Services for chlorine service; and
    (2) With an emergency kit for controlling leaks in fittings on the 
dome cover plate.
    (f) A cargo tank motor vehicle used for transportation of chlorine 
may not be moved, coupled or uncoupled, when any loading or unloading 
connections are attached to the vehicle, nor may it be left without the 
power unit attached

[[Page 753]]

unless the vehicle is chocked or equivalent means are provided to 
prevent motion. For additional requirements, see Sec.  173.315(o) of 
this subchapter.
    (g) Each liquid discharge valve on a cargo tank motor vehicle, other 
than an engine fuel line valve, must be closed during transportation 
except during loading and unloading.
    (h) The driver of a motor vehicle transporting a Division 2.1 
(flammable gas) material that is a cryogenic liquid in a package 
exceeding 450 L (119 gallons) of water capacity shall avoid unnecessary 
delays during transportation. If unforeseen conditions cause an 
excessive pressure rise, the driver shall manually vent the tank at a 
remote and safe location. For each shipment, the driver shall make a 
written record of the cargo tank pressure and ambient (outside) 
temperature:
    (1) At the start of each trip,
    (2) Immediately before and after any manual venting,
    (3) At least once every five hours, and
    (4) At the destination point.
    (i) No person may transport a Division 2.1 (flammable gas) material 
that is a cryogenic liquid in a cargo tank motor vehicle unless the 
pressure of the lading is equal to or less than that used to determine 
the marked rated holding time (MRHT) and the one-way travel time (OWTT), 
marked on the cargo tank in conformance with Sec.  173.318(g) of this 
subchapter, is equal to or greater than the elapsed time between the 
start and termination of travel. This prohibition does not apply if, 
prior to expiration of the OWTT, the cargo tank is brought to full 
equilibration as specified in paragraph (j) of this section.
    (j) Full equilibration of a cargo tank transporting a Division 2.1 
(flammable gas) material that is a cryogenic liquid may only be done at 
a facility that loads or unloads a Division 2.1 (flammable gas) material 
that is a cryogenic liquid and must be performed and verified as 
follows:
    (1) The temperature and pressure of the liquid must be reduced by a 
manually controlled release of vapor; and
    (2) The pressure in the cargo tank must be measured at least ten 
minutes after the manual release is terminated.
    (k) A carrier of carbon monoxide, cryogenic liquid must provide each 
driver with a self-contained air breathing apparatus that is approved by 
the National Institute of Occupational Safety and Health; for example, 
Mine Safety Appliance Co., Model 401, catalog number 461704.
    (l) Operating procedure. Each operator of a cargo tank motor vehicle 
that is subject to the emergency discharge control requirements in Sec.  
173.315(n) of this subchapter must carry on or within the cargo tank 
motor vehicle written emergency discharge control procedures for all 
delivery operations. The procedures must describe the cargo tank motor 
vehicle's emergency discharge control features and, for a passive shut-
down capability, the parameters within which they are designed to 
function. The procedures must describe the process to be followed if a 
facility-provided hose is used for unloading when the cargo tank motor 
vehicle has a specially equipped delivery hose assembly to meet the 
requirements of Sec.  173.315(n)(2) of this subchapter.
    (m) Cargo tank motor vehicle safety check. Before unloading from a 
cargo tank motor vehicle containing a liquefied compressed gas, the 
qualified person performing the function must check those components of 
the discharge system, including delivery hose assemblies and piping, 
that are readily observed during the normal course of unloading to 
assure that they are of sound quality, without obvious defects 
detectable through visual observation and audio awareness, and that 
connections are secure. This check must be made after the pressure in 
the discharge system has reached at least equilibrium with the pressure 
in the cargo tank. Operators need not use instruments or take 
extraordinary actions to check components not readily visible. No 
operator may unload liquefied compressed gases from a cargo tank motor 
vehicle with a delivery hose assembly found to have any condition 
identified in Sec.  180.416(g)(1) of this subchapter or with piping 
systems found to have any condition identified in Sec.  180.416(g)(2) of 
this subchapter.
    (n) Emergency shut down. If there is an unintentional release of 
product to the environment during unloading of a

[[Page 754]]

liquefied compressed gas, the qualified person unloading the cargo tank 
motor vehicle must promptly shut the internal self-closing stop valve or 
other primary means of closure and shut down all motive and auxiliary 
power equipment.
    (o) Daily test of off-truck remote shut-off activation device. For a 
cargo tank motor vehicle equipped with an off-truck remote means to 
close the internal self-closing stop valve and shut off all motive and 
auxiliary power equipment, an operator must successfully test the 
activation device within 18 hours prior to the first delivery of each 
day. For a wireless transmitter/receiver, the person conducting the test 
must be at least 45.72 m (150 feet) from the cargo tank and may have the 
cargo tank in his line of sight.
    (p) Unloading procedures for liquefied petroleum gas and anhydrous 
ammonia in metered delivery service. An operator must use the following 
procedures for unloading liquefied petroleum gas or anhydrous ammonia 
from a cargo tank motor vehicle in metered delivery service:
    (1) For a cargo tank with a capacity of 13,247.5 L (3,500 water 
gallons) or less, excluding delivery hose and piping, 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 when the internal self-closing stop valve 
is open during unloading operations that take more than five minutes to 
complete.
    (2) For a cargo tank with a capacity greater than 13,247.5 L (3,500 
water gallons), excluding delivery hose and piping, the qualified person 
attending the unloading operation must remain within 45.72 m (150 feet) 
of the cargo tank and 7.62 m (25 feet) of the delivery hose when the 
internal self-closing stop valve is open.
    (i) Except as provided in paragraph (p)(2)(ii) of this section, the 
qualified person attending the unloading operation must have an 
unobstructed view of the cargo tank and delivery hose to the maximum 
extent practicable, except during short periods when it is necessary to 
activate controls or monitor the receiving container.
    (ii) For deliveries where the qualified person attending the 
unloading operation cannot maintain an unobstructed view of the cargo 
tank, when the internal self-closing stop valve is open, the qualified 
person 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. In addition, by the compliance dates 
specified in Sec. Sec.  173.315(n)(5) and 180.405(m)(3) of this 
subchapter, the cargo tank motor vehicle must have an emergency 
discharge control capability that meets the requirements of Sec.  
173.315(n)(2) or Sec.  173.315(n)(4) of this subchapter.
    (q) Unloading procedures for liquefied petroleum gas and anhydrous 
ammonia in other than metered delivery service. An operator must use the 
following procedures for unloading liquefied petroleum gas or anhydrous 
ammonia from a cargo tank motor vehicle in other than metered delivery 
service:
    (1) The qualified person attending the unloading operation must 
remain within 7.62 m (25 feet) of the cargo tank when the internal self-
closing stop valve is open.
    (2) The qualified person attending the unloading operation must have 
an unobstructed view of the cargo tank and delivery hose to the maximum 
extent practicable, except during short periods when it is necessary to 
activate controls or monitor the receiving container.
    (r) Unloading using facility-provided hoses. A cargo tank motor 
vehicle equipped with a specially designed delivery hose assembly to 
meet the requirements of Sec.  173.315(n)(2) of this subchapter may be 
unloaded using a delivery hose assembly provided by the receiving 
facility under the following conditions:
    (1) The qualified person monitoring unloading must visually examine 
the facility hose assembly for obvious defects prior to its use in the 
unloading operation.
    (2) The qualified person monitoring unloading must remain within 
arm's reach of the mechanical means of closure for the internal self-
closing stop valve when the internal self-closing

[[Page 755]]

stop valve is open except for short periods when it is necessary to 
activate controls or monitor the receiving container. For chlorine cargo 
tank motor vehicles, the qualified person must remain within arm's reach 
of a means to stop the flow of product except for short periods when it 
is necessary to activate controls or monitor the receiving container.
    (3) If the facility hose is equipped with a passive means to shut 
off the flow of product that conforms to and is maintained to the 
performance standard in Sec.  173.315(n)(2) of this subchapter, the 
qualified person may attend the unloading operation in accordance with 
the attendance requirements prescribed for the material being unloaded 
in Sec.  177.834 of this section.
    (s) Off-truck remote shut-off activation device. For a cargo tank 
motor vehicle with an off-truck remote control shut-off capability as 
required by Sec. Sec.  173.315(n)(3) or (n)(4) of this subchapter, the 
qualified person attending the unloading operation must be in possession 
of the activation device at all times during the unloading process. This 
requirement does not apply if the activation device is part of a system 
that will shut off the unloading operation without human intervention in 
the event of a leak or separation in the hose.
    (t) Unloading without appropriate emergency discharge control 
equipment. Until a cargo tank motor vehicle is equipped with emergency 
discharge control equipment in conformance with Sec. Sec.  173.315(n)(2) 
and 180.405(m)(1) of this subchapter, the qualified person attending the 
unloading operation must remain within arm's reach of a means to close 
the internal self-closing stop valve when the internal self-closing stop 
valve is open except during short periods when the qualified person must 
activate controls or monitor the receiving container. For chlorine cargo 
tank motor vehicles unloaded after December 31, 1999, the qualified 
person must remain within arm's reach of a means to stop the flow of 
product except for short periods when it is necessary to activate 
controls or monitor the receiving container.
    (u) Unloading of chlorine cargo tank motor vehicles. After July 1, 
2001, unloading of chlorine from a cargo tank motor vehicle must be 
performed in compliance with Section 3 of Pamphlet 57, Emergency Shut-
off Systems for Bulk Transfer of Chlorine, of the Chlorine Institute.

(Approved by the Office of Management and Budget under control number 
2137-0542)

[29 FR 18795, Dec. 29, 1964. Redesignated at 32 FR 5606, Apr. 5, 1967]

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